Portable multi-speaker wireless audio system for hall

Hello All,

We have various halls that we carry out school events in - our own, smallish, hall, the church hall across the road and another couple of locations scattered around central London. Our own main hall, used for assemblies and so on, has listed wooden panelling, so we can't mount speakers or start nailing cable all over the place. We currently use a trolly with a 19" rack-mount mixing deck, amplifier and CD player mounted in the front with a Bose 802 Series II speaker in the back. This proves adequate for our small assembly hall but can't really produce enough sound for the larger hall accross the road. The setup is also poving a bit unweildy as one large cabinet with all the equipment in takes a bit of moving, especially if we're trying to get it in to the minibus to drive it down the road somewhere.

We do have a second speaker, but getting that set up means setting up a stand, attaching the speaker and running cables back to the amplifier in the cabinet - not the quickest of jobs if you only have half an hour to set a hall up at short notice. I'm thinking of how to set up a system to replace/complement this setup that will produce decent sound (we don't require anything too fancy, just voice amplification for assemblies and the ability to play CDs/MP3s). Is the cheapest/best option therefore a bunch of guitar-practice style amps from Argos:

Buy 15W Practice Amp at Argos.co.uk - Your Online Shop for Musical accessories.

Strapped into a trolly each:

Buy Cookworks Solid Wood Kitchen Trolley with 2 Shelves at Argos.co.uk - Your Online Shop for Kitchen trolleys.

With decent castors added:

4 Heavy Duty Rubber Castor Caster Wheels Plate 100mm 4" | eBay

And then a wireless audio receiver connected to the input of each amp:

2.4GHz Wireless Audio Video AV Transmitter Receiver 4CH | eBay

With one transmitter transmitting from the mixing deck. This way, I figure I should be able to transmit a wireless audio signal to however many speakers we want, and all we have to do is find a mains socket for each speaker. Each speaker/trolly/wheels set would cost around £100, and we should be able to add as many as we like to cover whatever area we need with audio.

Does anybody have any comments, or a better way of going about this? Does anyone know if the wireless transmitters used will cause too much inteference with wireless networking? Do they work okay alongside wireless microphones, or do the two systems intefere with each other? Can I use two transmitters and transmit the left stereo audio signal on one and the right on the other, setting up speakers in appropriate places and getting proper stereo sound?

Nhrrrgghhh...

This will all be a bit "in most cases", but here goes...

The 802 is a good speaker (waits for cries of "they are Bose, they are cr@p"; they aren't), much better than the driver in that practice amp. 2.4gig will be pretty crowded, and you may have trouble with existing stuff, but probably not radio mics. Unless you have either cheap & nasty Argos systems, or the relatively new pro digital stuff.

The principle is fine; one transmitter, many receivers. Or two transmitters if you can select transmission frequency/channel. I'd give stereo a miss, no one will notice!

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Originally Posted by Andrew_C

The 802 is a good speaker (waits for cries of "they are Bose, they are cr@p"; they aren't), much better than the driver in that practice amp.

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We could, of course, buy a couple of amplifiers of some kind to fit in the bottom of a couple of those wooden trollies and power each of those speakers independently. Any idea what kind / model of amplifier I'd need to look for?

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2.4gig will be pretty crowded, and you may have trouble with existing stuff, but probably not radio mics. Unless you have either cheap & nasty Argos systems, or the relatively new pro digital stuff.

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We have a couple of Sennheiser FreePort wireless microphone units, which seem pretty decent.

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I'd give stereo a miss, no one will notice!

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Good point - this will mostly be used for amplifiing mono mics anyway, and I can't think offhand of any situation where I've ever needed different sounds coming from the left and right speakers.

Sorry for jumping off your idea but have you considered a portable PA system? I have had a Phonic one - Portable PA :: RoadGear 260 Plus - Phonic | Manufacturing Quality Professional Audio Equipment since 1977 in the past (not quite that model but similar), yes its got separate speakers but it was portable and with a zip up back with a mic stand, 2 speaker stands and cables it worked well. The unit has a store in the back for Mics and small leads as well. Would that possibly work, it certainly didn't take more than 5 minutes to setup each time I used it.

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Originally Posted by john

have you considered a portable PA system?

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It's a good idea, but I'm not sure how expandable it would be - we want enough speakers to cover the spaces we use, and I was thinking maybe half-a-dozen of those guitar amps should just about do it. When we use a single speaker at the front on the stage in the hall next door at the moment the sound just gets totally lost beyond the first couple of rows of the audience - we would seem to need a fair few speakers around the room.

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Originally Posted by dhicks

We could, of course, buy a couple of amplifiers of some kind to fit in the bottom of a couple of those wooden trollies and power each of those speakers independently. Any idea what kind / model of amplifier I'd need to look for?

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Mono amp of some sort wouldn't be a problem, ISTR the 802 is good for 200+ watts continuous. Much more that you'd need for your application. However, there is a fly in the ointment. You need the Bose system controller to equalise the system. It might be possible to have this at your transmitter, but that would preclude mixing other speakers into the system.

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Originally Posted by dhicks

When we use a single speaker at the front on the stage in the hall next door at the moment the sound just gets totally lost beyond the first couple of rows of the audience

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What you need is height. Get the cabs up above the heads of the front rows. If there is a very reflective back wall, get them up, but tilted down. Think of trying to light just the tops of peoples' heads. You can get clever stand-top angle adjuster thingies. I'll try to find a link.

Edit - Studiospares

A lot of your problems seem to stem from manglements belief that this sort of thing just happens. You probably know that it would work better with dedicated support for presentations/theatre/music etc...

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Originally Posted by Andrew_C

You need the Bose system controller to equalise the system.

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I'm not exactly sure what that means - do we need a Bose 802 series II controller if we want to connect more than one speaker to the system? What, exactly, is an equalised system? At the moment, we seem to have a Denon 231 Graphic Equalizer and a QSC Audio RMX 850 Amplifier, no Bose controller involved - this kit was all put together by someone with rather more knowledge of audio equipment than me, so he could well have figured out some cunning way of getting around having to have a Bose controller.

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What you need is height.

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Indeed - and we have a couple of stands, but they take a while to get anywhere and get set up. I was hoping to get something sorted that would look a little more discreet and avoid having cables all over the place.

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Originally Posted by dhicks

all put together by someone with rather more knowledge of audio equipment than me,

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...but not very much!

OK, I'll try to keep this brief. The traditional way to design a speaker is to make a box about the size you want, put drivers in that will make it loud enough, and cut some ports. Listen to it, and then change the size of the box a bit, and cut different ports, [loop until sounds right]

Bose on the other hand, made a plastic box, put 8 drivers in, analysed the sound, and then tweeked the input electronically until it sounded right. They then built a box with the electronics in to replicate this tweeking that is sold with every pair of 802s (and a different one with the smaller 402s). Without this box, I'd lay good money on the system not being right, especially as the graphic (which might once have done this task, but I doubt it) will have been fiddled with at some point. You need the system controller with ONE 802, and believe me, there will be a huge improvement in quality if you use one.

Not using stands for aesthetic reasons is a mugs game. I fully understand that you are tying to streamline a chore, but you are going to struggle unless you get the boxes up.

I can vouch for 802s without controllers, we have a pair at work and no-one bought the controller, yes you can drive them but the sound is mush, you really do need the controller if you want quality and decent sound from them. We have sidelined them now for spares and had fitted a big AV system in our hall including some big EV speakers fitted to the RSJs in the roof which sound 100x better.

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Originally Posted by john

I can vouch for 802s without controllers, we have a pair at work and no-one bought the controller, yes you can drive them but the sound is mush, you really do need the controller if you want quality and decent sound from them.

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Ah, this explains the recent problem we had trying to show a DVD, then - you could hear the speakers, you just couldn't understand what people were saying on the screen. I'm sure that when originally set up the graphic equalizer was properly configured and so on but tinkering little fingers have since fiddled around with it.

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Originally Posted by Andrew_C

OK, I'll try to keep this brief.

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Many thanks - your explanation finally makes it clear just what was going wrong with our sound system. Right, next obvious question, then: anyone any idea where I get a Bose 802c Series II controller from? Am I right in thinking these things date from the mid 1990s? And that the original Bose 802 speaker dates from around 1980 (just from the search results that come up on eBay)? The current Series III speakers seem to be designed for "medium sized clubs, halls and outside locations" according to the Bose website, so they certainly sound like they should be able to handle a school assembly.

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Not using stands for aesthetic reasons is a mugs game. I fully understand that you are tying to streamline a chore, but you are going to struggle unless you get the boxes up.

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Unfortunatly, we are very limited on space here, so having equipment up on stands might not be practical - we often have football and so forth in the hall right after assembly is finished. You're right, though, that's probably most of the problem - we'll have to get a system organised to get the speakers up on stands properly when needed.

Certainly loud enough for you. I'd watch Fleabay, Bonza (although they seem to have stagnated), Bazza'a bazaar or even the likes of Stage Electrics and AC Lighting. The later would be expensive, but, and I'm guessing a bit, that they may still be available new.

The older ones come up on eBay from time to time, I was told one for our system came up for £200 or so a few years ago but no-one could find the cash to buy it at the time, if we used ours often I would be hunting for one. People like Stage Electrics maybe worth dropping a mail to they may have an old one that is not often hired and may sell it for the right £ instead though? Maybe also looking at Audio Hire places they again might have a spare to sell or consider selling to give funds for a newer better rig

I simply use two of these for our Sports hall (which is slightly longer then a full basket ball court 30/35m deep). On custom trollys our DT Dept Made (which are just a square cut out of wood with a bump which is stand size.) We then run 2 Jack leads back to the Amp which is in a flight case although its slightly smaller then that and also has rack mounted wireless JTS microphone receivers. Works well and never had any problems with the sound not being loud enough.

You can also daisy chain speakers. Our student technicians (aswe make the kids setup :)) can set everything up including laptops/projectors in about 5 mins.

EDIT: we angle the speakers up rather then put on stands. Also stops the kids at the front being deafend.