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Author Topic: Sound Module Coupling  (Read 1142 times)

BarryM

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Sound Module Coupling
« on: May 14, 2007, 08:25:51 PM »

The answer to this will be simple to someone - it's not to me but maybe I'm just simple.

I have a Robbe sound module (destroyer siren) feeding a speaker. So far so good.

Question - If I couple another sound module (http://www.quasarelectronics.com/30a63.htm) directly to the same speaker and arrange the switching such that only one module can be powered up at any time, will I have a problem?

In answer to those who say "try it and see", I'd rather not risk that interesting burnt component smell without first consulting better minds than mine.  My fear is damage to either module by feedback current from the other. Do I neeed to insert a diode - and if so, what spec?

Thanks in advance,

Barry M
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malcolmfrary

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Re: Sound Module Coupling
« Reply #1 on: May 15, 2007, 11:34:26 AM »

It all depends on the configuration of the sound units' outputs. 
The safe way is to get an amplifier module (Maplin do a sealed unit fairly cheaply) to drive the speaker and feed the outputs from the various sound modules into a set of volume controls so that the level of each sound can be set.
The outputs of the various output stages do not mind feeding a high resistance load, but they will object to feeding back into another output stage.  The diode just wont work not least because the signal is AC and the diode wil lose half the signal modifying the sound produced.  A capacitor transmission bridge circuit might work, but an extra amplifier wil probably be more compact.
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BarryM

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Re: Sound Module Coupling
« Reply #2 on: May 15, 2007, 06:24:21 PM »

Malcolm, Thanks for info - it confirms ny fears. Will you indicate which amp module would be suitable? Maplin lists 16!

Thanks again,

Barry M
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malcolmfrary

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Re: Sound Module Coupling
« Reply #3 on: May 15, 2007, 09:01:23 PM »

Have a look at N65AW and N66AW.  Both are OK on 12 volts and both will be OK with any normal 8 ohm speaker that can handle the power.  Space and weight determine the speaker you can use - this determines how much power you can handle.  Remember that a relatively small speaker can handle quite a lot of power in short bursts, and continuous noises are usually at a relatively low level, and we are not really into proper Hi-Fi.
In a big enough boat, powered speakers like those for MP3 layers and PCs can be used.  This sorts out amp, speaker and power supply in one go.  For two sounds, each one can be wired for each sound.
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BarryM

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Re: Sound Module Coupling
« Reply #4 on: May 16, 2007, 08:16:29 AM »

Malcolm,
Thanks for that - I'll give it a try.  :)

Cheers

Barry M
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