+1. This was my reaction when I first heard the mid and sub bass of the Q40 with my E11 on bass setting #2:

+1. This was my reaction when I first heard the mid and sub bass of the Q40 with my E11 on bass setting #2:

come on , i amped them, but did not eq them. straight out of an amp, there is more sub bass on the denons, thats for sure.

While their bass is deep and powerful, they just aren't made to be pure bass cannons, but if you are looking for overall SQ, they are fantastic.
I have the XB500 and thats not enough bass for me :D Well at least when I want a good head shaking so would they mash up my brains with the ZO2? If so I might use those with the ZO2 for brain mashing and the M50s for regular listening since I do listen to other types of music such as Jazz, Rock, etc. And does the ZO2 produce good bass or does it sound distorted and yucky :p
Thanks for the help though 
This^^^^^^ +212039214973585459230
But with the ZO, HOLY the quality of bass never goes down, but the rumble just keeps increasing, and bass never gets in the way of mids, nor dos the bass ever 'take up sonic real estate' as craigster put it in the M-100 thread.
with a ZO, the M-100 is my DREAM basshead can. It's definitely a great all rounder headphone, but if you want it to be a basshead can, the ZO would probably be the best pairing imo - bass quantity to taste.

I have the XB500 and thats not enough bass for me :D Well at least when I want a good head shaking so would they mash up my brains with the ZO2? If so I might use those with the ZO2 for brain mashing and the M50s for regular listening since I do listen to other types of music such as Jazz, Rock, etc. And does the ZO2 produce good bass or does it sound distorted and yucky :p
Thanks for the help though 
The ZO doesn't 'produce' the bass so much as it EQs the bass quantity. If the headphones have muddy bass, then the ZO will EQ the muddy bass up. But if there's nice tight, textured and controlled bass, like the m-100s, then the ZO will EQ that nice bass up.
So would you say the ZO2 is worth it? I was debating getting that or the Fiio E11 and have heard great things about both but right now I just have the XB500's and want to either get something to turn up the bass in those to make a basshead can or getting a new set of headphones AND an amp to make the basshead can. But if the XB500's with the E11 or ZO2 would be face melting then I'll just pick up the M50s for my non-face melting experience :)
Are there any cheap bass heavy headphones out there(under $100)? I am more into punchy bass similar to the Sony mdr-xb500s (which i already have).
My experiences were the opposite, D1100 was very midbass focused. For my taste it lacked some subbass compared to midbass. Q40 however has a nice balance between subbass and midbass for me.
+2