Portable Speaker Configuration

[jdcountryboy91]

I run 4 Renkus Heinz tops, 2 per side. In a venue that does not require both speakers on a side to achieve proper coverage, I have thought about splitting the band and vocals up and assigning each to separate speakers to improve clarity and intelligibility. Is this really the case?

To achieve this configuration on an M7CL, I would assign vocals to one matrix and band to another and assign the matrices to separate outputs. Correct?

Thanks!

[Josh Scott]

Or depending on what you want, run the board LR mono, LR for the band and a Mono signal for the Vocals might be a little more user friendly

I would turn off two of the speakers and try that first to make sure you have enough coverage and spl

[Brad Weber]

The concept of an A/B or dual system was popularized by Dave Rat at Rat Sound and is pretty well proven. The basic concept is to reduce Intermodulation Distortion, the distortion caused when a speaker cone trying to vibrate smaller amounts quickly at a higher frequency may also be moving larger amounts at slower speeds for lower frequencies. Another factor would be a cone already at maximum excursion from one driving frequency trying to move further due to another driving frequency. These factors are most noticeable when driving a speaker system right to the edge and when using a speaker where a single driver (especially a direct radiating cone) covers a wide frequency range

If you have the equipment and an appropriate application then why not try it and judge for yourself?

[jdcountryboy91]

Thanks for the replies!

Josh, That does sound a lot easier than my idea. That is probably how I will end up running it.

Brad, Thanks for putting a name to it and explaining the concept. I will try it out when I can and report back.

[Josh Scott]

Here is Dave Rat said about it on another forum

Hello hello audio friends!

I just read through all the posts and will try and clarify some.

The double hung V-Dosc PA was two clusters per side hung as close as we could get them. Due to a follow spot truss needing to fit between the clusters for space reasons, the gap between the clusters was about three feet. There were a few outdoor shows that we were able to hang the clusters closer.

The reason for getting the clusters close together is that it is very important that both clusters have as close to identical coverage patterns as possible. Otherwise sections of the audience will not get a balanced mix.

There was a small center hang of dV-Dosc that was fed from a separate matrix and was primarily a vocal fill. For some larger shows we split that center dV cluster into two separate clusters, to mirror a mono version of the main PA.

Battling the negative artifacts of IM distortion turned out to be the most noticeable advantage of the double hung PA. Another advantage was being able to increase the system size without increasing the trim height. The HAAS effect was audible from the mix position (150 to 200 feet) but not as much so with a full band as it was with just two instruments. There is one jam that is only bass and guitar and Flea and John play back and forth. Since I could easily move any instrument to either PA, during that song I put Flea's bass in one PA and John's guitar in the other. The effect was quite audible and sounded awesome, it added a new separation between the instruments even with the HF sections about 8 feet apart and I am 200 feet away.

Going further into moving instruments between the PA's, since I could move things so easily, it was very simple to demonstrate the sonic advantage of the double hung system in real time during the show. I could start a song with everything in the outer, and one by one, slide instruments to the inner system, while listening to the variations. I settled on Kick, Snare and Vocals on the inner and everything else on the outer.

I considered the possibility of using dissimilar systems for the multi hung systems. I.E. V-Dosc for instruments and Kudo for vocals. The issue is that it is almost impossible for the different system types to have precisely the same coverage patterns both vertically and horizontally. Size differentials and the sheer complexity of trying form and tune to nonidentical arrays to act identically is a task beyond the scope of what I was willing to attempt.

The goal was to create a simple repeatable way to improve the sonic experience for the majority of the attendees.

As far as costs, it was not really that much of a budget increase in the big picture of a rock tour. Especially considering that lighting and video budgets so often dwarf the sound budget on modern rock tours. Is it not time that sound stepped up and brought something new to the table? The lighting and video designers pitch their custom designs to the band for approval, not sure how or why the sound humans seem to have missed that boat on most tours and just run with a stereo rig and enough boxes to cover.

That said, I was approached by the band management wanting to drop the double hung PA after the second tour leg. Fortunately I was able to demonstrate it's sonic advantages to the band manager while he stood next to me during a show, he heard the difference and I got to keep the dual rig. I must admit, that was easily the best sounding and most fun PA to mix on I have ever used.

One thing to be aware of is he needed as close to identical coverage as he could get from both PAs.

[ServantForLife]

A word of warning on doing the dual hang, or in your case dual stack. Dave's rig was perfectly hung side by side using the best designed PA in the industry. Stacked PA will not have the same result and you could actual cause more comb filtering due to the interaction of the speaker cabinets. Watch your physical alignment of the speakers and do a test run before trying it during the service.

[jdcountryboy91]

My PA is on speaker stands two boxes per side shoved right beside each other. They are 60 degree boxes so in a wide venue I have them turned to achieve 120 degrees of coverage per side. For this I will have them pointed in the same direction. I will definitely try it out before a service though.

Thanks again for the tips.

[Brad Weber]

Originally Posted by ServantForLife

A word of warning on doing the dual hang, or in your case dual stack. Dave's rig was perfectly hung side by side using the best designed PA in the industry. Stacked PA will not have the same result and you could actual cause more comb filtering due to the interaction of the speaker cabinets. Watch your physical alignment of the speakers and do a test run before trying it during the service.

Typically the major problems with combfiltering result from having the same content coming from multiple sources. The concept here is actually to have different content run to each source (speaker). While the speakers will still interact, with different content in each the result is not necessarily that different than the interaction you might experience naturally from two instruments some distance apart on stage.

It may also be relevant to note that during a discussion of the dual PA concept Dave Rat commented "It is important to keep in mind that the dual PA primarily deals with IM distortion issues. IM distortion issues are less of an issue in horn loaded PA systems and less of a factor at lower volumes." A system with one R-H box per 'channel' and possibly not being pushed hard may not benefit as much from the dual PA concept as the large scale line array, need every dB systems to which Dave and other have applied the concept. But if you already have everything needed to do it then try it and please let us know how it turns out.

[pdc]

We were doing this long before DR was doing it.

If you look back through the articles of Mix Magazine back in the 80s, you will find some successful arena tours, Brian Adams IIRC, were doing this with horizontal arrays (EAW KF850s, etc).

Back in the day, we were doing surround mixes as well, with reverbs, delays and pans surrounding the audience. But, those were days when it was about the production and not the buck or the venue aesthetics.

Something similar but different: If you go back and read about the "wall of sound" popularized by The Greatful Dead, you will find something similar. Basically, each member had a pa, and the pa was chosen to match the instrument or voice, and it was controlled by the musos themselves. There really is no phantom stereo image, but their set up was as close as you could get.

[pdc]

Originally Posted by ServantForLife

A word of warning on doing the dual hang, or in your case dual stack. Dave's rig was perfectly hung side by side using the best designed PA in the industry. Stacked PA will not have the same result and you could actual cause more comb filtering due to the interaction of the speaker cabinets. Watch your physical alignment of the speakers and do a test run before trying it during the service.

As others have stated, comb filtering is not an issue because each speaker is reproducing different signals. One is vocal, one is instrumentation. You can even get creative in this set up, spacing the vocal speakers closer together if needed. If I had a small venue, like a REALLY small venue, and my stage was only 10' wide, I would go for it and try to get a phantom image. It would only work for the people at the top of my equilateral triangle, but it would be cool to try.

As far as the whole horn loading thing goes....that should be taken with a grain of salt. Topologies can be misapplied and do not necessarily ensure a level of performance.