making a spectrum analyzer...

[Dj Task Manager]

I need a spectrum analyzer for a project, and ive scoured e-day for an old hi-fi i can rip one out of with little success.  Ive also thought about building one, but i fear it will just be another unfinished project under my bed. 
I found this:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260454979889&ssPageName=STRK:MEWAX:IT

which i though could be used with filters to do it but of course i'd have to build the filters...
has anyone build one? or have any thoughts on how to aquire one? or know how to build easy filters?...

cheers

mike

[Gordonjcp]

PC, soundcard, bit of commonly-available software like xspect.  Dead easy.

[Dj Task Manager]

cheers but it has to be a real one with leds for a thing im building...

[noystoise]

how about this
http://cgi.ebay.com/Funny-Dancing-Gadget-LED-Sound-activated-EL-T-shirt-L_W0QQitemZ390123714437QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5ad52f7785

[Gordonjcp]

So use the computer to drive a bank of LEDs...

An audio spectrum analyser is really just a bank of narrowish bandpass filters (similar to those in a graphic equaliser) and some level meters.  Sounds like you're going to be buying some LM324 quad opamps and LM3915 bargraph chips...

[Dj Task Manager]

Well the t-shirt jobby is a nice idea but im dubious as to weather it actually does analyze frequencys and ting.  Do you recon it does? or do you think it just has fun bars that go up and down?...

I dont really want to use a computer cos its for a homemade devices live setup.  I like the idea of escaping the ubiquitous glowing rectangle.

I recon I'll just wait till i find an old hifi i can rip one out of.

cheers for the suggestions all the same!!