multiple speakers

neosurreal

hello all,

yes, i'm a newbie!!!

i'm working on an interactive art project where the input data will play various sound samples. i would iike to achieve this w/ multiple speakers so that they can generate sounds independently/simultaneously. also, to make sure the sound quality is decent, i would like the speakers to be directly connected to my computer, but controlled w/ the board. would this be possible? is it even possible to hook up multiple speakers to the computer w/o using a fancy audio interface?

thank you in advance!!

ns

Mike Green

If you just want to switch the audio to different speakers, you could use small relays. If you're using the computer as a sound source, you'll also need some kind of small amplifier or amplified speaker. Your computer is probably designed only to produce one stereo channel which is probably not what you want. How many independent channels do you want? How long are the longest sound samples? How big are your speakers? How loud do you want them?

Have a look at Vinculum's VMusic2 (www.vinculum.com/prd_vmusic1.html#vmusic2). Here's a 4 watt monaural amplifier that I've used for some sound installations: www.hobbytron.com/vk4001.html. Radio Shack has a relay you could use between speakers and an amplifier (www.radioshack.com/product/index.jsp?productId=2062480&cp=2032058.2032230.2032277&parentPage=family) or (www.radioshack.com/product/index.jsp?productId=2062478&cp=2032058.2032230.2032277&pg=2&parentPage=family). The larger relay would have to have some kind of switching transistor to drive it. See the tutorial "What's a Microcontroller?" for examples of this (www.parallax.com/dl/docs/books/edu/wamv2_2.pdf).

neosurreal

hi mike,

thanks for much for the response. i'll for sure check out those resources.

to answer your questions: i would like about 8 channels (each w/ different sound), w/ the capability of being played simultaneously. so if i understand it correctly, the relay set up won't work, right? that being said, the longest sound samples shouldn't be more than 60 sec. from speakers no larger than 6" dia.

the volume doesn't have to be so loud. i want viewers to notice that there are sounds coming out, but have to be in a close proximity to be able to really clearly hear the sound.


ns

Mike Green

It sounds like you need multiple independent sound channels. You could use a VMusic2 plus an amplifier for each channel. You might also look at Quadrovox's new MP3 player (www.quadravox.com/QV606/QV606.htm). This is a replacement for their QV306 which uses a Winbond sound chip which is much more limited. I've used the QV306 with a Stamp in a kiosk and it worked very well. I believe I needed an amplifier for this since it was in a very noisy exhibit space, but the built-in amplifier was adequate in a quieter gallery. The QV606 has a more powerful amplifier and may not need an external one.

Robert Kubichek

Why don't you use a fet input mixer, there is a fet for each input and the output is just one channel...
It would save on amps, and you could always have more than one speaker on an amp...

Bob

T Chap

When you say "controlled w/ the board", you mean a Stamp? There are plenty of audio devices that will allow 8 outs from a PC

www.m-audio.com/products/en_us/Delta1010-main.html


Something like the 1010 would require a music software to access each of the 8 analog channels, which could probably be triggered by the Stamp into the PC by USBtoSerial or serial to MIDI converter. I'll have to give some thought on how to route 8 simultaneous sounds to 8 outputs in a PC, it is done all the time though.

There are a lot of midi/sequencer/sample players too, you could with some effort get the Stamp into a MIDI cable, then connect that to this device linked above, and play the sounds via MIDI. I am sure there are serial to MIDI converters somewhere.

Depending on your budget, this might be the ultimate simple solution below:

Stamp>MIDI>Sampler device(or PC based sample player)

There are tons of sampler devices on the market that will play any length audio fil(aiff/wave/mp3) Search for:

Reason, Battery, alll are software based sample players that could take a midi input, output to 8 analog outs.

***Google serial to midi and see tons of ideas, even off the shelf boxes for serial to midi.

www.compuphase.com/electronics/midi_rs232.htm

Post Edited (TChapman) : 3/26/2007 8:27:18 PM GMT

neosurreal

wow, thanks for all the replies, guys. i love this forum.


i might must fork out the $ and get an audio interface like the m-audio 410 just to make things easier.
i'm not a programming buff by any means so it'll probably save me a lot of time and headache.

thanks again!

ns

T Chap

"Reason" is great stand alone sampler/synth, it will allow tons of sounds routed to 8(or more) outs, triggered by midi in on the Delta or other midi interface. There are serial to midi boxes on google I just noticed. The nice thing about Reason would be plenty of great effects processing per sound, level control(even automated if you have amidi sync source = progarmmable LRpanning, programmable level changes etc ).

Chris Savage

Does this post involve a BASIC Stamp?

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Chris Savage
Parallax Tech Support

T Chap

Chris, I assumed it was and attempted to clarify, this probably should be moved if it is just audio and not Stamp related.

Post Edited (TChapman) : 3/26/2007 9:54:26 PM GMT

Mike Green

I don't know what neosurreal intends, but my experience with multi-channel and interactive sound installations have always used Stamps as the controller and I've been very pleased with the results and the relative ease in achieving it (especially quick fixes in the field).

T Chap

I was only responding to the requirement to playback 8 separate channels from the PC, assuming it was Stamp triggered.

neosurreal

hello,

well, to clarify some points, yes the project itself is very much 'stamp related' for it's a larger interactive project w/ other mechanical components such as motors etc. being controlled by the board. however, i wasn't sure of the most efficient way of achieving the audio element of the piece and everyone's been very helpful.

for the AUDIO part, i think i'll just use an audio interface w/ reason as some of you pointed out for that would be easiest. i also don't want to overwhelm the board.

thanks, all!

ns