For the RC-3, 30 or 300:
If you are having issues with your Instrument Input Level in relation to your Backing Track or Imported Track WAV file audio Volume, the Backing Track or Imported WAV File Volume may be too loud.
Adjust the Volume of the Tracks: connect your RC- via USB, find the Files/Tracks import them into your preferred audio software editor, adjust the Volume of the tracks with the editing software.
HALF the Volume of the track(s), export the correct format.
Then replace or copy to the Tracks to the folder location of origin on the RC-.
(Data Format: WAV, Bit Rate: 16-bit linear, Stereo Sampling Frequency: 44.1 kHz)
The Backing Tracks are at CD quality and Volume while the Input is set to not cause unexpected issues with other pedals later in your signal path.