I bought my ATH-AD700s awhile back (4months+) and have burned them in but I still don't like them.
 
They are extremely comfortable but they don't sound that good.
 
Super bright and lacking in bass. Midrange is slightly recessed. Soundstaging is superb but instrument separation is mediocre and sometimes results in a muddled mess with some fast paced classical full orchestra symphonies as well as big band jazz. 
 
It is mid-high and high range centric and its like having a sun shine directly at your eyes; annoying and painful. 
When I bought them, I expected something to help with my Jazz collection because drum set cymbals lacked sizzle and some instruments lacked sparkle. They do give the needed high end extension but are bright. The high range is not harsh at all, but extremely "piercing". It isn't fatiguing and unbearable like Bose "speakers" but a sort of overly bright, overexposed feeling. Think of a screeching sound from a sharp claw scratching a chalkboard. 
 
Are there any modifications that I can do for the AD700s that will increase the bass and smooth down some of the highs? 
 
Or should I just sell them for some green paper?
 
Note that I am not an experienced audiophile or do I claim to be. I am solely basing these opinions on my experience with mid-low end headphones (HD 650, 600, 555, 448, 25-ii, MS1i, IEMs Brainwavz M2, Monster Turbines). I do wish I had the dough for some Summit-fi range cans. 

Sell them or PIF and give them away.

sell them and get ad900s

Quote:

kchau said:

sell them and get ad900s

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If you don't like the AD700s sound, the AD900s won't change much (very similar sounding).
 
I wouldn't bother modding them, I would sell them for that paper / try another phone.
 
I will plug the Q701s for jazz, classical, instrumental listening

Have you tried an aggressive equalization? I mean, it can't hurt at this point. Try something like a parametric equalization with +10dB at 20hz with a higher Q value than the base one. I found the AD700s had a rather nice and tight bass response if pushed for it aggressively enough -- it certainly wasn't the big impactful resonating bass, but it was nice in its own way.