The Phiaton MS400's have a very enveloping bass, not to the point that I would call it boomy per se, but it does boom.
These headphones seem to enjoy forward presentation, especially on vocals, they are right up there in your face.
All tracks are ripped into FLAC or of higher quality. Played in Foobar with ASIO4ALL to my Pico Amp/DAC.
Infected Mushroom - Classical Mushroom - Sailing In The Sea of Mushroom
The headphones felt bass heavy to the point they were overpowering the mids. The bass was clear and punchy, had great kick but not very detailed. The phones couldn't handle the more complex passages in the song and would become sluggish. There is a definite difference in how crisp the notes are compared to the Grados HF2.
Infected Mushroom - Classic Mushroom - Dracrul
The howling wolves at around 35 seconds were not noticed on my first play through. Upon hearing the wolves clearing on the ATH-AD2000 I listened through the track again on the Phiaton MS400's and found that once again the bass has overpowered the rest of the presentation making details harder to notice.
Eric Clapton - Unpluged - Hey Hey
Eric's voice is less natural, the deep feeling did not feel as real when compared to the Grados HF2. I guess the best word to describe it would be hazy. The headphones can keep up but I felt the lower notes felt "thick" when they were strummed.
Disturbed - Believe - Darnkness
Once again, the bass has saturated the mids. The headphones had trouble keeping up with this song making instrument separation very difficult. Everything was sort of muddled. There was a night and day difference listening to this track on the Grado HF2.
Disturbed - Believe - Liberate
I didn't feel the bass was overpowered in this track. I was easily able to pick out each separate drum strike and the song was a blast to listen to. Presentation was very forward with the drums feeling distant at some points and close at others; very odd.
Nine Inch Nails - The Slip - Letting You
Noticeable boom in the bass but it wasn't boomy. Where the bass felt distant on the Grado HF2 the Phiaton MS400 made it feel very close. They handled the bass fine until the passages got more complex and the headphones had trouble keeping up with the pace of the song.