No, the iOS App Store is not short of synth apps and, amongst the more routine offerings, there are also some truly impressive virtual instruments on offer that are easily on a par with their desktop equivalents. Yonac, who regular iOS music-makers will be very familiar with through their long-standing presence on the App Store, have, however, decided that there is room for at least one more: Kauldron.
At its heart, Kauldron is a fairly conventional virtual analogue synth. You get three oscillators, a noise source, a very nice filter selection, amplitude envelope, some cool modulation options with twin LFOs and an envelope generator, a very interesting arpeggiator, modulation, delay and reverb effects and some cool X-Y pads for real-time sound shaping, all spread across a number of screens that can be tabbed through via the buttons at the top of the display. The virtual keyboard is well featured and you also get the option to switch to a ribbon controller mode if you prefer. Yonac also have a comprehensive user manual PDF available from their web site and linked to from within the app.
Yonac are keen to make the point that the underlying modelling is all new and the sound is most definitely punchy, warm, and with plenty of sonic depth; the synth engine is most certainly very capable. There are some very good bass presets and I also enjoyed a lot of the arp-based sounds. Throughout the pretty extensive preset collection, though, the sense of ‘analogue-ness’ was very obvious. Whatever the underlying modelling algorithms, Yonac have clearly got a pretty good grasp of how to turn zeros and ones into something pretty organic sounding.
However, one of the most interesting features of the app is something Yonac call Spawn 2. This is a system for random preset generation, and while lots of synth apps offer this, Yonac have really taken this process to another level. You get considerable control over just how ‘random’ the changes are when you trigger Spawn to do its thing, including the ability to just nudge a parameter or two within an existing preset with each iteration of the process.
Technically, the app is universal, has a solid MIDI spec including MIDI Learn, IAA, Audiobus 3, Ableton Link and — yay! — it also works as an AU plug-in. This behaved very well with Cubasis as my AU host. Kauldron is a 38MB download, requires iOS 10.3 or later and should run well on an iPad Air 1 or iPhone 6 or later.
In terms of the style of sounds, analogue-type synth tones abound. There are, of course, lots of other iOS synths that already do this very well, but Kauldron is most certainly up there in terms of sonics and, with the combination of the range of features, that impressive Spawn 2 system, and a very competitive price, it is most certainly an app worthy of a slot within your synth app collection.