Here's KM Tuner in action:
There are the usual Java permissions dialogs, though happily only on the very first 'run'; in action, you get real time analysis of a tone being played (check out the five decimal places), tuning indication and a pretty waveform.
If your note is within a fraction of a percent of a recognised open string for your instrument, you get a green indicator and line, otherwise it's red and you're out of tune!
KM Tuner works by doing successive short recordings and then analysing them. Yes, there will be short gaps of dead time between recordings, but I think this is acceptable for a typical tuning use case. As shown above, there are a few things you can fiddle with if the default doesnt work well for you; (right) a selection of instrument presets means that the notes will auto-snap to the right frequencies/strings, etc.
There's a simple, but graphical Help screen - very clear, and good to see.
I do have a number of small complaints about the applicaton:
- some musicians might need more arcane tunings - for baroque instruments, for example
- there's no manual string selection, so you're reliant on the software guessing which string you're tuning properly - in the case of a string which is some way out to start with, this can be a problem
- there's no preset for a 12-string guitar (in my case)
- there's no screen timeout override in place, so after a minute or so of tuning a problematic string you have to reach down and unlock the phone screen - yet again
You can buy KM Tuner here in the Nokia Store for £1.50 or download the ad-supported free version here.