[Ardour-Users] Ardour input level issues

[John Rigg]

On Thu, Oct 25, 2007 at 01:56:50AM +0200, David wrote:
> On Wed, 24 Oct 2007 20:26:00 +0100
> John Rigg <au at sound-man.co.uk> wrote:
> 
> > FWIW I've been using three Delta 1010s with an analogue mixer
> > for quite a while without any level problems. I just make sure
> > that analogue signals are a sensible (non-clipping) level on the
> > mixer's meters, and that the digital signals are a sensible level
> > (also non-clipping) on Ardour's meters.
> 
> IIRC, Delta 1010s use an ICE1712 chip like other Deltas. For my
> information, what are your settings for the "analog volume" controls
> (DAC/ADC) and why ?

There is no "analog volume" control for the Delta 1010 (unlike some
of the smaller ice1712 based cards). There is however a -10dBu/+4dBu
switch next to each input and output on the breakout box.

I do have an Audiophile 2496, and on that I set "analog volume" to 
maximum, which gives no attenuation (or gain). Why? Because reducing
levels in the sound card potentially reduces resolution eg. if
it attenuates by reducing the integer sample values.

> Also, I've always wondered what the two Deemphasis controls (as
> seen in alsamixer) were and what I should do with it. I have set them to
> Off for now.

With ice1712 cards you should be using envy24control (from alsatools
package) instead of alsamixer. envy24control is specifically for the
ice1712/envy24 chips. Don't use deemphasis unless the sound source
was recorded with emphasis (effectively a treble boost, hardly ever
used).

John