[sdiy] Cheap audio spectrum analyzer

[Richie Burnett]

For a frequency analyser with built-in tracking sinewave generator that 
price is likely towards the bottom end of the price range.

You can surely hack something together with a Raspberry PI and a decent 
external audio interface, with the sinewave sweep generator and FFT all done 
in software, but it depends what's more important to you: your time or your 
money.  It's also not too difficult to make an audio network analyser with a 
suitably programmed DSP board, but for a piece of test equipment that you 
can trust it's results, it will take some real development time.  That's 
what you're paying for in an off the shelf commercial solution.

Have a think about what you actually want to do with the results once you've 
got the response on your small VGA screen.  Most "network analysers" will 
assume some sort of PC connectivity to download the detailed measurement 
data for graphing in Excel, publishing in the spec sheet of the product your 
working on, or whatever.  Something that is truly stand-alone might not be 
as flexible as you think in the long-run.

You can easily characterise the frequency response of something by playing 
out a pre-calculated sinewave sweep from your PC, and capturing the output 
from whatever system you're trying to characterise.  Then run an FFT on the 
captured wave file to get the frequency response.  I'm sure there are loads 
of bits of software that will do this for you, and help with things like 
calibration, etc.  if you could accept going down the PC software route.

-Richie,




-----Original Message----- 
From: Jean-Pierre Desrochers
Sent: Monday, October 26, 2015 2:43 PM
To: Richie Burnett
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Cheap audio spectrum analyzer

Hi Ritchie,
Did you notice the price tag for these things ??
$1500 and more...

I was just thinking of a Raspberry PI DIY audio analyzer project
that could connect on a small VGA screen. Easy to put around my test
equipments
taking lots of place so far ....
I'll do some looking on the web.
Thanks anyway.

Le 2015-10-26 10:34, Richie Burnett a écrit :

> https://www.omicron-lab.com/bode-100/product-description.html [1]
>
> These are relatively cheap and very capable instruments with a built-in 
> tracking generator.
>
> Any particular reason why you don't want to use a laptop, audio interface 
> and software bundle? This would probably represent the best tradeoff 
> between cost/performance with minimal effort required on your part.
>
> -Richie,
>
> -----Original Message----- From: Jean-Pierre Desrochers
> Sent: Monday, October 26, 2015 1:58 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Cheap audio spectrum analyzer
>
> Hi list,
> Do you know of a cheap audio spectrum analyzer I could
> buy to check 20-20khz frequency response on audio stuff ?
> That would includes sinus generator + analyzer in the same box.
> I checked on eBay and most analyzers are RF band based and are
> so $$$$$ expensives. But 2 things:
> - I don't want to use analysis software on a separate PC
> - Any DIY projects with micro/graphic LCD would do..
> I want a standalone analyzer.
> Thanks
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy [2]
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com [3]
> Version: 2014.0.4842 / Virus Database: 4447/10892 - Release Date: 10/26/15



Links:
------
[1] https://www.omicron-lab.com/bode-100/product-description.html
[2] http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
[3] http://www.avg.com


-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4842 / Virus Database: 4447/10892 - Release Date: 10/26/15