[sdiy] Cheap audio spectrum analyzer

[Richie Burnett]

An interesting bit of kit Rick!

JP have you thought of just using an analogue scope and a sweep generator to 
automatically measure the frequency response?  You probably already have 
these two items.  You set your function generator to produce a sinewave 
sweep between 20Hz and 20kHz with a pulse at the start of each sweep.  Then 
set your oscilloscope's timebase to trigger off the pulse at the beginning 
of each sweep, and display the output of whatever your testing on the 
Y-channel of your scope.  It's a cheap and dirty way to plot a magnitude 
frequency response.

Not the best video but hopefully you get the idea...

https://www.youtube.com/watch?v=xb3cLtAtE1s

-Richie,



-----Original Message----- 
From: Jean-Pierre Desrochers
Sent: Monday, October 26, 2015 5:01 PM
To: Rick Jansen
Cc: synth-diy
Subject: Re: [sdiy] Cheap audio spectrum analyzer

Le 2015-10-26 11:51, Rick Jansen a écrit :
> http://www.cnx-software.com/2013/07/24/359-red-pitaya-board-combines-an-oscilloscope-a-spectrum-analyser-a-waveform-generator-and-more/
>
> ~360 US$
>
> rick
>

Thanks Rick but,
This still needs a PC to run...




>> On 26 Oct 2015, at 16:25, Jean-Pierre Desrochers <jpdesroc at oricom.ca> 
>> wrote:
>>
>>
>>> Again, what do you mean by "cheap"...? What is your budget, and what
>>> level of performance do you want to measure?
>>
>> Lower than $500.
>>
>>
>>
>> Le 2015-10-26 11:18, Neil Johnson a écrit :
>>
>>> Jean-Pierre Desrochers wrote:
>>>> Do you know of a cheap audio spectrum analyzer I could buy to check 
>>>> 20-20khz frequency response on audio stuff ?
>>> Define "cheap".
>>>> That would includes sinus generator + analyzer in the same box.
>>> Ok.
>>>> I checked on eBay and most analyzers are RF band based and are so $$$$$ 
>>>> expensives. But 2 things:
>>> You're looking for the wrong kind of thing.
>>>> - 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.
>>> Well, for a complete standalone box I would recommend an HP Dynamic
>>> Signal Analyser, such as the venerable 3561A, or something a little
>>> more modern such as a 35660A. Pros: all-in-one, built-in screen, will
>>> do amplitude and phase response. Cons: dynamic range ok but won't get
>>> down to the very low levels of noise and distortion.
>>> The next step up would be audio analysers, such as the HP 8903 or
>>> something from Audio Precision. While the 8903 does have a built-in
>>> computer and can do sweeps, the display is 7-seg LED so you'll need a
>>> pencil and some graph paper. The Audio Precision kit needs an
>>> external control computer, but can measure the very lowest noise and
>>> distortion.
>>> Again, what do you mean by "cheap"...? What is your budget, and what
>>> level of performance do you want to measure?
>>> Neil
>>> --
>>> http://www.njohnson.co.uk [1]
>>
>>
>>
>> Links:
>> ------
>> [1] http://www.njohnson.co.uk
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


-----
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