Sound in installation help

[mercifulrelease]

Hi

I wonder if there is anyone who can help.

My girlfriend is producing a sound installation as part of her final year project which has 160 TOA CS-64 - 6 watt speakers mounted on two freestanding walls (80 on the left & right).

We found when trialling wiring 48 speakers the sound dropped using 10k 1w.

 

Our problems are

1) do we wire series or parallel

2) which settings to set the speakers as they have various settings as we haven't got a clue what they mean 100 V line : 1.7 kohms (6 W), 3.3 kohms (3 W), 10 kohms (1 W)

70 V line : 830 . (6 W), 1.7 kohms (3 W), 3.3 kohms (1.5 W), 10 kohms (0.5 W)

3) what sort of amp to buy

 

Any help will be appreciated

[paulears]

Welcome to the world of 100V line distribution. The essential rule is that the amplifier you drive it with must have a rated output of more than the addition of the settings you select on the individual speakers.

 

So your speakers all connect accross the speaker line - in parallel, and you use the taps to select how loud each one will be. So at the lowest setting, you can have 100 of them, or at the 3W setting, 33 etc.

 

The idea is that the system is very different from the normal type of systems used - which are all low impedance systems. 100V distribution systems don't need heavy speaker cabling, quite thin stuff will do.

 

70V line systems are similar. Most PA amps designed for these kind of systems can have 70 or 100V output.

The idea of the different taps is so one speaker can be louder than another. If you are going to have them in walls, then if they all need to be the same, use the same taps. PA amps of this kind are rarely mega powerful, so you can use one per 'clump' of speakers if you need to use them at the higher tap settings for max volume.

 

I don't quite get the point of what she is doing though - what is the idea behind it? Sounds a bit odd?

[cfmonk]

I'm guessing that it's some sort of modern art installation rather than an installation for playback as we know it!

[johndenim]

Have I read this post wrong or did the OP say that 160 individual speakers were being used?

 

What's the point?

I'm not being sarcastic but have never heard of anything like this!

 

John Denim.

[MarkPAman]

Paul, you undoubtedly know what you're talking about, but that second paragraph has left me confused.

 

With regards to the original questions:

 

Wire in parallel, and as Paul said you can use thin cheap cable for this.

 

The tappings on the speakers need to be chosen for the volume you want from each speaker - but choose 100V or 70 V throughout to keep it simple.

 

The amp(s) will depend on how you tap the speakers. Add up the total number of Watts you've got and get a 100V amp (or 70, though as Paul says most do both) which is at least as big, and ideally slightly larger, than that. If you have chosen one of the higher tappings, then you may need more than one amp.

 

Also, if the speakers are not all playing the same thing at the same time, then you'll need extra amps, so if it's to be stereo you'll need two.

 

That should be enough to work it out, but, if you'd like to give more details about what the speakers will be doing, we may be able to be more helpful.

 

I assume the installation is only for a short time - look into hiring amps. Companies that do sports days etc. are the ones to talk to.

[mercifulrelease]

Paul, you undoubtedly know what you're talking about, but that second paragraph has left me confused. :unsure:

 

With regards to the original questions:

 

Wire in parallel, and as Paul said you can use thin cheap cable for this.

 

The tappings on the speakers need to be chosen for the volume you want from each speaker - but choose 100V or 70 V throughout to keep it simple.

 

The amp(s) will depend on how you tap the speakers. Add up the total number of Watts you've got and get a 100V amp (or 70, though as Paul says most do both) which is at least as big, and ideally slightly larger, than that. If you have chosen one of the higher tappings, then you may need more than one amp.

 

Also, if the speakers are not all playing the same thing at the same time, then you'll need extra amps, so if it's to be stereo you'll need two.

 

That should be enough to work it out, but, if you'd like to give more details about what the speakers will be doing, we may be able to be more helpful.

 

I assume the installation is only for a short time - look into hiring amps. Companies that do sports days etc. are the ones to talk to.

 

 

 

 

Hi Paul,thanks for reply,we are starting to get a grip on this! The speakers are being attached to two plinths 8ft long x 6ft high x 2ft deep which will be placed opposite each other about 2ft apart so you walk between them.

 

We have one stereo track that will be played by a CD player, one bank of speakers will play the right track and the other side the left. The idea is that the PA speakers are having a dialogue.

 

Could you please explain how to read the tap settings on the back of the speakers we are not sure which is the lowest setting?

 

Your help is very much appreciated.

[paulears]

You turn the switch on the back witha screwdriver blade to the most anti-clockwise bar one setting. Labeled 10K. It's the quietest setting. Bear in mind when recording your material that these speakers have hardly any bass content - so anything that has important bass content won't work that well - or will they actually be speaking to each other?

 

Sounds very odd to me. Forgive m for asking, but this seems a very expensive way of doing it? Why not just recess small speakers into the plinths? or is it a visual thing too?

[mercifulrelease]

You turn the switch on the back witha screwdriver blade to the most anti-clockwise bar one setting. Labeled 10K. It's the quietest setting. Bear in mind when recording your material that these speakers have hardly any bass content - so anything that has important bass content won't work that well - or will they actually be speaking to each other?

 

Sounds very odd to me. Forgive m for asking, but this seems a very expensive way of doing it? Why not just recess small speakers into the plinths? or is it a visual thing too?

 

Thanks again, yep it does sound weird but its a visual piece as well as sound. Bass isn't a prob as its all vocals.

Have been lucky enough to get the speakers on free loan so that's not a prob either!

You mentioned we need 2 amps, could you recommend any or let me know what to search ebay for? I am prepared to rent or buy depending on price.

Thanks again.

[soundspider]

Hi there.

 

CPC stock a couple of 100v line amps by EAW - go to cpc.co.uk and search for CXA120 and CXA240. 2 of the 120's will be enough if you're tapping each speaker at 1W. They sell for about £80 + VAT. Hope that helps!