Interfacing Linux: RME HDSPe AIO Pro

In 2000 RME announced the HDSPe AIO Pro. It offered the same high channel count as the original AIO but with the reference AD/DA converters from the ADI-2 Pro along with a bunch of other goodies.

Unfortunately the original snd-hdsp driver was incompatible with the AIO Pro so work began on a new Linux driver and configuration utility.

Finding out RME discontinued the production of the AIO and now offers the AIO Pro, which was not supported by the hdspm driver, was the trigger that made me develop the new driver. There is no reverse engineering in this driver. RME was so kind to share their windows and mac driver source code with me.

–Philippe

The snd-hdspe driver is a work in progress but that’s not going to stop us from poking the AIO Pro with our Linux stick.

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Drivers

In order to use the AIO Pro on Linux you will need to compile the kernel module and user space configuration tool. This installation guide is for Debian 11.

Install kernel headers

sudo apt-get install linux-headers-$(uname -r) 

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Install dependencies

sudo apt install git libasound2-dev wx3.0-headers libwxgtk3.0-gtk3-0v5 build-essential libncurses-dev xz-utils libelf-dev libwxbase3.0-dev libwxgtk3.0-gtk3-dev dkms

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Clone the snd-hdspe repository

git clone https://github.com/Schroedingers-Cat/snd-hdspe.git

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Enter the snd-hdspe directory

cd snd-hdspe

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Checkout the 5.18 branch

git checkout support-v5.18

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Compile the driver

make -j `nproc`

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A little prelinking

sudo ln -s $(pwd) /usr/src/alsa-hdspe-0.0

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Install the kernel module

sudo dkms install alsa-hdspe/0.0

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HDSPe Configuration Utility

Clone the snd-hdspe repository

git clone https://github.com/PhilippeBekaert/hdspeconf.git

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Enter the hdspconf directory and compile the utility

cd hdspeconf/ ; make depend ; make

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You will now have the hdspeconf utility needed to configure your AIO Pro.

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HDSP Mixer

While we don’t get Totalmix, Totalmix Remote, or DIGIcheck on Linux but we do have hdspmixer. You can install it with the following command.

sudo apt install alsa-tools-gui

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Jack

In Cadence/QjackCtl select the ALSA driver to connect your RME AIO Pro to the Jack server. 

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Pulseaudio

The RME AIO Pro will function like any other sound device in pavucontrol.

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Round-trip Latency

While many kinds of audio latency metrics exist, one useful and well-understood metric is round-trip latency; the time it takes for an audio signal to enter the input of a device, get processed, and exit the output.

The following measurements were taken using jack_iodelay. The AIO Pro managed 6.28ms, a full 3.64ms faster than the RME 9632 on the same machine using a period/buffer size of 128 at 48K. For comparison, the MOTU M4 achieved 7.53ms with the same settings.

Using a period/buffer size of 32 at 192K the AIO Pro was able to achieve a round-trip latency of 0.57ms.

When it comes to speed there is still no replacement for PCIe.

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Testing setup

CPU	AMD Ryzen 7 1700
RAM	Corsair Vengeance LPX 16GB
Motherboard	MSI B350 Tomahawk
GPU	Nvidia 2060 FE
SSD	Samsung 840
PSU:	EVGA 600 B1
Firewire:	Syba SY-PEX30016
Network:	Intel i350-T4
OS:	Debian Bullseye
Kernel:	5.10 RT
Desktop:	XFCE 4

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Verdict

The RME Aio Pro works as intended under Linux. You will need to build the driver and user space configuration tool from source. HDSP Mixer is available if you need it. Unfortunately, Totalmix is not available on Linux.