I get very low volume when playing WAVs. What can I do ?

This is a major problem and as a result it requires careful consideration.

For one, use compression (audio, not data) to make the sample "stronger".

Also, make sure that the original sound sample files are recorded very strongly. If you have to, use a sound editor program to increase the volume of each sample. Keep doing this even if the signal starts to clip if you want to get more volume.

It is a matter of personal preference as to how much clipping you wish to do to the sample. The more clipping you do the louder the sample will be with the trade off of adding more distortion. Some samples will be more tolerant of distortion than others so keep this in mind.