yeah, I mean, the PSU is only going to draw out what power it has capable in Watts anyway, and this only really depends on the load of hardware...not exactly what you are running on it when its running.
Like for example if its running off CD Audio, your having to set up a CD drive in the computer (about 3-5watts?), okay, not a biggey...and then you need speakers which usually draws from a seperate power source (This can be a slight bit heftier in power usage, but not much really...) but yeah, a music program is not really going to make any difference.
If you want, get some headphones that have really good bass and quality, and use them. They only draw out what the sound card uses