HilcrRWise Posted January 9, 2012 Share Posted January 9, 2012 I have been asked to spec a sound system for our school dining room area to include CD playback and a radio mic. It doesn't have to be deafeningly loud, but it will need to be loud enough to be heard over the top of 400 or so chattering pupils. As always being a school it will need to cost as little as possible (prefereably under £2,000). Currently I have come up with the following, could you please have a look and let me know what you think or if you have any alternative suggestions (in particular if you think it will be loud enough for our requirements. I have attached a plan of the area with some room sizes, aswell as a couple of pictures to give you a better idea. 1 x Rackz Drop Down Wall Rack1 x Add on 2U Brackets for Rackz Drop Down Rack1 x Monacor PA-6600 600W 6 Zone (100W per zone) Mixer Amplifier1 x Monacor PA-1130RCD Tuner/CD module for PA-66001 x Trantec S4.16 Handheld Radio Mic1 x 19" 1U Rack Tray for Trantec S4.162 x Kramer SPKIO608 80W (120W Max) In Wall Speakers (Pair)1 x Kramer SPKOC608 80W (120W Max) On Wall Speakers (Pair) The In Wall speakers will be mounted where the yellow X's are on the attached diagram (I know it would probably be better having a speaker in each of the four corners, however there is no existing trunking accessible to run the cables to the back wall and we don't want to stick a long run of trunking along the wall), the On Wall speakers will go where the red X's are, and the rack cabinet with control equipment where the Blue X is. Each speaker would be connected to individual zones on the amp so the volume of each speaker can be controlled seperately. I know the above speakers listed are low impedance (8Ω) speakers so on their own would not work with the Monacor amp as it is a 100V Line amp, however I understand that it would be possible to add a 100V line transformer in between the amp and the speaker so they can be used. I know Adastra used to make these but they no longer appear to be available. I have also found the McGregor 100V line transformers, although these appear to be advertised for use with low impedance amps to allow them to use 100V speakers where as I need them the other way around, can these be wired up differently so they will work with this setup? If not do you know of an alternative transformer that will work, or point me in the direction of some alternative 100V speakers (so far I have only found low wattage versions, 20W and below, which I don't think will be loud enough for this system). If you have any alternative suggestions please be aware of the following:Preferably we want all kit to take up no more than 4U rack space so we can still use the Rackz Drop Down Rack as we have no real space for a full rack where it will be out of the way while still being easily accessible.Ideally we want to use In Wall speakers in the new area for aesthetic reasons. Thanks http://www.hillcrest.dudley.sch.uk/ITSupport/Dining%20Room.jpg Link to comment Share on other sites More sharing options...
HilcrRWise Posted January 11, 2012 Author Share Posted January 11, 2012 I have been in contact with McGregor about the 100V transformer and it looks like they will not work, however I have recently come across a Monacor alternative (TR-1120LC - 100V LINE TRANSFORMER 120W) which after contacting the company they seem to think it should work with the above equipment, does anyone disagree? Can someone also confirm if this cable will be fine to connect up the speakers (PRO POWER - 2192Y-0.75MMWHT100M - CABLE FLEXIBLE 2192Y 0.75MM WHT 100M) Link to comment Share on other sites More sharing options...
HilcrRWise Posted January 19, 2012 Author Share Posted January 19, 2012 bump Link to comment Share on other sites More sharing options...
Brian Posted January 19, 2012 Share Posted January 19, 2012 I don't think you've got anywhere near enough speakers in your scheme. I can't see the layout of the room but I'm guessing that if it seats 400 it's going to be at least 30m x 30m? That's a lot of area to cover with just 6 speakers. You are aiming for very even coverage. If not the kids nearest the speakers will just talk louder to make themselves heard and you'll have to turn the system up so the others can hear and then the kids nearest.... Also, if there any option for speakers in the centre of the room? Hanging from the ceiling or even in the ceiling? My first doodled plan had 36 speakers in it! Link to comment Share on other sites More sharing options...
PDD Posted January 19, 2012 Share Posted January 19, 2012 I can't see your attached plan and pictures; that may generate a few extra replies - is the link broken? I agree with Brian. I installed a (relatively) cheap 100V line system in our Dining Hall, and it took 12 loudspeakers in the end - and still isn't particularly optimal, but was the limit of the £3,000 budget. In a loud environment like that, it's better to have many distributed sources (despite the inevitable delay effects, which don't really matter unless absolute clarity is a must). The 12 speakers are 5 per side, 1 in each window bay, with a pair of 'main' speakers at the dais end. Our Dining Hall seats about 400 too, so could be roughly the same size. I'm ignorant on the 100V/8Ω convertors but surely it's easier to buy matching 100V loudspeakers for your 100V amplifier, rather than trying to use a transformer? Link to comment Share on other sites More sharing options...
Brian Posted January 19, 2012 Share Posted January 19, 2012 100v speakers are cheap. CPC have ceiling units at £10 and wall units at £20 each. Link to comment Share on other sites More sharing options...
HilcrRWise Posted January 19, 2012 Author Share Posted January 19, 2012 Sorry about the dead image link here is a fixed version which should hopefully stay up longer. http://www.smbc.pwp.blueyonder.co.uk/Dining%20Room.jpg Unfortunately we cannot put speakers any further in to the room as there is no accessible ceiling/wall void and the head teacher does not want additional trunking installed along the complete length of the room. I would happily use 100V speakers if I could find any 100W versions however the only ones I have come across so far are around 10W or below. Link to comment Share on other sites More sharing options...
Brian Posted January 19, 2012 Share Posted January 19, 2012 I would happily use 100V speakers if I could find any 100W versions however the only ones I have come across so far are around 10W or below.That's because, as I alluded to above, 100v speakers are meant to be used in large numbers in a given install. If you're hoping to cover the whole of the area shown on your plan then I'm sorry but your proposed solution isn't going to work. The kids near the speakers will be blasted out just so those at the far end can hear. The whole thing will sound loud and mushy. Looking at your floors they seem to be concrete with a Marley type covering. Just made to reflect sound. Link to comment Share on other sites More sharing options...
MarkPAman Posted January 19, 2012 Share Posted January 19, 2012 If there's really no other way, then at least get the speakers up as high as you can as this will help even the volume out. There are 100V speakers out there much larger than 10W - here's an example (not a recommendation, just what I found with a quick search). Link to comment Share on other sites More sharing options...
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