Speaker Distance/Quantity in Ballroom Used for Events/Big Parties

[Ghost Pepper]

We are trying to convert an old barn into a nice ballroom for events like weddings and big parties where there is a need for loud music. The ballroom is 75' x 40' x 13.5', flat ceiling. I need to make sure the sound system gets loud enough (without distortion). My idea was having 18 cabinet bookshelf speakers suspended (professionally) from the ceiling: 6 rows with 3 in each row, where all edge speakers are about 10 feet from the walls, and speakers are 10 feet away from each other. Speakers have sensitivity 88 dB and the amp pushes out 65 watts RMS to each speaker. Do you think think this is enough speakers for loud events with maybe 200-250 people? What do you suggest?

Also, for outside the ballroom, on two sides (a 75' foot side and a 40' side), I want to put outdoor speakers slightly below the roof. I was also thinking of having speakers be 10' apart. These outdoor speakers also have sensitivity 88 dB and I'll be using the same type of amp, which will push 65 watts RMS to each speaker. We won't have the outdoor speakers be on late (maybe 8 pm), but when they are on, we are hoping to achieve a loud, outdoor party-type environment for about 200-250 people total. Same questions as before: Do you think think this is enough speakers for loud events with maybe 200-250 people? What do you suggest?

Note: speakers will only be used for music, specifically for big events like weddings, exc.

Note: all speakers will be playing in mono (not stereo).

Also, to make it clear: this is a very rural, spaced out area, so there is no big worry about disturbing the neighbors (they are about 1/2 mile away).

 

[Ghost Pepper]

Sorry, I should have made it clear: the speakers will be about 13 feet above the floor in both the inside and outside situations.

 

[TLS Guy]

Really this is beyond the scope of this forum. That installation needs pro gear with pro
installation.

You really need a cinema installation. Your idea is a total mess and will be awash in time delay interference. You can only use that type of distributed system for low volume voice PA applications.

You need the stage flanked with two powerful biamped speakers and four powerful amps. JBL pro cinema speakers with large 15" drivers bi-amped to sectoral horns via active crossovers for the top end is what you need.

 

[Ghost Pepper]

I was hoping that using the minidsp ddrc-88a to put the 15 indoor speakers into 3 zones (left, right, middle) and hopefully be able to correct the time delays using just 3 zones. Do you think this is unachievable?

Also, for outdoor speakers, since there are no walls or ceilings outside and all the speakers are at the same height, do you think atleast the outdoor speakers will not have time delay issues?

 

[WaynePflughaupt]

Just to reinforce what TLS said, I used to work for a large pro-audio company, and the only time we installed a distributed system like this was for situations where the client was trying to keep volumes fairly low – a church for instance. And each zone (front to back) was properly delayed relative to the stage.

Which brings up an important point: Naturally, in a live performance setting, the point of reference for setting up the delay zones is the stage, where the orator or performers are. In a background-music situation like yours, there is no readily-defined reference point.

This whole project seems poorly-conceived. For instance, if the speakers are 13 ft. off the ground, they don’t need to be a mere 10 ft. apart. It almost sounds like you’re going to have the speakers pointing straight down at the floor. Even if that is the intent, which is silly to begin with, you won’t need that many speakers.

I was in an American Eagle Outfitters store a few weeks ago, and they had music playing from some mid-sized JBL speakers (I’m guessing maybe 6-1/2” woofers) mounted on the walls around the store, maybe 9 ft. off the floor, and I’d estimate they had about 8 speakers in the store. They covered the sales floor well, and I didn’t really notice any delay issues. To be fair, I wasn’t really listening for that, but I think I would have noticed if it had been obvious. Just going by memory, I’d say the store size was about 50’ x 65’. So really, I can’t imagine a scenario where you’d need 15 speakers for a room the size of yours.

You should probably reconsider your speaker choice too. Several fairly-insensitive speakers (by pro-audio standards) getting 65 watts may or may not get the “loud” levels you’re looking for indoors. Your 65 watts will go a lot further with some commercial speakers with sensitivity in the 95 dB range or higher.

And certainly, a mere pair of 88 dB-sensitivity speakers @ 65 watts outdoors isn’t going to get anything resembling loud. As far as delay for outdoor speakers, as long as the indoor speakers can’t be heard outside , it won’t be an issue.

Regards,
Wayne A. Pflughaupt

 

[TLS Guy]

The inside and outside situations are totally different.

I have built these systems previously. To create that live event atmosphere you are wanting with lots of volume, you need just two powerful speakers, driven with lots of power. Crossover should be active.

For the outside a low power system is what you need. You will not be popular if you build a loud outside system.
Powerful bass carries a long way. (Miles). So for the outside a low power distributed system is a good way to go.

When you talk of zones, I suspect you are thinking of doing this with a domestic receiver. That is a total non starter.