I recorded some flute samples myself, and I'm trying to create loop
points for use with loscil.

Using Sonic Visualizer (wow what a great tool) I was able to find some
good points, ascending at the zero crossing. Even so, there is a
slight glitch at the loop point I'd like to eliminate.

My thought was to modify the sample about 2 cycles or so on each side
of the sample points, using a weighted average, as follows:

Two cycles before the starting loop point, the signal is unmodified.
Starting there I slowly begin averaging in the signal around the end
loop point, so that at the loop point I have a 50/50 average of
starting and ending signal. After that the weighting on averaging in
the signal around the end loop point tapers off, so that 2 cycles
later I'm back to my unmodified signal.  I do the same with the end
loop point, averaging in signal from around the starting loop point.
This gives me the same waveform around the loop points and should be
smooth.

My questions are:

1) Does this sound like it would work?

2) Are there any existing free linux tools to do something like this?

Also, from reading the archives, it seems that both .aiff and .wav
formats have a way to set loop points in the header that loscil will
use? (The manual still just says aiff). How does one set those
headers? Where is the format documented?

Forrest

I suggest a crossfade, which is close to what you have now, but over a
larger number of samples. I think two loopers playing with gentle
amplitude envelopes, each envelope 180 degrees out of phase with the
other, would be the best way to do this.

On 3/29/12, Forrest Cahoon  wrote:
> I recorded some flute samples myself, and I'm trying to create loop
> points for use with loscil.
>
> Using Sonic Visualizer (wow what a great tool) I was able to find some
> good points, ascending at the zero crossing. Even so, there is a
> slight glitch at the loop point I'd like to eliminate.
>
> My thought was to modify the sample about 2 cycles or so on each side
> of the sample points, using a weighted average, as follows:
>
> Two cycles before the starting loop point, the signal is unmodified.
> Starting there I slowly begin averaging in the signal around the end
> loop point, so that at the loop point I have a 50/50 average of
> starting and ending signal. After that the weighting on averaging in
> the signal around the end loop point tapers off, so that 2 cycles
> later I'm back to my unmodified signal.  I do the same with the end
> loop point, averaging in signal from around the starting loop point.
> This gives me the same waveform around the loop points and should be
> smooth.
>
> My questions are:
>
> 1) Does this sound like it would work?
>
> 2) Are there any existing free linux tools to do something like this?
>
> Also, from reading the archives, it seems that both .aiff and .wav
> formats have a way to set loop points in the header that loscil will
> use? (The manual still just says aiff). How does one set those
> headers? Where is the format documented?
>
> Forrest
>
>
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>
>