[LAU] digital volume sounds better at 0 dB?

[Niels Mayer]

On Fri, Jun 18, 2010 at 1:41 PM, <fons at kokkinizita.net> wrote:
>
> If that soundcard really has the dynamic range that the
> sales blurb claims it has, then its output level will be
> a lot higher than what is expected by the average non-pro
> amplifier, including 'audiophile' ones.
>

Shouldn't the output level be the same, and only the resolution improved --
whatever is the standard peak-to-peak voltage
for consumer audio (~ 2vpp?). Otherwise, we'll risk electrocution when they
invent 64 bit DACs :-)

What a strange soundcard: i'd rather buy something with only digital outs
and connect an external DAC.
W/r/t the "AV100" chip,  I wonder if there's bugs lurking given the fact
that it's a relatively new and probably not widely used card:/chip.
http://alsa-project.org/main/index.php/Matrix:Module-virtuoso
http://alsa-project.org/main/index.php/User:ClemensLadisch#CMI8788_driver_status
Xonar Essence ST AV100
Details[PCI] [ANALOGio] [RCAo] [TOSo] [24bit] [192kHz]
front panel mic input does not work ALSA 1.0.22 or kernel 2.6.33


> Check the digital level with e.g.
> jkmeter, For classic use the K20 mode and ensure you
> have a level around 0 dB. For pop use the K14 mode
> and again ensure you have around 0 dB.
>

Many thanks for pointing out jkmeter ( jkmeter-0.4.0-1.fc12.ccrma.x86_64 ).
I had to read
/usr/share/doc/jkmeter-0.4.0/README to get an idea of what you meant by K14
and K20:
..........
Instead of providing extra gain for the RMS level,
the K-meter displays it on the same scale as the
digital peak level, but puts the '0dB' mark and the
color change well below the OdB full scale level.
For the K-20 meter it is 20dB down, for the K-14
this is (surprise !) 14 dB.
.........

jkmeter feature request -- MIDI AGC: A MIDI output (!) which in it's most
simple form, sends a note-on/note-off on the midi channel where clipping has
occurred (then you can use something like Dominic Sacré's
http://das.nasophon.de/mididings/ to route to a mixer such as
envy24control).
In a more useful form, each clip would reduce the value of a MIDI controller
(one per midi channel) by a configurable amount.
A midi input (!) would  read output slider values from a mixer
like "envy24control -m -M":
-m, --midichannel midi channel number for controller control
-M, --midienhanced Use an enhanced mapping from midi controller to db slider
The midi output of jkmeter++ would then decrement the given controller in
envy24control by a configurable amount each time clipping occurred.

.......

>
> The correct alignment procedure would be:
>
> 1. Play a piece of music representative of what you
> normally listen to.


I usually prefer testing fine soundsytems with Muppet heavy metal (
 http://www.youtube.com/watch?v=HKGiOY72ru4&feature=related )
or black death metal (
http://www.youtube.com/watch?v=Qvsq6_8Hzo8&feature=related ). (PS: j/k :-) )

-- Niels
http://nielsmayer.com
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