To begin, I will limit my consideration to the best supported and most mature operating systems. In 2013, this means iOS and Android. The innovative Nokia projects have died off. Windows 8 is ugly. So be it.
It turns out that iOS and Android are poles apart when it comes to audio development. Both can of course play back sounds just fine, but when it comes to music creation, recording, and control, a great deal more is expected of both hardware and software. How do these systems deliver? The answer focuses on latency and applications.
Latency is simply defined as how long one waits to hear a sound after taking an action. Until recently, only iOS was purpose-built for audio, with latency more than acceptable at 20ms. Though Android devices support full duplex audio (input and output simultaneously), their latency can run from 100-200ms, which is completely unusable for any sort of real-time control.
This situation is changing, but slowly. Android 4.1 introduced several beneficial features. First, HDMI multichannel audio output was supported, along with encoding and decoding AAC 5.1. This is great for surround-sound movies and the like. Of more interest to music creation, it is now possible to output audio over USB. Best of all, the output latency has been significantly reduced.
Of course, these OS features must be supported in hardware in order to become a reality. Currently only three devices, all from Google, reduce latency to 20ms. These are the Galaxy Nexus phone, the LG Nexus 4 phone, and the Google Nexus 10 tablet (but not the Google Nexus 7).
The second big issue is the availability of applications. While Android is well-served in most task domains, only a handful of apps cut it for professional audio. The rest are fairly toy-like. (Once I have more experience I might report back on my favourites.)
On the flip side, iOS has dozens of fantastic programmes ranging from synths (Korg iMS20, Animoog) to excellent sample playback engines (Akai MPC, Samplr), from DAWs (Cubasis) to DAW control surfaces (Neyrinck's V-Control), and more besides. Not to mention an ecosystem of hardware add-ons, from microphones to piano keyboards to DJ mixers.
This is disappointing result. An iDevice fits neither my budget nor my ethos (since all my devices are black). The new Google phones are also more than I want to spend and have certain annoying limitations -- not relative to Apple phones, but relative to other Android devices. (There is no card storage, for one.)
So, for now, I will give up on this particular goal. I won't count on exploring audio in any depth on a smart phone, at least not at this time.
But this is not particularly disheartening, when I consider that a phone is simply too small to be a pleasant control surface for audio applications. A 7" or 10" tablet is much more suitable. So for now I will stick to my laptop, which is, after all, much more powerful and versatile than any tablet or phone.
By removing audio creation from the main criteria, my smart phone purchase decisions are simplified. Which brings me to my next post.: A great Android phone for 100 bucks.