In recent years, using iOS-based synthesizers onstage and in the studio has become a practical reality. One reason is that the latest iPads and iPhones contain more powerful processors than even some recent laptop computers. Apps are growing considerably more sophisticated and more closely resemble their computer-based equivalents, often by leveraging all that processing power. Thanks to economies of scale and the difficulty of pirating iOS apps, they’re also less expensive than computer-based soft synths and much, much less expensive (and often more versatile) than synthesizer hardware.
With dozens of synth apps available, you may want some guidance about which ones are worth your time and money. Although this list is by no means comprehensive, I recommend all 20 synths in this article for increasing your timbral range and musical creativity. All are polyphonic, all support Apple’s Core Audio, and all except for Roli Noise support Core MIDI and Audiobus. Some provide in-app purchases at extra cost to enhance or expand their capabilities, and additional presets are available for all of them.
The developer who created iVCS3 (iPad, $15) deserves heaps of credit for making such a faithful emulation of the classic, quirky EMS VCS 3, the first truly portable modular synthesizer. Launched in 1969, the VCS 3 had no hardwired connections; you connected circuits by inserting pins in a patch matrix. To connect a VCO to a VCF, for example, you inserted a pin at their intersection in the matrix. Although iVCS3 adds a keyboard and 16-step sequencer from later EMS instruments, it duplicates the original synth so precisely that I recommend reading the original VCS 3 manual if you want to master it.
iSEM (iPad, $10) re-creates the Oberheim SEM (Synthesizer Expansion Module), which was introduced in 1974 and supplied each voice in Oberheim’s legendary Two-Voice and Four-Voice models. Like the original, iSEM has two oscillators, a 2-pole multimode filter, and two 3-stage envelopes, and its warm, virtual analog sound might fool even a purist. Unlike the original, it also has a suboscillator, second LFO, arpeggiator, and 8-slot modulation matrix, as well as overdrive, chorus, and delay effects. You can offset the values of six parameters so that each of eight voices generates a different sound, making iSEM 8-part multitimbral, too.
Sunrizer (iPad, $10) is an analog-modeling synth with a distinctively digital personality. Resembling Roland’s JP-8000 in more ways than one, Sunrizer gives you two oscillators featuring stackable super-saw waveforms and two independent filters with a selection of 15 types. In addition, it offers numerous effects, an onboard audio recorder, MIDI CC mapping, up to 20 voices of polyphony, and an arpeggiator that lets you design your own patterns. Sunrizer is also available as an AU and VST plug-in ($50) for the Mac and Windows, and a scaled-down version called SunrizerXS ($3) is available for the iPhone.
Bit Shape TC-11
TC-11 (iPad, $25) isn’t quite like any other synth. Instead of employing knobs and sliders, it relies on iOS’s unique capabilities to graphically and expressively control dozens of parameters simultaneously. Using the iPad’s multitouch, accelerometer, gyroscope, and compass, TC-11 measures the position and motion of your iPad in space, as well as how many fingers are touching it and the speed, angle, distances and timing of their movements. TC-11 is modular in that you link “synth objects” such as oscillators, filters, and modulators together onscreen to create patches. Best of all, it’s great fun to play.
In addition to a bestselling DAW for Windows, Cakewalk makes outstanding soft synths, including Z3TA+ (iPad/iPhone, $20) for the iPad. It’s almost identical to the Mac and Windows version, with six oscillators, two multimode filters, six ADSRs, six LFOs, loads of effects, and an arpeggiator with over 200 patterns. You get an impressive variety of waveshaping tools for warping, twisting, and otherwise mangling a substantial collection of waveforms. Add a modulation matrix with 16 routings, an assignable x-y pad, and the ability to exchange presets with computer-based versions, and you have an app that demonstrates how tablets are catching up with desktop computers.
Chris Carlson Borderlands Granular
Like TC-11, Borderlands (iPad, $10) eschews the musical keyboard paradigm in favor of multitouch. One of the best apps for exploring granular synthesis, Borderlands lets you import or record multiple audio clips and then superimpose one or more grain clouds to play selected portions. Double-tapping on a cloud summons buttons to change pitch, duration, filter resonance, polyphony, and similar parameters. Buttons overhead change playback direction, select amplitude envelopes, and so on. You can automate your gestures by recording them, and save and recall your configurations as scenes. Borderlands lets you manipulate sound grains directly and generate unique sounds in the process.
Chris Wolfe Jasuto
Jasuto (iPad/iPhone, $1) is a comprehensive modular app for designing and building onscreen instruments and audio processors by selecting and connecting oscillators, filters, envelopes, effects, a 64-step sequencer, an accelerometer, and other modules. It supports OSC and handles mathematical functions and spectral processes such as convolution and Fourier analysis. It also furnishes a fully functional sample editor. Double-tap on modules to specify their parameters, or modify values in real time by changing the distances between them onscreen. Jasuto isn’t for everyone, but it will let you create sounds beyond the reach of most synthesizers.
Cassini (iPad, $6; iPhone, $4) is a straightforward emulation that doesn’t focus on any particular synth in the real world. Beyond the initial keyboard and performance control page, an entire screen full of knobs and buttons is devoted to each of Cassini’s three virtual analog oscillators, two multimode filters, amplitude modulators, delay, programmable polyphonic arpeggiator, and global parameters. You also get 9 DAHDSR envelopes, 6 LFOs, audio recording, and a ton of excellent, usable sounds that desperately need more descriptive names than they currently have.
Igor Vasiliev Soundscaper
With a GUI resembling an airliner’s control panel, Soundscaper (iPad, $9) has three sample-playback oscillators, each with its own resonant filters, LFOs, spatial modulators, and random parameter generators. Soundscaper can import user samples in an astonishing variety of formats, and a generous collection of content is included. You manipulate samples by modulating their playback speed, processing them with delay, and applying functions that realistically simulate lo-fi circuit bending. Although it may take a while to fully grasp how to use Soundscaper most effectively, it excels at synthesizing bizarre background noises, glitchy rhythms, and otherworldly textures.
IK Multimedia SampleTank
At 1.3GB, SampleTank (iPad/iPhone, $20) needs more space on your device than other music apps, but that’s the price you pay for a virtual ROMpler with so much usable content. And if you opt for any expansion packs, they’ll need even more space. Nonetheless, SampleTank is definitely the way to go if you want lots of sampled instruments, as well as riffs, grooves, and patterns designed for specific instrument types. Similar to the Mac and Windows versions, the iOS version has some terrific user-interface touches all its own. A free lite version is also available.
Inspired by all-in-one music production workstations, Korg has taken its popular app for Nintendo’s pocket-sized DS game console and expanded it. iDS-10 (iPhone, $20) combines two analog-modeling synths (with virtual patch cords), a voice synth, drum machine, KAOSS pad, mixer, and 64-step sequencer with 32 chainable patterns. The voice synth lets you create vocoder-like wavetables by typing words or phases or by speaking into your iPhone’s microphone. You can shape synthesized speech by altering playback speed, formant settings, effects, and more. iDS-10 can also automate parameter changes, load preset keyboard scales, and display animated waveforms in an onboard oscilloscope.
KV331 Audio SynthMaster Player
A 2016 Editors’ Choice Award winner, SynthMaster Player (iPad/iPhone, free) is the iOS counterpart to SynthMaster, a fully featured (and highly recommended) soft synth for the Mac and Windows. The free version gives you 200 presets in a variety of categories, along with eight knobs and a pair of x-y pads to modify specified parameters. Upgrading to the Pro version ($10) scores 800 additional presets and the ability to save parameter changes. Many additional banks are available via in-app purchase. If SynthMaster is on your computer, Player can import all its presets, too.
Animoog (iPad, $30; iPhone, $6) has long been one of the most formidable and popular music apps for iOS. Beginning with samples of various synths and effects that have been resynthesized into wavetables, Animoog lets you define a 2-dimensional path that modulates individual notes and animates them on an x-y pad. By superimposing modulation animation over a real-time waveform display, you get a vivid representation of dynamic changes in timbre as the index moves through wavetables. Outstanding features include a versatile filter, three ADSRs, four LFOs, 22 editable scales, 4-track audio recording, and “touch” keys that control modulation as you play.
PPG’s Wolfgang Palm, who invented wavetable synthesis in the late 1970s, began developing iPad apps a few years ago and has since ported them to the Mac and Windows. WaveGenerator (iPad, $20) not only comes with a generous assortment of wavetables, but also allows you to roll your own. Once you’ve created and edited individual waves and chained as many as 256 of them into wavetables, you can build complete programs using three oscillators, a lowpass filter, 14 ADSR envelopes, 4 LFOs, an arpeggiator, and more. WaveGenerator can even transform your photos into sounds.
Many Propellerhead Reason users were thrilled when Thor Polysonic Synthesizer (iPad, $15) migrated to the iPad. It looks, sounds, and operates almost exactly like the Reason-based version, with all the same functionality and identical, compatible presets. You get six synthesis types, including wavetable, FM, and phase modulation; four filter types, including state-variable and a formant filter for vocal-like effects; and 6-channel, 16-step sequencing. The 16-slot modulation matrix routes dozens of sources to dozens of destinations, and the onscreen keyboard simulates velocity and aftertouch in response to how and where you touch it.
Roland Sound Canvas
When General MIDI was standardized in 1991, one of the first instruments to embrace it was Roland’s SC-55, the first of 19 modules to bear the Sound Canvas moniker. Last year Roland resurrected Sound Canvas (iPad/iPhone, $20) as a faithful emulation of its hardware forebears. It duplicates the SC-8820’s sound and features and supplies sound maps compatible with four vintage Canvases, making it ideal for playing standard MIDI files. It even supplies a MIDI file player that lets you edit the key and tempo, repeat song sections, and arrange songs in any order you like.
You’ve probably heard of the Seaboard Rise, a polyphonic multidimensional controller that’s a cross between a squishy keyboard and a ribbon controller, paired with the computer-based soft synth Equator. Recently Roli introduced the Seaboard’s iOS counterpart, Noise (iPhone, free). On the iPhone 6s, it senses how much pressure you apply to the display using 3D Touch to generate aftertouch. Even with older devices, you can control velocity, release velocity, and vertical and horizontal finger movement to play expressively. Noise supports MIDI over Bluetooth, and it comes with 25 Equator-derived sounds, with more available through in-app purchase.
VirSyn Tera Synth
Fifteen years ago, VirSyn Tera (iPad, $20) was a Windows-based modular soft synth called VirSyn, which quickly evolved into the cross-platform Tera. After releasing the waveshaping microTera on the iPad in 2014, VirSyn (the company) introduced a full iPad version, sporting many features that made the original so cool. A scrolling front panel affords access to knobs and sliders for all parameters. Tera Synth has oscillators with waveguide and subharmonic options and a formant filter bank supplementing the dual multimode filters. Modulation routing is extensive, too, with four ADSRs and four envelopes with up to 64 stages.
The app that gives you the firmest grasp on wavetable synthesis is Nave ($20, iPad), a 2014 Editors’ Choice Award winner. Along with standard analogstyle waveforms and a great selection of wavetables, Nave can transform audio files into wavetables and text into synthesized speech. You get three loopable envelopes, numerous effects processors, and a modulation matrix with 8 scalable slots to customize your sounds. Add a 4-track audio recorder, a sophisticated arpeggiator and an alternate keyboard that lets you control modulation directly on the keys, and you have the means to create totally original sounds.
Magellan (iPad, $7) is a straightforward virtual analog synth comprising two independent synth engines. Each has three oscillators, an arpeggiator, and dual filters with 11 types. Magellan can display separate keyboards for each engine or stack them as a single 6-oscillator synth. The control panel is spread out over ten screens that display all synthesis parameters (including one-note chord programming) and ten simultaneous effects processors. Route either LFO for each synth to any four of 13 destinations, and link as many as 16 patterns to compose complete songs using the 32-step sequencer. An iPhone version called Magellan Jr. ($5) is also available.
Check the Requirements
For usable performance in more-than-casual music environments, many of the apps outlined here require a recent iPad or iPhone running an up-to-date version of iOS. Although iPhone apps run on iPads, most iPad apps don’t reciprocate. The iPod Touch, however, is totally compatible with iPhone apps.
Though some apps will function on your old iPhone 4, others require the very latest iOS and at least an iPad Air or iPhone 5s. Getting refunds from Apple can be a pain, so it’s your responsibility to check the hardware and iOS requirements before purchasing. Also remember that if your device has additional memory, then not only can you install more apps, but also you can store more audio data—very helpful for apps that import user samples.
Playing Well Together
You can link soft synths and other music-production apps together so that they communicate with one another within a system. Although Apple has introduced plug-in functionality for iOS apps by means of Audio Unit Extensions, apps that support Audio Units aren’t yet commonplace. Until they are, Audiobus (iPad/iPhone, $10) is essential for anyone who wants to route audio between apps. It enables you to stream the output of one of more synths to effects apps for processing and then to a multitrack recording app, for example.
Numerous devices are available for getting high-quality audio and MIDI signals into and out of your iPhone, iPad, or iPod Touch. You can also integrate your iOS apps into your computer-based studio using one of several interfaces from iConnectivity. With iConnectAudio and iConnectMIDI interfaces, you can exchange audio and MIDI data to and from your iOS apps with your computer’s DAW as if the apps were plug-ins, using your MIDI keyboard to play the apps or an iOSbased sequencer to play computer-based software or external hardware synths.