The best Linux music player is, in my opinion, Elisa.
“Elisa is a music player developed by the KDE community that strives to be simple and nice to use.” explains the KDE Community Wiki.
For those new to Linux, there are a number of desktop environments for Linux. Two of the most popular ones are Gnome and KDE.
Yes, I am using the Gnome desktop. But Elisa is that good of a music player. It has a modern look and feel and can handle hundreds and hundreds of music files.
So if you are looking for a Biorhythm replacement try Elisa. I highly recommend it.