Music for Tablets – Shoom by Yuri Turov


For your consideration: Shoom, a tri-timbral X-Y matrix synthesizer with full microtonality implementation for the iPad.


by Warren Burt, May 2016


Occasionally, a new synth app comes along that promises to be a lot of fun, and also doesn’t cost a lot.  So you download it, and then, sometimes, it fulfils the promises in full, and then some.  These are delightful moments for a software reviewer.  Shoom has provided me with one of those moments.  It’s really a very delightful app, with a lot of composing and sound design power, and a very simple and elegant interface.

Shoom, by Yuri Turov, is called a “triple-synth audio playground,” and that’s as neat a summary of it as I can imagine.  You get three fully programmable subtractive synthesizers, an X-Y pad, where the horizontal X direction controls pitch (ANY pitches covering the WHOLE audio range), and the vertical Y direction can control any 3 of 15 different parameters.  The simplest use for the Y axis is to control volume of a voice, but a number of the included 60+ presets show other ways of using the Y axis.

The pitch world of the app can cover gliding pitches, and time-specifiable portamento times, or, if you want stable pitches, you can use any of the included tunings, or make your own.  Your tunings can be of any number of tones, and they can cycle at any desired interval, not just the octave.  Then each of these tunings can have “scales” – which are subsets of the tuning.  Again there are a number included, or you can make your own.  The XY pad can play over the entire audio range, or you can narrow the range with a slider on the bottom of the screen to any portion of the audio range.  When you do this, and zoom in far enough (say, to about 6 octaves or less), colored numbered tabs appear on the bottom of the screen, giving you either note numbers or note names for pitches, depending on the size of your scale.

It’s also Audiobus2-compatible and Inter-App-Audio-compatible, so you can use it in conjunction with other apps, including effects.  For example, I’ve been having a lot of fun routing the output of Shoom through Sugar Bytes Turnado effects unit.


The Synthesizer

Shoom has three identical subtractive synthesizers to play with.  These are selected by a colored switch in the top middle of the screen.  The three synths are indicated by blue, magenta, and orange dots. 

Only one synth can play at a time, but if you use the latch mode, notes from one synth can sustain while notes from another synth are being played.  The latch mode is selected in the lower left.  If it’s selected, any note touched on is sustained until a double touch turns it off.  If it’s not selected, notes sustain only as long as your finger is on them.  At the lower right are two circles with X’s in them. The colored one turns off all notes from the currently selected synth.  The white one turns off all notes on all synths.  The decays of the envelope generators are respected when these notes are turned off.  That is, turn off all notes, and they will decay at their given rates.

Control panels for each synth include Osc (oscillator controls), Env (envelope settings), Mod (modulations), Effects (a delay line and a reverb), and Control (glide controls and a pan control and randomizer).  Additionally, all panels provide access to a master volume control and a mixer for the three synthesizers.

The Osc panel provides Wave (4 types), Pulse Width, Octave, Semitones, and Cents control for each oscillator.  Additionally oscillator 2 can Frequency Modulate oscillator 1.  There’s also a noise generator with a color control, and a mixer for the 2 oscillators and the noise.  All of these controls, as with all others described below, can be externally controlled with MIDI continuous controllers.

The Env panel provides ADSR plus Level and Slope (linear or logarithmic slopes and anywhere in between) controls for both an amplitude envelope and a filter envelope.  The filter is a low-pass filter with cutoff, resonance, drive and pitch tracking controls.  The filter sounds very clean and good.

The Mod panel has 2 LFOs plus a Y Axis control.  Each of the LFOs can have one of nine different shapes (including random sample and hold, and random gliding sample and hold), they have a frequency range of 0.02 Hz (50 seconds per cycle) up to 40 Hz.  Each LFO can control three different parameters with scalers for each of the three parameters.  The three parameters can be selected from a list of twelve, which includes things like Osc2-1 FM Depth, Filter Cutoff, LFO2 Frequency, and Oscillator Pitches.  Again, all the level of these controls can be externally controlled with MIDI CCs.  The Y axis can control three different parameters, and now there are fifteen to choose from, including the frequency and depth of each of the LFOs.  This provides quite a range of control.  In fact, this is almost like having an old style patchable analog synth to play with.

As said above, Effects provides two effects: a Delay and a Reverb.  The Delay can be connected to Ableton Link, or Synced to an external clock.  The reverb sounds quite good and transparent and has a number of useful controls.

The Control page is concerned with Pitch and Pan.  You can turn on or off a Pitch Lock, which prevents the drifting of held notes if they are accidentally touched, and you can turn on or off glide, portamento, and snapping-to the nearest pitch.  With these controls, you can have either a wildly gliding complex of tones, or a very precise selection from a carefully specified tuning and scale.

Remember, each of the three synthesizers can have its own timbre (patch) and all three can sound at once, although you can only play one at a time.  Maximum polyphony, depending on the power of your iPad, is 30 voices. 


The Tunings

The Session Settings menu, selected with the icon picturing three horizontal lines next to the synthesizer selector in the middle of the top panel, allows one access to the tuning and scale controls, as well as other controls for base frequency and voice stealing.  There are a handful of bundled tunings, but the real fun of this comes with specifying one’s own tunings.  In the User section of the tuning selector, press the “+” in the upper right corner of the panel.  A tuning panel appears.

For our example, we’re going to make a five-note scale, one of Lou Harrison’s “Garland of Pentatonics” from his 1970 book “Lou Harrison’s Music Primer.” (A book worth looking up, even if out of print, for its very sweet, no-nonsense explanations of many of the formerly mystifying aspects of contemporary composition.)  Here’s our scale:

  0:          1/1             0.000000 unison, perfect prime

  1:          8/7             231.174094 septimal whole tone

  2:          4/3             498.044999 perfect fourth

  3:          3/2             701.955001 perfect fifth

  4:         12/7            933.129094 septimal major sixth

  5:          2/1            1200.000000 octave

Simply tap on the “Add Pitch” bar one more time than the number of notes you want in your scale.  We want a five-note scale, so we have six notes.  Then, simply enter the cents values in the column on the right.  Since we want this scale to repeat at the octave, we simply enter “1200” into our last box. If we had wanted to repeat our scale at any other interval, we could just type that interval into the bottom box instead of 1200.

Then, give your scale a name in the Tuning Name panel up the top, and press Save in the upper right to save the scale.  Voila, a new tuning is available.  If you want to edit your scale, just slide left on the name of the scale in the listing of the scales, and a control comes up saying Edit/Rename/Delete.

To set a scale, simply select a tuning, then select a scale.  You’ll come to a similar panel to the Tuning Selector.  Click on the + sign at the top right to make a new scale.  Here we’re going to select a new subset of a 12 note scale.  In this scale, I’ve selected tones 2, 4, 7, 9 and 10 of a 12-note just-intonation scale.  Notice that the selected notes are colored blue after you’ve selected them.

There is one wrinkle here – when you then specify your scale – here five of the twelve notes of the given tuning, and you zoom in on the XY panel you’ll find the scale degrees listed as C# D# F# G# A, and not the scale degrees from your original scale.  If your scale had more or less than twelve notes, the scale degrees would be displayed as 1, 2, 3, 4, 5.  This makes sense, but maybe in a future revision, the programmers might consider making displaying of the original scale degrees a possible option in a scale.

There’s also a MIDI panel.  At the moment, this allows different routings of MIDI CCs on any channel to any control in the app.  A promised future development is the use of external MIDI control with the three synthesizers in the app.  I hope this happens, because, although the XY panel provides a wonderfully flexible performance interface, to have this powerful synthesizer, with its very powerful tuning options available for an external MIDI sequencer control would be very nice indeed.

One possible addition which might be nice in the future would be the addition of importing Scala .scl files into the Tuning page.  That would just make things a bit more convenient.  I’ve seen some reviewers on the web also say an arpeggiator would be a nice addition – I can concur that that could be quite handy, especially if you have a chord latched to sustain – you could then have that chord shimmering with selection of the held tones. 


The Final Verdict

The synthesizers can have a very wide range of timbres programmed into them.  The tuning facilities are very simple, but powerful.  The XY grid is a blast to play with.  The effects are useful.  The Audiobus2, IAA capabilities give much additional power.  And it’s very economically priced at $9.99 US. ($14.99 Australian in the
Australian app store!).   At that price, and with this much power, it’s just about the most musical fun you can have with any app around.


Wait … This Just In …

My colleague Geary Yelton over at Electronic Musician has just published an excellent overview article where he does thumbnail reviews of twenty iOS iPad and iPhone softsynths.  Here’s the link:

And here’s a list of the softsynths he writes about:

ApeSoft iVCS3; Arturia iSEM; BeepStreet Sunrizer; Bit Shape TC-11; Cakewalk Z3TA+; Chris Carlson Borderlands Granular; Chris Wolfe Jasuto; iceGear Cassini; Igor Vasiliev Soundscaper; IK Multimedia SampleTank; Korg iDS-10; KV331 Audio SynthMaster Player; Moog Animoog; PPG WaveGenerator; Propellerhead Thor; Roland Sound Canvas; Roli Noise; VirSyn TeraSynth; Waldorf NAVE; and Yonac Magellan.

It’s a great round up of a lot of the available synthesis products out there for the iOS platform, so if you have any interest at all in this field, I warmly recommend that you check it out.


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