Re: [Audacity-nyquist] hp filter was Problem with this plug-in...

[David R. S. <dav...@sh...>]

Hi Sami,

the problem Edgar was speaking about when applying a highpass filter was=20
the initial 50 milliseconds of 'ripple' or something, which I can hear=20
after repeated application of the rectifier plug (I have to rely on=20
sighted people's feedback about this since I can't see the screen to=20
check). Do you know what that initial ripple is and how to remove it=20
without further distortion? Or how to at least reduce it?

David

On Tue, 29 Nov 2005, Sami Jumppanen wrote:

> Hi,
>
> if you guys just understood something about the audio itself instead
> of just witing DSP code... ;)
>
> Firstly, we cannot "center" the audio by the use of min / max peaks.
> What counts, is the "weight balance" of the signal. To find out that,
> we need to calculate the average with n samples. However, we cannot do
> that with a fixed number of samples, nor with the whole audio file -
> because the average varies constantly.
>
> We need to remove the DC component, and DC (or high-pass) filter is
> just the tool for doing that. In real life, we let the audio go
> through a capacitor with suitable resistance to ground to discharge
> the capacitor.
>
> --
> Sami "Some-E" Jumppanen
> sam...@gm...
> http://netti.nic.fi/~some-e/
>
>
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