Well, for a moment I thought I would go ahead and sell my 04...but I changed my mind...whenever I picked it up and give it a listen.
1/ It is a 4 BA drivers that doesn't sound like neither BA nor Dynamic....(no ears pearcing sibilant, no sticking, plastic kind of bass decay/body, slamming bass with great low-end, excellent decays to reveal that real housing resonances)....details retrieval are superbly and realistic. Even though it is tuned to get the vocal a bit recessed in with bass stand out a little more than trebles (1.75 bass, 1.25 vocal, 1.5 trebles) or so, the details overall is very realistic, enough brightness, warmer, smooth and musical.
2/ vocals have so much air and energy....but it is a bit recessed (lower in volume power compare to bass and trebles), which makes me turn the volume up in order to enjoy it....
3/ It stated 15-20khz respond, but I tested it with ZX2 and it turned out that it could go as low as 10hz with eases.
Now this, again is on stock cables.
04 is an expert quality
Today I made some very comfortable ear tips for myself. Very good in preserving bass/trebles with that thick inner cores, noise isolation at max that can be obtained from (ear tips) due to that super soft comfy memory foams...it also reduce any movement noises (which u gets with silicone tips)
Wide open bores for maximized sonic quality playback achievements from the phones.
The mods went like
1/ 50 pairs of earplugs bought from wallgreen which states 32db noise reduction rating
2/ Scotch scrape booker glue
3/ unused comply foam T500
A/ cut the earplugs in halves
B/ peel off the outside foams from comply tips clean and clear
C/ use a bamboo chopsticks or anything that can help you stabilize the bores
D/ Use tweezers and or small scissors to induce the middle hole about the size of the Comply bores, a little smaller is better (we will stretch it out and pull it in over the bores)
E/ apply enough Scotch glues on the bores
F/ stretch the earplugs foam, and pull it on over the bores
G/ cut and trim excessive foams for better appeal, if you care
Let's dry in 2 hours and Voila, your best and top foam tips possible