We have acquired a few headphones to audition. These headphones are: JVC wood cone HA-SW01 (56 Ohms), HIFIMAN HE400i (35 Ohms), AKG K702 65th Anniversary (62 Ohms), Sennheiser HD6xx, HD600 (300 Ohms), Beyerdynamics DT880 Pro (250 Ohms), and the following 600-Ohm DT990 Edition, DT990 Pro, DT880 SE, T1-2nd Gen. We also removed the felt-pads that under the protective grilles of the DT880s and DT990s. The sonic characteristics of HA-SW01 and HE400i are similar. They sound balance with good bass. However, we prefer the HA-SW01 due to its sweet mid-tone. The AKG K702 delivers detail trebles and mid-tone; but, lack of bass. While HD6XX offered by Drop seriously lacks treble, the regular HD600 presents good mid-tone with lower output in treble. The lower treble level matches the infamous public opinion "Sennheiser Veil". However, this may be a desirable feature for listening to string musics and operas. The advantage of using high impedance headphone is enhanced detail. However, the low-end non-removable stock cables and felt-pads have defeated this purpose. So, we replaced the stock cable of our DT880 and DT990 Edition with the silver plated 4.4mm balanced cable. This modification made our DT880 and DT990 Edition sound outstanding. We like these two modded headphones more than the T1 2nd Gen though the T1 sounds excellent without modification.