Audiomux review – easy system integration via AppBC’s new audio over USB app for iOS and OSX

Download from iTunes App StoreAudiomix logoAs I posted a few days ago, AppBC have now launched Audiomux – their companion app for Midimux that I reviewed a couple of weeks ago – and that allows you to send audio in both directions between an iOS device and a computer running OSX. Using both apps together (and the relevant OSX ‘server’ apps on your Mac; these are available as a few download from AppBC’s website), you can, therefore, link your iPad or iPhone with your desktop/laptop Mac via a simple USB-to-Lightning/30-pin cable and, as if by magic, pass both MIDI and audio data between them.

Audiomux - audio connectivity between iOS and OSX via a simple USB cable.

Audiomux – audio connectivity between iOS and OSX via a simple USB cable.

With the right configuration, this essentially means the two devices become part of an integrated system for the price of the two apps; no extra hardware is required. While we have been able to link our iPhones and iPads to our desktop computers for some time using a suitable MIDI or audio interface, or even wirelessly (although with somewhat unpredictable performance depending upon your wireless network), in terms of both cost and convenience, the Midimux/Audiomux combination is a very attractive one for iOS/OSX users… although, obviously, not so helpful for those using Windows-based computers. I’ve no idea with a Windows-based version of the apps is something that AppBC have considered… I guess we will just have to wait and see.

Audiomux basics

Audiomux is currently priced at UK£4.99, is a 4MB download, is universal and requires iOS7.0 or later. It is a separate app from Midimux and, like Midimux, requires a small ‘server’ app to also be running on your Mac (and available as a free download from the AppBC website). There is, apparently, a ‘bundle’ of both Midimux (UK£7.99) and Audiomux awaiting approval on the App Store and that will save you something on the pricing of both apps when purchased individually.

At present, once Audiomux is correctly configured between your iOS and OSX devices, you get a single stereo audio signal in both directions. If you were actually running multiple iOS apps with the aim of sending their output to your OSX DAW (for example), their audio output is combined within the iPad before passing via the USB connection to your Mac. This is not such a major restriction in a recording context as you can easily monitor in this fashion while developing a song idea and then simply render each instrument/app as a separate pass to your desktop DAW/sequencer to get more control at the final mix.

Audiomux - ready and waiting to transfer audio between your iOS device and OSX computer via a simple USB connection.

Audiomux – ready and waiting to transfer audio between your iOS device and OSX computer via a simple USB connection.

Which direction you might want to send audio in is obviously dependent upon your own personal workflow. In my own case, I can imagine most of the audio flow would be from iOS to OSX as I send the output of some of my favourite iPad music apps over to my Mac to record them within Cubase. However, I could also imagine sending audio in a circle if I wanted to use some of the creative effects apps I have on my iPad (Turnado, Flux: FX, DFX, etc.) as send/return effects within Cubase on my desktop. If technically possible, that could be quite an attractive option.

If, alongside that kind of audio handling via Audiomux, I could also run Midimux, then that would be a big plus. So, I could sequence MIDI within my desktop version of Cubase, have Midimux send that MIDI data out to my iPad where it would drive one of my favourite iOS synths such as Thor, Nave or Z3TA+ and then Audiomux could handle bringing the audio output from that synth back from my iPad, back to my Mac, and straight into a suitable audio track within Cubase. Equally, I could imagine using one of my favourite MIDI performance apps on my iPad to pass MIDI to Cubase on my Mac to trigger all that in the first place….

… if, of course, it all works in as simple and as reliable fashion as required my make the system feel ‘integrated’. Let’s find out…

Mining aggregate

While setting up Audiomux is pretty straightforward, depending upon how you are going to use this audio link – and the audio/DAW software you are running on under OSX – there might be a little extra bit of configuration to be done in terms of audio settings.

For example, Cubase under OSX only allows you to use a single audio device at any one time. This might be some mega-channel audio interface or a simple 2-in/2-out affair, but t has to be a single device (not all DAWs have this restriction by the way). In Cubase, I usually have my Focusrite audio/MIDI interface selected for this function.

However, when you launch Audiomux on your iPad/iPhone and run the free OSX ‘server’ app, this appears as a separate audio device under OSX so, in Cubase, I would have to select either the Focusritre or Audiomux; I couldn’t use both. That is, of course, not ideal because what I really want is to monitor everything through my Focusrite (and my nearfield studio monitors connected to that) and just have Audiomux pass audio back and forth between my iMac and iPad.

OSX allows you to create an 'aggregate' audio driver so that any audio software 'sees' the different audio hardware available as a single audio device.

OSX allows you to create an ‘aggregate’ audio driver so that any audio software ‘sees’ the different audio hardware available as a single audio device.

Fortunately, under OSX, there is a fairly simple solution; creating an ‘aggregate audio device’. This rather clever process combined the features of both audio devices into a single ‘aggregate’ device via a it of software trickery. Then, within Cubase, I can simply select this aggregate audio device as the single audio device to use and I have access to both my Focusrite audio features and those of Audiomux.

Cubase allowed me to select the aggregate device as my audio driver.

Cubase allowed me to select the aggregate device as my audio driver.

I’ve no idea whether this aggregate device then functions as efficiently (for example, in terms of audio latency) and I’ve not done any formal testing of the performance for speed or CPU overhead (although if you know about this issue and feel able to share, then feel free to leave a comment below). If setting up an aggregate audio device is something that you might need to do, then there are plenty of guides available that a quick Google search with soon find… but you could start with this simple guide available from Apple’s own support pages.

Bilateral agreement

So, let’s start with a fairly simple situation based upon one of the example applications for Audiomux that I mentioned above; hooking up a single iPad to my iMac and getting audio from an iOS synth (or three) into Cubase assuming, in this case, that I’m simply after an audio-only setup and I’m playing the iOS synth from its own virtual keyboard.

The Audiomux side of the setup is very simple; you run the iOS app on your iDevice (in this case, my iPad Air 1 test system) and then run the ‘server’ Audiomux app on the OSX computer. This places a tiny icon in the Menu Bar but, that aside, there is nothing to configure.

On the iPad, you then need to setup Audiomux – and any other apps you want to use with it – within Audiobus. In the screenshot, I’m using Z3TA+ in the Audiobus Input slot and have Audiomux in the Audiobus Output slot. Configured this way, audio from Z3TA+ will, via Audiobus, get passed to Audiomux and, from Audiomux, get passed on to my iMac… and, hopefully, more quickly that I’ve been able to type the actual description of what’s happening!

A simple Audiomux setup with a single iOS synth sending audio to Audiomux via Audiobus...  and then on to my iMac.

A simple Audiomux setup with a single iOS synth sending audio to Audiomux via Audiobus… and then on to my iMac.

Once Z3TA+ and Audiomux are in place within Audiobus, if you flip back to the Audiomux main screen, you can see a visual representation of the connection made…. an arrow goes from Z3TA+ to my iMac.

As shown in the earlier screenshot, the flow in the other direction is empty as, in this example, I’m not sending any audio from the iMac back to my iPad. This is perfectly possible though and, if you put an instance of Audiomux in the Audiobus Input slot (and providing you are sending audio in your desktop software to the Audiomux outputs there), you could then put (for example) a recording app in the Audiobus Output slot to record audio coming from your iMac.

If there is a complex stage to getting this all working (and, even then, it’s not all that complex) it is not with Audiomux itself but with whatever audio ‘receiving’ software (such as your DAW/sequencer) that you are running on the desktop. As mentioned above, for Cubase, I needed to create an aggregate audio device but I suspect that will not be the case for all DAWs and there may be other minor details of configuration within the DAW that don’t apply within Cubase… suck it and see is (unhelpfully!) about all I can offer on this front at this stage as I haven’t had the opportunity or time to experiment with other DAWs as yet.

Incidentally, setting up the aggregate device was a one-time operation, not something required every time I used Audiomux. So, having configured the aggregate device, when I wished to use my iPad within a Cubase project, it was simply a case of selecting the already-created aggregate device when starting Cubase so that I got access to both my Focusrite audio in/out ports and my iPad audio in/out port. Note that most DAWs (Cubase included) allows you to add suitable labels to your various audio ins and outs… so I simply used an ‘iPad in’ and ‘iPad out’ label and I could then select that with whatever audio destination or source I was using in Cubase to make sure the audio either arrived where required (on a Cubase track) or was sent where required (off to the iPad).

With this simple setup, I was easily able to send Z3TA+'s audio output to a suitable track in Cubase.

With this simple setup, I was easily able to send Z3TA+’s audio output to a suitable track in Cubase.

Once this is done, in order to get Z3TA+’s audio output from my iPad onto a Cubase audio track simply requires me to select the ‘iPad In’ as the audio input source for that track (as shown in the screenshot). This really is very straightforward and, if my own testing was typical of the experience, also produced a very smooth performance.

My iPads audio outputs become available within Cubase as an audio source thanks to a combination of Audiomux and the aggregate audio device.

My iPads audio outputs become available within Cubase as an audio source thanks to a combination of Audiomux and the aggregate audio device.

Oh, and incidentally, if you lower the audio output level on your iPad to zero, while you still seem to get an audio signal received on the desktop via Audiomux, (and which you can hear via any monitoring system you have hooked up to your desktop system), you don’t also have to listen to the audio output directly from the iPad’s speakers.

Return to sender

My next experiment was simply to send audio from Cubase back to my iPad just to demonstrate that it works. It does, and it is very simple to do so I could, for example, send an audio track from Cubase and, if I placed Audiomux in the Audiobus Input slot, it would receive that audio and then pass it on to the rest of my Audiobus signal chain.

In my screenshot example, that involved Flux: FX in the Audiobus Effects slot. I was also able to have audio going in both directions at the same time so I could also have my Z3TA+-to-Cubase connection in operation also.

However, there is – at present at least – one limitation that it would be great to see overcome. While you can have Audiomux positioned in an Audiobus Output slot (to send audio from the iPad to the desktop) and an Audiobus Input slot (to receive audio from the desktop to the iPad), you can’t have Audiomux in the Input and Output slots of a single Audiobus chain.

Going both ways at once? Audiomux seemed perfectly capable of sending audio data in both directions at the same time...  but not in the same Audiobus signal chain.

Going both ways at once? Audiomux seemed perfectly capable of sending audio data in both directions at the same time… but not (yet, at least) in the same Audiobus signal chain.

What this means is that one of the scenarios I outlined above – where you use this link to process desktop audio tracks through an iOS audio effect in a send-return context – can’t currently be achieved. There are relatively few hints on the AppBC website about what other features are planned for Audiomux but it would be great if making this possible was one of them. There are other apps that can appear in both Input and Output slots of a single Audiobus chain (Cubasis for one) so it is technically possible… whether it is technically possible given everything else Audiomux is dealing with is another matter…. fingers crossed.

There is one final point to emphasise here… currently, what you get is a single stereo audio signal going in both directions. So, even if as in the very first screenshots at the top of the review, you were actually running multiple iOS apps, their audio output is combined within the iPad before passing via the USB connection to your Mac. This is not such a major restriction in a recording context as you can easily monitor in this fashion while developing a song idea and then simply render each instrument/app as a separate pass to your desktop DAW/sequencer to get more control at the final mix. Rather wonderfully, there is a hint on the AppBC website that multichannel audio might well be a possibility at some point in the future. That would also be great to see. Even if it only meant a couple of stereo channels in both directions, it would considerably increase the possibilities of what is already quite an impressive bit of software technology.

Being bilingual

My next experiment was an obvious one; to run Audiomux and Midimux at the same time. For me, the obvious application for this is to send MIDI data from Cubase on my iMac through to an iOS synth app running on my iPad (via Midimux) and for the audio of that synth to then be sent from the iPad back to the iMac for recording (via Audiomux).

Midimux configured on my iPad and with Z3TA+ ready and waiting for MIDI data from my iMac.

Midimux configured on my iPad and with Z3TA+ ready and waiting for MIDI data from my iMac.

I set Midimux up as described in my review of that app when launched (and, again, ran the OSX Midimux ‘server’ on my iMac). It seemed to sit quite happily alongside Audiomux both under iOS and OSX. I’ve no idea whether there is an overhead involved under iOS (well, there is bound to be some CPU loading required… I’m just not sure how much) but, for just adding a few synth parts from virtual instruments sat on my iPad, this whole process was completely unproblematic.

Here, MIDI data is being send to my iPad via Midimux while, at the same time, the audio that results from the MIDI reaching Z3TA+ is being recorded back to Cubase via Audiomxu; very neat!

Here, MIDI data is being send to my iPad via Midimux while, at the same time, the audio that results from the MIDI reaching Z3TA+ is being recorded back to Cubase via Audiomxu; very neat!

MIDI was sent from my iMac through to the iPad without any fuss, it triggered my chosen iOS synth (or synths) and the audio was then returned to the iMac from the iPad as described above. Given that the only additional hardware required to make this happen is the USB/Lightning cable supplied with my iPad, I think this is pretty remarkable. As this is the most obvious way I would wish to use Midimux and Audiomux in combination, it is rather wonderful that (a) it seems to work, (b) it seems to work well and (c) it is very easy to set up; If you are a music maker who loves both iOS and OSX, integration of your favourite iOS music apps with your favourite OSX music apps just got a whole lot easier.

Three’s a crowd?

As noted in the Midimux review, if you have multiple iOS devices, you can connect more than one to your desktop computer and run Midimux on all of them. Suitable MIDI ports will appear on your desktop allowing you to direct MIDI data to multiple iOS devices at the same time. Again, rather wonderfully, Audiomux offers the same feature; you can connect multiple iOS devices, run Audiomux on all of them and you ought to be able to send/receive audio to/from them all concurrently.

To test this out, I hooked up my iPhone 5 in addition to my iPad Air 1, added the iPhone to my aggregate audio device under OSX, and attempted to get Cubase to run both MIDI and audio to/from both the iPad and iPhone at the same time. The results in my testing to date were encouraging… but not quite perfect. The iPad behaved absolutely fine (as when used on its own) and Midimux seemed very happy sending MIDI data to my iPhone at the same time as I could hear my iOS app (bs-16i in this case) responding to MIDI in a smooth and swift fashion in I turned up the iPhone’s own audio so I could hear playback through the iPhone’s own speakers.

Audiomux running within Audiobus on my iPhone 5. Multiple iOS hardware talking to my iMac at the same time?

Audiomux running within Audiobus on my iPhone 5. Multiple iOS hardware talking to my iMac at the same time?

However, the audio that was returned to Cubase via Audiomux had a distinct delay to it and despite trying various tweaks to see if I could remove this (including just switching everything off and starting again), I could seem to find the source of the problem. Of course, the problem could lie with Audiomux itself, my iPhone 5 or some aspect of the aggregate audio device system under OSX when combining multiple devices into a single aggregate. By removing the iPad from the equation, I was eventually able to resolve the issue and got the iPhone working on its own just as well as the iPad had done…. Anyway, as and when I get more time to explore, I’ll report further.

This minor glitch aside – and which I might be able to resolve with a little more experimentation – I have to say that I’m still just very impressed that the combination of Audiomux and Midimux works as well as it does considering these are both first releases. The potential here is obvious…. so let’s hope that AppBC can get enough support to keep moving this technology forwards.

I'm not sure why I couldn't get both my iPad and iPhone working at the same time without a little audio latency...  but I'll keep digging.

I’m not sure why I couldn’t get both my iPad and iPhone working at the same time without a little audio latency… but I’ll keep digging.

In summary

Talking of moving the app forwards might seem a bit on the picky side given just what AppBC have already achieved here and especially so given that both apps have only been with us for such a short time. However, the potential is both obvious and (in iOS/OSX integration terms) huge.

The two obvious things that would be great to see are (a) the option to place Audiomux into both the Input and Output slots of the same Audiobus signal chain (so you can use your iOS device as a send-return effects processor within your DAW) and (b) the option for multichannel audio to be returned from your iOS device to your OSX computer (so you can run multiple synth but return each to a separate audio track within your desktop DAW). These apps are already impressive – but with these additional capabilities, they would be doubly so.

We do, of course, also have Music IO from Secret Base Design to consider. The MIDI side to that app works very well also and the audio element is promised shortly. It will be very interesting to see how these two competing products stand up to one another – and perhaps help to drive each other forwards – over the next few months.

Whether both gain traction or just one (and we will just have to wait and see at this stage), the ability to pass both MIDI and audio data between your iOS and OSX music technology using mothering more than some clever software and a USB cable (and no additional hardware) is impressive stuff. I love working on my iPad for music making… but the level and easy of integration offered by the Midimux/Audiomux combination means that using one system to the exclusion of the other is no longer something that has any significant cause other than personal preference.

Audiomux – like Midimux (and, indeed, like Music IO) is already brilliant and, if you are using both iOS and OSX for your music making, these apps are as close to a ‘must buy’ as you are likely to get. I sincerely hope this technology gets ported to the Windows platform because I’m sure a lot of iOS/Windows users would be just as happy to snap it up.

Audiomux


Midimux



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    Comments

    1. Psysword says:

      Awesome. Thanks for the in depth look.

    2. Hey John,

      I read on the Synthtopia website, that they are planning a Windows version as well – This came from one of the devs I believe.

      • Hi Steve… thanks for this… good to know. I’ll follow up and see if I can find out anything else that is available for public consumption… Best wishes, John

    3. That’s great that you pushed these apps pretty far…good job. I agree that these seem to have perfectly wonderful functionality, but with a little more…we’d have awesome sauce!

      I’m on Windows so you can imagine how that feels right now! But I am hopeful that Patrick at SBD will have a windows solution for us in the not too distant future.

      (Off topic side note: John, did you know that Sunrizer synth had gone to the desktop?)

      • Hi Toz… agreed… It’s a great start and impressive stuff… but it is difficult not to always start an ‘if only….’ thought stream :-) Let’s hope Windows support is also something on the cards…. Oh, and yes, I did know about Sunrizer and I’ve been trying to chase a copy for review as I think it would be interesting for the iOS community (as with BIAS going to desktop). best wishes, John

    4. Hi John… great tutorial, thanks.
      Regards Scotty

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