Quote:
Originally Posted by charles Tauber
Having done it the "old-fashioned" way, I like the idea of doing a spectral analysis to aid in troubleshooting. What set-up (hardware, software) is required or do you use to perform spectral analysis?
Thanks.
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What Gitnoob said.
A couple of valuable features not immediately visible in Audacity are the expansion of the wave view and the EXPORT option in the analysis window.
By expanding the wave view, you are able to see the shape of the wave, where the attack of a note and other features are visible. You are also able to see beat frequencies, as shown in this very thread.
The resolution of Audacity's analysis is much greater than it is able to display on its graph. The EXPORT feature in the analysis window produces a text file showing two columns: frequency and amplitude. This is very important in dealing with resonances because they tend to have such high aplitude differentials in very short aplitude ranges that are difficult to display. Again, using the sound clip in this thread as an example, the graph shows a spike at 124 Hz that shows other features, but not clearly. The export produced a table that showed the frequency at 118 Hz was -50 db, but at 123 Hz jumped to -16 db. That wasn't easy to see on the graph. This table is .txt, so it can easily be imported to other software (Excel, LibreOffice, etc.) for better graphing.
Beyond a PC and free software, the hardware is still pretty cheap. I use very inexpensive input devices - a cheap Radio Shack audio microphone and a Korg CM100 contact microphone. Remember a mic detects vibration of air, where the contact mic detects mechanical vibration. Audio mics are often weighted for a particular purpose, but are still still usable for relative applications. When I need something more absolute, I use a Radio Shack mic capsule that is flat 30 Hz to 30 kHz.
You already have a PC. You probably already have a mic. Audacity is free. The learning curve will be pretty short given your engineering background. I think this setup could be useful to you very inexpensively and very soon.
I can't emphasize this enough, though. You will be amazed that so very much of what you see on those graphs will so much agree with your ears.