Audiomux 2 review – first look at v.2 of AppBC’s audio over USB app for OSX and Windows

Download from iTunes App StoreAudiomix logoI posted a full review of the first release of AppBC’s Audiomux iOS music app a few months ago. Audiomux allows you to stream audio between your iOS device and OSX desktop computer using nothing more than the standard USB charging cable that is supplied with your iPad or iPhone. It also complements AppBC’s Midimux app that does the same sort of data transfer for MIDI data.

Both apps seems to work very well from the off and, used together, they make integrating your iOS music making technology and your desktop music making technology a much simpler affair; no unpredictable wireless connections, no other hardware required…  just the apps, the associated ‘server’ apps for your Mac (free from the Audiomux website) and a cable Apple have already supplied for you. An update soon after the initial release introduced multi-channel audio support allowing you to stream up to 16 channels of audio at the same time.

However, over last week-end, v.2.0 of Audiomux arrived on the App Store along with updated versions of the server apps on the Audiomux website. There are some big changes listed for this new version. First, IAA app integration is now included with the app so you can easily utilise IAA compatible apps directly from within Audiomux. Second, the graphical layout has been overhauled so you can see both instrument and effects app connections on the same screen (this change was also perhaps required to accommodate the IAA support). Third, you now get a mixer option within Audiomux itself. This make it much easier to balance the various input/output audio streams that are going to and from your desktop computer.

Audiomux 2 - new look and new underlying approach - but same multi-channel audio connectivity to your desktop.

Audiomux 2 – new look and new underlying approach – but same multi-channel audio connectivity to your desktop.

However, it is perhaps the final two headline changes that are the most significant. First, Windows users can now officially get in on the action. AppBC have been beta-testing Windows support for some time…  but it is now included in a release version of the app. This ought to open up the potential user base considerably. Second, the app now uses a VST and AU plugin for easy integration with the host desktop DAW. This is, of course, the approach already adopted by Music IO with its approach to ‘audio-over-USB’ but is different from Audiomux 1 where, under OSX for example, the desktop end of the communication was handles by creating an Aggregate Audio Device.

On the iPad, you can now add IAA-based apps into an Audiomux audio stream.

On the iPad, you can now add IAA-based apps into an Audiomux audio stream.

I’ve not yet had a chance to fully explore v.2 under Windows yet….  but I will get on to that in the next few days. However, I have had a chance to explore v.2 when using iOS with OSX so I thought that might be worth reporting here…

Plugin baby

As mentioned above, v.2 of Audiomux brings a substantial change to how audio is handled at the desktop end. While the previous approach undoubtedly had some advantages, I suspect it was a solution that worked better under OSX than under Windows. Equally, I suspect it might also have been a solution that worked better with some DAW/sequencers than others (although it worked great on my iMac with Cubase, for example).

Audiomux v.2 now uses either VST or AU plugins to manage the audio communication with software on the desktop. Yes, you still have to download and installed the server version suitable for your OS, but that process now also adds the appropriate plugins and, rather than Audiomux’s desktop audio inputs appearing as virtual hardware inputs alongside those of your soundcard, now you simply load an instance of the plugin and tell it which Audiomux audio stream to work with. This is, now, pretty much the same technical solution as used by Music IO and, given the ubiquitous support within the majority of desktop DAW/sequencers for the VST or AU plugin format, should ensure the widest compatibility possible.

Ah, found it!

Ah, found it!

Having got Audiomux running on my iPad and the latest server version on my iMac, at first, I was scratching my head to find the Audiomux plugin within Cubase…. It did, however, turn up….  just filled under the ‘zerodebug’ folder within the Cubase plugin browser rather than being filed under (for example) ‘Audiomux’. Your desktop host may vary in this regard but just be reassured that the plugin is there if, at first, you can’t track it down.

New pad

Audiomux 2 adds support for IAA-based apps as well as allowing connections through Audiobus. Probably as a consequence of this – and of some of the other ‘under-the-hood’ changes in the app, the UI for the iPad end of things has undergone something of an overhaul. Now, instead of separate screen for either ‘instrument’ or ‘effects’ apps, instead, all connections can be made on a single, multi-lane (8 lanes in total as you can have up to eight audio streams) screen that is not so far removed from something like Audiobus.

As with Audiobus, you can tap on an empty cell within the screen to add an app. You get prompted to choose whether the app is an effect or instrument app, and then you get a list of all the suitable IAA apps available on your system. You can simply scroll this list to find the app you want. On the whole, this worked well enough but I did find the occasional glitch at this stage in terms of the UI performance. Presumably, these workflow issues will be tweaked in subsequent updates and it was certainly nothing that would stop me wanting to take advantage of the option to integrate my iPad audio into my desktop system. Audiobus apps can also be added once you have set them up within Audiobus as in Audiomux v.1.

The Audiobus route is still available using Audiomux 2.

The Audiobus route is still available using Audiomux 2.

Once you have added an app, if you want to delete it, then you can swipe it away. This does take a bit of practice to get the required gesture…  but stick at it as it does work.

A further significant change is the inclusion of a Mixer option within Audiomux 2. While you can, of course, visit each of your individual apps and adjust their levels, having an input/output level mixer for each of the eight audio streams all in one place is a very useful feature. It allows you to easily attenuate the output levels of your various instruments and, if you are using some of Audiomux’s audio streams as send-return effects with an iOS effects app or two, then you can set both the input (audio from your desktop) and output (processed audio to return to your desktop) levels. Very neat.

Audiomux now includes a Mixer screen.

Audiomux now includes a Mixer screen.

The other feature well worth mentioning is the ability to save an iPad Audiomux configuration. Once you have a set of apps loaded, you can save this selection and, if required, later recall it again. While it may not be quite the same as State Saving in Audiobus (that is, the apps may not return to their previous settings if you have subsequently used them in another context), rather wonderfully, all the apps do launch automatically when you reload your saved session.

Audiomux sessions can be easily saved for later recall.

Audiomux sessions can be easily saved for later recall.

Again, I experienced a couple of minor glitches when exploring this system but, on the whole, it worked very well and is a great time saver. Hopefully, any remaining rough edges will be smoothed out with a suitable maintenance update.


Finding the plugin aside, the initial configuration of Audiomux on your desktop computer is now much more straightforward. With the desktop server running in the background, you simply open your DAW/sequencer of choice (providing it supports VST or AU plugins), set up an audio track and then place the plugin as an insert effect on that audio track.

If you then open the plugin, you can configure which audio stream from your iOS device is going to be used by that instance of the plugin. This is straightforward and you see the app icons to help guide you. Options for both audio input and audio output are provided. You would, of course, use both input and output if you are hoping to process audio from your desktop using an audio effects processor running on your iPad.

In that context, I had no problems setting this type of routing up but, within Cubase, found the easiest way to do it was to use a standard FX Channel as I would if using an internal effects plugin to process audio via a send-return configuration. You can, however, also apply an effect to a standard audio track if you wish.

Three instances of the Audiomux plugin side-by-side in Cubase. Each is installed on a different track and each controlling a different Audiomux audio stream.

Three instances of the Audiomux plugin side-by-side in Cubase. Each is installed on a different track and each controlling a different Audiomux audio stream.

Providing you set your audio track to be internally monitored (that is, you hear any incoming audio after it has passed through any plugins; in Cubase, that means activating the little speaker icon for the specific track within the track list), then you can monitor the audio coming in from your iPad without any difficulty. However, as I explained in some detail when reviewing Music IO, depending upon the audio routing options provided by your DAW/sequencer, actually recording that audio may require a little more work.

Most DAWs apply insert effects on an audio channel in real-time and, whether you are listening to live audio arriving on the tracks input, or you have recorded something on the track and are simply playing it back, then the insert effects are applied ‘afterwards’.

You can easily identify which audio stream is to be used within an instance of the plugin via the list of app icons.

You can easily identify which audio stream is to be used within an instance of the plugin via the list of app icons.

In practice, what this means for Audiomux (as for Music IO) is that, while it easy enough to monitor the audio arriving from your iOS device, it is not quite so straightforward to record said audio. When you record (for example) a simple microphone input on an audio track, what gets recorded is the ‘dry’ direct signal; you can hear the insert effects but they are not recorded…. and, as Audiomux is sitting there as an insert effect, then the same applies.

Indeed, within Cubase, the setup process is now exactly the same as I used with Music IO. While there may be other ways to achieve the same end result, in Cubase Pro 8, for each audio source I wanted to bring in from my iPad, I ended up with three audio-related tracks (plus, of course, any MIDI tracks sending MIDI data out to my iOS apps via Midimux). The first audio track was simply used as a home for the Audiomux plugin for that particular audio input stream (as above).

However, I then set up a dedicated FX Channel (bus) for that audio track and used one of the audio track’s Send slots to pass the incoming iPad audio on to the FX Channel. I didn’t put any effects plugin onto this track. I also set both the output of the original audio track and the FX Channel to route to ‘No Bus’. This meant that the incoming audio from the iPad was only be routed to the FX Channel and not directly to my main stereo outputs. For the FX Channel, it meant that its audio was also not going to go directly to the main stereo outputs either.

To actually record one of my iPad Audiomux audio streams, I used a combination of three tracks; it's a bit cumbersome to set up initially but is flexible and works very well.

To actually record one of my iPad Audiomux audio streams, I used a combination of three tracks; it’s a bit cumbersome to set up initially but is flexible and works very well.

Finally, I set up a further audio track. This is the audio track that will, eventually, record the audio being streamed from one of the iPad Audiomux audio inputs. For this track, I set the audio in (source) to be the appropriate FX Channel. I then engaged the ‘monitor’ button for this audio track (in Cubase, this is a small speaker icon and it glows yellow when on).

So, the end result of all this setup was that, for each of the audio inputs from my iPad that I wanted to use within my desktop DAW, the audio arrived on the first audio track via the insert effect Audiomux plugin (where it can’t be recorded and I disabled monitoring by routing to ‘No Bus’), was passed to a dedicated FX Channel (bus; also with its monitoring disabled by sending its output to No Bus) via a Send from the original audio track. From that bus, the audio was then routed back to the audio input of a further audio track where it was eventually sent to the main stereo outputs for monitoring. Hit the record button in this track and it could also be recorded.

Easy? Well, it sounds more complex to explain that it actually is to configure and the process soon becomes second nature… I’m sure there are other ways to achieve the same end-result (in Cubase and other DAWs) but this worked well enough for me and gave me a clear signal path through Cubase that was both easy to follow and easy to toggle monitoring on/off.

All muxed up?

While I did experience a few graphical and/or operational glitches during my own testing, given just what is being attempted by Audiomux – and given that the software has gone through a fairly substantial transformation between the previous release and this one – I think I’d have been very surprised if it had been a perfect, super-smooth, experience from the off. Over and above the issues mentioned above, I also experienced the very occasional audio glitch but I think this was more to do with the load I was placing on my iPad than Audiomux specifically; close down a few apps and things soon smoothed out.

If an IAAfeatures an IAA control strip, that will appear when used via Audiomux and can be used to toggle quickly back to the Audiomux app itself.

If an IAAfeatures an IAA control strip, that will appear – as seen here for SampleTank – when used via Audiomux and can be used to toggle quickly back to the Audiomux app itself.

While I am mainly working with iOS/OSX, I do occasionally make use of a couple of Windows-based machines for specific musical tasks. As soon as I can, I’ll try and repeat this process on a Windows machine (perhaps using a different host DAW for the fun of it) and report back on that. However, if the use of VST plugin format means that Audiomux’s very clever technology is now available for Windows users to exploit, then the underlying change of approach will, I’m sure, be welcomed by many. Here’s hoping it works as smoothly as with OSX and that any wrinkles can be quickly ironed out. Even with those wrinkles, however, this is mighty impressive stuff.

My only other comment is that Audiomux is most certainly an app that could do with some comprehensive documentation for new users. Here’s hoping AppBC can add some further guidance on their website or within the app – written or video – that can step users through the initial learning curve.

In summary

Given the change of approach adopted within Audiomux, there is now perhaps less of a difference between using Audiomux or Music IO for this iOS-to-desktop audio connectivity; both use plugin technology at the desktop end and require similar audio routing options in order to record the incoming audio. This change for Audiomux may be something that some current users are disappointed by but I can appreciate why, as a technical solution, the plugin route may be easier to handle as a cross-platform solution in development terms.

There are still operational difference though and differences in the details of the feature set and/or workflow. I think at this very early stage it is difficult to see which app might end up on top. Both have obvious potential and both have demonstrated the proof on concept. It will be interesting to see which way their various their development pathways now go and who can do the most to convince users that they are offering the best performance and smoothest workflow.

For users, however, neither are particularly expensive technologies…  and if you have to buy both until that particular bit of competition sorts itself out, then so it it; it will not break too many banks. I think the competition is a good thing though. It is bound to drive the development forward at a somewhat faster pace than would otherwise be the case….

Anyway, if you are interested in integration of your iOS music software with your desktop music production system, Audiomux 2 is well worth checking out – alongside the obvious competition – whether you are using OSX or Windows as your desktop platform.



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    1. What abour sample quality? I coulnt find any info anywhere, and it is rarely discussed or documented, and thats a major drawback of ios music prodution,until higher sampling is available its all just toys and sketch tools

      • Hi Yon…. I agree it would be helpful if developers could indicate the sample rate/bit-depths used in their audio processing. That said, we have recording apps capable of handling 24-bit/44.1kHz audio and, while I’m happy to admit to being less precious than some about audiophile status, that’s the format I use on my desktop system for all my own commercial work without any issues…. And having heard a lot of our better iOS synths/virtual instruments over some decent monitoring or through live rigs/PA systems, they can sound very good indeed. All that said, some folks want to work at higher sample rates and bit depths…. and that’s a perfectly valid personal decision…. If so, maybe iOS isn’t (quite yet) able to deliver the level of performance required? best wishes, John

    2. I have been dinking around with Music IO for transfer to my PC studio. Haven’t had a chance to dig in totally. But will have to give this a look as well. There are some of these synths and such I would really like to have VST versions of :)

    3. Henk Velkers says:

      Thanks John for your fine review and testing of Audiomux ! I have purchased MusicIO and found your instructions real easy to follow, because both apps are using the same technology now to stream audio and midi between an Ipad and a desktop computer. So far i am able to play my keyboard and receive audio back into Cubase Elements 7, but recording is a real challenge. I wonder, if this version of Cubase is capable of setting an audio tracks input to an effect channel as you described in your article. Is there no other way to record audio in Cubase ? Or do i have upgrade to an other version ?

      • Hi Henk… sorry for the slow response… I only just spotted this as I re-read the post myself while getting ready to write a further post on the latest update…. As far as I’m aware, Cubase 7 Elements should be able to cope with the routing required to do this…. It has the necessary audio and FX channels…. However, without that exact version of Cubase in front of me, I can’t really comment on what’s possible in terms to ‘routing’ audio between the various channels required. I’d be surprised if it wasn’t possible though…. Good luck and let us know how you get on…. best wishes, John

    4. John can you please mention, is Audioubus “required” to use Audiomux within your DAW ?
      I like you use Cubase/Nuendo.
      Thank you for considering.
      (I’ve had no luck getting a reply (?) from AppBC since purchasing)

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