Help me choose a lens? (Hypothetical)

[PunkSweeper]

I've been keeping myself busy lately designing a fairly killer PA-ish system for pre-recorded Trance, House and Dubstep Music.

-It would be actively crossed and generally processed bt a Behringer DCX 2496.

-It would use my Super Subs For the low end. They model to be good for 125 db at 25 hz, at RMS wattage, anechoic, with only 3mm of excursion past Xmax.

-The Kick Bins are 4th order bandpass boxes with Dayton series II 12s in them. They're good for about 120 db in the 50-120hz passband, and only breach Xmax by 1 mm at that level.

-The satellites will have Delta 10s, the 8 ohm version. They too stay well below Xlim at 120db.

-I'd like to use this (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-446) compression driver, but I'm open to suggestions. For that matter, I'm flexible on the mid too.

Anyway, I'm looking for the best horn for splaying the cabs. If that's truly a wretched and implausible idea (even a little), my next favourite option is pole mounting them elsewhere and separate, with some delay if necessary.

[killersoundz]

Anyway, I'm looking for the best horn for splaying the cabs. If that's truly a wretched and implausible idea (even a little), my next favourite option is pole mounting them elsewhere and separate, with some delay if necessary.

Personally I preach to people to avoid basically any array of HF horns unless it's a line array. Putting multiple HF horns next to each other just causes awful comb filtering that sounds like crap. I was at a new venue last night and the guy had JBL M-pro mains with some Yamaha club series mains side by side.....holy crap the HF response was so nasty, you could really tell on vocals and the trumpet especially. People like that just think more is better, when it's not, the JBL mains would have sounded better on their own. Any multiple HF horn cluster array I've heard always sounds bad. I've heard quite a few, the Cleveland Agora Theater has a cluster of something like 12 main PA cabs per side, each with a HF horn, SOUNDS AWFUL, I've also heard an outdoor event with a couple of Carvin Mains clustered beside each other, one of the worst vocal sounds I've heard.

If you don't think one pair of 1" exit HF horns is going to give you enough output maybe you could step up to a 2" exit pair. Costly though.

[wg_ski]

I looked long and hard at many coverage options for a conventionally-splayed array and found that the only thing that works is a narrow pattern with good control. Anything with too much coverage, too much overlap, or God forbid, different crossover frequencies between cabs is going to sound like Killer describes. I ended up with the HL4750 40x20 2" (and a bunch of extra mismatched 2" horns from failed experiments still sitting on a shelf). It does work, and comb filtering is not a problem in this arrangement. Too bad they don't make anything like this for a 1", but usually when you do this for anything serious, you want the output of a 2".

And I tried a 90x40 in the center cab (because I already had them) and no dice. They've gotta be uniform. And you need the mids to narrow down to about the same pattern by the time it hits the crossover frequency (read: horn).

[Sydney]

...Anyway, I'm looking for the best horn for splaying the cabs. ...
I suggest getting a copy of Meyer Sound Design Reference handbook:
It discusses directivity and pattern control and the pluses/minuses and issues involved with speaker configurations in pro sound.

[billfitzmaurice]

If that's truly a wretched and implausible idea (even a little),It is. Here's why:
http://homepage.mac.com/randyhyde/webster.cs.ucr.edu/AudioStuff/audioStuff.html

[madmallard]

but ''crossfired" is better?

[AMC]

It is. Here's why:
http://homepage.mac.com/randyhyde/webster.cs.ucr.edu/AudioStuff/audioStuff.html

So Bill, on your crossfireing horns, is it the proximity that keeps that from happening?

[PunkSweeper]

It is. Here's why:
http://homepage.mac.com/randyhyde/webster.cs.ucr.edu/AudioStuff/audioStuff.html

So are you saying crossfire or poles? Either way, what kind of lens?


Also, what's your opinion on these?
http://www.doctorproaudio.com/doctor/noticias/messe2006-funktion1.jpg
I'm not trying to challenge your statement on splaying, I'd just like to know if they could really perform as advertised. Supposedly each speaker has extremely tightly controlled directivity...

[Sydney]

Supposedly each speaker has extremely tightly controlled directivity... Definitely:
This is "an example" of placement considerations:
http://bobmccarthy.files.wordpress.com/2010/03/fig-9-21-design-ref-unc-pt-source1.png

[PunkSweeper]

Definitely:
This is "an example" of placement considerations:
http://bobmccarthy.files.wordpress.com/2010/03/fig-9-21-design-ref-unc-pt-source1.png

So if I could limit the dispersion of my theoretical caps to 90 degrees, then splay them by 90 degrees, I would have 180 degrees of coverage free of egregious lobing?

[Sydney]

That is the theoretical goal: Confine overlap areas to -6db down points of dispersion so that summation at intersection is flat.
Easier said than done: because uniform dispersion across the frequency spectrum is hard to maintain.
McCarthy lists the issues and gotchas for set up /Eq of this config, in detail in the Meyer Sound Design Reference Handbook

( That is a pic of a Meyer setup I fairly sure )

[PunkSweeper]

That is the theoretical goal: Confine overlap areas to -6db down points of dispersion so that summation at intersection is flat.
Easier said than done: because uniform dispersion across the frequency spectrum is hard to maintain.
McCarthy lists the issues and gotchas for set up /Eq of this config, in detail in the Meyer Sound Design Reference Handbook

( That is a pic of a Meyer setup I fairly sure )

It's a Funktion One rig.

Anyway, I'm for sure not going to get perfectly uniform coverage control with this project, not even down to where the woofer could sum without excessive lobing. Splaying is out.

I guess it's down to cross-firing or "stereo" pole mounting.

[Sydney]

It's a Funktion One rig.
I sit corrected :) ( There is a Meyer rig that looks strikingly similar ).
Again; McCarthy is very helpful in showing how to setup desired dispersion.

[billfitzmaurice]

but ''crossfired" is better?It is if you absolutely positively must horizontally array.

Also, what's your opinion on these?After attending a few hundred major venue concerts I can say that the worst line array I ever heard was better than the best cluster array. Horizontal arrays can work if they are imbued with the very high level of engineering epitomized by Don Keele's CBT. As of today they are unique. All other horizontal arrays are unfortunate compromises, because the individual elements don't have the same polar response across their entire bandwidth.

[PunkSweeper]

After attending a few hundred major venue concerts I can say that the worst line array I ever heard was better than the best cluster array. Horizontal arrays can work if they are imbued with the very high level of engineering epitomized by Don Keele's CBT. As of today they are unique. All other horizontal arrays are unfortunate compromises, because the individual elements don't have the same polar response across their entire bandwidth.


I thought you might say something like that. I was beginning to question what I've learned here as all I could find on them elsewhere was laymen's praise and jargon-laced tech explanations.


Right, then, what lens for pole mounting? CD? Conical perhaps? Waveguide or horn?

[Sydney]

I can say that the worst line array I ever heard was better than the best cluster array.
That's unfortunate...
I've heard some very good clusters and some very bad line arrays.
I'm thinking it has most to do with implementation/setup and operation with respect of the venue.

[killersoundz]

If you absolutely have to use a pair of mains together, how about sitting one upside down on the other?

[Sydney]

If you absolutely have to use a pair of mains together, how about sitting one upside down on the other?
I built 4 boxes ( ea w 12" & Horn ) with the intent of inverted pair stacking - WTTW and it works well.

[killersoundz]

I built 4 boxes ( ea w 12" & Horn ) with the intent of inverted pair stacking - WTTW and it works well.

Yeah I would think that would work OK, there would be vertical lobing but the horizontal response may be intact.

[Sydney]

there would be vertical lobing but the horizontal response may be intact. Yes: as happens when transducers are overlapped along a line; the desired effect is the main vertical beam tightens by 50%.
Since these speakers were to be played where the audience was not tiered ( as an auditorium/stadium or raked seating ) the dispersion worked fine.
Also they were for possible low ceiling venues.

[billfitzmaurice]

If you absolutely have to use a pair of mains together, how about sitting one upside down on the other?That's SOP. If you do want to widen the field you then rotate one out and one in. It's not perfect, but since the width of the radiating plane is half or less than that with splayed cabs it works much better than splaying.

[Sydney]

It's not perfect, Yeah, but what is. :).
( Perfection in sound reproduction is a human construct; how often has "Perfect Sound Forever!" been proclaimed )

[PunkSweeper]

So... what kind of lens for minimal beaming, wide dispersion (or not), crossover frequency and such?

[PunkSweeper]

Anyone? I like the idea of a round horn or waveguide...

[billfitzmaurice]

Anyone? I like the idea of a round horn or waveguide...
Why? Do you need the same dispersion on both planes? If not then you don't want a round horn. I can't recommend specific commercial horns because I don't use them.

[PunkSweeper]

Why? Do you need the same dispersion on both planes? If not then you don't want a round horn. I can't recommend specific commercial horns because I don't use them.

The matched dispersion pattern between the tweeter and "woofer" seems like a good idea. If not, I'm mainly looking to see what format of horn to put in this thing for consideration of wide, even coverage and crossover point.

[billfitzmaurice]

The matched dispersion pattern between the tweeter and "woofer" seems like a good idea.Not really. The last thing you want in pro sound is to send as much content at the ceiling and floor as you do into the audience. One of the purposes of a horn is pattern control, so that you don't do that. Obviously you can't effectively control the pattern of a direct radiating woofer, though having the baffle as narrow and tall as possible helps, as does using two smaller woofers vertically aligned rather than one larger one.

[Sydney]

So... what kind of lens for minimal beaming, wide dispersion (or not), crossover frequency and such?
As an operator you have to determine what dispersion is necessary for your needs.
Below is an illustration of a suggested general guideline for placing a typical 2 way box on a stick.

http://emusician.com/tutorials/Speaker-Placement-Fig-1.web.jpg

In this situation: the on-axis of the tweeter is aimed above in an attempt to get sound to the back, and prevent those in back from being in the acoustic shadow of those closer. Those closer hear less energy and are not blasted by being on-axis.
In a touring situation or a permanent install a different approach ( flown ) would implement a different dispersion and aiming strategy.
Sound isn't lighting but the goals are similar - controlled placement and dispersion.

[PunkSweeper]

Cool. I guess I'd use a CD horn of about 90x60 degrees as there would be DSP in the equation.

Thanks guys!