I've been checking out the free version of this app, which seems to be surprisingly full-featured and looking sharp for something free. It combines a couple of bassline synths modelled on the TB-303 (with similar methods of programming), a flexible analogue synthesiser which can be used for leads and other parts with an on-screen keyboard and also a drum machine that emulates the programming of an 808 or 909. These are favourable comparisons with vintage gear and means that it is very easy to jump straight in to the app and get programming. Patterns can be saved, play orders readjusted and otherwise manipulated really quickly, so you can build up complex phrases and ideas with very little fuss - I have no doubt that the full featured app will be worth the price tag. Go check it out!
Otoone is a basic synthesiser that is arranged in four octaves across landscape view. The synth is multi touch enabled, allowing for basic chord play, with additional glide as you move across the screen. Controls are simple for adjusting parameters, such as the built-in reverb, whilst recording is perhaps the most rudimentary. I managed to record a phrase easily enough, but I found it difficult to find a playback button. There are plenty of nice sounds and effects here, but I don't think there's much use for this other than a jamming tool.
I did have a look at Caustic 2 but felt that now that it had been updated a whole version number that it should be worth looking at. Caustic is the closest you can get to a fully-fledged DAW that is optimised for a tablet screen, with an interface that mimics a rack unit system akin to Reason from Propellerhead. Caustic comes complete with nicely presented and full-featured synthesisers for pads, basslines, piano emulations and drum machines. It even has a decent modular synth! These are supplemented nicely by effect units and a piano roll to start things off, together with pattern sequencing similar to RD4. Sufficed to say, if you are familiar with Reason, it will be easy enough for you to get started. Of all these apps, Caustic is the one for me that looks, sounds and feels the most professional and the one that I find the easiest to get stuck into. The full app works in a demo mode so you can try everything out with save functionality missing, so do give it a look!
Whilst Caustic or RD4 aim to be more complicated/sophisticated music apps, this app presents itself out as a sketch app with which to generate ideas. It's a simple system of placing and dragging note points on a screen that are played from left to right. Placing and swiping creates held notes with a glide effect (as well as pitch bend) and notes can also have a specific effect (delay for example) applied to them. This means it is very fun and fast to build little patterns, but of course, the limitations of this app are clear. Circle does not try to be something more complicated and what it does and the manner it presents it in are executed really well and for these reasons I wholeheartedly enjoy it.