TheGame21x
1000+ Head-Fier
The M31 is great for midbass lovers but if you listen to a lot of music with a lot of sub bass presence, you'll probably like the Phillips SHE3580 more. It's very cheap, hovering at around $10 - $15 or so and sounds better than the M31 overall in my opinion (and far better than you'd probably expect an IEM that cheap to sound).