AUM review – does Jonatan Liljedahl’s brilliant app change the iOS music-making landscape?

Download from iTunes App StoreAUM logo 1Within the iOS music-making community, there are some developers that qualify for almost universal hero worship; Jonatan Liljedahl is one of those. Whether it is the ubiquitous utility app AudioShare, the truly inspiring (and sometimes mind bending) electronic rhythm/groove app Sector, or the minimalist audio effects of the AUFX series, Jonatan creates brilliant apps that almost any iOS musician would want to own. And, with his latest app – AUM – that has appeared on the App Store today, he may well have done it again. Stand by for action; AUM is quite a piece of work….

At it’s most basic, AUM can best be described as an audio mixer for your iOS music apps but, as it is capable of acting as an AU host, routing audio to and fro between Audiobus and IAA apps, includes it’s own internal effects options, offers as many audio channels and sub-mix (bus) channels as your iOS hardware can manage, includes MIDI routing support for synths, other virtual instruments or MIDI control, Ableton Link, latency compensation and the option to record any or all audio channels (or busses) directly to AudioShare (for exporting elsewhere) and… well, it doesn’t take a genius iOS musician to realise this might be quite a useful app to have around.

AUM - a potential game changer for the iOS musician?

AUM – a potential game changer for the iOS musician?

There is genius involved in the design and implementation though…. Having been fortunate enough to have had access to the release version over the last couple of days, while I’m certain that I have not yet uncovered all the things AUM has to offer, if you want me to cut to the chase then I’m happy to do so. If you are the kind of iOS musician who tends to work with more than a few apps at a time – and you have hardware that lets you do that – then AUM is going to be very appealing. This is a top-notch stuff.

Incidentally, just a few weeks after I posted this initial review, AUM received quite a substantial update….   I’ve therefore updated this review by adding a section at the end to cover the changes introduced in that v.1.1 update.

AUM fun

Let’s get some of the basics out of the way first. AUM is a universal app and is priced at UK£13.99/US$18.99. At just an 6MB download, it is also an app that is easy enough to provide a home for. This is most certainly a ‘utility’ type app in that it doesn’t actually create any noise of its own. However, it does provide a way of routing, mixing and processing your various audio signals from any multi-app setup you happen to be using.

As it offers audio routing options – and the ability to apply audio effects apps to an audio input app before sending that audio to the output – there is an element of Audiobus in AUM. However, AUM can also work with Audiobus (as we will see in a bit more detail later). And while this isn’t necessarily an app to replace Audiobus, depending upon just how you like to work, and the combination of apps that you use, you might find AUM offers a feature set that does allow you to use AUM rather than Audiobus.

By some, AUM might be used as a direct replacement for Audiobus... but it can also work with Audiobus for some additional audio routing possibilities.

By some, AUM might be used as a direct replacement for Audiobus… but it can also work with Audiobus for some additional audio routing possibilities.

As AUM offers a means of mixing (and, indeed, sub-mixing) the audio from your various iOS music apps, there is also an element of MiMix about AUM. However, as AUM can work with Audiobus, IAA or AU-based apps, and not just Audiobus, AUM is perhaps aiming at something a little broader in design than MiMix.

Channel stripper

While AUM is a software-based mixer, it brings something closer to Audiobus in terms of the visual representation of that mixer rather than the more familiar graphical representation of a hardware mixer as found in some of the more popular DAW/sequencers or, indeed, MiMix. I don’t think either approach has a particular advantage but, if you are a musician with a background in hardware, you might have to pinch yourself as a quick reminder ‘this is a mixer’ until the AUM interface becomes familiar.

AUM offers MIDI routing options as well as audio....

AUM offers MIDI routing options as well as audio….

On first start-up, you simply tap the large ‘+’ icon to create a new channel. Do note, however, that this initial screen also includes a ‘Reload Last Session’ button; tap this and, as advertised, whatever setup you had previously loaded will reload itself. This is a very nice touch and the reload process does the best it can to cope with any changes in your connected hardware (for example, a different audio interface) or selection of apps.

That said, the app also includes the option to save your AUM configurations for later recall. Again, this is great to see in an app that is, essentially, a means of managing more complex app configurations. Having a ‘one button loads everything’ options for getting multiple apps set up is a big time saver…. although this doesn’t guarantee that all those apps will come up with the same settings/presets that they might have been using the last time you happened to load your AUM project.

Channels in AUM offer you three types of 'nodes' rather like Audiobus.

Channels in AUM offer you three types of ‘nodes’ rather like Audiobus.

When you create a new channel, as shown in the screenshot, as well as a volume fader, a bit like Audiobus, you also get three ‘nodes’ into which you can insert an input source, an effect app (and you can create additional slots for multiple apps if you tap on the vertical signal chain line below the first effect and slide upwards until the ‘+1’ icon appears ) and an output destination.

For the input slot, this can be an audio input from your audio interface (and multi-channel audio interfaces are supported) or a specific app. In terms of apps, this can be an IAA app, an AU app (yes, AUM is also an AU host) or an app from an Audiobus channel. For the later to work, AUM needs to be selected in the appropriate output slot within Audiobus and, in fact, once you set this up in Audiobus, AUM will automatically create a new channel. So, whether it’s just an audio signal from a mic or DI’ed guitar, or any one of the dozens (gulp) of iOS synths, drum machines or virtual instrument apps that you have installed, AUM has you covered.

There are two other input source options; File Player and Mix Bus. File Player does pretty much what is says on the tin and, as you might expect given the developer here, you can load any audio file for playback that is sitting within AudioShare. There are some very useful options here including the ability to loop the audio file; this is great if you have a rhythmic loop that you want to work alongside.

AUM's input sources include IAA apps as it acts as an IAA host....

AUM’s input sources include IAA apps as it acts as an IAA host….

If you select Mix Bus you get 8 possible Mix Bus sources to pick from (labeled A to H). As we will see in a minute when looking at the output options for a channel, if you select a Mix Bus as an input source to a channel, that channel then effectively becomes a sub-mix (group channel) for any other AUM channels where that same Mix Bus is selected as their output destination. If you have either a hardware or software mixer environment that supports this kind of mix bus/group channel system then this concept will be familiar. However, if not, one application of this kind of system is that it can give you one fader to control the overall level of several channels at the same time.

For example, let’s imagine you have several apps on other channels that are all contributing to a drum/rhythm track. You can adjust their relative levels via their individual faders. However, if you then send all these channels to a single Mix Bus within AUM, the fader on the Mix Bus channel can then be used to provide an overall ‘drum/rhythm’ volume control (and can have some global effects applied to it) relative to any other elements of your project such as synths, guitars or vocals that are on other AUM channels.

OH, and AU support is also included... as seen here of iSEM.

Oh, and AU support is also included… as seen here of iSEM.

In terms of effects apps in the effects nodes, this is pretty much what you might expect. However, AUM does go a bit of an extra mile in that it offers the option for effects to be placed either pre- or post-fader; simply tap and hold on the app’s icon next to the fader and the option will slide out. Tap and immediately drag right, and you get the option to reorder the effects chain if you are using multiple effects apps on a channel.

As well as inserting effects into a channel directly, you can also create a ‘send’ (a Bus Send in AUM-speak) from a channel via the effects slots. This adds a send level control to route audio to one of the 8 Mix Bus channels mentioned earlier…. And if you add something such as a reverb or delay effect in an effect node on that Mix Bus, you can use it as you would a send effect within a DAW/sequencer such as Cubasis, Auria Pro or MultitrackStudio for iPad.

AUM is supplied with a range of built-in effects... but you can also use IAA and AU effects in this role and the audio routing options allow you to configure send-return effects as well as insert effects.

AUM is supplied with a range of built-in effects… but you can also use IAA and AU effects in this role and the audio routing options allow you to configure send-return effects as well as insert effects.

In terms of the output nodes, you can either specify a specific audio output in your audio interface (or just the main speakers of your iOS device if you are relying on the built-in audio in/out) or, as described above, one of AUM’s 8 Mix Bus channels. For the Mix Bus channels themselves, you can send to an audio output or to a different Mix Bus. The latter option lets you set up one of the Mix Bus channels as a sort of ‘master output’ channel as you might get on a standard mixer (hardware or software).

There is more though…. Via Audiobus, you can also put AUM into an Audiobus’ Input slot and feed its output to another app. If you do this, then this output destination becomes available within AUM and you can pass any channel’s output – including that of a Mix Bus – to the Audiobus Output slot app. I tried this with Cubasis and it worked a treat. AUM offers up to four ‘ports’ of this type so you could, in principle, send to four different destination apps or send multiple audio streams to the same app. This means you can record up to four stereo audio channels within (for example) Cubasis at the same time with each being supplied by audio from some combination of AUM’s channels. Very cool… and also very powerful if you build your iOS creations from complex combinations of apps.

AUM's outputs can be routed to various destination including, as shown here, onwards to a DAW app such as Cubasis.

AUM’s outputs can be routed to various destination including, as shown here, onwards to a DAW app such as Cubasis.

The other option for routing AUM’s audio to something like a DAW/sequencer is even easier though; via IAA. If your DAW supports IAA hosting, AUM will offer four input ports within that host (see the screenshot taken from Cubasis; just note that in Cubasis at least, these appear in the alphabetical list under ‘K’ for Kymatica). Once one of these ports is selected as an IAA input to a track within your DAW, back in AUM itself, it then becomes available as an output destination for a channel. You even get a mini transport panel for the host next to the output port. Again, this worked very well in my own testing with Cubasis and the end result is the same as going via Audiobus; you can pass up to four stereo audio signals to your DAW from AUM at the same time. This is impressive – and very useful – stuff.

I had no problems bringing multiple stereo channels of audio into Cubasis from AUM.

I had no problems bringing multiple stereo channels of audio into Cubasis from AUM.

All inclusive

As mentioned earlier, AUM includes some of its own effects that can be added to a channel’s effects nodes (slots). These are organized into three groups; stereo processing, filter/EQ and dynamics. There is nothing too drastic here in terms of features and, in each case, you get a single parameter that you can adjust that appears alongside the node once the effect/processor has been added. Tap on the effect node though and, for many of the effects, some additional controls will pop up. I suspect that all these processing options are pretty low impact in terms of CPU but, for many routine tasks, are well worth having around.

There are some useful tools amongst the various built-in effects including a number of different dynamics options.

There are some useful tools amongst the various built-in effects including a number of different dynamics options.

The Stereo Processing group are quite interesting as they offer things like ‘stereo to mono’ and some mid/side processing options. The latter is something that you find in many desktop DAWs but less common under iOS with the obvious exception of Holderness Media’s rather brilliant Stereo Designer.

The Filter & EQ options include the usual low/high pass and shelf options plus a parametric EQ. The latter, for example, offers the usual frequency, bandwidth (Q) and gain controls when you tap on the icon. Finally, the Dynamics group offers gain, hard clip, peak limiter and saturation options.

The stereo processing effects are also very useful.

The stereo processing effects are also very useful.

The matrix

AUM is not just about audio though; it also caters for MIDI data routing. Indeed, the app includes a virtual MIDI keyboard (tap the mini keyboard icon located bottom-left of the display to open this up) and will happily manage MIDI data incoming from suitably connected external MIDI hardware.

You can configure how MIDI data is handled in a couple of different places. With the virtual MIDI keyboard open, you can tap the wrench (spanner) icon located to the keyboard’s right. This allows you to set the destination of any MIDI data generated by the virtual keyboard. However, if you open the main menu (located top-right), you get options for configuring both MIDI routing and MIDI control.

As well as the MIDI routing matrix, you also get MIDI control options if your hosted apps support it....

As well as the MIDI routing matrix, you also get MIDI control options if your hosted apps support it….

The MIDI routing offers you a ‘matrix’ for making MIDI connections and, while the wonders of MIDI under iOS are such that nothing is foolproof (!), it’s great to see this kind of functionality built into AUM. While I suspect you will still have to delve into the murkier corners of the MIDI settings for some of your other music apps, having a simple, central, hub for making MIDI connections is a very attractive proposition. For making basic connections – including multiple MIDI sources – between sources and destination, AUM’s MIDI routing matrix is a very neat feature.

AUM’s MIDI control options are also impressive. You can select multiple MIDI sources for MIDI CC data input and then use the built-in MIDI Learn system to link an external controller to almost any suitable parameter on any of the channels. This includes the basic channel controls themselves (for example, volume, mute or solo), any of the AUM’s built-in effects that have been added to the channel and any AU plugins inserted as inputs or effects. OK, this is just for AU plugins (and not, at present at least, anything connected via IAA) so it is as much about potential at this stage rather than a solution that will already work with every app….   but it is impressive anyway.

What else?

The key features described above aside, the main interface is a stylish affair with a fairly minimal set of additional options to get in the way. Along the top of the display you get access to the tempo setting and the Ableton Link toggle plus the master transport panel. This can be used to trigger any Ableton Link enabled apps that are connected.

Top-centre you get output level meters…. although it is also worth noting that there is metering on each channel, albeit of the very minimal ‘three coloured dots’ kind. Still, this is useful enough to see when a channel might be getting a bit hot.

The Ableton Link support seems to be very well implemented and I was able to run several apps locked together via Ableton Link within AUM.

The Ableton Link support seems to be very well implemented and I was able to run several apps locked together via Ableton Link within AUM.

The other elements of the top-most strip include a very useful ‘load’ indicator, a battery indicator and, of course, the button to open the main menu. That aside, the rest of the display is dominated by the channel displays. By the way, it is also worth noting that channels can be repositioned left/right and, while this does not change anything about their audio routing, if you prefer to have your channels organized in a particular order, then that’s possible and easy to adjust on the fly.

AUM in use

While there is a bit of a learning curve with AUM, it is a fairly modest one. Anyone who has used a more feature-rich mixer (hardware or software) will not find too many concepts here to challenge them even if graphically things don’t ‘look’ like a conventional mixer environment.

I’m sure in the short time I’ve spent with AUM I have not yet discovered all it might have to offer but I have to say this is a powerful and flexible ‘iOS audio mixer and MIDI router’. That is can host IAA and AU apps is a real positive and the ability to integrate with Audiobus and to provide Ableton Link support means AUM really could form a ‘hub’ for your complex iOS music projects.

AUM was hugely impressive in use.... the audio routing offered is both flexible and powerful.

AUM was hugely impressive in use…. the audio routing offered is both flexible and powerful and the option for recording individual channels – as shown here – within the app is very neat.

The thing I found most impressive was just how flexible the audio routing is. Almost regardless of the format of the app (standalone via Audiobus, IAA or AU), I could get the audio where I wanted it, whether that was to a particular hardware audio output or, in my case, into Cubasis as my DAW/sequencer. AUM’s MIDI routing options also made getting MIDI data to the required destination easier in many cases.

The recording options are also well executed so, if you don’t wish to record directly to your DAW, you can record any selection of channels or Mix Bus channels directly to AudioShare. This works brilliantly and you could, for example, use the Mix Bus system to create ‘mix stems’ of each group of instruments if you set up the audio routing and Mix Bus channels required.

All of which begs some rather interesting questions about established iOS music making workflows. The most obvious question is whether AUM is a complement to Audiobus (it most certainly can be) or whether it is a replacement for it. Audiobus has become such an established part of what many iOS musicians do – and has been absolutely pivotal in making the platform viable for music production over the last few years – but, if you fully invested in a workflow via AUM, would your need for Audiobus become significantly less?

In terms of just audio routing, I think there is most certainly a case for reaching that conclusion. OK, the two apps do things in somewhat different ways but the core functionality is similar; they allow you to route audio between linked apps and send it to your chosen final destination. AUM just happens to do that in a model based around a virtual mixer and includes the ability to control level, mute, solo and provide send effects.

The AUM main menu is logically organised and gives you access to all the file handling features amongst other things.

The AUM main menu is logically organised and gives you access to all the file handling features amongst other things.

As an aside here, one thing I have remarked on several times over the last couple of years is the lack of a decent mixing environment within GarageBand for iOS. I’ve not had time as yet to try GarageBand with AUM… but it would be an interesting experiment to see if the app can help GarageBand users overcome (even if only in part) what is an obvious limitation in an otherwise excellent recording environment.

In an iOS recording context AUM is an interesting proposition. IAA, for all its imperfections, enables you to get close to a desktop DAW/sequencer experience under iOS using software such as Cubasis or Auria Pro or MultitrackStudio. AU, if it gains ground and is refined by Apple, promises to bring that desktop workflow even closer; everything managed and mixed within a single software environment and all the 3rd party apps operating as plugins. In that world (when it gets to be a perfect one), apps such as Audiobus and AUM may be less of a necessity.

However, if your iOS music making is as much about live performance as it is about recording, then AUM is going to make a lot of sense even when AU becomes more widespread. You can configure all your app-based signal chains into a series of AUM channels, control where any MIDI input is going to end up, send the resulting audio out to any connected hardware outputs and control the mix levels via the individual channels or Mix Bus channels. Oh, and if things need to be triggered in sync then Ableton Link is also available…. AUM has considerable potential in this context therefore and I can see live performers getting a heck of a lot of use from this app with or without any recording workflow options it might also bring.

Having tried a whole range of different IAA and AU apps within AUM, the vast majority seemed to perform very well indeed.

Having tried a whole range of different IAA and AU apps within AUM, the vast majority seemed to perform very well indeed.

Is AUM the ‘new Audiobus’? Perhaps that depends upon the take up by the iOS music making community but it is certainly a viable alternative as well as being able to be used alongside our established Audiobus ‘app glue’ workflows.

Addition: the AUM v.1.1 update

As I mentioned earlier, only a few weeks after the initial launch, Jonatan was back with a fairly substantial update to AUM. This included the usual round of fixes and minor tweaks…  but also added, and improved upon, a number features. For example, the initial four IAA/AB output port option was increased to eight, 88.2kHz sample rates were supported, better support was offered for handling multi-channel audio inputs on any connected hardware and the option for multiple AU windows to be open at the same time was offered.

The update to AUM allowed multiple AU windows to be open at the same time.

The update to AUM allowed multiple AU windows to be open at the same time.

On top of this, the FilePlayer was improved in a number of ways, sync options were refined for both Ableton Link and host sync and a number of workflow tweaks were made to refine the operation of the app. The bottom line, however, is that Jonatan simply made a brilliant app even better….

In summary

While AUM is a utility app, in that context, it is brilliant on a number of levels. Technically, it offers a very flexible virtual mixing environment for your various iOS music apps. It might not look like a conventional mixer but the key features of audio routing, insert and send effects and group channels are all there. That it adds MIDI routing and MIDI control options plus app sync via Ableton Link is also a bit of a technical triumph.

The app is also brilliant in terms of the design. OK, some might actually have preferred it to look like a conventional mixer. Instead, Jonatan has gone for a minimalist combination of flow diagram and abstract faders. It looks modern and is very slick in use. It takes a few minutes to orientate yourself but you very quickly find your way around.

So do you need to add AUM to your iOS music app collection? I’d hesitate to say that this was an essential purchase for every iOS musician because I think it depends upon just how your existing workflow is structured and the kinds of projects you assemble. However, if you like to combine multiple apps into more complex projects, whether that’s for recording or live performance, I think AUM is going to be hugely tempting.

I suspect, however, that if you are an iOS music app fan, whether you think AUM might become part of your daily workflow or not, this is an app you will want to experience for yourself. It might not be as sexy as the latest mega-synth but, in the utility app class, this is up there with the likes of Studiomux, Music IO and, yes, Audiobus itself in terms of significance.

Jonatan Liljedahl…. I take my hat off to you…. AUM is a brilliant idea that has been brilliantly executed. Top-notch technical stuff and highly recommended.

AUM – Audio Mixer

Preview of AUM – Audio mixer app from Jonatan Liljedahl on Vimeo.


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    1. Luís Silva says:

      This is an app that I can’t see usefulness in music production. Why carve a mix of instruments if there isn’t an arranger? The result is a salad of instrumentos playing at same time. I really don´t know what to do with this. Sorry to say this.

      • Hi Luis…. whether AUM will be useful to you or not will most certainly depend upon the kinds of things you do with your iOS music making and your usual workflow…. In one sense, AUM is an audio mixer in an app. Rather like you would connect multiple audio sources together for a live performance or recording session via a hardware mixer in a traditional music production environment, AUM can perform that role in an iOS app environment. Those using their iPads live, with multiple apps running, would find this really useful.
        In another sense, it is like Audiobus – but with mixing capabilities built in and support for AU and IAA hosting. Some will therefore use it as a direct replacement for Audiobus.
        I’m not sure if that helps at all….? But, like Audiobus, which certainly has been an important app in terms of iOS music workflow, AUM has quickly become an essential part of their working process…. Very best wishes, John

        • Luís Silva says:

          Hi John, yes you are absolutely right. The way I work on music hasn’t given me need to use this program. I’m sure it’s very good. I use the Korg gadget that I love and I export for Ableton Live 9.5. I Also convert many sounds of my VST Ableton’s to use in Korg Gadget. I really like your Blog! I come here every day to see if there is news! Keep up the excellent work.


          Luis :)

    2. Hello John
      I use a lot of Loopy HD on love performance, and a limes the concept of AUM a lot, but i havent been able to use Loopy to record The sounds out of AUM. I tried to route AUM into Loopy via audiobus, pero ten it records nothing. I would love to be able to use Loopy as a “effect ” unit rather tan a audiosource en AUM. Do you know if theres about this? Best wishes, Jorge

    3. i cant get things to stop clipping, anyone has this same issue. For ex I got a clap that clips at 0.0db. it clips to +2.9 db, but i can lower the track volume to minus, well all the way down and the clap is still clipping and I made sure it wasent clipping when i recorded the wav file..? Anyone might help me out by telling me were I might have went wrong?. Other wise evrything is super. And thing they probably add an arranger in future.

    4. I just bought it, and I am really impressed! I didn’t find it confusing at all and it’s the first time I have got apps to work together without a major struggle! What would be really good (maybe it is already possible?) would be a way of being able to stop and start apps maybe from a controller(?) so you could get them all playing together and in sync…

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