Ardour6 Supercharged my Zoom R24 Audio Interface?

After years of using Reaper in Windows as my DAW of choice, I decided to abandon Windows for Linux.

I used Reaper on Studio1337 (Puppy linux evolution) with great success. Then on Ubuntu Studio with some success. I decided to find a new DAW better suited for use in Ubuntu Studio, my main OS now which brought me to Ardour6.

So far, I’ve found it pretty intuitive and similar in some ways to Reaper, etc…

One thing that is BLOWING MY MIND though, is that Ardour6 is seeing all 8 mic/line inputs on my Zoom R24 instead of just the L/R Stereo output when using it as a USB Audio Interface. All my other OS/DAW combinations I’ve tried, the R24 is only showing as a 2 channel (Stereo L/R) input.

To be clear, I’ve always been able to use this mixer “stand-alone” to record 8 mics (or line) simultaneously. However, as a USB Audio Interface, it’s 8 in, 2 out:
(Straight from the website specs)

  • 8-in/2-out USB audio interface for Macintosh/Windows computers

Somehow, Ardour6 sees all 8 mic/line inputs? I even tested by sending two line inputs from my guitar (split into 2 paths with different effect/amp/cab ) and an XLR microphone for vocals. All 3 tracks were recorded into Ardour and verified with playback each track is the individual (not a mix of all 3) – I didn’t test all 8 at the same time, but if it got me the first 3 channels, it should do all 8…

Either I’ve misunderstood the capabilities of this unit for the last decade +, or somehow Ardour6 gave my Zoom R24 superpowers?! if all 8 inputs AND the mixed Stereo Output are also available, it’s now an 8-in/10-out Interface?

Can anyone help me wrap my head around this?

Ardour does not directly access the audio device, it uses whatever channels are exposed by the ALSA driver.

That seems likely. The specs on the Zoom web page state clearly and directly:
“8-in/2-out USB audio interface”

The specs on the Zoom web page state clearly and directly:
“8-in/2-out USB audio interface”

And so I have used it for many years… And as Macky compatible OSC.

Yes that too - it also can be used as a controller for your DAW if you want! I don’t use it that way much, but it’s another feature of the Zoom R24… for something that came out in 2012 or maybe earlier, this unit is sooooooo good!
I also bought a used R16 and can now slave it to the R24 and record 16 tracks simultaneously (stand-alone)!
Anyway, thanks for the comment, Sciurius !

Thanks Chris (ccaudle) for the response!

Ok so the ALSA driver in Linux is probably better than what Zoom provided for the R24 on MAC/Windows OS… very interesting indeed.

I just installed a Windows 11 VM on my Ubuntu Studio… I may try poking around in Windows to see if I can replicate this with Ardour… and try my Linux version of Reaper to see if it also sees the mic inputs… this is sooooo cool though!


I’m surprised that you couldn’t see these within Reaper on Linux.

In general, DAWs will see whatever the underlying Operating System presents, but you often have choices of which underlying audio subsystem to use because there are different use-cases for PC audio.

Very roughly speaking, there’s 3 types of audio subsystem:

Desktop Audio

These subsystems support simple access to audio devices for most common desktop use-cases: using a web-browser with Youtube, using a media player to play music, playing games, etc.

On Windows, there’s a variety of subsystems including WDM, MME and WASAPI which provide this sort of audio capability.

On Linux, the modern desktop audio subsystem for the last several years has been PulseAudio.

Some key characteristics of desktop audio subsystems:

  • They provide audio access for multiple applications at the same time, so you can (for instance) watch Youtube whilst also playing a game and get audio from both. They normally do this using software mixing.

  • They make assumptions about your audio hardware to try to keep it simple for most users. For instance, if you have a multi-channel audio interface, they tend to assume this is a surround-sound system (because, for the majority of users, it will be).

They will often also provide simple “profiles” for audio devices. For instance, on Linux with my multi-channel interface, I get these options:

It’s entirely possible, if you were using the standard Windows audio, that Windows assumed your audio interface was a stereo device and set up the channels accordingly.

  • They tend to have poor latency

Pro Audio

“Pro-audio” subsystems are designed to work with professional audio applications, like DAWs. They tend to be focused on supporting fidelity, low-latency, and tunability.

On Windows, Steinberg’s ASIO has become the primary pro-audio subsystem and most serious audio interface vendors will provide an ASIO driver.

On Linux, ALSA is built into the OS and provides very similar baseline capabilities to ASIO.

Key characteristics of “pro audio” subsystems:

  • They, typically, only support one audio interface per application at a time. This means that if you are using a DAW with your audio interface, no other application can use that audio interface. This is for audio fidelity reasons.

  • They provide little or no software mixing capability

*The provide low-latency access to the audio interface hardware (subject to hardware constraints).

Note that these are general categories, not hard and fast rules.

Enhanced Pro Audio
These subsystems provide something more than just access to the audio hardware, but are designed to be low-latency to support pro-audio applications.

Typical capabilities include:

  • Virtual cable capability to allow audio to flow between applications
  • Session Management
  • Other capabilities like global tempo and transport

On Windows, Mac and Linux, Jack Connection Kit is such a subsystem. On Linux it sits over ALSA and provides virtual cables, tempo, and transport capability.

To confuse things a little, there’s now also Pipewire which has emerged in the last few years which provides many of the capabilities of Jack and Pulseaudio in a single subsystem (with broadly compatible APIs).

My gut feeling is you may have been using Desktop subsystems on Windows and, perhaps, with Reaper on Linux and, in those cases, the subsystem can abstract the audio device down to a simple stereo device.

On Linux, ALSA (and, by extension, Jack/Pipewire) will normally expose the audio hardware at a very low level which includes all of the inputs and outputs, MIDI interfaces, etc. So if you select ALSA as the audio subsystem, you will normally get everything that the audio interface offers.



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Keith - (Majik) - thanks so much for taking the time to explain that.

Your explanation makes a lot of sense! And currently I’m using JACK/ALSA with my UbuntuStudio (22.04) OS as you’ve mentioned.

I was using the Free ASIO driver (I think?) with my Studio1337 Linux distro (Puppy Linux evolution) – it’s possible I just didn’t think to even try, since the Windows/Mac specs for the Zoom R24 is 8-in/2-out with Zooms proprietary driver(s).

Either way, this is really exciting for me to have this capability. I intended to use it a stand-alone (not as a USB Audio Interface with PC) to do my basic tracks live (IE > live performance) and then use it as an Audio Interface to record overdubs etc… but now possibly being able to record directly into my PC with all 8 tracks simultaneously, may improve my workflow - now I don’t need to transfer the recorded files into my PC to use in a DAW… they’ll already be there :slight_smile:

I also bought a used Zoom R16 to slave to the R24 and can record 16 tracks simultaneously (stand-alone) — now I’m wondering if the two connected together may also be seen by JACK/ALSA… I have some experimenting to do!

Thanks again for the response Keith!