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Dual subwoofers placement, in real life
Old 1 week ago
  #31
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Quote:
Originally Posted by Samc View Post
Nobody said any of the proposed setups are perfect...I am saying that one system offers better performance than the other period. You started by talking about what looks good and glasses rattling etc. There is a lot of informative papers and videos about this on the internet, I suggest you check them out.
You and DeeDee seem to be saying that centre-clustered subs are the be-all and end-all of subwoofer setups. I don't deny for a second that they do have advantages, and I deploy them when I think they'd be the best solution for the events I'm providing for.

I'm saying that subs under mains will mean better alignment between the subs and mains. It's also a more practical setup for the band and venue in question.


I've also done plenty of reading on the subject and have found that, as ever, things are not as clear-cut as we might like.


Chris

PS - I'm also done with this thread. Apologies to the original poster. I hope this post will make my stance clear.
Old 1 week ago
  #32
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Quote:
Originally Posted by chris661 View Post
You and DeeDee seem to be saying that centre-clustered subs are the be-all and end-all of subwoofer setups. I don't deny for a second that they do have advantages, and I deploy them when I think they'd be the best solution for the events I'm providing for.

I'm saying that subs under mains will mean better alignment between the subs and mains. It's also a more practical setup for the band and venue in question.


I've also done plenty of reading on the subject and have found that, as ever, things are not as clear-cut as we might like.


Chris

PS - I'm also done with this thread. Apologies to the original poster. I hope this post will make my stance clear.
it would help if you would read more carefully what other folks are proposing:
i did not say centrally positioned subs are to be favoured in any case nor does avoiding spaced subs mean they have to go to the center (see my previous posts)!
i wasn't denying that subs under mains is often the most simple way both in terms of alignment and positioning but the disadvantages in terms of coverage, coupling, max. levels, rear attenuation, pattern, blocked sightlines, power distribution etc. imo by far outweight the only two above mentioned benefits!
and reading on the topic doesn't make up for decades of practical experience, something which sam and i indeed have in common...
Old 1 week ago
  #33
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Quote:
Originally Posted by Samc View Post
Nobody said any of the proposed setups are perfect...I am saying that one system offers better performance than the other period. You started by talking about what looks good and glasses rattling etc. There is a lot of informative papers and videos about this on the internet, I suggest you check them out.
Quote:
Originally Posted by chris661 View Post
You and DeeDee seem to be saying that centre-clustered subs are the be-all and end-all of subwoofer setups.
Will you stop this foolishness already...where did we say or even imply any such thing, your claim is not even remotely true. If that's what you get from, or after reading the quote above something is very wrong.

Subwoofers at both ends of the stage is generally considered to be the WORST setup option by professionals...and the alignment between subs and tops argument is bogus, absolutely not relevant in this situation.
Old 1 week ago
  #34
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JayTee4303's Avatar
Quote:
Originally Posted by deedeeyeah View Post
not much of a disussion in technical terms:

this is what you get from two spaced subs...
You WIN my Hero Of The Internet Award for the day!

I did NOT wanna find the Mapp XT image necessary here... OR go thru the hassle of posting it up... and thanks to you, I don't!

ONE sub array. ONE point source for LF radiation.

OR... pay the price in "strobing"... uneven LF coverage.

And yes... I do multiple sub clusters frequently. When I need to. That doesn't change the Best Approach.
Old 1 week ago
  #35
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Quote:
Originally Posted by jallejulius View Post
Thank you deedeeyeah and Samc for your answers!

I totally agree with you that coupling the subs are better sound wise, but how do you compare this to the benefits of having the subs under the tops? Like having more space on stage, easier setup, less gear/cables and a better look?

And ofcourse coupling the subs are shown to have lots of benefits in theory but how much of a change would it be in real life, when there are 200 people in the room with the sound bouncing around all over the place?
Would the power ally really be noticeable? Would the even be a noticeable difference at all? I mean the calculations are all made in an open space, with no people, no sound comping from the tops, no walls/ceiling and a constant stream of frequencies, but that's far from what it will be in a gigging scenario.

I'm not here to argue about the coupling effect, I'm just curious about how the theory applies in real life, when there are a lot more to take into consideration.
I'm the guy who fixes the computers for a local audio legend in a top ten US city that is NOT a major market.

I am also the audio physics guy.

I do a lot of room/acoustics modelling in the software domain, and I back that up by walking the real rooms with my ears and a meter.

Empty, full, and in between.

ONE sub cluster, when I can.

Do you REALLY want FOH sitting in one of DeeDee's nulls or strobes?

There's something else, too... low end... clarity... power... thump... focus... tightness... muscle...etc.

Give the singer a place to practice gymnastics, and your guitars a leg prop for those solos. Guitarist in particular, have been a bit list, since wedges went away.
Old 1 week ago
  #36
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JayTee4303's Avatar
Quote:
Originally Posted by Samc View Post
Apart from safety and sight-line concerns do people actually go to live concerts and obsess about how good the loudspeaker setup looks...?!? What kind of concerts are these...I'm guessing these are not concerts where the music performance is the primary source of entertainment and interest, but events (weddings, conferences, a cruise etc) with music tacked on the end as secondary or background entertainment?
I do.

Big, badass hangs give me wood.

I can safely assume I'm in a tiny minority here, so your point is valid.
Old 1 week ago
  #37
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Quote:
Originally Posted by JayTee4303 View Post
I do.

Big, badass hangs give me wood.

I can safely assume I'm in a tiny minority here, so your point is valid.
A lot of people will be awed by the sight of a massive stack and hang of loudspeakers....but a good sounding system will impress everybody all the time, regardless of it's size.

I any case this is different from what we were talking about...do you decide not to see a band in a bar because they put the subs in front of stage instead of under the tops at the sides of the stage....especially if the system sounds good?

Last edited by Samc; 1 week ago at 06:54 PM..
Old 1 week ago
  #38
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Quote:
Originally Posted by Samc View Post
A lot of people will be awed by the sight of a massive stack and hang of loudspeakers....but a good sounding system will impress everybody all the time, regardless of it's size.

I any case this is different from what we were talking about...do you decide not to see a band in a bar because they put the subs in front of stage instead of under the tops at the sides of the stage....especially if the system sounds good?
If that were a deciding point, it would go the other way. I very much like the impact I get from a single center sub cluster, over a spaced pair.

But I rarely "go to shows" or "decide." I'm running pretty much flat out... there are several large, close to out of control fires burning around here, and the next two hour chunk of time I have "free" is covered, several layers deep.

Working several shows a week, in between setting up, tearing down, repairs, prepping rentals, etc, and I'll center cluster my subs every time I can make it happen.

I don't hesitate to block sightlines up to vox knees if need be. I work with software to mapp rooms and then walk them, with and without a meter to balance theory with empirical fact, and I just don't want LF phase probs in my rooms if I can possibly help it.

Appearance... I'll closely observe any hang or stack, especially larger ones, I'll climb it, if possible, for any info I can gain, rigging, cabling, design, splay, whatev, but most days, a minute or two is all there is to spare and I shouldn't really even indulge myself that far.

In a perfect world... well... if one world at a time is all I get, I'm pretty much there. Multi-dimensional space-time constructs, yeah, one of them would be big rigs, 27/4.

(We work long days.)

:-)
Old 6 days ago
  #39
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Setting up a band PA like a PRO!
https://i.snipboard.io/dOF5J7.jpg

One question remains!
Is it better to put the subs on the same line/angel as the tops or is it better to have them closer to the wall, just like we have now?
Old 5 days ago
  #40
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Quote:
Originally Posted by deedeeyeah View Post
stop talking about things of which you obviously have no knowledge or experience at all! - wondering which software takes room modes, ceiling heigh, distance to side walls etc. into acount and works with any mi-gear of choice in predictable ways...?!
EASE
Old 5 days ago
  #41
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Quote:
Originally Posted by jallejulius View Post
Setting up a band PA like a PRO!
https://i.snipboard.io/dOF5J7.jpg

One question remains!
Is it better to put the subs on the same line/angel as the tops or is it better to have them closer to the wall, just like we have now?
I would typically answer yes, have them in line with the mains if feasible. But looking at the picture, it honestly isn't going to matter in that scenario.

As for the spaced pair versus center argument - there's no question that center location for subs is desirable. But it isn't always practical. Especially when architecture gets in the way like a center located series of steps up to stage. That will put a hitch in your center located giddy-up real quick.

It was mentioned that spacing between the center located pair of subs can make a difference. I find it more valuable to offset from the centerline by half or one whole sub cabinet.

I've been doing center arrays of subs for a long time as a result of both extensive modeling of different scenarios as well as real-world application. My favorite is three, or more, center located and offset by one enclosure with very discrete successive delays of outside pairs (usually around 2msec or less).

These generic comments are applicable for the typical MI setup. It should be noted that there are plenty of scenarios where things get quite a bit more or less complicated. Otto as on example. Using Nexo subs in carioid arrays where the quantity may require the subs to be rotated 90 degress or somewhere around 20 degrees less than that if utilizing fewer boxes (funkiest configuration I know of - where the subs actually end up at a weird angle in relation to the mains but if you add two more cardioid boxes they end up at an even 90 degrees).

It is fun stuff and should be discussed with a lighter heart so that it stays fun.

Cheers!
Brock
Old 4 days ago
  #42
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Not disputing the heat-maps, which are pretty conclusive about the virtues of centre sub placement and cardioid arrays etc....

One thing that puzzles me about all this is why full range loudspeakers - producing significant LF at the left and right positions - don't all suck? This goes for PA, studio monitors, hi-fi setups etc... Are we just saying that we tolerate a very tight sweet-spot in these scenarios, so lots of nulls/allies don't matter? This also implies 'full-range' PA speakers (let's say those with 15"+ woofers) are basically a bad idea?

Another thing on practicality... I used to run a rig with one sub and always tried to position it centre 'stage' (though as has been pointed out, one sub on one side isn't so bad...). Trouble is that often put it rather close to the kick drum so you can imagine the issue there (and no - there would def not be room for a cardioid array lol!)....

I guess most of you guys who are able to run centre sub arrays are talking about rooms/venues/outdoor events with large stages that can accommodate them beneath or in front of the stage?

That's great - and sometimes I'm fortunate enough to be running shows or performing in such spaces - but then there's your typical pub/club/wedding venue with the audience at the same level as you. Sticking a couple of 18" cabs as a ground stack or endfire array may look pretty awesome to me and other audio geeks, but that just doesn't work in a stageless tudor manor house! At the same time, sometimes one sub just isn't enough at these venues....

So what's best practice? Basically, if you can't run a centre array, run a single sub or stacked subs to one side?

Never run spaced subs and steer clear of full-range boxes?
Old 4 days ago
  #43
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Quote:
Originally Posted by jh_audio View Post
Not disputing the heat-maps, which are pretty conclusive about the virtues of centre sub placement and cardioid arrays etc....

One thing that puzzles me about all this is why full range loudspeakers - producing significant LF at the left and right positions - don't all suck? This goes for PA, studio monitors, hi-fi setups etc... Are we just saying that we tolerate a very tight sweet-spot in these scenarios, so lots of nulls/allies don't matter? This also implies 'full-range' PA speakers (let's say those with 15"+ woofers) are basically a bad idea?

Another thing on practicality... I used to run a rig with one sub and always tried to position it centre 'stage' (though as has been pointed out, one sub on one side isn't so bad...). Trouble is that often put it rather close to the kick drum so you can imagine the issue there (and no - there would def not be room for a cardioid array lol!)....

I guess most of you guys who are able to run centre sub arrays are talking about rooms/venues/outdoor events with large stages that can accommodate them beneath or in front of the stage?

That's great - and sometimes I'm fortunate enough to be running shows or performing in such spaces - but then there's your typical pub/club/wedding venue with the audience at the same level as you. Sticking a couple of 18" cabs as a ground stack or endfire array may look pretty awesome to me and other audio geeks, but that just doesn't work in a stageless tudor manor house! At the same time, sometimes one sub just isn't enough at these venues....

So what's best practice? Basically, if you can't run a centre array, run a single sub or stacked subs to one side?

Never run spaced subs and steer clear of full-range boxes?
the principles apply to full range speakers/array too - so yes, regarding the pattern one gets for their lf content, they suck! :-)

(mostly) the best practice for those situations in which one cannot (or should not...) use centrally placed subs is to stack them on one side.

but again: in small rooms, the room dominates the sub's behaviour so one might be better off trying to get optimum loading - this can get achieved by putting subs to two opposing walls...
Old 4 days ago
  #44
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As was said several times already...the specifics of the situation determine how the situation is managed. There is no one size fits all solutions method, and yes, those full-range boxes (which are a compromise actually) will suck in many situations because they don’t offer the flexibility of dedicated subs. Good sounding recording studio control rooms are specifically designed to not have these (and other) problems...it doesn’t happen by magic.

I suffered one of my worst mixing nights last night in a beautifully designed/built theatre in northern Italy mainly because there was a huge orchestra pit in front of the stage and the sound contractor was not prepared to deal with it. Mix position all the way in the back of the hall and under the balcony just made a bad situation worse.

Based on timing, there was no way to make the necessary changes To “fix” the situation...in all of the advancing nobody told me about the pit, so I’ve sent emails asking about specific system setups for the coming gigs. I spent a good part of the night trying to get a compromise balance in the venue Which was so big in some locations that I finally gave up and just concentrated on the biggest most populated area. I spent a lot of time reflecting on this thread.
Old 4 days ago
  #45
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As far as placing subs on either side of the stage and closer to walls in the structure I have not seen anyone consider boundary cancellation.
This must also be taken into consideration when placing loudspeakers.
Here is a handy chart.

http://www.padrick.net/LiveSound/CancellationMode.htm
Old 4 days ago
  #46
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Quote:
Originally Posted by Samc View Post
A lot of people will be awed by the sight of a massive stack and hang of loudspeakers....but a good sounding system will impress everybody all the time, regardless of it's size.

I any case this is different from what we were talking about...do you decide not to see a band in a bar because they put the subs in front of stage instead of under the tops at the sides of the stage....especially if the system sounds good?
Indeed an accurate and amazing sounding system should disappear and not be noticed by the audience. The focus is the talent on stage. "The show".
Period end of story.
Old 4 days ago
  #47
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Quote:
Originally Posted by Pro Sound Guy View Post
As far as placing subs on either side of the stage and closer to walls in the structure I have not seen anyone consider boundary cancellation.
This must also be taken into consideration when placing loudspeakers.
Here is a handy chart.

http://www.padrick.net/LiveSound/CancellationMode.htm
good point - when i said close to the walls, i meant 'as close as possible', the woofer touching the wall!
Old 4 days ago
  #48
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Quote:
Originally Posted by Pro Sound Guy View Post
Indeed an accurate and amazing sounding system should disappear and not be noticed by the audience. The focus is the talent on stage. "The show".
Period end of story.
I know this kind of rhetoric makes us feel warm and cosy inside, but in my experience people always notice when the concert sounds really good or bad, they always notice when the production is slick and trouble free...

The idea that they will just be absorbed by the artist/band is false...on mars anyway. Because the production (sound, lights, set design, performance etc) are what makes the show.
Old 4 days ago
  #49
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Quote:
Originally Posted by Pro Sound Guy View Post
Indeed an accurate and amazing sounding system should disappear and not be noticed by the audience. The focus is the talent on stage. "The show".
Period end of story.
Sorry, but that may be the end of the story for you and those in the biz. And it’s the end of the story for architects.

For promoters and the average consumer - they hear with their eyes and expect to see the system. And in some instances, in my experience, demand it. Hence the prevalence of line arrays where a point source system would be more beneficial.
Old 3 days ago
  #50
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Quote:
Originally Posted by deedeeyeah View Post
chris is wrong - in so many ways that i really don't wanna address each mistake but just bring up a few things:

- subs are an integral part of a pa or else it cannot achieve full range reproduction (except for some very rare speaker systems which the vast majority of posters here will newer ever get to use): so in live sound, we're talking about alignment and not integration.

- one cannot time-align subwoofers! one can only phase-align them and only for a specific frequency and for a specific distance!

- there is no such thing as off axis lobing when using two omnidirectional center subs.

- the suggested spacing is valid for use amongst subs but not between the sub array and the mains! (if it'd be the case, there would only specific distances between mains and subs possible and the idea doesn't take into account that many systems use asymmetrical x-overs and that there can be additional sub-systems yet at other distances to the subs...)
Actually thats also not entirely correct. The spacing of two subs in a subarray is depending on the frequency that you want to couple.
There is a formula for that.
It needs to be smaller then half the wavelength of the highest frequency I want to couple.
100 HZ for example needs to be less then 1.7 between the driver centers of each sub. Pattern control is then achieved by either using CSA and or mechanically or electronically shaping the curve of the array.
And Phase alignment and time alignment are practically the same thing. Because in audio, time is phase and phase is time. You can only separate those in FIR Filters.
Its all frequency depending anyway. Luckily Music is not just a single sinewave. Its much more complex the that.
Old 3 days ago
  #51
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Quote:
Originally Posted by max headroom UK View Post
Actually thats also not entirely correct. The spacing of two subs in a subarray is depending on the frequency that you want to couple.
There is a formula for that.
It needs to be smaller then half the wavelength of the highest frequency I want to couple.
100 HZ for example needs to be less then 1.7 between the driver centers of each sub. Pattern control is then achieved by either using CSA and or mechanically or electronically shaping the curve of the array.
And Phase alignment and time alignment are practically the same thing. Because in audio, time is phase and phase is time. You can only separate those in FIR Filters.
Its all frequency depending anyway. Luckily Music is not just a single sinewave. Its much more complex the that.
well... - when only having simple means to align subs, it is recommended to put them not within half but within a quarter of the wavelength of the frequency one is aiming at (to get phase within 90° or less) for optimum coupling. now coupling does not necessarily need to be the only or highest design principle: in the example i posted above, four out of seven subs were 180° off relative to each other which helped to lower the otherwise dominant boom at 100hz very efficiently!

and no, phase is not time, at least not when having more sophisticated tools available: that's why we often use allpass filters for alignment which allow you to align phase depending on frequency but not on time...
Old 2 days ago
  #52
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Quote:
Originally Posted by Samc View Post
(...) I suffered one of my worst mixing nights last night in a beautifully designed/built theatre in northern Italy mainly because there was a huge orchestra pit in front of the stage and the sound contractor was not prepared to deal with it. Mix position all the way in the back of the hall and under the balcony just made a bad situation worse.
(...)
strange kinda coincidence: i suffered one of my worst logistical nightmares that night (more details in another thread)... - must have been that day or the stars or whatever?!
Old 2 days ago
  #53
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We ended up stacking the two subs in order to get more space, and it worked out very well! For a venue like that, our PA worked out perfectly The two Alto TS315's are load as F### ! Plenty of headroom left for a venue like that.
https://i.snipboard.io/5UdA6L.jpg
https://www.youtube.com/watch?v=On4B...ERRaFm36V5Mae8
Old 2 days ago
  #54
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Quote:
Originally Posted by jallejulius View Post
We ended up stacking the two subs in order to get more space, and it worked out very well! For a venue like that, our PA worked out perfectly The two Alto TS315's are load as F### ! Plenty of headroom left for a venue like that.
https://i.snipboard.io/5UdA6L.jpg
https://www.youtube.com/watch?v=On4B...ERRaFm36V5Mae8
Great...the audience didn't seem to concerned ab
out your loudspeaker placement, I hope the 'gilets jaunes' will invite you back to entertain them.
Old 2 days ago
  #55
mdc
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Quote:
Originally Posted by deedeeyeah View Post

and no, phase is not time, at least not when having more sophisticated tools available: that's why we often use allpass filters for alignment which allow you to align phase depending on frequency but not on time...


At what point isn’t the phase difference between two waveforms a function of time?
Old 2 days ago
  #56
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Quote:
Originally Posted by mdc View Post
At what point isn’t the phase difference between two waveforms a function of time?
damn, do some of you folks have to mis-read/mis-interpret every other post on purpose?!

what i'm trying to get across in simple non-geek-speech is that allpass filters allow for more sophisticated control for alignment and pattern control of subs as they add another level of affecting phase, besides positioning/arraying and simple time delay.

happy now?
Old 2 days ago
  #57
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Quote:
Originally Posted by deedeeyeah View Post
damn, do some of you folks have to mis-read/mis-interpret every other post on purpose?!

what i'm trying to get across in simple non-geek-speech is that allpass filters allow for more sophisticated control for alignment and pattern control of subs as they add another level of affecting phase, besides positioning/arraying and simple time delay.

happy now?
Nice backpedal
Old 2 days ago
  #58
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fugazzi

Quote:
Originally Posted by Bstapper View Post
Nice backpedal
interesting YOU were the first to comment, not on topic as so often but getting snarky - trying to fuel another vendetta?

pls go ahead; maybe better though to write in german, french, spanish, italian (or latin if you feel very fancy) to avoid further misunderstandings...
Old 2 days ago
  #59
mdc
Gear Head
 

Quote:
Originally Posted by deedeeyeah View Post
damn, do some of you folks have to mis-read/mis-interpret every other post on purpose?!

what i'm trying to get across in simple non-geek-speech is that allpass filters allow for more sophisticated control for alignment and pattern control of subs as they add another level of affecting phase, besides positioning/arraying and simple time delay.

happy now?
Why the pissy response? I certainly meant no disrespect!

There are people reading this thread that might be trying to wrap their heads around the concept of “phase”. To say that phase isn’t “time” maybe adds more confusion.

An all pass filter changes the phase relationship between two signals by introducing delay into one of the signals without affecting the amplitude or frequency response of the delayed signal.
Old 2 days ago
  #60
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Quote:
Originally Posted by mdc View Post
Why the pissy response? I certainly meant no disrespect!

There are people reading this thread that might be trying to wrap their heads around the concept of “phase”. To say that phase isn’t “time” maybe adds more confusion.

An all pass filter changes the phase relationship between two signals by introducing delay into one of the signals without affecting the amplitude or frequency response of the delayed signal.
The issue is that it isn't "time", it's "times".

So it is more correct to refer to alignment of subs as "phase alignment". And although it is common to refer to it as "time alignment" it may not be the best way to describe it although it could be argued that it is just as valid if the goal is to send the molecules packing and unpacking via the same virtual physical axis and point in time regardless of their speed. The physical reality of the difference in impulse over frequency suggests that ain't gonna' happen.

As a result you have to pick your poison and typically go for what is happening at the crossover point and shoot for the best phase relationship at those frequencies (as my preferred compromise) which will typically provide for acceptable results in the intended space and time.

Don't sweat Mr. Sunshine there. Audio Engineers are often known for their "unique" social skills


Cheers!
Brock
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