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[Scott Van Den Elzen]

There was a post not too long ago about how Rat Sound is hanging a separate array on the RHCP tour for vocals, which allows for more clarity by not forcing the same cabs to produce too many simultaneous frequencies.  (Correct me if I'm not summarizing that correctly.)

So...  I'm wondering about that...  do the two arrays interfere with one another where frequencies overlap?  How would you avoid that?  For example, lets say a guitar part has a lot of 600Hz.  At the same time, the vocal part hits a note right around there.  Will there be cancellation and summation issues in the room as a result?  Can someone help me understand why or why not?

I have 4 Yamaha Club V tops, (usually only use two, except some wide outdoor venues) and enough processing and power to run my vocals separately, and put one set of tops inside, and one set outside, or one on top upside-down.  I guess it would be kinda like "aux fed vocals."  This all has me sort of curious.  Does anyone think it would be worth the extra effort to try this out?  Has anyone here tried it with a smallish system?

[Bennett Prescott]

Scott,

The problem with two separate arrays is only if you're running identical (or near identical) source material through them. Since Dave is using them for different stuff, no big deal, and the advantage of having each array work half as hard is no doubt significant.

While the two arrays will still interfere with each other on the occasions that they're both produce identical amounts of, say, 400Hz, this is much less destructive and much more pleasing to the ear than conventional box overlap phase issues.

[Mike Summa]

Scott Van Den Elzen wrote on Wed, 02 May 2007 22:42

There was a post not too long ago about how Rat Sound is hanging a separate array on the RHCP tour for vocals, which allows for more clarity by not forcing the same cabs to produce too many simultaneous frequencies.  (Correct me if I'm not summarizing that correctly.)

Kind of reminds me of the Wall of Sound.

[Scott Van Den Elzen]

Bennett Prescott wrote on Wed, 02 May 2007 20:47

While the two arrays will still interfere with each other on the occasions that they're both produce identical amounts of, say, 400Hz, this is much less destructive and much more pleasing to the ear than conventional box overlap phase issues.

Are you saying that it works better specifically because it's arrays, or just because the program material is different?  

So, if I understand the premise correctly, on the upside...  reducing the complexity of the signal by splitting to two boxes means more headroom and less distortion.  on the downside...  when there is occasionally overlap in the program material, there can be detrimental interference between the boxes.  That about right?

It seems like, if you're NOT saying that this works better with arrays than trap boxes, I might find some reasonable benefit to flipping one set of tops upside-down on top the other (reducinging interference concerns) and running vox through one and the rest through the other.

I may have to do some experimenting.  It might enable me to cover more people with my existing rig, and it could certainly improve clarity, especially vocals.

[Bennett Prescott]

Nooow you've gone and done it.

[Scott Deeter]

Bennett Prescott wrote on Thu, 03 May 2007 00:21

Nooow you've gone and done it.

Guess your along for another ride Bennett
I'll be watching from "behind" the railing......again also.

[Bennett Prescott]

Scott, sorry, I didn't mean to imply that there would be any difference in how this works between a line array and a trap array, although getting two full trap arrays per side aimed and flown would be quite a pain for any large audience.

The long and short of it is, if you can afford to carry twice the PA to every show, there are definite sound quality advantages to using one only for vocals. The interference that you will get is almost nonexistant compared to what exists when running identical signal to two overlapping speakers not designed for it (say, two generic 15"x2" arrayed flat) and I talk about it more as a textbook case so nobody thinks it goes away. It exists in the same way that any two sources reproducing the same frequency separated by more than a half wavelength or so will interfere... since the source material will be different between the two, however, the interference will be constantly changing and audibly insignificant, especially compared to the benefits of running the second PA.

[Justice C. Bigler]

Here is the blog post in which Dave talks about what he sends to each array:

Dual PA

I was at the RHCP show in Oklahoma City, but I can't really comment about how it sounded because I was off the stage right, listening to the side fills. Damn security wouldn't let me hang out at FOH while the show was running!  

From where I was sitting, I couldn't hear the vocals very well, everything else sounded all right, but the vocals were pretty muddy from where I was.

Dave is also using a sub set up which he calls "Sub Cannons" which you can find HERE

EDIT: Here's the blog posts where Dave talks about setting this rig up and why he think it works better:

Dual PA 1
Dual PA 2

I'm not sure that you would get any practical benefit to using this set up with any but the biggest systems, in the biggest venues, at very high SPL levels.

[Scott Deeter]

Scott Van Den Elzen wrote on Thu, 03 May 2007 00:21

I may have to do some experimenting.  It might enable me to cover more people with my existing rig, and it could certainly improve clarity, especially vocals.

Bennett Prescott wrote on Thu, 03 May 2007 00:26

The long and short of it is, if you can afford to carry twice the PA to every show, there are definite sound quality advantages to using one only for vocals.

Sorry, I feel the urge to add a thought on this now. Could it be possible you wouldn't need "twice" the PA. My thinking is using a 3-way Full range cab (maybe Bi-Amped) with no subs for vocals only, and maybe a 2-way mid/hi box with subs for the music/instument part?

[Bennett Prescott]

Sure, it all depends on how hard you're going to be working it. I do some shows in a venue with an installed LCR system, and I always use the center box for vocals and the outside two for instruments. They all cover the venue well, but my "vocals PA" is obviously half as much as my "everything else PA". As long as it's appropriate for your needs that won't be a problem.