Out of the box, and with the pleather pads, the NightOwl is rather midbass forward. The upper mids, specifically in the 1.5kHz to 3.5kHz region, are somewhat recessed. Across the entire treble frequency range, the Nightowl is extremely smooth sounding, so no brightness or harshness is present. The instructions say they completely burn in after 150 hours, but in my experience, this is not true. The burn in period actually continues until the headphones reach their final sound at around 350-400 hours. I prefer the sound with the ultrasuede pads, as snare drums just don't sound correct to me with the pleather pads, even with EQ. With the ultrasuede pads, the elevated midbass is still there, but only slightly. The treble is also more detailed, but still not bright at all. Either pair of pads will give a very smooth sound, but the ultrasuede, IMO, sounds far more natural. After the headphone is completely burned in you will notice that the elevated midbass bloat will tone itself down somewhat, and upper mids will become more present. The bass will become tighter sounding as well. Be aware that if you decide to reduce the midbass somewhat with EQ, as a result, the treble extension and detail with increase. Reducing the midbass also results in the lower bass tightening itself up.
