Buying advice. PA system

[jackoneil]

hi all;

I need to choose a sound system for a large room, approximately the size of a tennis court.
It has high ceilings and this room is goin to be used for multiple purposes, like for conferences, meetings, small movie show, mainly presentations.
The sound system should be able to ;
· Accept inputs for wired (atleast 4 ) and wireless mics (atleast 4 ) .

· Accept inputs from DVD, usb, computer, iphone

· Multiple Speakers shall be mounted on side walls top high.

(is there a way I can control the volume of different speakers. I mean what if I want to increase the volume of front speakers and lower the volume of back ones. )

· Plus , an audio conference mic system. Where multiple people will talk by having a PUSH to talk gooseneck kinda mic on their table. this conference mic system should be able to connect to the room PA system and produce sound through the room speakers.

Your help will be highly appreciated.

Thanks
jack

 

[turk 182]

don't know what's available to you where you are but most major brands like Yamaha,Sennheiser, Toa have all the bits and pieces you'll need. conference mic systems,zone page mixer amps and tailored speaker systems.

 

[bear]

Jack, what you describe is a job for a professional company that does this sort of work.

One of your big problems will be controlling feedback from those conference mics (not so simple a job) and reverberation in your room.

This is not an inexpensive installation, as you describe it.

 

[jackoneil]

turk ;
my main objective is to;

a) have multiple speakers distributed evenly in room. (instead of just 2 speakers)
b) volume control of those speakers .In case of active/powered speakers that can be done form the speaker box too. (hope i am right)

To connect more than 2 till 8/10 speakers , i've found this option so far; "Constant Voltage" as described by ENZO in this thread...
http://www.diyaudio.com/forums/pa-systems/201926-connecting-8-speakers.html

I didn't find anything of this sort offered by big brands like Peavy , bheriger, yamaha etc.
can you give me some links if they have products which are able to connect multiple speakers.

BEar ;
exactly. feeback would be big trouble to shoot. so lets drop the idea of conference mic system 🙂 as its expensive too.

 

[turk 182]

some of the "brands" you mentioned certainly won't have what your looking for.
but with the ones i mentioned they most certainly have multiple zone control/multi speaker stuff.
so no conference system? will there still be any open microphones involved?
a 70v line distribution system can serve you well it just means having to go to the individual speakers to adjust the volume or run more wire/cable to centralize controls.
so there's really no budget behind this is there? which means low quality mic's and an inexpensive mixer and certainly no thought to acoustic treatment of the space.
i hope you have quick reflexes as that's probably the only means of "feedback control" your going to end up with on a low budget.

 

[dprimary]

Can you get us dimensions of the room>

 

[chrispenycate]

i hope you have quick reflexes as that's probably the only means of "feedback control" your you're going to end up with on a low budget.

How about a Behringer FBQ 100 Shark?


Ouch - your 'tennis court' reference reminded me of an actual tennis dome, inflated, so reflective plastic concave sides all around focusing in the audio, where I was expected to amplify chamber music, composed forsmall, intimate spaces, and comprehensible speech from certain who already contained enough alcohol that face to face comprehensibility was quite low (but fortunately for people who'd already indulged, and weren't that critical about what was being said. All quite irrelevant to the subject, and anyway it was quite a lot bigger, containing the bleachers.

No need to scrap conference mics - if you can pick them up cheap, which you should be able to. The problem is that the on button can have different logics, some being straight toggle (in which case the sound technician needs an overall deselect button for all the representatives who proudly sit down to applause after their speech, invariably forgetting to turn their mic off. Or else it can be push to talk, non-latching - generally for communications mics, as speakers need one hand for their notes, and the other to gesture, and yet another to change slides on the power-point. I've added foot switches in the past. Then there are the ones where an impulse switch only comes out to a pair of contacts, for remote controlling an external system - flexible, but requires more wires than a simple XLR twinscreened. If we now set the impedance of this mic at, say, two kilohms (with series resistors), and feed into a relatively high impedance mic preamp, each time a new mic is added it reduces the gain of all the others, so reducing the risk of feedback. Obviously, if the mic is open circuited at source there's a lot of unterminated cable picking up interference, but the cabling is balanced so most of it will be cancelled out (hopefully). Obviously, switching close to the mic input is better, and this will not be as effective as a true automated conference mixer, but it doesn't cost the same, either.

Personally, when it comes to speech comprehension, I'm not that enthusiastic about distributed sources. With the delays from different speakers you rapidly hit the 'railway station effect' (that's from my youth - it might be airports, now) where you know perfectly well that the person is talking, but have no idea about what. I much prefer a central cluster or, if there is a fixed stage or podium (in the side towards the projection screen) a cluster of fairly directional speakers over this (which also helps with feedback, although you might find yourself needing a pair of little monitor speakers as fill in for the front rows). There are numerous distribution amps that can set the levels of your individual channels - I myself carry a Behringer 1u line amp that gives individual outputs from a mono in, or six inputs to a general out. Only six levels, but it has sufficed up to now. Or, if you're not into balanced line (and I know a number of low budget projects aren't) but do want to keep stereo routing (I suppose some presentations will have stereo music important enough to maintain, but this feels more like a monophonic project) then look at headphone distribution preamps - designed to run a few dBs hotter than line amps, but essentially compatible. Since this is a diy forum I'm tempted to draw you the plans for a routing matrix, complete with switchable crossovers for sub-woofer signals, but I suspect you're not that happy with drill and soldering iron🙂.

100 volt line amps nearly always have output transformers. There's no need for this - transistors running at 600 volts (300 for bridge, only about 200 for Stateside 70 volts and bridge) are easy to find, but it seems traditional, and not only does this make the amps heavy - even an advantage in an installation system - it makes them expensive. Decent high power audio transformers can not be made on the cheap. Which means few amplifiers, and individual power set by taps on the matching transformer in the speaker, involving ladders and sacks full of straw simulating human absorbers. Active loudspeakers mean the level can be tweaked from the mixing point, although power wiring as well as signal wiring needs to be installed.

Oh, I've gone beyond the reasonable. Acoustic treatment can make a major difference, and doesn't need to be expensive (except in man hours), I'd consider an inductive loop for those with hearing aids, you only need bass frequencies for music and programs about earthquakes, if the films you're showing are in 5.1 you're going to complicate your system wiring considerably, if - OK, OK, I'm leaving - you need more infoooor…

 

[bear]

chrispenycate, I think ur being a bit optimistic about your suggested approach.

without a LOT of more information, nothing that anyone says no matter how expert the person amounts to more than random speculation.

_-_-

 

[jackoneil]

well;
the room has the official capacity of 150 people. but we recently had it filled with 200 people , by squeezing chairs close to each other.

any help is appreciated.

thanks

 

[Wwan]

Hi mate. Get a mixer with 24 inputs, preferably digital type and you can grow from there. Full small band with drum mic in say 10 to 15 inputs but i doubt you are going for that. Normally digital mixer have 8 to 16 outputs so enough to serve many foyer even in the toilet.

Our church serves max 180 and full band max 12 ppl and aux inputs for dvd, cd, computer,ipod etc. We use Behringer x32(in). Cheap and good. Ho have a read and know what the mixer can do. It is the heart of PA system.