Many modern built-in audio cards do not have midi functionality. (Even if your motherboard have it, most likely, quality will be very poor.)
If you want better sound, you'll need download instruments for timidity.
Either
freepats or
eawpats. This will make tracks sound better.
Eawpats IMO is better, but it is free only for non-commercial purpose. Freepats is truly GPL (AFAIK), but some instruments are missing (quite a lot of instruments). Eawpats can be found somewhere using google. I have both eawpats and freepats, but I don't remember where I've got eawpats. Also, I think timidity should be running as daemon in alsa sequencer mode.