Pieter Palmers wrote:
Erik de Castro Lopo wrote:
Robin Gareus wrote:
hey LADs.
For those of you who have not followed the 'fuzztone' thread on LAU. I'd
like to announce a /cool hack/ to ngSpice that provides soundfile I/O
capabilities. - it's more a LAD than a LAU issue anyway.
This is a CoolAsAllFsck (tm) hack as far as I am concerned.
Congrats.
Simple tests sound rather promising; but my fuzztone experiment is not
really satisfying yet. well, maybe it's just meant to sound *that* weird
;)
I used Spice as part of my engineering degree and also in jobs later,
but my memory of this is definitely hazy.
However, my memories of how spice works is my discretizing the
differential equations that describe the components. I believe
the specification of the time step determines how fine grained
(in time) a grid will be used for operating on the diff equations.
One thing you might have missed is matching up the samplerate of
the input file with the time grid of the spice calculations. You alos
want to be *really* careful about how you interpolate
the file data to spice sample rate. Please, please, please, do
not use linear interpolation. Secret Rabbit Code is probably the way
to go here.
All spices I use (although this excludes ngspice) have an option to
force them to calculate the response at specified timesteps (along with
the ones they need for accuracy). In this case it seems obvious to set
this timestep to 1/Fsample. Then use only the values at these timesteps.
This is way better than interpolation because the differential equations
are actually solved at these points.
Also worth to mention is that as far as my experience goes, you need to
crank up the precision quite a lot to make sure that the 'signal vs
simulation noise' is more than 100dB.
Pieter
_______________________________________________
Linux-audio-dev mailing list
[email protected]
http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
