iOS: The Moog Modular Model 15 is one of Moog's more popular synths, but it retails for around $US10,000 ($13,059), which is far too expensive for most of us. If you've got an iPad sitting around, you can snag a digital recreation for $46.99. The Model 15 app follows in the steps of apps like Korg's MS-20 where it's a digital recreation of an analogue synth. We've seen plenty of these kinds of apps before and most work far better than you'd expect. That means you'll find plenty of knobs, switches and buttons alongside patch cables to manipulate sound. You'll get the same modules you would on a real Model 15, a bank of oscillators, low/high pass filters, a filter module, delay unit, loop recorder and an input (this time it works with MIDI/inter-app audio). You can scale the various elements to suit your needs, which means the app is a little easier to use than the real world unit.
If you're not terribly interested in tinkering, there are plenty of presets here too, and you can tweak those as much as you like. The Model 15 app works well considering it's a touch screen, so if you're worried about dropping $46.99 on ill-made app, rest assured, it works much better than you'd expect. That said, while the app's universal, I wouldn't bother on an iPhone because it's just too small. The iPad or iPad Pro are a much better fit.
Model 15 ($46.99) [iTunes App Store]