Re: [LAD] Wavetable synthesis : Creating fat wavetables

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
To: Fons Adriaensen <fons@...>
Cc: <linux-audio-dev@...>
Date: Friday, August 24, 2012 - 11:44 pm

--e89a8ff2509e93fef204c80b8d20
Content-Type: text/plain; charset=ISO-8859-1

On Fri, Aug 24, 2012 at 11:48 PM, Fons Adriaensen wrote:

> The easiest way in the case of wavetable synthesis is to upsample

So the preparation process is:
-record the sounds
-upsample x8

Live playing:
-downsample the wavetable to the size needed for the frequency that is
played

Do I understand the steps correctly?

> Provided you have a *good* interpolation method, two things follow.

You mentioned linear interpolation, I think that will be sufficient
considering its an instrument not an emulator, crunchy aliasing? Thats
meant to be there :)

The alternative

I don't know how to compute the phase trajectory or that, but it sounds
like its not strictly necessary so I'll leave that for the time being.
The loop points on the wavetables I'm currently using are just "ear
picked", and slightly visually tuned.

Other concepts I've read about and would be interested in experimenting
with after a working prototype is done:
-2d interpolation between wavetables and linear interpolation between the
wavetables values. Time and phase of wavetables must be exact.
-Randomizing phases and loop positions within wavetable for different
timbres

-Harry

PS: Random idea: Create a program which scans trough a short recorded
frament, and analyzes the number of samples per cycle. Some sort of "take
sample, check sample" loop should do the trick really, and then output the
largest repeated period. That with a sensitivity control is essentially all
that's needed to create perfectly looped synthesized recorded wavetables
right?

--e89a8ff2509e93fef204c80b8d20
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

On Fri, Aug 24, 2012 at 11:48 PM, Fons A=
driaensen <fons@linuxaudio.org> wrote:

The easiest way in the case of wavetable synthesis is to upsample
your waves by a factor of say 8, then use linear interpolation.=A0So the preparation process is:-record the sounds-u=
psample x8Live playing:-downsample the wavetable=A0 to the size=
needed for the frequency that is played
Do I understand the steps correctly?=A0
Provided you have a *good* interpolation method, two things follow.You mentioned linear interpolation, I think that will be suff=
icient considering its an instrument not an emulator, crunchy aliasing? Tha=
ts meant to be there :)
=A0
The alternative
is to compute the phase trajectory of the entire waveform, which will
tell you the exact pitch with much more precision than looking at the
waveform.I don't know how to compute the phase t=
rajectory or that, but it sounds like its not strictly necessary so I'l=
l leave that for the time being.The loop points on the wavetables I&#39=
;m currently using are just "ear picked", and slightly visually t=
uned.
Other concepts I've read about and would be interested in experimen=
ting with after a working prototype is done:
-2d interpolation between wavetables and linear interpolation between=20
the wavetables values. Time and phase of wavetables must be exact.
-Randomizing phases and loop positions within wavetable for different timbr=
es-HarryPS: Random idea: Create a program which scans troug=
h a short recorded frament, and analyzes the number of samples per cycle. S=
ome sort of "take sample, check sample" loop should do the trick =
really, and then output the largest repeated period. That with a sensitivit=
y control is essentially all that's needed to create perfectly looped s=
ynthesized recorded wavetables right?

--e89a8ff2509e93fef204c80b8d20--

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

Messages in current thread:
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Gabriel M. Beddingfield, (Sat Aug 25, 2:33 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Julien Claassen, (Fri Aug 24, 7:39 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Fons Adriaensen, (Fri Aug 24, 10:49 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Harry van Haaren, (Fri Aug 24, 11:44 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Fons Adriaensen, (Sat Aug 25, 9:12 am)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Robin Gareus, (Fri Aug 24, 10:18 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Harry van Haaren, (Fri Aug 24, 11:26 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Devin Anderson, (Fri Aug 24, 9:05 pm)
Re: [LAD] Wavetable synthesis : Creating fat wavetables, Julien Claassen, (Fri Aug 24, 8:43 pm)