Being a guitar player through out the years. I always needed a way to slow down the fast parts of a guitar solo so I could figure the notes out by ear. I first changed the turntables speed of vinyl record from 33 to 16 and later found cassette tape audio players that would do the same. The problem came when you slowed the audio down the pitch was changed an octave down and it was all garbled. Later there where digital audio players and software applications that would slow down music parts and bring the pitch back to the same. They were still always noisy and garbled and you could barley hear the notes being played. The technology is finally here and it has been done by the software developers of Transcribe MP3 player.
They found a way to slow down the parts and bring back the pitch the same and filter out all the noise so you can hear the parts clearly. There is also another problem of keeping track of the music parts of a song that your trying to listen in on. You have to write down the track time so you know the point of where back up to. This has been solved by making an audio wave activity graphic with a visual time line and setting in start and stop tap in point that can be put anywhere and be labeled with any identifying text you want. This is a one of a kind quality application that does the job.