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JBL SRX835p 60x40 dispersion WHY? Studio Monitors
Old 10th April 2019
  #31
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Quote:
Originally Posted by kirkus View Post
There are four main general technical requirements for a point-source loudspeaker to work well in an array:
1. Constant directivity index through its intended coverage area
2. Smooth and sharp roll-off in the transition outside the coverage area
3. High degree of attenuation outside the coverage area
4. Physical form factor that allows their acoustic centers to be placed close enough to eliminate comb-filtering.
This is just basically four different ways of saying the same thing, we just need the elements in the system to combine seamlessly.

Quote:
There has not yet been a PA loudspeaker produced (by humans at least) that achieves anywhere near perfection in any of these criteria (let alone all) . . . even though there are of course wide degrees of deviation from perfection in the current market. Even within the unambiguously "professional" segment, different manufacturers give different weight to these criteria, and solve their challenges with different approaches. There are inherent compromises with each, and every speaker's performance in an array will of course be intrinsically tied to the application in which it's used.

Ergo, logic dictates that "arrayability" cannot be a mere binary condition.
The simple question and argument here is if the damn box will perform well or not when "splayed"...? Good enough for the price and good enough for the gig are extremely nebulous and useless terms that can mean anything, and usually means different things to different people. Your argument that: "it makes technical and logical sense that they could indeed perform quite satisfactorily when paired horizontally, provided that they are the appropriate class of product for the event in the first place." is, (with all due respect) meaningless.
Old 10th April 2019
  #32
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mintaka007's Avatar
Running out of ammo in this thread Samc, should probably start a new argument in another thread to feed off of. Has to be someone asking for advice somewhere you can tear into.
Old 10th April 2019
  #33
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Quote:
Originally Posted by Samc View Post
This is just basically four different ways of saying the same thing, we just need the elements in the system to combine seamlessly.
Actually Sam, these four design criteria are absolutely not the same thing. If you ever dip your foot into the swimming-pool of horn and waveguide design equations, you'll find that their realizations are actually mathematically divergent from each other . . . and also at odds with the basic parameters of bandwidth and periodicity. The acoustical theory behind this has been known for almost a century, and there are landfills full of physical artifacts that are a testament to our efforts to strike acceptable compromises between these requirements.

It's only since the availability of computers that we've been able to approximate "constant directivity" behavior, and it's not because of any seminal discovery . . . it's that highly iterative calculations are now possible to come up with very highly-optimized and complex compromises for the basic criteria with which we've always been struggling.

You mentioned earlier something about arrayability being a hallmark of narrower-beamwidth horns, and this does indeed make it easier to achieve the aforementioned design requirements. This is precisely why the horns of eighty years ago were multicellular designs . . . they use exponential flares and thus are NOT constant-directivity, and not very smooth in their transition off-axis. But each individual cell does have outstanding attenuation outside the coverage area, and their design (operating from a single compression driver) allows their acoustic centers to be packed together almost perfectly (especially compared to modern designs). By hitting two out of four of the requirements very strongly, they were able to achieve an array that can give predictable, scalable performance, and the compromises in bandwidth and periodicity were deemed acceptable for their intended application.

Quote:
Originally Posted by Samc View Post
Good enough for the price and good enough for the gig are extremely nebulous and useless terms that can mean anything, and usually means different things to different people. Your argument that: "it makes technical and logical sense that they could indeed perform quite satisfactorily when paired horizontally, provided that they are the appropriate class of product for the event in the first place." is, (with all due respect) meaningless.
The technical basis for my conclusion is having modeled and measured arrays using JBL's professional products with similar types of horns (i.e. the aforementioned AM7200), and the logical leap is that the SRX835P will deliver similar enough behavior to these products . . . making it plausible for a horizontally-arrayed pair of them to deliver results that I'd consider to be acceptable for their price class and intended application. No more, no less.
Old 11th April 2019
  #34
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Quote:
Originally Posted by kirkus View Post
The technical basis for my conclusion is having modeled and measured arrays using JBL's professional products with similar types of horns (i.e. the aforementioned AM7200), and the logical leap is that the SRX835P will deliver similar enough behavior to these products . . . making it plausible for a horizontally-arrayed pair of them to deliver results that I'd consider to be acceptable for their price class and intended application. No more, no less.
Your technical basis is speculation...you didn't measure or model this product, you even pointed out in a previous post that these boxes did not sound like or as good as the professional box with the supposedly "similar" horn. You instead stated that you don't know if the components are the same, but the design of the horn is different, and that the material used to construct the horn is also different...so what pray tell makes your conclusion a "logical leap"?

Can you please explain what the sentence in bold actually mean...seriously, this all sounds like speculative opinion trying really hard to pose as fact to me. seriously man, I always though of you as one of the more knowledgeable and enlightened people here...
Old 11th April 2019
  #35
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Quote:
Originally Posted by Samc View Post

... seriously, this all sounds like speculative opinion trying really hard to pose as fact to me. seriously man, I always though of you as one of the more knowledgeable and enlightened people here...
Meanwhile, Sam, who has even less experience with the 835 sells his speculative opinion as fact.
Old 11th April 2019
  #36
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Quote:
Originally Posted by Samc View Post
Can you please explain what the sentence in bold actually mean...seriously, this all sounds like speculative opinion trying really hard to pose as fact to me. seriously man, I always though of you as one of the more knowledgeable and enlightened people here...
Thanks for the compliment . . . and it's mutual . . .

In the early 1990s, I worked for a guy that made a successful small business providing sound for gigs that look very much like the picture in post #2 . He had a dozen or so pairs of very nice self-built 15" two-way tops and matching single-18" reflex subs, using JBL large-format 2-inch drivers on 2383 60x50 lenses, JBL 15" woofs, and Gauss subs. They were tri-amped with heavy QSC iron, and Ashly analog crossovers IIRC.

Frequently, the setup and/or promoter demanded coverage that wrapped around the sides of the stage, and to this end we'd put pairs together on each side. They certainly didn't array perfectly, and there was a bit of weirdness and comb-filtering in the transition . . . but it could be mitigated to a degree by twiddling the EQ and crossover, and it wasn't much of an issue in the whole scheme of things. His rigs always sounded fantastic, and were a pleasure to mix on . . . and he had every part of his capital investment, deployment, labor, and maintenance costs worked out where he both made a solid living and was always in high demand for his quality.

I do see many instances of side-by-side MI tops these days, even down to plastic Altos and EONs . . . and I fully agree that they're pretty much always a sh!t-show. But in the specific case of the SRX835P . . . while I wish there were polars provided, I'm pretty confident from listening to them that their midrange pattern control is an improvement over that old 2383 lens, which itself was hugely, vastly superior to the typical MI two-way on the market today. Thus, if somebody is claiming that they get good results from SRX835Ps in horizontally-arrayed pairs . . . when used in gigs like the photo from post #2 . . . my response is that while I haven't specifically heard them like this . . . I've personally seen situations where this is wholly plausible. And I understand that the SRX series is so inexpensive as to be an extremely attractive option from an ROI standpoint to a small sound-provider business, and that pro products that do have superior arrayability probably don't work in this regard.

I do turn my nose up at the idea of the SRX835P as being suitable to really deliver professional results a in a music venue. I don't think this is true for singles or arrays . . . so in this context, what's the point of going on about it's arrayability, or lack thereof? That is, in a situation where it's not that great in any configuration?
Old 14th April 2019
  #37
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Christof's Avatar
Quote:
Originally Posted by Wyllys View Post
JBL no longer publishes their polars, however the mid-range horn-loaded driver covers 330hz-2.4Khz so there exists the possibility of fairly decent control for two octaves below the mid-hi crossover.
Horizontal coverage JBL SRX 835P:


Source: Review by "Production Partner"
Many other measurements (probably done by Anselm Görtz) are shown for the JBL SRX815P and the SRX835P
Old 14th April 2019
  #38
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Wyllys's Avatar
 

Quote:
Originally Posted by Christof View Post
Horizontal coverage JBL SRX 835P:


Source: Review by "Production Partner"
Many other measurements (probably done by Anselm Görtz) are shown for the JBL SRX815P and the SRX835P
Thanks for the link. I'm always looking for sites giving such detailed information. Takes a bit of time to decipher the spectrogram when you're used to polars due to the "extra" degree of information, but it looks like my guesstimate was close.

It would be great if you would post the same info for a JBL 2-way speaker for comparison.
Old 14th April 2019
  #39
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Quote:
Originally Posted by Wyllys View Post

It would be great if you would post the same info for a JBL 2-way speaker for comparison.
In the review of production partner in the link you will find the diagramm for the 815.
Old 15th April 2019
  #40
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Christof's Avatar
As mentioned - here's the 2-way SRX 815P:

Old 15th April 2019
  #41
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Great article; thanks for the link. The horizontal pattern is actually very respectable, especially for the price . . . but on the vertical plane it gets pretty ratty around the mid-high transition. That very basic passive crossover is surely a major contributor to this . . . if it was a true three-way active system (tri-amped) I would think it could be improved considerably. But whether or not the increased cost would then make it a non-competitive product would be the big question . . .

Certainly NOT a speaker you'd want to fly . . . best in a portable ground-stacked application where people will be within a pretty narrow range on the vertical axis.
Attached Thumbnails
JBL SRX835p 60x40 dispersion WHY?-835-ver.jpg  
Old 15th April 2019
  #42
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Quote:
Originally Posted by kirkus View Post
Great article; thanks for the link. The horizontal pattern is actually very respectable, especially for the price . . . but on the vertical plane it gets pretty ratty around the mid-high transition. That very basic passive crossover is surely a major contributor to this . . . if it was a true three-way active system (tri-amped) I would think it could be improved considerably. But whether or not the increased cost would then make it a non-competitive product would be the big question . . .
Care to give a brief summary, I don't read German and have no clue what the authors of the article are saying. I'm not particularly surprised by the graphic.

Quote:
Originally Posted by kirkus View Post
Certainly NOT a speaker you'd want to fly . . . best in a portable ground-stacked application where people will be within a pretty narrow range on the vertical axis.
My thoughts exactly after having heard them, and yet four of them (2 per side flown) were recommended for a 1500 place venue in another thread....go figure.
Old 16th April 2019
  #43
Quote:
Originally Posted by mintaka007 View Post
Running out of ammo in this thread Samc, should probably start a new argument in another thread to feed off of. Has to be someone asking for advice somewhere you can tear into.
Too late.....
Old 16th April 2019
  #44
Quote:
Originally Posted by kirkus View Post
if somebody is claiming that they get good results from SRX835Ps in horizontally-arrayed pairs my response is that while I haven't specifically heard them like this . . . I've personally seen situations where this is wholly plausible. And I understand that the SRX series is so inexpensive as to be an extremely attractive option from an ROI standpoint to a small sound-provider business, and that pro products that do have superior arrayability probably don't work in this regard.

Thank you for that very balanced and well written post, which was soundly based in REALITY.

Re what I quoted you on above, in my real-world experience (which I have ironically taken a beating for from several folks here who do not have the same real world experience with the product) this is the case.

They are NOT the massive disaster that some would like to make us believe in a 2 per side configuration. Absolutely 100% there are better options, but my reference to these (a point that seems to be consistently overlooked by those who perhaps do not have much background around the financial realities of small market /budget constrained / regional sound co requirements) has always been in connection with them being a low cost, good value for the money product within their price range.
Old 16th April 2019
  #45
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Pro Sound Guy's Avatar
 

That passive xover to the hi/mid.
I was quite surprised about that.
In fact that kind of sucks.
I have some old QSC HPR153 3ways.
Those are active from top to bottom.
No passive xovers in them.
Old 16th April 2019
  #46
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Quote:
Originally Posted by bambamboom View Post
Thank you for that very balanced and well written post, which was soundly based in REALITY.
He wrote this, in a later post:
Quote:
Originally Posted by kirkus View Post
I do turn my nose up at the idea of the SRX835P as being suitable to really deliver professional results a in a music venue. I don't think this is true for singles or arrays . . . so in this context, what's the point of going on about it's arrayability, or lack thereof? That is, in a situation where it's not that great in any configuration?
And this:

Quote:
Originally Posted by kirkus View Post
Certainly NOT a speaker you'd want to fly . . . best in a portable ground-stacked application where people will be within a pretty narrow range on the vertical axis.
Even you wrote that you wouldn't use them if you had the budget to do the job right.

Quote:
Re what I quoted you on above, in my real-world experience (which I have ironically taken a beating for from several folks here who do not have the same real world experience with the product) this is the case.

They are NOT the massive disaster that some would like to make us believe in a 2 per side configuration. Absolutely 100% there are better options, but my reference to these (a point that seems to be consistently overlooked by those who perhaps do not have much background around the financial realities of small market /budget constrained / regional sound co requirements) has always been in connection with them being a low cost, good value for the money product within their price range.
Well...this is not really the truth, and reads like you're just shoveling mud into the water...you suggested 4 of them for use in a 1,500 place venue, with a lot of sketchy supporting arguments. I disagree with the idea that these loudspeakers are 'good enough' for that job regardless of the price, and I disagree with the idea that the budget justifies using anything. I and others, have suggested that you either have the budget to do the job right or not...instead of the idea that anything is better than waiting to do it properly.

Nobody has suggested that the OP in this thread not use them for his purpose, but apparently, with the argument above they can be recommended for use in any situation...after all the do "border on pro".
Old 16th April 2019
  #47
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Quote:
Originally Posted by Samc View Post
Care to give a brief summary, I don't read German and have no clue what the authors of the article are saying. I'm not particularly surprised by the graphic.
Well my German certainly has its gaps in fluency . . . but insofar as the measurements are concerned, the text focuses primarily on comparing the 835P with the 815P, and leave it to the reader to draw their own conclusions in comparison to other products on the market. Most specifically, they talk about the 835's superior time-domain response through the lower midrange over the 815, as a result of the horn covering this range instead of the woofer. They also make note of the fact that they use the same bass driver, but different box tunings . . . making it sound subjectively "bigger".
Quote:
Originally Posted by Pro Sound Guy View Post
That passive xover to the hi/mid.
I was quite surprised about that.
In fact that kind of sucks.
I have some old QSC HPR153 3ways.
Those are active from top to bottom.
No passive xovers in them.
Actually a passive crossover can deliver excellent results . . . and judging from those in the AM7200 and the PD5000 series, JBL certainly knows how to design and build them. But from the photo, the 835P's crossover is obviously second-order, the extra cap perhaps being an additional low HP pole on the tweeter to improve power-handling capacity. There's no getting around the fact that there will be significant out-of-band energy with these slopes, and the two horns won't remain in phase with each other through the transition region. If the horns and drivers are basically well-engineered, it can be pretty well bodged together on-axis and the power response compensated in the DSP . . . but as the relative path lengths to the two horns changes as one moves up and down on the vertical plane, it all falls apart rather quickly.

This is one of the strongest indicators that ALL of the PRX/SRX products are engineered to a price point. I would be very surprised if the basic amp/input module wasn't common to every one of these products . . . with an additional display module added for all of the SRX series, and maybe with one channel of the amp PC board left unstuffed for the single subs. They obviously couldn't make the economics work for the SRX835P by bolting in the mid-high horns and passive crossover from the AM7200, even though they already had the design and production-engineering work done.

So for the SRX835P to have its own special version of the electronics with extra DSP horsepower, an additional DSP output channel, and an extra amplifier . . . that would make for a MUCH more expensive product. And even then, everything else would still be SRX . . . making the product uncompetitive in both price and performance.
Old 16th April 2019
  #48
Sam, on the "good enough" point, let's just agree to disagree on where that line is and what factors (such as cost) are relevant to it. It's extremely subjective and what is good enough to one person may not be to another.

Regarding the German article, just use Chrome and press the translate button. Done.
Old 17th April 2019
  #49
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Pro Sound Guy's Avatar
 

Quote:
Originally Posted by kirkus View Post
Well my German certainly has its gaps in fluency . . . but insofar as the measurements are concerned, the text focuses primarily on comparing the 835P with the 815P, and leave it to the reader to draw their own conclusions in comparison to other products on the market. Most specifically, they talk about the 835's superior time-domain response through the lower midrange over the 815, as a result of the horn covering this range instead of the woofer. They also make note of the fact that they use the same bass driver, but different box tunings . . . making it sound subjectively "bigger".
Actually a passive crossover can deliver excellent results . . . and judging from those in the AM7200 and the PD5000 series, JBL certainly knows how to design and build them. But from the photo, the 835P's crossover is obviously second-order, the extra cap perhaps being an additional low HP pole on the tweeter to improve power-handling capacity. There's no getting around the fact that there will be significant out-of-band energy with these slopes, and the two horns won't remain in phase with each other through the transition region. If the horns and drivers are basically well-engineered, it can be pretty well bodged together on-axis and the power response compensated in the DSP . . . but as the relative path lengths to the two horns changes as one moves up and down on the vertical plane, it all falls apart rather quickly.

This is one of the strongest indicators that ALL of the PRX/SRX products are engineered to a price point. I would be very surprised if the basic amp/input module wasn't common to every one of these products . . . with an additional display module added for all of the SRX series, and maybe with one channel of the amp PC board left unstuffed for the single subs. They obviously couldn't make the economics work for the SRX835P by bolting in the mid-high horns and passive crossover from the AM7200, even though they already had the design and production-engineering work done.

So for the SRX835P to have its own special version of the electronics with extra DSP horsepower, an additional DSP output channel, and an extra amplifier . . . that would make for a MUCH more expensive product. And even then, everything else would still be SRX . . . making the product uncompetitive in both price and performance.
Lets talk phase and time alignment.
I just purchased a pair of PRX812's. I am highly considering dumping them because of the passive crossover. Are we kidding here? Why not just offer them without self power and offer them as a passive box?
Old 17th April 2019
  #50
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dispersion not only depends on the horn characteristics but also on the size of the lf woofer: larger diameters tend to be more directional - it makes sense to use 12" or 15" woofers and pair them with horns which have a more narrow dispersion (to get more even dispersion over a larger frequency range).

but just because it's somewhere stated that boxes can get physically 'arrayed' doesn't mean that they behave as an array which was designed as such: measuring could tell a lot more (although measuring, comparing and interpretation of data is not always as easy is it may seem at first glance).

and regarding passive x-overs: of course they are mostly crap/cannot compete with external dsp! rip them out, get additional/suitable amps and dsp to control the speakers - problem is that for this amount of money, one then could easily get a better speaker which doesn't need modification...
Old 17th April 2019
  #51
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Quote:
Originally Posted by Pro Sound Guy View Post
Lets talk phase and time alignment.
I just purchased a pair of PRX812's. I am highly considering dumping them because of the passive crossover. Are we kidding here? Why not just offer them without self power and offer them as a passive box?
That’s what the prx400 series is
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