I got my HD-672 (white) today and I`m quite surprised by its build quality and most importantly sound quality! I even think it is better than my HW filter/cable-modified HD-681 (red) by short listening time without comparison.
I even think it might come close to my Fidelio X1 in SQ.
Need to get behind my desk setup to confirm and let it have little playtime before judgement.
Even stock rubber-pads are actually comfy ( I have already some velour pads to replace them and test sound differences.
Anyway, for ~25€ - HIGHLY RECOMMENDED BUY by me
EDIT: Naah... Fidelio X1 is still way better (especially mids) with my desk gear. More natural timbre and better balanced/ tuned highs (672 has little hills around 6-8kHz I`m quessing but no idea atm, must dig some graphs out to confirm. While I think HD-672 is very good value, I still think it needs some simple mods (maybe some more complicated) to get best out of it.
Will let it play for week and try some different simple mods also. Currently using velour pads.
Btw, swapping pads is super easy with HD-672 - just click-off - new ones - click on, no screws or dismantling.
EDIT: Yeah, I was right about highs, hill starts around 6kHz and goes up to 10kHz:
Bass is pretty tight & punchy, sub-bass is extended but well balanced without bleed or overshadowing. If those highs would get some dampening it would sound pretty close to KPE signature with "floating" clear mids (but 672 lacks mids warmth and naturality compared to X1).
Channel separation and soundstage are above average and executed well I would say (with velour pads).
EDIT: I had itch to try out some modding and I think I almost nailed it where I see its full potential (for my ears). That meant destroying stock pads but IMHO it`s worth it (I was not going to use those anyway). Three things needed - kitchen paper hand towel, stock pads (outer ring edge part) and littlebit electrical tape
Well... velour pads also needed though. I use these:
https://www.aliexpress.com/item/32980473807.html?spm=a2g0s.9042311.0.0.10844c4dVl2Ojm
To my ears noticeably better highs and warmer/natural more prominent mids.
Ordered those also but haven`t received yet:
https://www.aliexpress.com/item/4000096272168.html?spm=a2g0s.9042311.0.0.27424c4dflj5XG
One LQ photo also:
Will do removable dual-entry cable mod also.
Okay, got some time to do some comparing and evaluation with HD-672.
Notes about how HD-672 was compared against Fidelio X1:
1) Using 4-layer kitchen paper between driver housing and pads fabric to tame highs peak.
2) Using aftermarket non-angled velour pads (very soft velour fabric and very comfy).
3) Using "fit-rings" cut from original pads to improve fit of velour pads and gap-filling
of removable pad discs.
4) Venting holes of driver housing plate under pads disc closed with tape.
Test songs (FLAC 16/44):
A Perfect Circle - Eat The Elephant
Bruce Soord - Cut The Flowers
Heilung LIFA - Fylgija / Futhorck LIVE
Lifesigns - Different
Tesseract - Smile
TOOL - Pneuma
Test gear:
Aune T1 (hardware modified):
Main power supply capacitors - Panasonic FR
Secondary power supply capacitors - ELNA SilmicII (black/gold)
Headphone amplifier coupling capacitors - ELNA SilmicII (black/gold)
Headphone amplifier rail voltage capacitors - ELNA SilmicII (black/gold)
HO opamp upgrade (roll-able): OPA2228PA
DAC differential opamp upgrade (roll-able): OPA1692IDR
CMC gold plated OFC pins ceramic socket
Main tube - Siemens/Halske E88CC goldpin
USB data cable +5V power rail disabled
Software - ASIO4ALL > Musicbee
Using HO @ medium-gain - vol. @ about 45%
Fidelio X1 (dual cable entry modified) + custom low impedance copper Litz cable (DIY CC1HP)
____________________________________________________________________________
Sub-bass:
X1 has more sub-bass extension/reach and percussions seem more deep & "lively"
HD-672 sounds tad more balanced/neutral in that department but lacks those deep
deep drums hits and rumble/reverb, though it doesn`t seem to lack sub-bass without
such head-to-head comparison and still sounds pretty good.
bass (mid-bass):
X1 has more natural timbre and hit in percussions.
X1 has tad more quantity in mid-bass.
HD-672 has little more clarity due to less mid-bass but doesn`t sound
so "lively" and also some instruments timbre naturality somewhat "suffer" due to this.
Bass tightness and speed are pretty good though.
mids:
X1 has more natural timbre in mids and more natural sounding.
Better acoustic guitar. More natural piano and vocals.
highs:
X1 has more natural and smoother highs.
HD-672 has spike-hill at highs and without little/simple modification it is too much and gets annoying.
Still, with mods, cymbals/hi-hat/snare seem slightly "artificial" and too "sizzly & dry" at times with some songs. Experimenting with different placement and amount of filtering could improve it somewhat.
Otherwise highs details and resolution is pretty good.
treble-extension (air and micro details):
X1 has noticeably more open/airy and surrounding soundscape, more soundstage depth.
Live recordings more real sounding.
imaging/presentation/soundscape:
X1 has more enveloping and natural imaging/presentation.
HD-672 is pretty good in soundstage width and instrument separation/layering but X1
is just noticeably better.
Improvements & tips:
Get velour pads but not too high (distance from skin contact surface to driver) and not
too firm. Best is probably angled pads similar to AKG K7** series. Average or smaller head-sized
ppl should go with these kind of pads.
Over average size head-size ppl, when using velour pads (like I linked before)
get improvement from little stronger clamp force which helps
with perceived timbre/tonality naturalness and mids. Using non-angled and higher/softer
velour pads are recommended in this case.
Stock silicone pads are actually very good with getting fit and have better
sound isolation than velours but I personally didn`t like the feel of material against my skin.
Some ppl are probably fine with this and might even prefer those sound/isolation-wise to velours.
HD-672 needs some paper layers filtering under pads fabric (easy to do and adjust to person liking)
to damper highs peak and improve overall tonality balance of FR.
It might get some improvement from cups inner surface dampening (needs confirmation).
It might benefit from thicker/more stranded full-copper cable (needs confirmation).
Overall build quality, fit & comfort:
Build quality is very good for 25€. Seem to be improvement over HD-681 for sure but only time will
tell about durability (to me it seems to beat older versions).
Fit is great and cups have enough angle-movement on every axis to get good fit.
Clamp force is average and good for average-size head.
Cable quality seems much better than older versions but atm have no idea about conductivity (Ohm)
and AWG/core/strand count. When I do more mods and replace cable, will post measurements and findings.
Conclusion:
Well worth the money if modified littlebit and it doesn`t have so typical overdone clear V-shaped FR signature.
I would say pretty well balanced sound signature if You get rid of that spike at highs with simple modding(filtering).
Fidelio X1 still way better with that gear but I give thumbs-up to HD-672 - for such money - no regrets.
Hope it helped someone