linuxaudio.org

On Sat, 2010-08-14 at 22:51 +0200, fons@kokkinizita.net wrote:

quoted text
> On Sat, Aug 14, 2010 at 12:19:33AM -0700, Niels Mayer wrote:

>

> > The big issue with having the full 144dB range is that the "business"

> > end of the slider is all at the top,

>

> I've never seen a real fader that has any practical resolution

> below -80 dB: the next tick, 5mm or so down,  is 'Off'. And most

> don't even go down that much.

I'm sure most people on here know this, but the decibel scale is a

relative logarithmic scale.  Saying "-80dB" means that whatever went in

was attenuated by 80dB, or 1x10E8 - if you put in a 1V signal, a 0.01µV

signal will result.  For normal line level, that would be 0.007µV, or

7pV, yes picovolts!  At 24-bit sampling for full-scale line level

(0.707V), the LSB encodes a value of 0.042µV, and at 16-bit sampling

that becomes 10.8µV - well below what your attenuator is letting

through.
For what it's worth, the channel faders on my Yamaha O1v go down to

-60dB, with "infinity" being the bottom stop.  To find what the values

discussed above would be at -60dB, multiply the voltages by 100.
Gordon MM0YEQ
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