[linux-audio-dev] Mixer controls

Dan Mills dmills at spamblock.demon.co.uk
Sun Nov 6 18:58:41 UTC 2005


On Sunday 06 November 2005 18:20, Tim Orford wrote:
> On Sun, Nov 06, 2005 at 03:21:54PM +0000, James Courtier-Dutton wrote:
> > It was just an example. The actual range depends on the sound card
> > hardware, but the typical limit is something like -60 dB or -80 dB.
>
> Ah, ok, yes i wasnt sure whether or not you were controlling the
> hardware.
>
> Also probably unnecessary for me to say this, but dont forget to
> preserve the L/R balance when the user reaches top and bottom of
> the fader's travel, unlike the current Alsamixer.
>

Also, worth noting is that most pro desks have a fader range that goes up 
above 0db (typically +10 -> -70 or so) and that the mapping of fader position 
to db value is not linear! 
Typically around one third to half the travel covers the +10 -> -10db range 
with the -10 to -70 range shoehorned into the remainder. 

Obviously the provision of 'gain' may not make much sense in something that 
basically controls the soundcard hardware but the fader position to db gain 
being non linear is a feature worth preserving.

IIRC there is a standard curve for midi CC values to gain that might be worth 
tracking down? 

Regards, Dan.



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