I tried to inspect the frequency spectrum using Audio Weaver. The input used is a headset microphone. The first figure is acquired from using the inspector function of the sink module. The second figure is acquired from a PC-based freeware. One can immediately tell the results are very different at low frequency range (0-100Hz). I tend to believe that latter is more accurate. Is there any tricks to overcome this issue?
4:51pm
Let me do some self-correction. In the freeware, the middle ear weighing option has been on. After turning off the option, the spectrum looks the same.
5:06pm
Ah. You got it before I did :)
5:05pm
Hi Paul,
I believe the difference that you are seeing is because Friture is showing you the 'dbA' (A-weighted before FFT) magnitude, whereas Audio Weaver is just giving you the frequency spectrum from the raw data.
To test if this is the issue, you can add an AudioWeighting module (set the weighting type to 'A') before the Sink module in your layout, and see if this matches Friture's output.
You could also record some data from your Mic and use a program like Audacity (or other) to see if there is a DC offset of ~30 dB as is shown by Audio Weaver, or no DC offset as shown by Friture.
I hope this resolves the difference you're seeing. If not, please reply.
Thanks
-Axel