Android does not have Audiobus app nor 'inter-app audio' (in iOS7). As far as I know, currently there are no equivalents. These allow you to internally output the audio into another (audio) app running simultaneously on the same device, so you could add an app running a pitch changer to process the audio pitch (key) before hearing it. (iReal Pro for iOS currently supports AudioBus.)
Here are 3 ideas to do this for Android:
- for real time, you could use a pitch changer guitar pedal (or similar) from the audio output of your device, then output it to an amp;
- if you have another device, run iReal Pro on this in the other key;
- you can export a screenshot (or PDF) of the song in the transposed key, then run iReal Pro in the background in concert key (actual sounding key.) Use a PDF viewer* or gallery etc. to view your image of the song.
* Mobilesheets app is a PDF or image app for musicians that will display your song charts. It can work with iReal Pro in the background. Or you can attach an audio file to each song and have it play in the background. Export the .wav file and image file and attach to each other in Mobilesheets.
If you search our forum, you will find other posts on Mobilesheets.
http://www.zubersoft.com/mobilesheets/
Thanks for the information about your instrument, nisor. It looks a little like a baroque oboe. Do you make your own reeds? (I have an English Horn—Cor Anglais, but have not played it for a while. I do not make my own reeds, I have to purchase, then hope they work.)
I am going to find out more about your instrument, it looks fascinating.