Sorry if this has already been suggested...
I was trying to think of a simple test for speaker distortion. Could you simply do an in-room measurement (eg mic at 1m) at many different volume levels?
Rather than a frequency sweep, just play a standard test piece of music (10s long).
By subtracting the expected waveform from the measured one you could quantify the errors. You could also do fft of the errors to get frequency information.
Importantly, by repeating at multiple volumes you can then make a second subtraction. Subtract the lowest volume recorded waveform, from each higher volume recorded waveforms (normalised to peak level). By doing this you will be able to plot how errors increase with volume.
By doing this second subtraction I suggest that you will remove errors introduced by the room response. (This assumes that the room response remains linear, whilst the speaker response becomes non-linear with increasing volume).
Any thoughts?
Could something like this be feasible?
Edit:
1) You would need to ensure that the microphone remains linear for all volumes, perhaps it would need variable gain?
2) I guess a frequency sweep could work just as well as a standard test piece of music.
I was trying to think of a simple test for speaker distortion. Could you simply do an in-room measurement (eg mic at 1m) at many different volume levels?
Rather than a frequency sweep, just play a standard test piece of music (10s long).
By subtracting the expected waveform from the measured one you could quantify the errors. You could also do fft of the errors to get frequency information.
Importantly, by repeating at multiple volumes you can then make a second subtraction. Subtract the lowest volume recorded waveform, from each higher volume recorded waveforms (normalised to peak level). By doing this you will be able to plot how errors increase with volume.
By doing this second subtraction I suggest that you will remove errors introduced by the room response. (This assumes that the room response remains linear, whilst the speaker response becomes non-linear with increasing volume).
Any thoughts?
Could something like this be feasible?
Edit:
1) You would need to ensure that the microphone remains linear for all volumes, perhaps it would need variable gain?
2) I guess a frequency sweep could work just as well as a standard test piece of music.
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