I'm using XmPlay long since, I absolutely adore it, and make a great use of it. Professional, compact, and customizable.
One of its useful functions is the Spectrum (3D) visualizer, which I use for "MIDIfying" music, it makes easier to determine the the pitch of some tones, the , and the rhythm.
If it isn't too hard to manage, I would kindly request to make it a bit more customizable, with options like these:
- minimum and maximum values of the displayable frequencies
- speed of the slow and the fast progression of the vis.
- a customizable horizontal reference line at a specified frequency or note, and its octaves
- ability to change between linear and logarithmyc vertical scale
These functions presumably can be found in professional studio and audio editor programs, and may wouldn't be too widely used, if they were integrated in XmPlay... They are just some ideas from me.