Bounced MP3 file do not play in iTunes

Question

Hi guys!
I'm a new Logic Express 9 user (and a complete novice in recording!). I just managed to connect my Roland RD-700SX piano to my Macbook Pro (USB connection). I managed to use Logic Express 9 to record a simple song that I played on the piano. If I understand it correctly, the flow of data and subsequent "creation" of sound is as follows:
- upon recording: piano keyboard (acting as controller) --> Logic Express (receiving MIDI-data from keyboard) --> sound generator inside the piano (receiving MIDI-data from Logic Express) --> speakers
- upon playback: Logic Express (sending the recorded MIDI data) --> sound generator inside the piano (receiving recorded MIDI-data from Logic Express) --> speakers
I then bounced the file to an MP3 (following the directions in the "Exploring Logic Express 9" manual).
Upon playing the MP3 file in iTunes, there is no sound. I can see that the file was compressed (the MP3 file is about a quarter of the original uncompressed file).
Why is there no sound after bouncing the file? Does it have something to do with the fact that the "playback" within Logic Express 9 is sending the MIDI data to the piano's sound generator, and therefore does not actually hold the "audio" data, but a mere projection of that data? If the latter, how can I record the "audio" that I hear when playing the recording in Logic Express? If not possible to record the exact same audio (which is based on a top-range grand piano pre-installed in the RD-700SX), is there a way to use the MIDI-data in the project file and record "audio" based on the instruments that came with Logic Express?
Thanks!

Answer 1

Hi man,
my sympathy for RD700sx users is unbroken
You gave the answer yourself: "Why is there no sound after bouncing the file? Does it have something to do with the fact that the "playback" within Logic Express 9 is sending the MIDI data to the piano's sound generator, and therefore does not actually hold the "audio" data, but a mere projection of that data?"
That's exactly what happens. You didn't record any audio in Logic, but only MIDI data streamed from and to your digital piano.
To have your song bounced, you must record the RD700SX' sounds into an audio track. To do this, it is not sufficient to connect the keyboard via USB, because it hasn't got an integrated audio interface.
Instead, go get yourself an audio interface (or, in case of missing funds, connect it with a suitable adapter cable directly to you Mac's inputs, you'll want to use the headphone jack of the RD700 as output perhaps). Then, aim a audio track for recording and hit record. The Mac will stream the MIDI data to your RD700, which in return will feed the audio track with audio (resulting in a visible waveform). Now this can be bounced.
Alternatively, you can use the MIDI data you've recorded to feed software instrument tracks which will produce audio as well.
Fox