Re: [fluid-dev] V2 Chorus/reverb parameter ranges

[Ceresa Jean-Jacques]

Hi

 

> I will fix the docs and related shell command. But I wonder whether it
> makes sense for chorus depth to have no upper limit at all?

 

I think that an upper limit should be fixed for chorus depth, but it must based on the lower limit of sample rate (22050Hz) (not the upper limit of sample rate ).

upper depth limit (ms) = (MAX_SAMPLES * 1000) / lower sample rate limit = 92 ms

with:

- MAX_SAMPLES: the actual chorus maximum delay length (in samples)

- lower sample rate limit: 22050 Hz

 

When the chorus unit takes account the chorus depth (in ms), it converts this in samples as this:

nbr sample = (depth / 1000) * sample rate

if (nbr_sample > MAX_SAMPLES) { nbr_sample = MAX_SAMPLES }

 

So it is always safe.

jjc

 

 

> > Message du 05/10/18 13:51
> > De : "Tom M." <address@hidden>
> > A : "Ceresa Jean-Jacques" <address@hidden>, address@hidden
> > Copie à : "FluidSynth mailing list" <address@hidden>
> > Objet : Re: [fluid-dev] V2 Chorus/reverb parameter ranges
> > 
> > > > Actually, the synth allows chorus.depth numbers only up to 21 (and I'm using 44100) Is that a glitch/problem?.
> > 
> > > Yes there is a mismatch between the old command and a the new one.
> > 
> > Ok, now I understand Ben's confusion. To clarify:
> > 
> > chorus speed always had 0.29 Hz as lowest and 5 Hz as highest value
> > allowed. Although cho_set_speed accepted any values, you should have
> > got a warning pointing out that it has been limited.
> > 
> > chorus depth has 0 as lower limit, but can be set to any higher value.
> > Seems that I misunderstood the existing limit 21 ms, which seems to
> > indicate the only "useful" upper limit.
> > 
> > @Ben: Were you trying to say that you're using 44100 ms for chorus
> > depth? And what sample rate are you using? (44100 Hz I guess?)
> > 
> > I will fix the docs and related shell command. But I wonder whether it
> > makes sense for chorus depth to have no upper limit at all?
> > 
> > Tom
> >