Arturia iSEM

Virtual SEM synthesizer expander module for iPad

By Phil O'Keefe

The original Oberheim SEM (Synthesizer Expander Module) was first released way back in 1974 and was the very first Oberheim-branded synthesizer. With no keyboard of its own, it was intended to be used with other synths and sequencers as a means of layering and fattening up sounds. Later, multiple SEM modules would form the heart of Obie's famous 2, 4 and 8 Voice synths.

The SEM was a two oscillator (VCO, with sawtooth and width-variable pulse waveforms) synth module with a 2-pole multimode filter, ADR envelopes, and LFO. While it had a fairly simple design by modern standards, it was capable of some thick analog synth sounds. The question is, how well did Arturia do at recreating this classic synth as an iPad app?

What You Need To Know

• iSEM uses Arturia's TAE (True Analog Emulation) instead of analog oscillators like the original, but you'd be hard pressed to tell based on the sound of iSEM, which is big, bold and fat, just like the original.

• iSEM retains the same basic voice architecture as the original SEM and even expands (no pun intended) on it, with two oscillators (VCO 1 and VCO 2), oscillator sync, noise generator, a sub oscillator (which is pitched 1 or 2 octaves below VCO 1, with sine, sawtooth and variable pulse width waveforms), two Attack / Decay / Sustain envelopes, two LFOs, and basic mixer for blending the oscillators & their waveforms, sub oscillator and noise generator, and a 2-pole (12db/octave) resonant filter with high pass, band pass, low pass and and notch filter types available.  

• A powerful modulation matrix allows you to select from any of eight modulation sources and apply them to any of twenty-six destinations. This wasn't available on the original Oberheim SEM and its inclusion gives Arturia's iSEM the ability to do things that are more along the lines of the capabilities of some of the later Oberheim synths such as the Matrix 6.

• Arturia also threw a really nice arpeggiator into iSEM, with up, down, up/down and random modes over a user-specified 1 to 4 octave range. Portamento is also included.

• A quite decent effects section is also included, with chorus, overdrive and delay so you can add grit, motion and repeats to the basic sounds generated by the synth. Of course, like the arpeggiator, the delay and chorus can be tempo synched to MIDI clock, WIST, or inter-app time references if desired

• iSEM is compatible with iPad 2 and later models, including the iPad mini and iPad mini with Retina Display, which is what I used for testing iSEM in the course of this review. It is not compatible with iPod or iPhones - it is iPad-only, and requires iOS version 6 or later. It works fine with iOS 7.

• The built-in virtual keyboard functions are as good as any I've come across on an iOS app. It has the expected mod and pitch wheels, 26 different scale presets, is scrollable, can be transposed, includes hold and chord functions, and you can even zoom in.

• iSEM can be set to play monophonically, or polyphonically, so it can easily simulate the old Oberheim 8-Voice.

• Do you want to use iSEM in combination with other iOS apps and external devices such as keyboard controllers or even another iPad? Then you'll be happy to know that connectivity is a non-issue since iSEM supports Audiobus 2.0, Korg's WIST, Apple CoreMIDI and Inter-App Audio.

• iSEM can be set to Omni mode, or any MIDI channel from 1-16. A MIDI learn function allows you to quickly and easily map external controllers to practically any on-screen knob or control.

• A ton of presets are included with iSEM, and they're well organized by category, with plenty of lead, bass, brass, pad, synth, organ, woodwind, keyboard and FX sounds to keep you busy for hours and hours auditioning them all. Arturia even thoughtfully includes several "Templates"; presets with names like Simple Brass, Square Lead and Simple Strings that can serve as the starting point for creating your own patches.

• An 8 Voice Programmer screen allows you to program each voice independently, with different settings for each one, just as with the old Oberheim 4 and 8-Voice synths.

• iSEM is patch compatible with Arturia's SEM V Mac and PC software, so if you have the virtual instrument running on your desktop or laptop, you can exchange patches between it and the iPad version via iTunes file sharing.

Limitations

• While there are certainly limitations compared to modern synths, iSEM expands on the feature set of the original hardware module, and with that in mind, and at this price, there are no significant issues or limitations to report.

Conclusion

If you're a musician and you have an iPad, you need this app! Five bucks for something this good is simply insane. Even at the regular price of ten dollars, this synth is an absolute steal. It works great as a stand-alone synth for stage or studio use, but it also works and plays well with other apps too, which makes it a must-have for more complex iPad based production setups. It takes the basic concept of the original SEM hardware module and improves significantly on its feature set while retaining the fat and thick sound that everyone loves about the original. Best of all, it's been rock solid reliable for me, with no crashes or unexpected and unwanted behaviors, which is essential for anyone interested in using it for live performances. I could continue to attempt to wax poetic about it, but it would be better if you just bought it and started getting to know it first-hand yourself. You won't be disappointed if you do. 

Resources

Arturia iSEM 1.02 ($9.99 MSRP, currently on sale for $4.99, available through the Apple App Store.)

    •    $4.99

    •    Category: Music

    •    Updated: Apr 02, 2014

    •    Version: 1.0.2

    •    Size: 72.1 MB

    •    Language: English

    •    Seller: Arturia

    •    © 2013 Arturia

Arturia's iSEM web page

Demo Video

Tutorial Video