[linux-audio-user] Low Input Level
hannu at opensound.com
Sun Dec 5 01:33:25 EST 2004
On Sat, 4 Dec 2004, fooman wrote:
> Now under Windows, a slider for the IPGA is not provided.
> There is only more limited access to the gain registers,
> allowing the inputs to be set for +4, 0, and -10 dB use.
> This was done, I imagine, to prevent someone from turning
> the gain up high, with the volume down, resulting in a
> noisy signal.
The same approach is being used by the OSS driver for Envy24 cards as
well. The reason is very simple. In professional environments audio cards
are always used on "full" level. All volume control is being done in the
mixer or output amplifier stages. The "trim" controls are only used to
match the level with the devices the audio card is connected with.
> Fortunately, the wise programmers of ALSA gives us the
> hardware's full range of control (256 steps I believe
> for this register) for the gain.
OSS lets customers to use the card in this way if they like. There is a
configuration option (envy24_gain_sliders=1) which makes the trim controls
to look like sliders. This is usefull when a professional card is being
used in home environment. If you have a mixer with balanced inputs/outputs
then you probably don't want to do this.
Notice that the other volume sliders only affect the output of the
on board digital monitor mixer.
>> So, My question now.
>> How do increase the input level gain of the M-AUDIO DELTA 1010?
Delta 1010 doesn't have any software adjustable trim controls but just the
level buttons in the rack unit. The Delta 1010LT model has software
adjustable trim (input/output gain) controls.
Hannu Savolainen (hannu at opensound.com)
http://www.opensound.com (Open Sound System (OSS))
http://www.compusonic.fi (Finnish OSS pages)
OH2GLH QTH: Karkkila, Finland LOC: KP20CM
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