[fluid-dev] kaaaabooom, Was: Jamming with FluidSynth :)

[Josh Green]

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Date: 18 May 2003 17:31:04 -0700
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> Hi Josh,
> 
> I'm pulling in this old mail from the iiwusynth-devel mailing list.
> 

I'm pulling this reply from the archives :)

> 
> 
> All the parameters for the reverb - roomsize, damp, width, level -
> should be between 0 and 1. It seems like Swami allows values
> outside that range. I changes the reverb module in FluidSynth: it now
> clips the values to the allowed range.
> 

I think we were discussing this in another thread, but.. I mentioned
that I like the ability to have harsh reverb sounds (width > 1.0). Are
you still going to clip the values to 1.0 or will there be a wider range
available? I notice that the damping parameter doesn't appear to have an
affect (at least not that I can hear).

> 
> You were right that the kaaaabooom problem comes from the filter and not
> the reverb. In particular, the filter interpolation seemed to cause the
> noise. The coefficients are now interpolated over one synthesis buffer
> (64 samples) instead of two buffers. This solved it.
> However, I can't find any bug in the interpolation code so I assume
> that the filter somehow becomes instable. IIRC, the direct form of the
> filter that Markus introduced is stays stable when the coefficients are
> interpolated. So it could be a problem with round off erros, or so.
> 
> Can you check on your side whether this change effectively removed the
> problem?
> 

Seems to be fine now :)

> Cheers!
> Peter
> 
> 
> BTW: I've been using Swami CVS (HEAD branch) a lot today. It rocks!
> 

Glad to hear it. I'm contemplating doing some more work on this branch,
since the development version is taking so long. There are still things
that annoy me from time to time with it :) See ya.
        Josh