Mixer controls of ice1712 (envy) based sound cards

The mixer controls of sound cards using the snd_ice1712 module are not complicted per se, but without explanation they are very hard to understand.


This section describes how envy24control represents the hardware.

Digital Mixer

This VU meter on the left, labeled “Digital Mixer”, shows the signal that comes out of the mixer in the sound card hardware. This is not neccessarily what comes out of the speakers! It is the sum of all signals mixed in on the next two tabs (“Monitor Inputs” and “Monitor PCMs”).

In the two monitor tabs there are two faders for a single audio channel. The faders determine how much of the (mono) input signal will be mixed into the left and right channels of the mixer. If both faders are up at the same time the stereo signal will be wrong – a mono signal mixed into the wrong channel. If all four faders for the two stereo channels have the same value, the signal that comes out of the mixer will be mono for this input.

Monitor Inputs

The VU meters on this tab show the raw input signals of the input connectors on the sound card hardware (line in, microphone etc.). Nothing except the physical level of the input signal affects the levels of this meters.

The faders control how much of the signal gets into the hardware mixer. The result is shown in the “Digital Mixer” VU meter). They can only reduce the level, not make the signal louder. It is safe to pull the faders all the way up.

Monitor PCMs

This tab is the same as “Monitor Inputs”, but for the PCM controls. These are the signals that are generated on the computer in software. The controls are labeled “Out” here instead of “In”. The functionality is nevertheless the same.

Patchbay / Router

The radio buttons select which internal audio source (label on the radio button) will be routed to which output (label on the column). Some examples

“H/W Out 1 (L)” and “H/W Out 2 (R)” are connected to the speakers. So the radio buttons select what you hear. I'm not sure what the “H/W Out” 3–6 outputs are for, but I think they are channels for the 5.1 sound.

There are two ways to hear sound: directly or via the hardware mixer.

Analog Volume

This faders control the levels of the outputs (DACs – digital to analog converter) and the levels of the input connectors on the hardware (ADCs – analog to digital converter). A level of 127 leaves the signal unchanged.

Hardware Settings

If you want to record from Line In, the “Line In Selector” must be set to the appropriate hardware.

In the same spirit phono and microphone share the same channels. Which one is active is defined with the “Phono Input Switch”.

Recording in audacity

By default audacity only records two channels (stereo). To capture the inputs of the card more channels have to be added. Phono/Mic is on channels 5 and 6.

DMX 6fire 24/96

Controls and their functionality

DAC Functionality
0 front left
1 front right
2 rear left
3 rear right
4 centre
5 LFE (subwoofer)

envy24control vs. alsamixer

Name in alsamixer Name in envy24control
PCM OutPCM Out 1
H/W In 0 CD In L
H/W In 1 CD In R
H/W In 2 Line In L
H/W In 3 Line In R
H/W In 4 Phono/Mic L
H/W In 5 Phono/Mic R
H/W In 6 ?
H/W In 7 ?
IEC958 In L Digital In L
IEC958 In R Digital In R
Digital Mixer Digital Mix (no left or right)
H/W Multi 4 Capture Phono / Mic L
H/W Multi 5 Capture Phono / Mic R
The “Mute” buttonsCapture


Licensed under the Creative Commons Attribution-Share Alike 3.0 License.