Background noise messed up with frequency detection

[johnny_lang]

hey dudes,
i use iDevice to detecting sounds coming outta piano, keys with higher frequency, it works rather ok, but keys with lower frequency, sometimes mixed up with background noise, unable to clearly detecting which key is pressed on piano.


any ideas, guys? maybe there's a way to detect a sound which is loud enough to be defined as the sound that is desired to catch. Throw me, anything. i appreciate it.