Re: [LAD] Mixing audio: Noiseless volume changes

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To: Fons Adriaensen <fons@...>
Cc: <linux-audio-dev@...>
Date: Tuesday, March 19, 2013 - 2:09 am

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On Mon, Mar 18, 2013 at 11:45 PM, Fons Adriaensen wrote:

> A critically damped

Although I understand the words & their meaning, I have no idea how to
start implementing such a filter.
I've found a 1st order algorithm on musicdsp:
http://www.musicdsp.org/showone.php?id=257
Since its second order I understand it needs the previous 2 outputs.
Critically dampened implies that the "factor" of influence of the previous
samples is very close to 1 ( 'a' in the algorithm linked )

How is the "rise time" determined here?
Noobie questions :) -Harry

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On Mon, Mar 18, 2013 at 11:45 PM, Fons Adriaense=
n <fons@linuxaudio.org> wrote:

A critically damped
second order lowpass with a rise time of 30 ms or so will eliminate all
audible artefacts. It's very low on CPU and you only need to run it whi=
le
the gain is changing.Although I understand the wo=
rds & their meaning, I have no idea how to start implementing such a fi=
lter.I've found a 1st order algorithm on musicdsp: http://www.musicdsp.org/showone.ph=
p?id=3D257

Since its second order I understand it needs the previous 2 outputs.Cri=
tically dampened implies that the "factor" of influence of the pr=
evious samples is very close to 1 ( 'a' in the algorithm linked )
How is the "rise time" determined here?Noobie questions :=
) -Harry

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Messages in current thread:
[LAD] Mixing audio: Noiseless volume changes, Tim E. Real, (Mon Mar 18, 9:50 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Mon Mar 18, 11:05 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Paul Davis, (Mon Mar 18, 10:47 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim E. Real, (Mon Mar 18, 11:05 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim E. Real, (Mon Mar 18, 11:43 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Mon Mar 18, 11:58 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim E. Real, (Tue Mar 19, 12:31 am)
Re: [LAD] Mixing audio: Noiseless volume changes, James Morris, (Mon Mar 18, 11:28 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Mon Mar 18, 11:45 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Harry van Haaren, (Tue Mar 19, 2:09 am)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim Goetze, (Tue Mar 19, 3:17 am)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 1:02 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim Goetze, (Tue Mar 19, 1:53 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 3:08 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim Goetze, (Tue Mar 19, 3:37 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 4:31 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim Goetze, (Tue Mar 19, 7:06 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Charles Z Henry, (Tue Mar 19, 10:26 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 10:57 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Charles Z Henry, (Tue Mar 19, 11:12 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 11:30 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Fons Adriaensen, (Tue Mar 19, 10:26 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Harry van Haaren, (Tue Mar 19, 1:31 pm)
Re: [LAD] Mixing audio: Noiseless volume changes, Harry van Haaren, (Tue Mar 19, 4:30 am)
Re: [LAD] Mixing audio: Noiseless volume changes, Tim Goetze, (Tue Mar 19, 3:22 am)