Re: [fluid-dev] Gain distortion with many soundfonts

[Bernat Arlandis i Mañó]

Thank you for your reply. I've finally found the problem and it was much 
easier than I thought. It seems it's a pretty common HW problem. I've 
explained it in the ticket to better document my case.

Several users on internet claimed that gain levels around 10-20 were 
necessary to avoid distortion. Finally, I've managed having a good 
output level from fluidsynth avoiding speaker output distortion. :)

Sorry for the annoyance, the info on internet pointed me in the wrong 
direction and I failed to go back on track.

Cheers.


Josh Green escrigué:
> Hello Bernat,
>
> Sorry it took me so long to answer your question.  Unfortunately I'm not
> sure currently what exactly causes this issue and I haven't yet really
> put any time into figuring it out yet either.  As you mentioned though,
> it does indeed seem like its a distortion that occurs even though the
> sound card output is not maxed, which would indicate internal distortion
> of some sort.  I suspect it might have to do with reverb or chorus (try
> turning them off) or perhaps with the volume attenuation of samples and
> how they are mixed.
>
> I've added a ticket for this issue here:
> http://fluidsynth.resonance.org/trac/ticket/13
>
> I'm currently working on getting Swami 2.0 released after which I'll be
> putting some more time into FluidSynth.
>
> Thanks for reporting this issue and your other findings.
>
>         Josh
>
>
> On Mon, 2008-03-17 at 02:03 +0100, Bernat Arlandis i Mañó wrote:
>   
> > I've done some more investigation. Connecting Fluidsynth output to
> > Rezound I've saved the waveforms with lower gain (no distortion) and
> > higher gain (with distortion). I've always avoided clipping that occurs
> > at very high gain levels. I've used piano soundfonts, mainly the
> > "Microfont piano collection (6MB)" soundfont.
> >
> > I've compared the same sound with distortion and without distortion and
> > I've discovered that the distortion is caused by the gain changes alone,
> > but I don't know why some samples don't get distorted. For example, the
> > "triangle simple" preset in Vintage Dreams soundfont can be maxed with
> > gain 140 without any distortion before it starts clipping.
> >
> > I'm not an audio expert and I certainly missing something. I've tried to
> > ensure soundcard and speakers are not the problem. I can supply the wave
> > files tested. Please, could someone throw some light?
> >
> > Thank you.
> >
> >     
>
>   


--
Bernat Arlandis i Mañó