New audio system funding awarded - opinions needed!

Thanks. I've been in contact with both and have a meeting/consultation tomorrow. I fully appreciate and understand your points, Brad, and am going into this full well knowing that everything will not be apples to apples, but I feel as if I have enough mind awareness to evaluate each bid in its own sense. That's where, to me, communication with each company will be just as important as the numbers and specs they provide. Our first estimate was designed and run through EASE, and I was shown documentation on the results. However, the others will be comparative not so much to that original but how it finds into our hopes for the system.
 
I wasn't clear about that: as you surmised Brad it isn't a true L/C/R system. Originally what had me confused is the first company we had out spoke about it quite a bit about providing an L/C/R system but then they ultimately designed a system with L/C/R speaker locations. Ultimately, we are spec'ing a system that provides uniform coverage across the seating area through a range of frequencies. To keep infrastructure costs items similar, we did mention to bidders that have come in thus far that any needed electrical work and modifications/removal of any sound panels above the stage (if obscuring a rig location for the speakers) would be taken care of by the district. To keep another constant, we gave each the same budget and our overall goals with the system.

So far, we've had two companies come in to provide a system bid, and it hasn't been apples-to-apples which has me excited: the first suggested single cabinet fills mounted on the proscenium wall L and R and two center mains. They also spec'd two subs on either side of the proscenium (on the deck). All cabinets/subs are EAW. The other is looking at a small line array (not a true but curvilivear) L and R rigged from the roof truss - likely 3-4 cabinets per side (spec'd JBL) with a flown sub on each side as well.

I know it's generally better to have the amp rack backstage closer to speakers; however, ours is current in the sound booth in the BOH (it has been since the auditorium's construction in '91). One company spec'd to move the rack backstage while the other didn't mention it. I'd like to get thoughts on this difference and any long-term concerns.

Also, we're switching our monitor outputs from 1/4" to speakON and with that means I'm going to pick up new cables. Is it generally recommended to just go 12 ga. instead of 16?
 
So far, we've had two companies come in to provide a system bid, and it hasn't been apples-to-apples which has me excited: the first suggested single cabinet fills mounted on the proscenium wall L and R and two center mains. They also spec'd two subs on either side of the proscenium (on the deck). All cabinets/subs are EAW. The other is looking at a small line array (not a true but curvilivear) L and R rigged from the roof truss - likely 3-4 cabinets per side (spec'd JBL) with a flown sub on each side as well.
A center array versus split left/right seems to go right to the heart of the intelligibility versus localization/'space' argument. Typically a center array would be expected to result in better intelligibility for spoken word and vocals, but be more limited in supporting 'space' for music playback and performances. Neither is right nor wrong, just emphasizing two different aspects that may be involved and you may have to decide which is more important to you.

Any explanation for the ground stacked subs proposed? I'm sure it saves some money but it also means dealing with level variations throughout the listener area and issues with time algining to the mains. If they claim added output due to boundary loading for ground stacked subs you might want to ask them what boundary that is since the listeners already occupy the floor and thus already get the advantage of that boundary (which can't be counted twice, the laws of superposition). It's probably mostly a cost issue so probably more important for you to understand the tradeoffs involved. You might also ask about potential 'power alley' with a mono system and split left/right subs and if that was considered.

I know it's generally better to have the amp rack backstage closer to speakers; however, ours is current in the sound booth in the BOH (it has been since the auditorium's construction in '91). One company spec'd to move the rack backstage while the other didn't mention it. I'd like to get thoughts on this difference and any long-term concerns.
The main advantage is limiting the speaker level lengths to minimize losses. But this is also an area where the existing infrastructure can matter as relocating system DSP and amplifiers can potentially require conduit and power changes that may not justify the potential benefit.
 
Update: we received full funding from a grant I'd written ($7,000) for the system so we're now at a budget of $34,000 (minimum) and possibly up to $38,000. I'll know this more within the next two months (another grant in the works for early January).

You're insight is invaluable Brad. The second bid which quoted the flown subs made mention of what you were touching on with regards to level variations and the models he suggested would result in a lobe on stage where not as much low frequencies from the subs would be directed which made sense to me. The bid involving the ground-based sub on each side didn't mention this at all. Plus, being a typical community PAC, I was worried about them being vulnerable sitting on the floor when students are in there frequently.
 
For the record: Long speaker cables have a number of disadvantages:
  • Voltage drop - the longer the run, the more you have to overspecify the cables; copper is both heavy and ...
  • Price - ...really, really expensive
  • Damping factor - on your subs, especially, you want as little copper as possible between the amp and the speaker; this is why powered subs are popular; we're talking "under 6 ft".
  • DC resistance - on the speaker cables, driving 8 or even 4 ohm loads, this is a much higher percentage of the total complex impedance than it is on line level connections. (And yes, this is the source of the above-mentioned voltage drop, but it has more than one effect.)
  • Inductance - longer cables will also tend to round off higher frequencies, though I don't remember whether this comes down far enough to affect audio, and especially power-level audio. This article points out that in power cabling, it's more the magnetic field generated that's the issue.
There are tradeoffs through the entire process, and as Brad points, out, experience in knowing which ones are best to make is important.
 
Thanks. The design we went with has all powered speakers and subs which is will eliminate those concerns. The four monitor feeds will have the longer run yet between amps in the booth and monitors themselves, but we've never had issues to this point with our single monitor feed, so I feel fine with that.
 

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