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Best FRFR Cab for Line 6 Helix Studio Monitors
Old 29th November 2018
  #1
Gear Nut
 
Sad Darwin's Avatar
 

Best FRFR Cab for Line 6 Helix

I'm finally taking the plunge and getting a Line 6 Helix Floor Processor. I already have a Firehawk 1500, of which the only drawbacks are weight, floor footprint in my studio, and general unwieldiness. I'm just getting into researching FRFR cabs through reviews and various other forums, but I figured I'd ask my fellow gearsluts for their two cents. It seems like the most highly recommended is the Atomic CLR, but it is sold out currently. Does the Line 6 L3T compare well? I'm looking for something that would work equally well as a reference monitor in my studio, an amp replacement for small shows, and a monitor for medium shows in which I could plug my Helix into front of house. Also, how do you feel the Firehawk compares to the Atomic CLR and L3T?

Thank you!
Old 29th November 2018
  #3
Here for the gear
 

In the circles I fare in, I am of the impression that Line 6's own Powercab and Powercab Plus are considered pretty good. I have two myself. They sound awesome to me.

I have also heard a lot about Mission Engineering Gemini 2. It's supposed to be even better, but is a 2-speaker stereo FRFR cab so it's not the same as most other FRFR cabs I've checked out.

And those two are really the only ones I've seen mentioned a lot other than Headrush, Alto and the Yamaha DBX series which isn't an FRFR but is supposedly really good for people that enjoy a bass rich sound. But those three are usually held up for being good for their price range, not for being especially good in a broader sense. Afaik.
Old 29th November 2018
  #4
Gear Nut
Quote:
Originally Posted by Sad Darwin View Post
I'm finally taking the plunge and getting a Line 6 Helix Floor Processor. I already have a Firehawk 1500, of which the only drawbacks are weight, floor footprint in my studio, and general unwieldiness. I'm just getting into researching FRFR cabs through reviews and various other forums, but I figured I'd ask my fellow gearsluts for their two cents. It seems like the most highly recommended is the Atomic CLR, but it is sold out currently. Does the Line 6 L3T compare well? I'm looking for something that would work equally well as a reference monitor in my studio, an amp replacement for small shows, and a monitor for medium shows in which I could plug my Helix into front of house. Also, how do you feel the Firehawk compares to the Atomic CLR and L3T?

Thank you!
Seems to me the Line 6 L3T doesn't help you much more than the Firehawk 1500 when it comes to weight, floor footprint, or general unwieldiness. Weighs about the same, and both are about the same volume in size. Doesn't look like a good solution to me.

I had the L2T at one point, and I liked it. L3T has one more woofer, and I'm guessing it's much the same. It's a good PA speaker with lots of features. And you pay for those features, so if you're not going to use them, I'd recommend you look for alternatives from Yamaha, QSC, JBL, etc.

PA speakers with 10"+ woofers are generally going to be poor for nearfield monitoring in a home studio. The transducers are too far apart to start with. I would highly recommend going with the CLR if you can wait at all, it excels for the diverse use cases you're looking for, in nearfield reference monitoring, stage monitor, as a backline, PA speaker, etc. It's quite good, it's a coaxial speaker that solves the usual problems that coaxial speakers have.

Firehawk is a cool speaker for guitar use, but not really a great speaker for general use. I think it probably works fine as a stage monitor or amp replacement, but it probably doesn't compare to other options for PA use or for studio monitoring use.
Old 29th November 2018
  #5
Gear Nut
Quote:
Originally Posted by Fresiki View Post
I have also heard a lot about Mission Engineering Gemini 2. It's supposed to be even better, but is a 2-speaker stereo FRFR cab so it's not the same as most other FRFR cabs I've checked out.
FWIW, "stereo FRFR cab" is an oxymoron. Stereo and FRFR - FAQ

Personally not a fan of the Mission Gemini stuff. Strange design choices on it. It's too heavy, too underpowered for the speaker they're using, and too expensive.
Old 30th November 2018
  #6
Quote:
Originally Posted by Fresiki View Post
In the circles I fare in, I am of the impression that Line 6's own Powercab and Powercab Plus are considered pretty good. I have two myself. They sound awesome to me.

I have also heard a lot about Mission Engineering Gemini 2. It's supposed to be even better, but is a 2-speaker stereo FRFR cab so it's not the same as most other FRFR cabs I've checked out.

And those two are really the only ones I've seen mentioned a lot other than Headrush, Alto and the Yamaha DBX series which isn't an FRFR but is supposedly really good for people that enjoy a bass rich sound. But those three are usually held up for being good for their price range, not for being especially good in a broader sense. Afaik.
Well, that's all Prosumer class gear. It's got a lot better in the past few years but it's still not pro.

If you want something professional that will work without a hitch for years go with something like the JBL PRX. Avoid the JBL Eon - that's their prosumer line.

The think is that the price difference between the PRX and prosumer stuff like the Atomic is very small compared to the difference in quality.

One other thing - avoid lightweight plastic cabinets. They resonate and add a boxy tubbniess to the sound when pushed. The JBL is touring grade plywood.
Old 30th November 2018
  #7
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
The think is that the price difference between the PRX and prosumer stuff like the Atomic is very small compared to the difference in quality.
Wondering, what's your measuring stick for what's prosumer and what's pro?

Have you had a chance to check out the Atomic CLR? It's actually quite the value for the money IMHO. Whether it's "pro" or not, I guess it depends on what one means by it, and that's why I ask.
Not to get too much into the weeds, so let me just mention it was designed by Jay Mitchell, who is a contemporary of people like Dave Gunness, Tom Danley, etc. It's a speaker with really great sound quality, and it'll especially excel for studio use or stage monitoring use compared to something like the PRX.
Old 30th November 2018
  #8
Quote:
Originally Posted by yeky83 View Post
FWIW, "stereo FRFR cab" is an oxymoron. Stereo and FRFR - FAQ

Personally not a fan of the Mission Gemini stuff. Strange design choices on it. It's too heavy, too underpowered for the speaker they're using, and too expensive.
The referenced article has a lot of BS and faulty assumptions. For example:

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s. If you look at the stereo content of a typical guitar signal, most of it is in the upper registers, in other words its the HF unit that will be carrying a lot of the stereo information.
Which is a total crock because a guitars' output, as perceived by a given member of the audience, is MONO. Any "stereo" effect is provided by room reverberation. Yes, different parts of an ACOUSTIC guitar emit different frequency bands. Wherein comes the erroneous assumptions about "close micing an acoustic guitar in stereo." Which is nonsense because when you get to the distance that even a very close member of a very intimate audience is listening from it has all coalesced into one mono signal.

It's even worse with an electric guitar, which has no stereo image at all since the pickups go into one amp driving one speaker (or bank od speakers) receiving the same signal. Now, if you're applying effects processing that synthesized an ersatz "stereo" signal that's a different thing, but that's not exactly FRFR, is it?
Old 30th November 2018
  #9
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
The referenced article has a lot of BS and faulty assumptions. For example:



Which is a total crock because a guitars' output, as perceived by a given member of the audience, is MONO. Any "stereo" effect is provided by room reverberation. Yes, different parts of an ACOUSTIC guitar emit different frequency bands. Wherein comes the erroneous assumptions about "close micing an acoustic guitar in stereo." Which is nonsense because when you get to the distance that even a very close member of a very intimate audience is listening from it has all coalesced into one mono signal.

It's even worse with an electric guitar, which has no stereo image at all since the pickups go into one amp driving one speaker (or bank od speakers) receiving the same signal.
I guess that's one way to read it

It's strange to me why anyone would read the article this way... do you really think the author doesn't know that the dry acoustic/electric guitar signal is mono? Was it worth the rant, giving someone zero benefit of the doubt? lol
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Now, if you're applying effects processing that synthesized an ersatz "stereo" signal that's a different thing,
This is how I'm reading it, the author's talking about an effected stereo guitar signal.
FRFR users often send their dry&wet signals to their FRFR. And when people ask for "stereo FRFRs," they're usually asking because they have stereo wet effects... not cus they think their guitar itself produces in stereo.
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but that's not exactly FRFR, is it?
Huh? I don't follow.

Anyway, the point of the article is that "stereo FRFRs" are a pointless mess. You can't provide remotely adequate stereo imagining to yourself or to your audience from something that's a size of a 2x12. And the close HF drivers are just going to cause comb filtering issues, a far-cry from flat frequency response.
Old 30th November 2018
  #10
Quote:
Originally Posted by yeky83 View Post
Wondering, what's your measuring stick for what's prosumer and what's pro?

Have you had a chance to check out the Atomic CLR? It's actually quite the value for the money IMHO. Whether it's "pro" or not, I guess it depends on what one means by it, and that's why I ask.
Not to get too much into the weeds, so let me just mention it was designed by Jay Mitchell, who is a contemporary of people like Dave Gunness, Tom Danley, etc. It's a speaker with really great sound quality, and it'll especially excel for studio use or stage monitoring use compared to something like the PRX.
Have you actually used the PRX? The PRX 800 series utilizes JBL's "differential drive" drivers that are used in their top of the line touring systems and incorporate a unique patented motor design with double voice coils that eliminates the problems conventional speakers have with assymeticality when the coil partially leaves the magnetic gap. They also use electronics deigned by Crown, JBL's sister company in the Harman group. They're quite different from JBL's lesser speaker lines like the Eon and the JRX, which I regards as being embarrassments to the JBL tradition.

As to the question of "what's pro" my yardstick is years of experience in the touring sound reinforcement and professional installed sound system industries. I was a tech with Bill Graham's PM Productions sound shop, toured with TASCO, which was at the time the largest sound company in the world (Bigger than Clair Bros and Showco), and did some work for John Meyers. Most sound professionals consider Meyers to be the systems by which all other systems are judged.

Frankly, I regard the who "FRFR" thing to be essentially an advertising buzzword fad contrived to sell small PA style cabinets to guitar players, since any high quality sound reinforcement speaker should be full range and have flat response - which is unfortunately not true of many "PA Systems" marketed to the prosumer combo musician/small nightclub market.

Last edited by John Eppstein; 30th November 2018 at 08:39 PM..
Old 1st December 2018
  #11
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
Have you actually used the PRX? The PRX 800 series utilizes JBL's "differential drive" drivers that are used in their top of the line touring systems and incorporate a unique patented motor design with double voice coils that eliminates the problems conventional speakers have with assymeticality when the coil partially leaves the magnetic gap. They also use electronics deigned by Crown, JBL's sister company in the Harman group. They're quite different from JBL's lesser speaker lines like the Eon and the JRX, which I regards as being embarrassments to the JBL tradition.
Cool, didn't know all that. And I'm not disagreeing the PRX is a pro equipment btw. And no, I haven't used it, but I'm familiar with speaker design principles.

I can tell you that for stage monitoring use, it'll have deep peaks and/or nulls in its crossover freq region well within its coverage area, within +/- 10, 15 degrees off-axis.
And for home studio use, it will not exhibit far-field behavior until you're at least ~7 ft away from it, which is likely too far for most home studio settings.

The CLR has a unique and great design, it doesn't exhibit the above issues. And it doesn't have the usual coaxial speaker issues either, of jagged response due to diffraction, bad directivity control, etc. It's quite good, I would encourage you to check it out if you get a chance. It's very much "pro" IMHO, I would not group it with the other "prosumer" products.
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As to the question of "what's pro" my yardstick is years of experience in the touring sound reinforcement and professional installed sound system industries. I was a tech with Bill Graham's PM Productions sound shop, toured with TASCO, which was at the time the largest sound company in the world (Bigger than Clair Bros and Showco), and did some work for John Meyers. Most sound professionals consider Meyers to be the systems by which all other systems are judged.
Very cool, I appreciate your experience.
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Frankly, I regard the who "FRFR" thing to be essentially an advertising buzzword fad contrived to sell small PA style cabinets to guitar players, since any high quality sound reinforcement speaker should be full range and have flat response - which is unfortunately not true of many "PA Systems" marketed to the prosumer combo musician/small nightclub market.
I completely agree, a lot of "FRFR" stuff sucks.
Old 1st December 2018
  #12
Gear Maniac
 
Stu Gutz's Avatar
 

I hated the Atomic CLR. I had the NEO magnet unit. Harsh sounding to me. I prefered QSC but I think it's best to just use a guitar speaker cab that you like. I liked a 2X12 cab with vintage Celestions and a bridged Bryston 3B amp the best. Also agree about the FSFR thing ...
Old 1st December 2018
  #13
Lives for gear
 

For me, *the* key things for getting happy with whatever kind of fullrange monitoring system for a modeler are these:

1) Take a *lot* of time to select and adjust a speaker sim (usually an IR with some addtional tweaking options). Make recordings along pretty busy backings (as that is usually the best way to find out how they work in context), record your amp signal without the cab portion (the Helix allows for that, as do most modelers) and go through your cab selection carefully. Ideally you won't have to do much EQ-ing.

2) Control everything you do at stage level whenever possible. There's the good old Fletcher-Munson effect, making our ears perceive things a lot differently at different volumes (in a nutshell, for low levels you usually dial in more lows and highs, which is also the reason for a loudness knob to exist on consumer HiFi things, once things get louder the sound might then become shrill and boomy).

3) Make sure to become close friends with your modelers global EQ. This EQ should be set to only be present on your monitor signal, so the FOH signal is not affected (not all modelers allow for such a routing but the Helix does). Even the best stage monitors suffer under certain conditions (certain stage sizes, positioning and what not). A dedicated monitoring EQ can adress a lot of these issues. It's a good idea to set it up so you have easy control about the lows and highs and possibly two mid bands, such as a lower one centered between 500-800Hz and a high band centeres somewhere between 1.5-3kHz. Low mids are great for more "vocal" qualities but can as well get you to a boxy sound. High mids are great to get you more "cut through" but also may be just too harsh. So it's good having quick access to these.
Note: This EQ is not meant to be switched on while programming sounds. It's a corrective thing that only should be used in "play mode".

And as far as the actual monitoring goes: It's pretty much about your budget. Many people praise coaxial solutions, but pretty much all of the decent ones come at a price. Typical wedge monitors aren't coaxial and you may run into certain phasing issues around the crossover frequency. I also noticed that pretty much all typical models don't sound too well when you place them straight behind your pedalboard or so. Give them one more meter of distance and you'll likely notice an improvement. Kinda like as if the woofer and driver need that space to "glue" together. Maybe it's less on some systems, but on the ones I tried, it was always like that.

Personally, I'm using an Alto TS310. Fwiw, should anyone know the older TS210s, there's no comparison, the 310s are a massive improvement. Compared them directly with Yamaha DXR10s (and also the cheaper DBR10s, which are almost identical in terms of sound) and prefered the 310s - but that is *only* because I'm making use of my global monitor EQ (in my case coming from a little mixer, I don't own a Helix). The Altos unfortunately have no dedicated monitor switch - those usually provide a tad more midrange while backing up the lows and highs, which is usually exactly what you want for a monitor. But with the additional options of an EQ, it's not an issue for me.
But I have also played with a bunch of other devices supplied by whatever venues - and I'm usually getting along just fine. Simply because of my monitoring EQ.

If money was no objection, I'd probably get a Dynacord AXM 12A. Tried one at a buddys place (with my own live board) and it was just amazing.
Old 2nd December 2018
  #14
Gear Nut
 
Sad Darwin's Avatar
 

Quote:
Originally Posted by John Eppstein View Post

Thank you for your detailed suggestion John. You explained a lot below that has opened up my mind about just going the PA route. How would you say this kind of thing compares to studio monitors? Pretty much just as flat?

I don't imagine that I'd care too much about some of the FRFR impulse response functionality, or even EQ curves on some of the PA stuff with more functionality, because at the end of the day that's what the Helix is emulating. It seem redundant. So that being said, in a PA I'd just be hoping for something that is like a high output studio monitor not greater than 40-45 pounds. As someone else mentioned that probably rules out an L3T. Your suggestion seems damn solid.
Old 5th December 2018
  #15
I have been satisfied with the Alto line of FRFR. Not expensive either.
Old 5th December 2018
  #16
Gear Addict
 
grannis's Avatar
if you play in a band that has its own PA, I suggest getting the same - then you can figure out how you sound FOH
Old 9th December 2018
  #17
Quote:
Originally Posted by yeky83 View Post
Cool, didn't know all that. And I'm not disagreeing the PRX is a pro equipment btw. And no, I haven't used it, but I'm familiar with speaker design principles.
If you say so.

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I can tell you that for stage monitoring use, it'll have deep peaks and/or nulls in its crossover freq region well within its coverage area, within +/- 10, 15 degrees off-axis.
How can you tell that? Do you know how the horn is designed? What do you know about the crossover and the onboard DSP?

I have heard that cabinet and I can tell you that it has none of those things - it's actually a surprisingly smooth full range design with none of the problems that lesser, similar looking cabinets have. I own a pair of the passive version of those cabs and even without the bespoke active crossover design and the corrective DSP the basic design is pretty phenomenal. But the active version holds up well against most studio monitors in that price range.

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And for home studio use, it will not exhibit far-field behavior until you're at least ~7 ft away from it, which is likely too far for most home studio settings.
They sound pretty good at around 4-5 feet as a midfield monitor. Most monitors for the small home studio won't cut it at all on stage, you have to choose according to the application. In the home studio you probably don't need it anyway, you've got your nearfields.

Remember, JBL has been a premier producer of recording monitors since the 1950s.

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The CLR has a unique and great design, it doesn't exhibit the above issues. And it doesn't have the usual coaxial speaker issues either, of jagged response due to diffraction, bad directivity control, etc. It's quite good, I would encourage you to check it out if you get a chance. It's very much "pro" IMHO, I would not group it with the other "prosumer" products.

Very cool, I appreciate your experience.

I completely agree, a lot of "FRFR" stuff sucks.
I do have a fondness for well designed coaxial speakers, but I take exception to some of their claims of uniqueness.

I also find their specifications to be rather incomplete - they don't state crossover frequency (but they do claim, that their horn provides "control extends a full two octaves BELOW the crossover frequency." which makes my BS detector itch, given their claim of directivity "90 degrees H x 90 degrees V, average from 650Hz and up", which would imply a crossover frequency of 650Hz, which, judging by the size of the horn in the photo, is impossible - the horn is too small. Low frequency cutoff is determined by horn length and that horn isn't long enough, there's no room.) Also, if it's a 90 x 90 degree horn - which I do believe - that would make the cabinet a mid to long throw - it's not wide enough to cover much of the field very close to the cab. Yet they claim a "wide soundstage".

Judging from the photos I'd guess that the horn's LF cutoff would be somewhere around 1000 Hz at best, so if they're stating 2 octaves of "control below crossover", either crossover would need to be 2.6K by their claims or 3K by my guess, but the directivity would not be controlled below that point as thye sound would be radiating from the woofer, not the tweeter, or the horn would need to be about 2 feet long for a half wave horn if 650 Hz is the actual crossover frequency. Either way, it doesn't make sense.

I'd really need to see it in person to give a proper evaluation, that ad copy's too hinky.

And the total power rating is given at 500 watts, which is 1/3 of the JBL's.

(I must admit being a bit put off by any company that calls itself "Atomic". I probably shouldn't be, buit it just doesn't seem very professional.)
Old 9th December 2018
  #18
Quote:
Originally Posted by Sad Darwin View Post
Thank you for your detailed suggestion John. You explained a lot below that has opened up my mind about just going the PA route. How would you say this kind of thing compares to studio monitors? Pretty much just as flat?

I don't imagine that I'd care too much about some of the FRFR impulse response functionality, or even EQ curves on some of the PA stuff with more functionality, because at the end of the day that's what the Helix is emulating. It seem redundant. So that being said, in a PA I'd just be hoping for something that is like a high output studio monitor not greater than 40-45 pounds. As someone else mentioned that probably rules out an L3T. Your suggestion seems damn solid.
Well, there's PA speakers and there's PA speakers.

As far as "comparing to studio monitors" I'd say the same thing. Yes on a certain level there are a lot of parallels. On other levels, not so much. The big soffit mounted studio monitors that used to be found in the big studios were essentially very well tuned medium sized PA speakers and often used the same components.
Old 9th December 2018
  #19
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
How can you tell that? Do you know how the horn is designed? What do you know about the crossover and the onboard DSP?

I have heard that cabinet and I can tell you that it has none of those things - it's actually a surprisingly smooth full range design with none of the problems that lesser, similar looking cabinets have. I own a pair of the passive version of those cabs and even without the bespoke active crossover design and the corrective DSP the basic design is pretty phenomenal.
All non-coaxial speakers with transducers of that size suffer from this issue. The effect is called lobing, occurs at vertical off-axis angles dependent on crossover frequency and transducer size. It's not fixable with the use of horn or DSP.

Here's a good article:
Tweeter Placement in Two-Way Loudspeakers

With crossover frequency of 1.8kHz, the JBL would need to have its transducers be <2 inches apart center-to-center for them to be coincident. It obviously cannot do this with a 12 inch woofer and a good sizable HF horn.

This arguably has lesser impact for PA use, but for monitor use where the speaker is laid down sideways and the user moves side to side, it's noticeably less than ideal.
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But the active version holds up well against most studio monitors in that price range.
Good to know. And I agree with your following post, studio monitors and PAs, often a distinction without much difference.
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They sound pretty good at around 4-5 feet as a midfield monitor. Most monitors for the small home studio won't cut it at all on stage, you have to choose according to the application. In the home studio you probably don't need it anyway, you've got your nearfields.
OP seemed to want to use them for home studio use, I assumed he had no nearfields.

If they sound good at 4-5 ft to you, great. But more strictly speaking, the far-field behavior is dependent on the size of the thing, so it's expected to be >7ft.
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Remember, JBL has been a premier producer of recording monitors since the 1950s.
They absolutely make great stuff.
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I also find their specifications to be rather incomplete - they don't state crossover frequency (but they do claim, that their horn provides "control extends a full two octaves BELOW the crossover frequency." which makes my BS detector itch, given their claim of directivity "90 degrees H x 90 degrees V, average from 650Hz and up", which would imply a crossover frequency of 650Hz, which, judging by the size of the horn in the photo, is impossible - the horn is too small. Low frequency cutoff is determined by horn length and that horn isn't long enough, there's no room.) Also, if it's a 90 x 90 degree horn - which I do believe - that would make the cabinet a mid to long throw - it's not wide enough to cover much of the field very close to the cab. Yet they claim a "wide soundstage".

Judging from the photos I'd guess that the horn's LF cutoff would be somewhere around 1000 Hz at best, so if they're stating 2 octaves of "control below crossover", either crossover would need to be 2.6K by their claims or 3K by my guess, but the directivity would not be controlled below that point as thye sound would be radiating from the woofer, not the tweeter, or the horn would need to be about 2 feet long for a half wave horn if 650 Hz is the actual crossover frequency. Either way, it doesn't make sense.

I'd really need to see it in person to give a proper evaluation, that ad copy's too hinky.
"control extends a full two octaves BELOW the crossover frequency" with directivity claim down to 650Hz would indicate that the crossover is ~2.6kHz.

And the woofer is horn loaded as well, it's not a direct radiating woofer design. That should clear up the various confusion and explain why it does indeed control down to 650Hz.
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And the total power rating is given at 500 watts, which is 1/3 of the JBL's.
There's no standard for power ratings. Even some cheap $300 PAs have 2000W ratings, it's not indicative of much IMHO.

I can tell you the CLR uses a Kappalite/Deltalite variant woofer, which is as high output as any 12" woofer can possibly go. I trust the designer used a sufficient power amp for the design. There have been comparison reviews on guitar forums, comparing it to various other PA speakers, and by all accounts it's reported as louder and cleaner. That's my experience as well.

This is the designer's comment:
"The active CLR has three power amplifiers - a bridged pair to drive the woofer, and a single-ended on for the HF driver - with a total average power well in excess of 500 watts. The "500 watt" rating is intentionally conservative. I refuse to play the fraudulent games many manufacturers play with power numbers, and Tom is in agreement with that philosophy."
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(I must admit being a bit put off by any company that calls itself "Atomic". I probably shouldn't be, buit it just doesn't seem very professional.)
I can understand that
Old 13th December 2018
  #20
Quote:
Originally Posted by yeky83 View Post
All non-coaxial speakers with transducers of that size suffer from this issue. The effect is called lobing, occurs at vertical off-axis angles dependent on crossover frequency and transducer size. It's not fixable with the use of horn or DSP.
Sure. But with careful design the effects can be minimized - especially now with active DSP correction which can go a very long way toward eliminating the phasing effects that cause lobing in older systems. You claim it's not fixable with DSP but if you knew anything about the advanced DSP processing currently in use in modern concert systems you'd know that's not true. These days manipulation of phase is quite common, both for controlling/eliminating such problems as lobing but also for pattern control and "steering" of audio directionality.

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It's Ok, as far as it goes. The one in Wikipedia is a little better but still not great.

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With crossover frequency of 1.8kHz, the JBL would need to have its transducers be <2 inches apart center-to-center for them to be coincident. It obviously cannot do this with a 12 inch woofer and a good sizable HF horn.
With a crossover frequency of 1.8KHz any phasing/comb filtering effects would be moved sufficiently high in the audio spectrum as to present no significant problem. When you're crossing down around 500-800Hz as in many older systems, it definitely is audible but when you more the crossover up the harmonics affected are close to or in dog whistle territory. Even with a well designed passive crossover.

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OP seemed to want to use them for home studio use, I assumed he had no nearfields.
He appears to have been working with amp sims and the like for awhile, I would be extremely surprised if he doesn't have nearfields. Usually when people start asking about "FRFR" speakers it means they're thinking about taking their act to the stage. I doubt I'd recommend either of the speakers we're talking about for home recording monitors.

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"control extends a full two octaves BELOW the crossover frequency" with directivity claim down to 650Hz would indicate that the crossover is ~2.6kHz.

And the woofer is horn loaded as well, it's not a direct radiating woofer design. That should clear up the various confusion and explain why it does indeed control down to 650Hz.
HMmmm. I don't have access to their cabinet plans and they give no useful specs on the website, but those cabinets do not look sufficiently large to me to contain a proper midbass horn off that 12. And loading a 12" speaker with an upper mid only horn seems kind of silly to me. I'm trying to imagine the geometry and it just doesn't work.

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There's no standard for power ratings. Even some cheap $300 PAs have 2000W ratings, it's not indicative of much IMHO.
Actually there very definitely IS a standard for power amp ratings, but most companies ignore it these days, now that the republican government starting with Reagan has gutted the FTC rating requirements. That being said, I'm more inclined to believe the power ratings for the JBL Professional Series than those of some company I've never heard of. Crown has a reputation to uphold. Who knows who makes the amp modules for Atomic?

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I can tell you the CLR uses a Kappalite/Deltalite variant woofer, which is as high output as any 12" woofer can possibly go.
Kappalite and Deltalite are nothing more than trademarked advertising buzzwords owned by Eminence. I spent a couple hours scouring their site last night and could find no technical information beyond the fact that they use Neodymium magnets, which these days is nothing all that special.

And it's not "as high output as any 12" woofer can possibly do. Not by a long shot. That crown belongs to the JBL Differential Drive woofers used in their professional (not their prosumer) sound systems. Unlike "Kappalite" and "Deltalite" "Differential Drive" actually MEANS SOMETHING - it refers to a revolutionary new (well, six year old) design for speaker motors that you won't be seeing from anyone else for at least another 10 years because it's protected under US patent. And since it's patented the specifics are available to anyone, just look up the patent. It provides higher efficiency and lower harmonic distortion than any other speaker motor design. And yes, it too uses a Neodymium magnet, although it could also work with Alnico. Up until about 2-3 years ago the didn't even make it available in any but their big touring systems. I was very impressed when they announced the new design at an AES show that I attended.

Quote:
I trust the designer used a sufficient power amp for the design. There have been comparison reviews on guitar forums, comparing it to various other PA speakers, and by all accounts it's reported as louder and cleaner. That's my experience as well.
Well, I have no doubt that it probably kicks ass on other speakers selling to the "FRFR" market. Most of the look pretty sucky to me.

And you are correct that the power ratings of most units sold in that market, the prosumer PA market" and the "Cheap and Light bass amp" market are vastly overblown, due to rating tricks. I've posted about that before but I really don't feel like typing another page and a half on it, especially since it wouldn't really be on topic.

Quote:
This is the designer's comment:
"The active CLR has three power amplifiers - a bridged pair to drive the woofer, and a single-ended on for the HF driver - with a total average power well in excess of 500 watts. The "500 watt" rating is intentionally conservative. I refuse to play the fraudulent games many manufacturers play with power numbers, and Tom is in agreement with that philosophy."
I give them points for refusing to play the exaggerated power game.

BTW, I see you appear to have a lot of information that wasn't readily available on the Atomic website - you wouldn't happen to be affiliated with the company in some way, would you?
Old 14th December 2018
  #21
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
Sure. But with careful design the effects can be minimized - especially now with active DSP correction which can go a very long way toward eliminating the phasing effects that cause lobing in older systems. You claim it's not fixable with DSP but if you knew anything about the advanced DSP processing currently in use in modern concert systems you'd know that's not true. These days manipulation of phase is quite common, both for controlling/eliminating such problems as lobing but also for pattern control and "steering" of audio directionality.
Within the scope of our conversation which has been on speaker design (not system design) and using speakers for monitoring use (on stage or for studio), it absolutely is true that DSP cannot correct for lobing in multi-driver non-coaxial configuration speakers.
Quote:
With a crossover frequency of 1.8KHz any phasing/comb filtering effects would be moved sufficiently high in the audio spectrum as to present no significant problem. When you're crossing down around 500-800Hz as in many older systems, it definitely is audible but when you more the crossover up the harmonics affected are close to or in dog whistle territory. Even with a well designed passive crossover.
Whether it's a significant problem or not is up to the end user. I personally think most people would not want there to be a deep null in 1.8 kHz within the coverage area of their monitor. And 1.8 kHz is certainly not in dog whistle territory, it's audibly significant.
Quote:
HMmmm. I don't have access to their cabinet plans and they give no useful specs on the website, but those cabinets do not look sufficiently large to me to contain a proper midbass horn off that 12. And loading a 12" speaker with an upper mid only horn seems kind of silly to me. I'm trying to imagine the geometry and it just doesn't work.
It does work. I own one, and can see the horn and observe its directivity effects.
Here's sort of what it looks like, from the designer's own brand: CAT 40
Quote:
Kappalite and Deltalite are nothing more than trademarked advertising buzzwords owned by Eminence. I spent a couple hours scouring their site last night and could find no technical information beyond the fact that they use Neodymium magnets, which these days is nothing all that special.

And it's not "as high output as any 12" woofer can possibly do. Not by a long shot. That crown belongs to the JBL Differential Drive woofers used in their professional (not their prosumer) sound systems. Unlike "Kappalite" and "Deltalite" "Differential Drive" actually MEANS SOMETHING - it refers to a revolutionary new (well, six year old) design for speaker motors that you won't be seeing from anyone else for at least another 10 years because it's protected under US patent. And since it's patented the specifics are available to anyone, just look up the patent. It provides higher efficiency and lower harmonic distortion than any other speaker motor design. And yes, it too uses a Neodymium magnet, although it could also work with Alnico. Up until about 2-3 years ago the didn't even make it available in any but their big touring systems. I was very impressed when they announced the new design at an AES show that I attended.
I've done a quick reading, and the JBL Differential Drive is certainly novel, very cool design. But on it having higher efficiency/output, I can't seem to find any specs that actually support that claim. JBL 12" Differential Drive woofers spec out at 96~97 dB 1W/1m, while Kappalite and its variants spec out at 97~101 dB 1W/1m at a similar operating power range. Both are very high-efficiency drivers, but one would assume the JBL would have a greater efficiency given your claim.

~100 dB 1W/1m is as high efficiency as any 12" drivers go that I've seen, and that's mainly what I wanted to point out in my previous post.
Quote:
Well, I have no doubt that it probably kicks ass on other speakers selling to the "FRFR" market. Most of the look pretty sucky to me.

And you are correct that the power ratings of most units sold in that market, the prosumer PA market" and the "Cheap and Light bass amp" market are vastly overblown, due to rating tricks. I've posted about that before but I really don't feel like typing another page and a half on it, especially since it wouldn't really be on topic.
Agreed!
Quote:
BTW, I see you appear to have a lot of information that wasn't readily available on the Atomic website - you wouldn't happen to be affiliated with the company in some way, would you?
No, just an enthusiastic owner and admirer of good speaker designs
Old 18th December 2018
  #22
Quote:
Originally Posted by yeky83 View Post
Within the scope of our conversation which has been on speaker design (not system design) and using speakers for monitoring use (on stage or for studio), it absolutely is true that DSP cannot correct for lobing in multi-driver non-coaxial configuration speakers.
I don't want to get into a "he said, she said" argument, but you are absolutely wrong.

However I'm not going to waste hours andf hours looking up esoteric papers on modern sound system design for an audience that won't understand them anyway. The technology papers I've seen are deeply technical and difficulty to follow even for a person who has been involved with sound system design for decades.

Quote:
Whether it's a significant problem or not is up to the end user. I personally think most people would not want there to be a deep null in 1.8 kHz within the coverage area of their monitor. And 1.8 kHz is certainly not in dog whistle territory, it's audibly significant.
There are no "deep nulls"in the crossover region of the JBL PRX speakers. None. Actually, if you know anything at all about crossover design you'd know that it's quite easy to avoid such nulls even without advanced DSP. (there are other ramifications though)

However with DSP it's possible to manipulate phase in very sophisticated ways independent to frequency and without more primitive techniques such as alternating polarity of adjacent bends to avoid nulling at the crossover.frequency.

Quote:
It does work. I own one, and can see the horn and observe its directivity effects.
Here's sort of what it looks like, from the designer's own brand: CAT 40
Thank you for the illustrations. The 12" speaker in those designs is not properly horn loaded, sorry. In order for a horn to function correctly it requires a constriction in the throat area. Those illustration show no such constriction - that's not a horn, it's a waveguide (Which does provide directivity control to some degree, but does not horn load the speaker.)

Furthermore, the waveguide shown has straight sides, not exponential. Which means that (A) the frequency response won't be totally even, (B) Harmonic distortion will be increased at some frequencies, and (C) directivity will not be totally even. There's a reason that well designed horns (and waveguides) have curved sides.

Quote:
I've done a quick reading, and the JBL Differential Drive is certainly novel, very cool design. But on it having higher efficiency/output, I can't seem to find any specs that actually support that claim. JBL 12" Differential Drive woofers spec out at 96~97 dB 1W/1m, while Kappalite and its variants spec out at 97~101 dB 1W/1m at a similar operating power range. Both are very high-efficiency drivers, but one would assume the JBL would have a greater efficiency given your claim.
AH, but that's not quite right again. The problem here is that no two speaker companies use exactly the same measurement techniques and many companies use methods specifically chosen to make their speakers look better than the competition. This is particularly common among companies that specialize (more or less) in guitar speakers. Eminence has got better in recent years but their measurement techniques are still chosen to make their stuff look good.

JBL, OTOH,. has always used the most conservative rating methods in the industry. (I'm talking about JBL PRO here, not the consumer/prosumer stuff that Harmon has stuck a JBL label on to sell to the rubes.)

The old K120 speaker was conservatively rated at 101 dB and that's a 1970s design, definitely not as efficient as the new differential drive speakers.

Here's a spec sheet on the K series: http://www.lansingheritage.org/image...ries/page4.jpg

JBL currently is not publishing spec sheets on their newest pro drivers and are not selling them to the public raw - they are only available in assembled JBL Professional series speaker systems, so I can't give you the specs on the speaker in the PRX cabinet, but I can give you the sheet on the system.
http://www.jblpro.com/ProductAttachm..._SpecSheet.pdf

What I can tell you from talking to a JBL engineer as AES a few years ago when the differential drive speakers were introduced is that it's significantly more efficient that the old designs it replaced and those were rated over 100 dB. It has a neodymium magnet and dual inline voice coils which eliminate the inefficiency that all other cone speakers have when the coil moves party out of the gap at large excursions. Here's their sheet on the technology: Differential Drive

Quote:
No, just an enthusiastic owner and admirer of good speaker designs
Me, too.

Have you heard of Voicecoil magazine? It's the magazine of the speaker industry if you have a technical interest. Free, if you can convince them that they should send it to you.
Old 19th December 2018
  #23
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
I don't want to get into a "he said, she said" argument, but you are absolutely wrong.

However I'm not going to waste hours andf hours looking up esoteric papers on modern sound system design for an audience that won't understand them anyway. The technology papers I've seen are deeply technical and difficulty to follow even for a person who has been involved with sound system design for decades.
If you understand the acoustic principle behind speaker lobing (again, not system design, but speaker design), it should be obvious why it cannot be corrected for with DSP. I invite you to please try to understand the acoustic principle.
Quote:
There are no "deep nulls"in the crossover region of the JBL PRX speakers. None. Actually, if you know anything at all about crossover design you'd know that it's quite easy to avoid such nulls even without advanced DSP. (there are other ramifications though)

However with DSP it's possible to manipulate phase in very sophisticated ways independent to frequency and without more primitive techniques such as alternating polarity of adjacent bends to avoid nulling at the crossover.frequency.
I was not talking about on-axis response (avoiding on-axis crossover null is quite easy as you've said), but referring to lobing -- there are deep nulls in the crossover region of the JBL PRX within its coverage area (or any other speaker in the same configuration -- most PAs.). I.e. There will be -15~20 dB null in the crossover region 10~15 degrees off-axis (vertical if you're using it on a pole, horizontal if you're using it as a monitor). And I think we can agree that 10~15 degrees is indeed very much within a coverage range of interest for monitoring, since you've said you feel that even 90x90 is perhaps too narrow.

The effect of the off-axis null should be audibly noticeable. Set a speaker on a pole, play noise or music, and move your head up and down so you go in and out of 10~15 degrees off axis. You should be able to hear the crossover range null.

If you really want to observe the behavior, you can make measurements with your PRX to confirm this. There's really no avoiding this, laws of physics and all.
Quote:
Thank you for the illustrations. The 12" speaker in those designs is not properly horn loaded, sorry. In order for a horn to function correctly it requires a constriction in the throat area. Those illustration show no such constriction - that's not a horn, it's a waveguide (Which does provide directivity control to some degree, but does not horn load the speaker.)
For a proper horn loading of the entire bandwidth of a full-response loudspeaker, it will require a speaker of an enormous size. This is obviously not possible in any portable PA/monitor/etc. format, and not the point of contention we've been discussing.

You disputed saying the CLR could not control directivity down to 650 Hz. Yes it can. This is measurable and observable.

If we want to go by math, the accepted formula is simple:
f = K / (theta * dimension)

Plug in the horn dimension of 17 in, with the directivity rating of 90 degrees, and you get 650 Hz.

650 Hz = 1*10^6 in*deg*Hz / (90 deg * 17 in)
Quote:
Furthermore, the waveguide shown has straight sides, not exponential. Which means that (A) the frequency response won't be totally even, (B) Harmonic distortion will be increased at some frequencies, and (C) directivity will not be totally even. There's a reason that well designed horns (and waveguides) have curved sides.
Your ABC points are too general and not relevant here. Bandwidth of interest matters. The CLR uses two horns. It uses a constant-beamwidth type horn for the HF (curved sides, yay). And for the LF, I can agree with you the horn is probably more of a MF waveguide, but sufficiently so (a POI FYI, it also uniquely employs foam in its horn design).

It certainly is a superior design than direct radiating woofers in most PAs. The JBL PRX812 is spec'ed "90x50 nominal," but it will only be able to keep this directivity above ~3 kHz.

(Exponential horn is passe btw. But you probably meant curved edges in general.)
Quote:
AH, but that's not quite right again. The problem here is that no two speaker companies use exactly the same measurement techniques and many companies use methods specifically chosen to make their speakers look better than the competition. This is particularly common among companies that specialize (more or less) in guitar speakers. Eminence has got better in recent years but their measurement techniques are still chosen to make their stuff look good.

JBL, OTOH,. has always used the most conservative rating methods in the industry. (I'm talking about JBL PRO here, not the consumer/prosumer stuff that Harmon has stuck a JBL label on to sell to the rubes.)
I don't see much fudging on Eminence specs AFAICT with regards to sensitivity and power rating. If you see it, please let me know where.
Quote:
The old K120 speaker was conservatively rated at 101 dB and that's a 1970s design, definitely not as efficient as the new differential drive speakers.

Here's a spec sheet on the K series: http://www.lansingheritage.org/image...ries/page4.jpg
No, the efficiency looks about the same (Perhaps some fudging by JBL by testing old spec from >500 Hz, but probably not. As you say, I trust they rate their stuff properly.). Please see specs I link in response to below quote. ~100 = ~100.

The current day high output woofers have >~4 times the power capacity, that seems where the output improvement lies in the case of the K120. Not really efficiency.
Quote:
JBL currently is not publishing spec sheets on their newest pro drivers and are not selling them to the public raw - they are only available in assembled JBL Professional series speaker systems, so I can't give you the specs on the speaker in the PRX cabinet, but I can give you the sheet on the system.
http://www.jblpro.com/ProductAttachm..._SpecSheet.pdf

What I can tell you from talking to a JBL engineer as AES a few years ago when the differential drive speakers were introduced is that it's significantly more efficient that the old designs it replaced and those were rated over 100 dB. It has a neodymium magnet and dual inline voice coils which eliminate the inefficiency that all other cone speakers have when the coil moves party out of the gap at large excursions. Here's their sheet on the technology: Differential Drive
I came across a few spec sheets where you can evaluate the sensitivity & power rating of Differential Drive 12" woofers:
https://www.jblpro.com/ProductAttachments/MRX512.pdf
https://www.huss-licht-ton.de/images...et_28153_2.pdf
https://www.parts-express.com/jbl-22...oofer--294-450

And so no, I don't see the high efficiency you're claiming. If "'Differential Drive' actually MEANS SOMETHING" as you've said, these speakers should have a higher efficiency per your claim.

I also skimmed over their Differential Drive white paper:
https://www.jblpro.com/pub/technote/...-33%20rev3.pdf
Their main claims of benefit behind Differential Drive transducers isn't high efficiency.
Quote:
Me, too.

Have you heard of Voicecoil magazine? It's the magazine of the speaker industry if you have a technical interest. Free, if you can convince them that they should send it to you.
Thank you for the heads up on the magazine! I'll try to see if I can convince them to give it to me for free, but I'm not in the industry so probably not :P

And this convo has been fun but way off-topic lol. Glad to meet another admirer of good speaker designs
Old 23rd December 2018
  #24
Quote:
Originally Posted by yeky83 View Post
If you understand the acoustic principle behind speaker lobing (again, not system design, but speaker design), it should be obvious why it cannot be corrected for with DSP. I invite you to please try to understand the acoustic principle.

I was not talking about on-axis response (avoiding on-axis crossover null is quite easy as you've said), but referring to lobing -- there are deep nulls in the crossover region of the JBL PRX within its coverage area (or any other speaker in the same configuration -- most PAs.). I.e. There will be -15~20 dB null in the crossover region 10~15 degrees off-axis (vertical if you're using it on a pole, horizontal if you're using it as a monitor). And I think we can agree that 10~15 degrees is indeed very much within a coverage range of interest for monitoring, since you've said you feel that even 90x90 is perhaps too narrow.

The effect of the off-axis null should be audibly noticeable. Set a speaker on a pole, play noise or music, and move your head up and down so you go in and out of 10~15 degrees off axis. You should be able to hear the crossover range null.

If you really want to observe the behavior, you can make measurements with your PRX to confirm this. There's really no avoiding this, laws of physics and all.

For a proper horn loading of the entire bandwidth of a full-response loudspeaker, it will require a speaker of an enormous size. This is obviously not possible in any portable PA/monitor/etc. format, and not the point of contention we've been discussing.

You disputed saying the CLR could not control directivity down to 650 Hz. Yes it can. This is measurable and observable.

If we want to go by math, the accepted formula is simple:
f = K / (theta * dimension)

Plug in the horn dimension of 17 in, with the directivity rating of 90 degrees, and you get 650 Hz.

650 Hz = 1*10^6 in*deg*Hz / (90 deg * 17 in)

Your ABC points are too general and not relevant here. Bandwidth of interest matters. The CLR uses two horns. It uses a constant-beamwidth type horn for the HF (curved sides, yay). And for the LF, I can agree with you the horn is probably more of a MF waveguide, but sufficiently so (a POI FYI, it also uniquely employs foam in its horn design).

It certainly is a superior design than direct radiating woofers in most PAs. The JBL PRX812 is spec'ed "90x50 nominal," but it will only be able to keep this directivity above ~3 kHz.

(Exponential horn is passe btw. But you probably meant curved edges in general.)

I don't see much fudging on Eminence specs AFAICT with regards to sensitivity and power rating. If you see it, please let me know where.

No, the efficiency looks about the same (Perhaps some fudging by JBL by testing old spec from >500 Hz, but probably not. As you say, I trust they rate their stuff properly.). Please see specs I link in response to below quote. ~100 = ~100.

The current day high output woofers have >~4 times the power capacity, that seems where the output improvement lies in the case of the K120. Not really efficiency.

I came across a few spec sheets where you can evaluate the sensitivity & power rating of Differential Drive 12" woofers:
https://www.jblpro.com/ProductAttachments/MRX512.pdf
https://www.huss-licht-ton.de/images...et_28153_2.pdf
JBL 2262HPL 338312-004X 12" Neo Woofer

And so no, I don't see the high efficiency you're claiming. If "'Differential Drive' actually MEANS SOMETHING" as you've said, these speakers should have a higher efficiency per your claim.

I also skimmed over their Differential Drive white paper:
https://www.jblpro.com/pub/technote/...-33%20rev3.pdf
Their main claims of benefit behind Differential Drive transducers isn't high efficiency.

Thank you for the heads up on the magazine! I'll try to see if I can convince them to give it to me for free, but I'm not in the industry so probably not :P

And this convo has been fun but way off-topic lol. Glad to meet another admirer of good speaker designs
I do understand the principle and yes, it can be corrected with DSP.

To be totally frank, I don't totally understand how they do some of the DSP tricks they do these days without inducing other types of artifacting, but judging by the acceptance of such DSP in large concert systems it would appear that they can. These days they can not only control lobing they can actually "steer" the dispersion pattern of the entire system to compensate for acoustic anomalies in the venue, which seems just weird to me but they do it.

The active PRX systems implement some of the same DSP developed for those concert systems.

As far as 4X the power capacity goes, generally higher power equates to lower efficiency due to increased mass of the moving parts and increased stiffness of the suspension, at least in conventional designs like the Eminence.
Old 26th December 2018
  #25
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
I do understand the principle and yes, it can be corrected with DSP.
Good sir, it seems you do not understand it.

Here's the explanation and math for two source wave interference, you can choose written or video:
http://webassign.net/question_assets...ion25dash1.pdf
Young's double slit problem solving (video) | Khan Academy

With the PRX812's crossover freq of 1.85 kHz and the transducers' c-t-c spacing of ~12 inches:

1.85 kHz -> 7.3 inches wavelength. For 1/2 wavelength interference (180 degrees out of phase), 7.3 inch / 2 = 3.65 inch

sine(theta) = 3.65 inch / ~12 inch
theta = ~17.7 degrees

Given that 1)the on-axis response of the PRX812 is well behaved (let's assume it is cus JBL doesn't make sucky pro-line stuff), and 2)c-t-c spacing is ~12 inches (I dunno exactly, looks about 12), there will be a destructive interference at ~18 degrees for 1.85 kHz.
Quote:
To be totally frank, I don't totally understand how they do some of the DSP tricks they do these days without inducing other types of artifacting, but judging by the acceptance of such DSP in large concert systems it would appear that they can. These days they can not only control lobing they can actually "steer" the dispersion pattern of the entire system to compensate for acoustic anomalies in the venue, which seems just weird to me but they do it.
I do understand how DSP is used to steer the dispersion pattern of sound systems (it seems to me you're referring to beamforming). This cannot be used to correct for lobing.
Quote:
The active PRX systems implement some of the same DSP developed for those concert systems.
I doubt you can support this claim. Do you know the DSP implementation in the PRX?

And again, DSP implementation cannot aid two source destructive wave interference. Laws of physics and all.
Quote:
As far as 4X the power capacity goes, generally higher power equates to lower efficiency due to increased mass of the moving parts and increased stiffness of the suspension, at least in conventional designs like the Eminence.
Generally comparing like for like, sure. But you were comparing stuff from 1970s and 2000s, and the specs don't bare that out.
Old 29th December 2018
  #26
Quote:
Originally Posted by yeky83 View Post
And again, DSP implementation cannot aid two source destructive wave interference. Laws of physics and all.
Sure it can. All you need to do is manipulate the phase and time constants of one or both sources.To do that you have to apply DSP after the active crossover but coordinated between the two bands.

I'll admit that when I'm confronted with the actual math involved I do get lost. But you don't have to be a math whiz to understand the principles.

Incidentally, that stuff was pioneered back in the late '70s by John Meyer in his proprietary speaker processing boxes. He's come a long way since. His Constellation system as installed in Berkeley's Zellerbach Auditorium can actually alter the acoustic characteristics of ther room.

Constellation | Meyer Sound

Quote:
Generally comparing like for like, sure. But you were comparing stuff from 1970s and 2000s, and the specs don't bare that out.
The mechanical principles involved really haven't changed since the 1940s. A lot of refinement has taken place and the materials involved have evolved considerably. And in this particular case the tech employed by a company like Eminence today is no different at all than the design tech used by JBL in the 1970s The one difference is the use of Neodymium as a magnetic material, but the actual physical designs have not changed. Both Neo and Alnico speakers used the same essential design of a central magnet with surrounding voice coil, enclosed in a ferrous return circuit. The only change in that technology has been by JBL in the differential drive driver designs. Eminence, however, is still using the same basic designs JBL used in the '70s. And that particular design peaked with JBL in the '70s and has not been surpassed. By anyone.

Last edited by John Eppstein; 29th December 2018 at 01:07 AM..
Old 29th December 2018
  #27
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
Sure it can. All you need to do is manipulate the phase and time constants of one or both sources.To do that you have to apply DSP after the active crossover but coordinated between the two bands.

I'll admit that when I'm confronted with the actual math involved I do get lost. But you don't have to be a math whiz to understand the principles.
If you manipulate the phase and time of one or both sources, you do not eliminate the destructive interference. You only move it around. Here's the mind-picture for you of what would happen:


You don't need to understand the math involved. But again, you don't seem to understand the principle. I'm really trying here, please give it a thought before replying again. There's two non-coincident sources. Their path length difference changes with the angle of the listener's location. At some angles the path length difference will be out of phase and destructive, at some angles in phase and constructive.

Even if you change the phase or time constants of one or both sources, the path length difference still exists, and all that will happen is that the in/out of phase angles will change. This does not fix the issue, but only exacerbates the on-axis response.

E.g. If you try to correct for location E by manipulating phase/time, you will create destructive interference at C & D.

Quote:
The mechanical principles involved really haven't changed since the 1940s. A lot of refinement has taken place and the materials involved have evolved considerably. And in this particular case the tech employed by a company like Eminence today is no different at all than the design tech used by JBL in the 1970s The one difference is the use of Neodymium as a magnetic material, but the actual physical designs have not changed. Both Neo and Alnico speakers used the same essential design of a central magnet with surrounding voice coil, enclosed in a ferrous return circuit. The only change in that technology has been by JBL in the differential drive driver designs. Eminence, however, is still using the same basic designs JBL used in the '70s. And that particular design peaked with JBL in the '70s and has not been surpassed. By anyone.
Again, I agree with you in the general. A woofer is a woofer for the most part.

But you're specifically comparing a speaker from 1970s with spec [101 dB 1W/1m; 200W program] to today's speaker with the spec [101 dB 1W/1m; 800W program]. I see a big difference there, and it does not support your specific claims.
Old 31st December 2018
  #28
I agree with that for the most part, as far as it goes. But what happens when you make the time and phase correction variable depending on the frequency content of the program? Furthermore, what are the distortion products going to be when your crossover frequency is up near 2k? Is it really going to make a significant difference to the listener's perception, given that most people don't differentiate pitches very well at higher frequency ranges?

Understand, historically I've always been a big fan of coaxial designs, mostly for the reasons you cite. In the last several years, however, I've started noticing a problem - Most of them don't actually sound as good as they're supposed to. And I'm a guy with two pairs of coaxials in my studio. Which I'd gladly trade for a pair of Harvey Gerst designed Tridents, if I could/can fit them in (and afford the trade-in....)


Quote:
Again, I agree with you in the general. A woofer is a woofer for the most part.

But you're specifically comparing a speaker from 1970s with spec [101 dB 1W/1m; 200W program] to today's speaker with the spec [101 dB 1W/1m; 800W program]. I see a big difference there, and it does not support your specific claims.
You're comparing printed specs from two different companies that don't use the same testing methods. JBL has always been the most conservative of companies when it comes to ratings. Eminence, not so much. The devil, in this case, lives in the detail of the definition of "program rating", which has never been standardized by anyone.

Typically a JBL "program rating" can be equivalent to a rating 2 to 4 times as high from some other manufacturers.

What is the frequency range of the "program"? What type of signal? (Single tone, noise, sweep, warble, burst, etc, etc, etc.) How long is the signal applied?

Over the past 10-20 years I've seen a constant escalation of claimed power ratings from many companies with no real increase in performance to back them up.

Last edited by John Eppstein; 31st December 2018 at 12:39 AM..
Old 1st January 2019
  #29
Gear Nut
Quote:
Originally Posted by John Eppstein View Post
I agree with that for the most part, as far as it goes. But what happens when you make the time and phase correction variable depending on the frequency content of the program?
Not sure why you're still bringing up time & phase correction again ("variable depending on the frequency content," what would that achieve?) if you agree and understand two source wave interference... the principle still holds.

There are some crossover design techniques that helps address this issue, but it in no way gets rid of it.
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Furthermore, what are the distortion products going to be when your crossover frequency is up near 2k?
Obviously it depends on the speaker. Wrt our discussion, seems neither here nor there.
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Is it really going to make a significant difference to the listener's perception,
Again, whether or not it's significant is up to the listener. You tell me, would you perceive the typical 20-degree vertical off-axis response shown here to be significant?


If you've ever heard, "don't lay studio monitors on their sides," this is why. People move their heads sideways into the lobing null regions and it makes a perceptually significant change for most.
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... given that most people don't differentiate pitches very well at higher frequency ranges?
I find this neither here nor there wrt this discussion. And are you suggesting ~2 kHz is a range where pitch differentiation is particularly difficult?
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Understand, historically I've always been a big fan of coaxial designs, mostly for the reasons you cite. In the last several years, however, I've started noticing a problem - Most of them don't actually sound as good as they're supposed to. And I'm a guy with two pairs of coaxials in my studio. Which I'd gladly trade for a pair of Harvey Gerst designed Tridents, if I could/can fit them in (and afford the trade-in....)
As I've said, many coaxial designs suffer from issues of jagged on-axis response and badly controlled directivity (bad off-axis response). But not all do.
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You're comparing printed specs from two different companies that don't use the same testing methods. JBL has always been the most conservative of companies when it comes to ratings. Eminence, not so much. The devil, in this case, lives in the detail of the definition of "program rating", which has never been standardized by anyone.

Typically a JBL "program rating" can be equivalent to a rating 2 to 4 times as high from some other manufacturers.

What is the frequency range of the "program"? What type of signal? (Single tone, noise, sweep, warble, burst, etc, etc, etc.) How long is the signal applied?

Over the past 10-20 years I've seen a constant escalation of claimed power ratings from many companies with no real increase in performance to back them up.
Good point, it's true we're comparing results from two different testing methods.

You make an experience based argument for JBL's favorable power rating. I can neither agree nor disagree since I don't have that experience, but point taken.

I still do take issue with your strong statements like "that particular design peaked with JBL in the '70s and has not been surpassed. By anyone." I wouldn't think even JBL would agree with that. You're saying they haven't improved that particular design since the 70's, and the stuff they're putting out today (that's not differential drive) is marketing fluff? No better than the 70's stuff?
Old 1st January 2019
  #30
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Originally Posted by yeky83 View Post
Good point, it's true we're comparing results from two different testing methods.

You make an experience based argument for JBL's favorable power rating. I can neither agree nor disagree since I don't have that experience, but point taken.

I still do take issue with your strong statements like "that particular design peaked with JBL in the '70s and has not been surpassed. By anyone." I wouldn't think even JBL would agree with that. You're saying they haven't improved that particular design since the 70's, and the stuff they're putting out today (that's not differential drive) is marketing fluff? No better than the 70's stuff?
AFAIK the design of conventional speaker drivers really has not changed very much since to '70s. It's a pretty mature technology. Companies play around with different combinations of techniques that have been known for a long time, but essentially not much has changed. There have been some advances in materials design, specifically doping, and there have been some new cone formulations, but none of that is really radical and the stuff that is newer than the '70s hasn't really found widespread favor with designers. Stuff like poly and aluminum cones are mostly fad stuff. Carbon fiber cones are an advance, but more along the line of a refinement of traditional cone design, not really much of an innovation per se. And none of those things really add to the efficiency of the driver, which is what we were talking about - in fact a lot of these modern materials seem to result in a somewhat LESS efficient speaker.

And the essential design of the speaker hasn't really changed and hasn't since Jim Lansing came up with ribbon wire voice coils and highly efficient magnetic circuits machined to extremely close tolerences.

One major change in recent years is actually a step backwards in my view, in thjat many speakers are less efficient than older designs, with the difference made up by drastic increases in amp power. THIS IS NOT AN ADVANCE IN SPEAKER DESIGN!

Substituting excursion for cone area isn't really an advance, either, since speakers with long excursions have greater distortion at higher SPL due to nonlinearity in the suspension system plus the fact that in speakers with conventional (non-differential drive) motors a lot of the coil is outside the magnetic gap at greater excursions.

I'll admit that I'm somewhat old fashioned in one respect - I do not like compact speakers that need lots of power to drive them. This is wasteful. I vastly prefer well designed large horn loaded cabinets that can achieve higher SPL with significantly less power. I also think that they sound better, for various reasons.

That doesn't mean that I like any old horn system - there are plenty of horrible sounding horn loaded systems - but the best ones are really good. The problem with them these days is transportation.
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