Converting audio files to work with the AP-16+ is really quite easy with our favorite piece of freeware, Audacity
. The steps that follow will show you how to take another file, for example, an MP3, and convert it to a proper WAV file for your AP-16+.
There are two areas in the Preferences (Ctrl-P, or Edit\Preferences) that I have set which helps streamline the overall process:
1) Click on the Quality section and set the options as follows:
This will set exports to default to 44.1kHz (CD quality). If you're going to use the AP-16+ with a Prop-1/2/SX and want to use the "S" command to speed up the audio, use 22.050kHz instead.
2) Click on the Import/Export section and make sure that "Use custom mix" is selected -- this simplifies converting mono files to stereo.
Click on OK to close the Preferences dialog.
3) Open the desired file by clicking File\Open... (Ctrl+O). One of the great features of Audacity is that it "knows" nearly every audio file format in use. Select the file and click the Open button in the dialog.
The file will be opened and displayed like this:
Note that this file is: 1) stereo, 2) has good levels (no clipping), and a sample rate of 24kHz (see lower right of image). To change the sample rate for output click on the Project Rate selection and select 44100 or 22050 (below this setting is not recommended -- audio quality will be reduced).
4) Click on File\Export..., enter the desired file name (see AP-16+ documentation for appropriate file names), and -- THIS IS IMPORTANT -- make sure that the output type is: WAV (Microsoft) signed 16-bit PCM.
5) Now click Save. You'll be presented with the Advanced Mixing Options dialog; as this is already a stereo file all you have to do is click OK; the file will be saved as a WAV with the sample rate you selected earlier.
If you're using Windows you can verify this locating the file in an Explorer window, right-click on the file, then select Properties from the context menu. In the Properties dialog select the Summary tab to verify the parameters of the newly-saved file.Converting Mono to Stereo
Converting a mono file to stereo is very simple with Audacity as setup above. Follow all steps until you get to the Advanced Mixing Options dialog. Move the Output Channels slider to 2, this creates a second channel. Click on the file name box (left side of dialog) and then click on the Channel 2 box (right side of dialog) -- a line will be drawn between them.
Click OK and you now have a stereo file that will work in the AP-16+.