Powerbw detecting large spikes around 0Hz

Hi,

New to Matlab, recently I have been trying to make some bandwidth measurements using powerbw. My file here is a white noise presented from a TV speaker, recorded through KEMAR manikin and I'm trying to get its bandwidth. I tried values like 10~30dB down and experimented different freqrange values to set the reference lvl differently. However, Matlab seems to always get stuck with the spikes around 0Hz and mess up the whole measurement.. I also tried applying a high pass filter in Audition which has a cutoff set to 50Hz and it didn't help either. Can anyone help me out here? Really appreciate it!!

So far, only when I set it to 25dB down and freqrange to [0.10] can i obtain a rather reasonable output..

[Mathieu NOE]

hello

did you make sure that the high pass filter is actually doing what it is supposed to do ?

did you compare the spectrum of the signal before and after the high pass filter ?

why not doing the high pass filter in matlab ?

attached a bunch of digital filters implementation

hope it helps

Answer 1

[Star Strider]

The 0 Hz value is just the mean of the signal.

Subtract the mean of the signal from the entire signal to produce a 0 Hz value of 0.