I've found the key to getting maximum performance from the GR07 a great seal in your ear.. not necessarily insertion depth.. if you have these phones and wondered why you don't experience the bass quality & depth many rave about.. check your seal.. I've found it more in this phone than others, that the room for error is smaller for hitting the sweet spot seal.. but if you find it, it will result in some of the best bass texturing and quality I've heard from a dynamic under $300. It's got such a nice balance between speed, weight, texture, and impact.. perhaps the best blend of BA & dynamic driver characteristics when it comes to bass.
Also, the mids on my GR07 are no longer recessed sounding.. or warm, or laid back.. they're dead neutral.. amybe even on the cooler, crisper side slightly.. and strike just the right balance between lush and dry sounding. The treble has fantastic sparkle, air, and clarity. The soundstage and imaging is really well presented and sorted out too, evenly filling the space from left to right.
It's such a cohesive sounding phone to my ears, now.. they're not overtly smooth now either.. more forward & crisp in fact. It's ironic that for all the stage monitor-friendly, uncolored characterizing of the sound, I've found the GR07 to be some of the most engaging, musical phones I own. Something about the weight and clarity they boast intrigues me. I'm kind of amazed by just how much they've changed from out of the box. Going from thick, mid-centered, smooth, and warm.. to neutral, crisp, detailed, and fast.
At 300+ hours, the novelty effect these phones could've had has long worn off and they've probably become my favorite universal IEMs.. even over the DBA & amped RE0. While the RE0 is has a touch more micro-details, it doesn't sound as cohesive, musical, and wide as the GR07. The DBA is wonderfully crisp and musical, but it doesn't posses the weight this dynamic has. The RE0 must be well-amped in order to get those microdetails out too, and who want to lung an amp, however portable, with them everywhere? The GR07 sound stunning unamped from the iPhone 4.. and even better from the sleek Arrow amp.