Gestrument music app review – touchscreen MIDI performances from Jesper Nordin

Download from iTunes App Storegestrument logoAs regular readers here will already be aware, I’m a bit of a fan of iOS music apps that bring a novel approach to creating musical performances via inventive uses of the touchscreen interface. Apps like Figure, Thumbjam, Triqtraq – and even the Smart Instruments in Garageband – instantly spring to mind as good examples. Equally, apps such as Chordion, which makes MIDI data entry for chords and melody lines so much easier for non-keyboard players (or keyboard players who don’t have access to a hardware keyboard and find the virtual keyboards in many synth apps a bit of a pain to use) are just brilliant illustrations of why iOS music making has so much potential.

Now, I appreciate that I’m perhaps a little late to this particular party, but I’d like to add another music app to this list; Gestrument. This app has been on the app store since November 2012 but it’s only recently – nudged by an email I received from Jesper Nordin (the designer of Gestrument) – that I dug in deep enough to put together a proper review. Incidentally, while Jesper is the designer of the app, Jonatan Liljedahl – the man behind Kymatica’s AUFX:Space and AUFX:Dub – was heavily involved in the iOS implementation.

Point the finger

The main performance screen - two fingers can generate an amazing number of MIDI notes. Click on the image to see a full-size version.

The main performance screen – two fingers can generate an amazing number of MIDI notes. Click on the image to see a full-size version.

Gestrument does include it’s own sound engine, built around a sample-based GM-compatible sound set, and while these sounds are perfectly respectable and allow you to experiment with what the app is capable of, the prime purpose of the app is really as a generator of MIDI data to be sent to other music apps. In that sense, it is very similar to Chordion, with its basic internal synth engine, but the expectation that most users will really want to feed the MIDI data to a more sophisticated sound source.

As its name suggests, you ‘play’ Gestrument through gestures. One-finger gestures will work but, with a second finger, you can also add some extra performance details such as dynamics (MIDI velocity); essentially, the wider you ‘spread’ your fingers, the higher the MIDI velocity generated, although this second finger can also be used to control other elements of the performance.

As described more fully below, the main functions of Gestrument are dived between two screen; a Performance screen with the main touchscreen playing area and the Editor screen where you can configure how the app will respond to your finger-based gestures. The app includes a recording facility for both audio and MIDI but also supports AudioCopy, AudioShare and Audiobus as well as being able to send and receive MIDI data via Virtual MIDI. You could, therefore, use an external MIDI control surface to tweak the app’s performance options while you generated MIDI notes on the touchscreen. Equally, the app will send MIDI data over a WiFi connection to your desktop (see the Music App Blog tutorials about linking your iOS device to your desktop computer here) if you want to use it as a performance surface for your desktop-based synths.

Noble gesture

Gestrument includes Audiobus support and these seems to work very well.

Gestrument includes Audiobus support and these seems to work very well.

Gestrument’s performance screen is dominated by the central playing surface, around which are arranged various performance controls. The exact configuration of the playing surface is user-configurable via the Editor screen but, in essence, the note pitches generated are lower at the base of the screen and get higher towards to top. The left-right axis controls how many notes are generated, with fewer to the left and more to the right.

To ‘play’ the instrument, you can tap or, more usually, tap and hold or tap and slide. As you do, Gestrument applies its magic and, based upon the ‘rules’ you have configured within the Editor, MIDI notes will be generated. One aspect of these rules is specifying which notes within a scale are allowed so, depending upon what key you are playing in, you can make sure you constrain all the notes to that key. As with some other touchscreen performances surfaces, Gestrument allows you to avoid duff notes unless you really want them :-)

One other interesting aspect of the app is that Gestrument can generate up to eight parts (sounds) from a single finger gesture. If using the internal sounds, each of these eight parts is monophonic and based upon one of the sample-based GM sounds built-in to the app, although there is no reason why you can’t set up the same sound on more than one part and create something polyphonic. When using the app to drive an external synth (iOS or on the desktop), as you can specify the MIDI channel that each of the eight parts is transmitted on, you can take your pick as to how your external synths respond; eight individual monophonic synths, eight note polyphony for a single synth or some combination between these extremes.

Along the base of the performance screen are the eight buttons that can toggle on/off the eight instruments (either the internal sounds or the MIDI channels if you are sending the MIDI data out of Gestrument). This enables you to easily switch in/out instruments in real time depending upon how complex or simple you want your performance to be. To the right of these eight buttons is the preset button. Tap this and you can load any Gestrument preset configuration you may have created or any of those supplied with the app.

Gestrument is supplied with a range of presets to get you started including some useful tutorials to help you learn the basics.

Gestrument is supplied with a range of presets to get you started including some useful tutorials to help you learn the basics.

On the left edge are the Rhythm randomness and Pitch fluctuation sliders. The purpose of these will become clearer once I’ve described the Editor options but, as their names suggest, they enable you to vary the timing and pitch of the notes generated by Gestrument within the ‘rules’ you have defined for each of the (up to) eight instruments you have defined as part of the current preset configuration. Directly beneath each of these sliders is a small triangle-like icon. Tapping these means that parameter is then also controlled by your second finger movements on the playing surface as well as the default setting of MIDI velocity.

Aside from a tempo control, the top edge features two further performance controls; Pulse density and Scale morph. Pulse density acts as a multiplier to the left-right axis of the playing screen, with higher values producing more notes and lower values producing fewer notes. Again, this allows you to change the intensity of a performance in real-time. As described below, the Editor screen allows you to define two different scales (sets of notes) that the engine can pick from as you slide your finger up and down the screen. If you define different note combinations on the two scales, the Scale morph slider allows you to blend from one scale to the other. This is also a very useful performance feature and can be used in various ways. For example, you might go from major to minor or from just a few notes to many notes, both of which would alter the resulting performance obtained.

The right edge contains a few other controls. At the base, you have a ‘hold’ option (you can tap and that position continues playing even after you remove your finger) and a glide button. Above these are the recording controls to enable both audio and MIDI recording within the app itself. Recordings can easily be exported for use in other apps. At the top of this edge is the Editor button (to open the Editor page) and the Pulse mode switch. When enabled, the app can be used to send MIDI clock data continuously to another app and the Pulse setting dictates whether the MIDI Clock data is transmitted continuously or just when you are actually playing the Gestrument touchscreen surface. Gestrument also responds to MIDI clock so, if you want to use the app sync’ed to other iOS MIDI apps or your desktop, that is possible.

Rules of engagement

The Editor screen where you can tweak the rules that apply to each of up to eight instruments and their MIDI performance.

The Editor screen where you can tweak the rules that apply to each of up to eight instruments and their MIDI performance.

While you actually create your performance from the touchscreen playing surface, the rules the app uses to generate that performance and the sounds available for selection are defined within the Editor screen. At the top of the screen you can define the two scales (A and B). These allow you to limit the notes that Gestrument has available when it generates MIDI notes from your finger work. Interestingly, there is also a Microtonality option so, if you want to defines notes-within-notes for some non-western musical ideas, now’s your chance.

The rest of the left side of the screen allows you to define which lengths of notes the app can generate. There are plenty of options here and, the more of these you toggle on, then the more vertical lines you will see back on the playing surface to guide you as you swipe from left to right.

The right-hand side of the screen allows you to define some performance rules for each of the eight instruments. The vertical strip of coloured buttons mirrors the horizontal strip at the base of the performance screen and whichever one of these is highlighted is the instrument you can currently edit within the main editing panel. You don’t have to have all eight instruments enabled and configured and, presumably, with fewer than eight, the app uses less CPU.

For each instrument you do enable, you can define a number of things. First, if you want to use the supplied internal sounds, then you can pick a sound from the list of those available. Should you wise, you can load your own samples in here provided they are in sf2 soundfont formats. You can also define the MIDI channel that each instrument will send MIDI data out on if you are passing the MIDI data to another app. Again, it’s worth emphasising here that you can have each instrument on a separate channel, all on the same channel or any other combination you might like. This is useful if you want, for example, to send four channels to a piano sound and then one channel to a bass sound, although there are plenty of other ways you might use this flexibility.

The internal synth sounds can be tweaked if required.

The internal synth sounds can be tweaked if required.

The rest of the controls allow you to define the rules that the app uses for each instrument when generating notes. You can constrain the pitch range, durations and velocities. In addition, you can set the level of pitch and rhythm variation. And while the ‘base’ pitch and ‘base’ note frequency are defined by where you swipe on the playing surface, in real-time, Gestrument uses these Editor settings to pseudo-randomly add in some variation. And as you can define these setting individually for each instrument, this gives you a lot of scope to control just how ‘variable’ the performance of each instrument is.

Other controls in the Editor allow you to disengage the internal synth (for when you want to use Gestrument with another iOS or desktop MIDI app), adjust the synths settings, configure the MIDI settings and adjust the glide time. And if things get out of kilter, there is also a MIDI Panic button (although, in testing, I didn’t need to use this). Finally, if you create a configuration you might want to recall, you can save all these instrument settings as a preset.

Swipe out

Gestrument will send MIDI data to other apps quite happily.

Gestrument will send MIDI data to other apps quite happily.

Of course, the real issue is just how does Gestrument play? I have to say that this is one of the most interesting and thought provoking musical experiences I’ve had for some time. While the app does, at one level at least, perform a similar function to Chordion – that is, the touchscreen interface can be used to generate MIDI performances to pass to another app – the nature of those MIDI performances is very different. Chordion does exactly what you tell it to; you get the chord you chose or the melody notes you played. It’s incredibly functional and practical, especially if your keyboard skills are a bit scratchy.

In contrast, Gestrument serves more of a creative function. While your finger swipes control the broad-brush strokes of the performance, it’s how those brush strokes trigger the various performance rules for your instruments that eventually dictate the exact performance you get. And, as those rules also include a certain random element, the performances you get also have a random edge; you never quite get the same thing twice. You can’t really control a chord progression or a melody using the app but as you play, you will certainly get some chords and melodic results.

The experience is really quite intriguing. At times, it can feel almost like abstract music creation and I can easily imagine some of what the app generates in a ‘mood’ context in writing music to picture. Set up the right set of sounds and rules and you could generate some truly atmospheric textures that could suit anything from the big, wide world of nature to the disturbing darkness of a horror scene. All very cool and anyone with two fingers could play it.

If your other iOS synths are able to receive MIDI data from Gestrument - as nLogSynth is here - then you are in for some fun.

If your other iOS synths are able to receive MIDI data from Gestrument – as nLogSynth is here – then you are in for some fun.

What the app is perhaps less useful for (or perhaps it requires much more time with it than I’ve currently devoted) is more structured musical pieces. If you write ambient soundscapes or absract electronica, then there is plenty to offer here but, if your thing is tightly structured three minute pop, then perhaps Gestrument might not be your first choice.

One thing I did experiment with was building a string section preset and, with a little more work, I can imagine this being very useful. For example, you could define separate bass and cello instruments that played longer notes, a low pitch range and with less pitch variation and then a series of viola and violin instruments that played at a higher pitch range, a wider range of note lengths and a more diverse set of pitch variation. One or two fingers then generate all sorts of ‘full strings’ orchestral sounds; with the right samples being triggered (the internal GM ones are not bad but it would be a lot more effective hooked up to a top-notch orchestral sample library), this could be a very interesting proposition.

Out of this world

I was able to record simulateous audio from Thor (triggered my Gestrument) and Gestrument's MIDI data into Cubasis without any problems.

I was able to record simulateous audio from Thor (triggered my Gestrument) and Gestrument’s MIDI data into Cubasis without any problems.

I had no problems getting Gestrument to talk to other iOS apps; both the MIDI and Audiobus implementation seem to be very solid. I was able to pass MIDI data to multiple other synth apps at the same time with, for example, NLogSynth responding to one MIDI channel and Nave responding to a second. Gestrument worked fine in the Audiobus Input slot, sending MIDI data to another Input slot synth and I was able to record the resulting audio into Cubasis without any problems. Equally, I could also record the MIDI output from Gestrument into Cubasis.

I think this last point is quite important and, while the app is intended very much as a ‘performance’ tool, that performance doesn’t have to be confined to gigs or jamming with your friends. As I indicated earlier, one of the strengths of the app is the slightly random (often abstract) feel to the output. This can be hugely creative and, if you are prepared to experiment, Gestrument can produce some wonderful music, from beautiful melodic soundscapes through to scary, atonal weirdness.

The microtonal scale options will appeal to those who want something less 'western' from their performances.

The microtonal scale options will appeal to those who want something less ‘western’ from their performances.

Used as a creative tool in this way – experimenting until that bit of magic happens – really comes into its own if you are also recording the MIDI generated. While you might not get quite the same performance out of the app when you repeat your finger swipes, with the MIDI notes captured you can go in and pick just the best bits of inspiration and then, via the magic of MIDI editing, craft those into a more structured piece. This is a really interesting proposition and I think more experimentally mined iOS musicians and/or composers would find Gestrument a brilliant tool for this task alone.

In summary

Gestrument is a very intriguing app. It combines the very best of what iOS touchscreen music creation is about into something that is both creative and inspiring without being difficult to play. Yet, beneath the surface is a very clever set of musical ‘rules’ that allow those who take the time to master their subtleties to define how the app generates a performance and point it into certain musical directions. Yes, the performance still has a random element to it but, from a creative perspective, that should be seen as one of the app’s key strengths.

If you like the way a touchscreen provides you with alternatives to MIDI keyboards for music creation, Chordion and Gestrument compliment each other brilliantly. If you have some chords and a melody in mind, pull out Chordion and get the job done that way. If you want something more experimental and want to be surprised and inspired by what might appear, then Gestrument is just the tool.

It will be very interesting to see how Jesper and his team might take Gestrument forward and whether they will add to the ‘rule’ base that controls the app’s behaviour. That said, this app is already deep. Don’t expect to buy it and to instantly master how it works. Yes, you can get instant results but you really need to take your time and think about what the Editor settings might offer and how they can be combined to control the resulting performance. Do that and there is a very sophisticated system of music creation available here.

Intriguing, occasionally bewildering, but undoubtedly inspiring and creative, Gestrument is a brilliant piece of iOS music app design. Highly recommended for those with a more experimental nature :-)

for readers in North America
for readers in Europe
Be Sociable; share this post....

    Speak Your Mind