Mackie 0 Report post Posted September 1, 2003 (edited) According to feedback from lengcm and Northern Oak who have tried AKG 501, DT990 is not as open sounding than the former, thus resulting in a relatively narrower soundstaging than AKG although the Beyer has much better bass performance. On this note, I have placed much thought into modding the 990 and after a close scrutiny of its internal structure, the mod was finally completed. The tweak is small and easy but improvement wrought is significant. From the picture above, U can see the cup (with grids) is ventilated but there's actually a solid white plastic cup inside with a concentric hole cut-out. There's a piece of synthetic cloth inserted between the ventilated and solid white cups and I believe this cloth is not acoustically transparent, thus resulting in a less open sound than other open-backed cans. Using a hot soldering iron with pointed bit, I trimmed the cloth covering the concentric hole from the insides after having removed the drivers and enclosures. After which, the metal parts of the drivers can be seen from the outside. Upon wearing the cans, ambient noise is much more noticeable and this reassures me the protective cloth is introduced to place more emphasis in averting dust. I proceeded with a hearing on classical music, both chamber and full orchestral works and I found the new sound is more expansive. Bass is still abundant and in no way pared by this mod. I will seek opinions from my nearest neighbour Oakey who used to own AKG 501. I wonder if the modded 990 has narrowed the gap in the race for soundstage width. Edited September 1, 2003 by Mackie Share this post Link to post Share on other sites