Using the Hammerfall HDSP on Linux

Testing the HDSP—Playing and Recording Sound

Now that the modules are loaded, and hdsploader has been run we can try to play a sound using aplay. Like any other ALSA driver, the HDSP driver mutes all channels at startup, so first you need to set the gain control, or volume, properly for your playback channels. One way to do this is to simply run alsamixer -c 1. When the bars are at 50% the channel is output with approximately 0dB gain. A more precise way is using amixer directly. The gain is as follows:

    0 = -inf dB
32768 =    0 dB
65535 =   +6 dB

A simple way to set all channels to 0dB gain is to use the following script:

for i in $(seq 1 18);do
	amixer -c 1 cset name=Chn,index=$i 32768

Now that you've done that, hook up your speakers to the first two analog outputs, and try the following:

aplay -D hdsp_analog some_stereo_file.wav

If all goes well you should see something like this:

Playing WAVE 'some_stereo_file.wav' : Signed 16 bit 
    Little Endian, Rate 48000 Hz, Stereo

By default, playback channels are connected to their respective hardware outputs; if this isn't true in your setup, you won't hear anything. If this is the case, read the following section on configuring the matrix mixer.

You also can change the -D option to send audio to different channels. For instance, using hdsp_adat would send the audio to the first two adat channels; hdsp_spdif would go to the spdif outputs. All of this is controlled by asoundrc.

If playing a sound worked, try recording a sound with arecord. This time, hook up a sound source to your first two analog channels, and run the following:

arecord -D hdsp_analog -f dat recording.wav

Press Crtl-C to halt recording. If everything worked, recording.wav should be a stereo file at 48kHz. In this case, the matrix mixer has no effect on what's recorded; the first channel recorded always corresponds to the first hardware input and so on.

Switching between SingleSpeed and DoubleSpeed Mode—Using 96kHz

As mentioned above, all software using the HDSP must be closed before switching between SingleSpeed and DoubleSpeed mode. But normally, software sets the sample rate. So what now? Well, there is a setting related to the AutoSync functionality (more on that later) that can do the job, Sample Clock Source. I won't explain exactly how it works just yet, but basically, by setting the internal clock to different frequencies, the card automatically switches modes. For instance, to switch to DoubleSpeed mode run:

amixer -c 1 cset numid=11 6

To switch back to SingleSpeed mode run:

amixer -c 1 cset numid=11 3

In both cases, don't forget to make sure that no application currently is using the sound card.

The Matrix Mixer

Sound routing is the most powerful feature the HDSP has to offer. Unfortunately, because it is not a feature found on many sound cards, the interface used to control it is not an ALSA standard. As of ALSA version 0.9.3, the matrix mixer interface is somewhat of a hack and is subject to change. It's possible to write values to it but not to read them back. In any case, the syntax used is source,destination,gain, where gain is as explained above, and source and destination are as follows:

For the Multiface:

input: 0-7 (analog), 16-23 (adat), 
      24-25 (spdif), 26-43 (playback)
output: 0-7 (analog), 16-23 (adat) 
        24-25 (spdif), 26-27 (line out)

For the Digiface:

input_source : 0-25  (physical channels), 
               26-51 (playback)
output_source : 0-25 (physical channels), 
               26-27 (line out)

The routing for the Multiface is also shown in Figure 1. By default, the playback channels are routed to the hardware output channels in order. All other possible connections are muted (0 or -inf dB gain).

To change an entry, use the following command:

amixer -c 1 cset numid=5 src,dest,gain

For instance, you could direct the SPDIF input to analog out with the following:

amixer -c 1 cset numid=5 24,0,32768
amixer -c 1 cset numid=5 25,1,32768

When you're finished, run the commands again, but with 0 as the gain instead of 32768. Don't forget that you can have multiple channels going to a single output or multiple outputs from a single input. Any combination is possible—use your imagination.



Comment viewing options


Getting Multiface to work with Pulseaudio oder Jack?

hamli's picture




I someone out there who succeeded in that respect?

I partly succeeded myself in

Anonymous's picture


pcm.hdsp {
        type hw
        card 1

ctl.hdsp {
        type hw
        card 1

pcm.hdsp_analog {
        type plug
        ttable.0.0 1
        ttable.1.1 1
        ttable.2.2 1
        ttable.3.3 1
        ttable.4.4 1
        ttable.5.5 1
        ttable.6.6 1
        ttable.7.7 1
        slave.pcm hdsp

pcm.hdsp_adat {
        type plug
        ttable.0.8  1
        ttable.1.9  1
        ttable.2.10 1
        ttable.3.11 1
        ttable.4.12 1
        ttable.5.13 1
        ttable.6.14 1
        ttable.7.15 1
        slave.pcm hdsp

pcm.hdsp_spdif {
    type plug
    ttable.0.16 1
    ttable.1.17 1
    slave.pcm hdsp

pcm.hdsp_dmix {
    type dmix
    ipc_key 1024
    slave {
        pcm {
            type hw
            card 1
        rate 44100
        format S32_LE
        channels 18
     bindings {
        0 16
        1 17

Hammerfall DSP 9632 on Ubuntu Studio

Viktor Mastoridis's picture






rick park's picture


and don't want to go back to WinXP ever again.



Jeanny Winter's picture

Hey Rick ... where is the Message ???


rick park's picture


Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

Thanks again,

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture




Anonymous's picture


Thanks a lot for the Info.

tefl tesol tesl course, tefl certificate, teach English

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture


Thanks! How do you specifiy other outputs besides 1,2

Anonymous's picture

In the example
aplay -D hdsp_analog some_stereo_file.wav
you get output on the first two analog outputs.

How do you indicate outputs 3,4 or 5,6 or 7,8 using this
type of command line?

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

at least. This allows you to control the matrix mixing function
graphically, very similar to the Windows application.



Anonymous's picture


Re: Using the Hammerfall HDSP on Linux

Anonymous's picture


Re: Using the Hammerfall HDSP on Linux

Anonymous's picture
