Re: Re: sound recording (solved)
46mkz5j02 wrote:
> Run the vcr audio through a low-pass filter before sending it to the
input of the sound card.
Thank you very much. I don't know how to set up an analog low-pass
filter, but I tried software filtering the digitalized track and the
whistle disappeared. I was afraid that that would also cut the higher
harmonics and distort the sound, but as far as my ear goes, that doesn't
seem to happen.
For those who might run into the same problem, I used this command:
sox original-track.wav filtered-track.wav filter -2200
2200 is the cutoff frequency of the low-pass filter, I tried several
values and that was the highest one that actually removed the whistle
from my track; your mileage may vary.
According to the man page, sox has two other low-pass filter effects
with different damping curves: "lowp" and "lowpass". I tried those too,
but at 2200 the whistle was still there, so I gave up.
Gerardo
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