Using the Hammerfall HDSP on Linux

Gain new flexibility in how you route and process audio data with this versatile, professional sound card.

SPDIF on the HDSP Multiface is pretty straightforward; however, because ADAT and optical SPDIF share the same optical connectors you need to tweak a few mixer controls. The Digiface uses a similar setup as well, though not having access to one, I do not know the exact details. To enable optical input for the SPDIF, change the IEC958 Input Connector setting:

numid=6,iface=PCM,name='IEC958 Input Connector'
; type=ENUMERATED,access=rw---,values=1,items=3
; Item #0 'ADAT1'
; Item #1 'Coaxial'
; Item #2 'Internal'
: values=2

On later versions of the driver, setting the value to Internal seems to autoselect between optical (ADAT1) and coaxial, on others it does nothing. I don't know what the behavior will be with your driver, so you should check yourself.

Optical output is similar. By default, SPDIF output goes only to the coaxial connectors, but when the IEC958 Output (also on ADAT1, numid 7) is enabled, output goes to the optical connector as well.

The Sample Clock and AutoSync

Like all digital audio devices, the HDSP needs a clock source to function. This can be from either the internal clock generator or an external digital source, such as the ADAT or SPDIF inputs or the Word Clock. This is important when recording from external digital sources; if the clock is not synchronized properly, dropouts and clicks can result. When the clock is coming from an internal source, the HDSP is said to be operating in Master mode, and if the clock is from an external source, Slave mode. As shown in Figure 2, the various clock sources go into the AutoSync system, which then sends a single clock signal to the clock users.

Figure 2. The AutoSync system decides which clock signal to use.

AutoSync decides which clock signal to use. This is controlled by the Sample Clock Source setting and the Preferred Sync Reference setting. The former, Sample Clock Source, determines if the HDSP operates in Master or Slave mode. Its possible settings are as follows:

numid=11,iface=PCM,name='Sample Clock Source'
; type=ENUMERATED,access=rw---,values=1,items=7
; Item #0 'AutoSync'
; Item #1 'Internal 32.0 kHz'
; Item #2 'Internal 44.1 kHz'
; Item #3 'Internal 48.0 kHz'
; Item #4 'Internal 64.0 kHz'
; Item #5 'Internal 88.2 kHz'
; Item #6 'Internal 96.0 kHz'
: values=0

If you specify AutoSync, 0, the HDSP operates in slave mode and follows an external clock source. In this mode, playing a sound works only if the sample rate matches the external sample rate; otherwise, you receive an error message. Also, if there isn't a valid external clock available, the driver will not let you switch to AutoSync mode. Any other setting will set the Internal Clock Source sample rate to the specified frequency. Once the card is not in AutoSync mode, playing a sound at a different sample rate to the current one changes the current sample rate.

The other setting, Preferred Sync Reference, is useful when you have multiple possible clock sources connected but need to specify which one to use as the clock source. Suppose you had a consumer CD player connected with SPDIF and an eight-track tape recorder connected with ADAT to your HDSP. Almost no consumer CD players can operate in slave mode and receive a clock signal. So the CD player will have to be the master device. However, AutoSync normally tries to sync to the ADAT first. What now? Well, by setting Preferred Sync Reference to IEC958 (SPDIF), AutoSync will synchronize the clock to the CD player. The tape recorder then can be synchronized though other means. The possible settings of Preferred Sync Reference on the Multiface are as follows:

numid=13,iface=HWDEP,name='Preferred Sync Reference'
; type=ENUMERATED,access=rw---,values=1,items=4
; Item #0 'Word'
; Item #1 'ADAT Sync'
; Item #2 'IEC958'
; Item #3 'ADAT1'
: values=2

ADAT Sync and ADAT1 are different things. ADAT1 refers to the optical ADAT connection, and ADAT Sync refers to the D-sub 9-pin ADAT Sync connector. There are also a bunch of read-only mixer items that show various aspects of synchronization, type amixer -c 1 contents to see them all.

The most common Linux sound complaint is, “I'm getting clicks and dropouts in my sound!” This could be caused by a number of factors, such as PCI bus bandwidth, nonconforming PCI cards, too-small block sizes or latency. If possible, install the low-latency kernel patches or the 2.6 kernel if it's available by the time this article is published, and make sure your audio program is set to use real-time scheduling. You also can try increasing the block size your program uses. For hardware difficulties various PCI cards, such as some 3Com network cards and RAID controllers, have been known not to follow the PCI bus specification and use more bandwidth then they should, starving the HDSP of bandwidth. You also might need to change the PCI latency timer settings; for information on this see Some motherboards also are known to have poorly performing PCI buses. RME's Web site is quite informative when it comes to hardware incompatibility. I recommend looking at the support section, both after and before buying a Hammerfall.



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Getting Multiface to work with Pulseaudio oder Jack?

hamli's picture


did someone succeed in getting the Multiface to work with Pulseaudio or Jack?

I am using Ubuntu Jaunty Jackalope and was successful so far to install the Multiface in such a way, that I can for instance play a music-file by entering the command "vlc --alsadev default". Even though I tried really hard I had no luck so far to integrate the Multiface in Pulseaudio oder Jack. Thus I currently cannot for instance use Rhythmbox together with my Multiface.

I someone out there who succeeded in that respect?

I partly succeeded myself in

Anonymous's picture

I partly succeeded myself in the meantime. I say "partly", because this solution creates trouble while watching videos. Anyway: The solution was, to use dmix. My file ~/.asoundrc looks like this:

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


I just plugged my new Hammerfall DSP 9632 on Ubuntu Studio and it works out of the box! It's such a great quality and such a great pleasure to listen to that magic sound coming out of the speakers in my new Linux/Ubuntu Studio setup.

Thank you to the Linux world for all this great software (audio and other) and the humanity which one gets while computing.

Thank you David for the beautiful, inspiring and insightful articles about making music on Linux.


rick park's picture


Ok. This is going to be a long message, so please be prepared for a longer
read - I have tried everything i could in order to get my HDSP 9632 working
on Suse 9.1...people you're my last hope ;-)
I absolutely want to get this working in Linux (i know its possible somehow)
and don't want to go back to WinXP ever again.

I've been browsing the net and tried every possible solution i could find, I
spent ages in IRC to get an answer, but still no luck.


Jeanny Winter's picture

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


rick park's picture

Oh sorry - my Browser went crazy, when I started to include all the questions i wrote. I will try later again.

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

Apparently, the 9652 and the HDSP are quite different, so while this article didn't help me as much as it might have, it did give me some insights on where to start. Thanks a lot for that.
I have a suggestion, on the 9652 front. gamix is UGLY, but it works to set things from ADAT to Internal, which helps immensly, as doing it int he asound.state file isn't all that easy. I don't know if it would work/help for the HDSP, but I think it might.
After a week of futile efforts, my card is finally working, and a large part of that is due to the hints this article gave me. I'm highly grateful for the help.
Thanks again,

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

I'm struggling to get this working under SuSE. I'm running ALSA 1.04 but I can't modprobe snd-hdsp without errors.

Does anyone know where a good place to get some support, or just a friendly ear would be?


Anonymous's picture

Well, this looks very intersting. When you can use every hardware you want, you are not limited to special vendors. I think, I will try one of those.

Thanks a lot for the Info.

tefl tesol tesl course, tefl certificate, teach English
teach travel, work travel, gap year, student travel, teach Asia

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

thanks for the article. I was trying to run my RME under a Knoppix boot from CD-rom. But reading this article it needs some files to be set up before it can run. I might try do a full install when I have the time...

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

Hi, alsa-tools also comes with a hdspmixer application - as of 0.9.8
at least. This allows you to control the matrix mixing function
graphically, very similar to the Windows application.

This provides an alternative to the 'src/dest/gain' mechanism.


Anonymous's picture

Another music app you really should try is Rosegarden. (All you Debian or Gentoo users out there should be fine with apt-get install or emerge.) It is a sequencing application which works with GNU Lilypond for professional music typesetting. Quite a trick!

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

This is a great article! Thank you Todd. Does anyone know of something similar for the older, Hammerfall Digi9652?

Re: Using the Hammerfall HDSP on Linux

Anonymous's picture

Thank you for this wonderful article. Linux and RME on an Athlon64 = way to go.