Verdict: Probably the biggest flaw in the HD668B is the treble. There's just this weird signature in it that makes it a little... honky. I prefer the M50's treble. I am going to let these burn-in for the next week or so using my burn-in files and see what happens. I hope the treble energy subsides along with the bass a bit and the mid-range opens up. If they don't change a lot though I think they may be a nice switch up from the warm sounding QNN headphone. I’m gonna play an opera or performance for monitoring opera, drama, performance.. anything that has wide performing space. The midrange frequencies in general have a character approaching neutral, accentuating a bit in the upper midrange registers. Vocals in general are presented with great naturalness and have good clarity and presence in their reproduction thanks to the slight elevation between 1.5 to 2.5 kHz. and now this headphone produce sound just like what its hype about..i don’t know why, but maybe i will leave my hp on with the music till morning..hopes it will gets a better peformance..time to sleep..sbelum plng ke desa..

Superlux HD668B Review (headphone) | Audio Science Review

Comfort is better on the 661. Sound quality, the 661 is better suited for music, where the 668B has a dryer but more articulate sound that would be better for monitoring. The 661 is a little warmer on the mids and bass, and has a fuller mid section. The treble is similar in tone to the 668B, but less dry. Except for the headband and the holders for the "wings" that rest on your head, the headphones are made of plastic. They dont squeak or rattle when handled, but apart from that, there aren't many more nice things to say about the build quality. Build wise these seem very well done aside from the pads which I do think I will replace with AKG velour pads. I also like the replaceable cable system and the different lengths given.The build quality regarding the rest of the headphone can best be described with the words: "You usually get what you pay for" Mids-wise, the HD681F is an improvement to the HD668B. They're slightly more forward, perfect now actually if not for the slightly far-reaching highs overpowering the mids a little. In the end, I feel that the battle mids-wise ends in a draw... I use good 'ole Mortite hand-applied caulk rope to damp all the "in-between" spaces around the face of the driver grills (behind the ear pads). I appreciate that Mortite is heavily mineral filled and very acoustically dead. Other rope caulk brands are too lightweight and are not as efficient (in killing resonances). Because of how I modify the 6 vent holes around the driver grill (behind the ear pad), I could not use something similar to Dynamat. To do so would make a mod irreversible.

Best version of Superlux HD-681 | Headphone Reviews and Best version of Superlux HD-681 | Headphone Reviews and

Living on a retirement income, my audiophile equipment days are over. Having at one time a 30K Phase Linear system, I got used to extremely good sound. So when I got these for a birthday present, I kind of put them to the side, as they didn’t feel as if they were really of any quality at all. They are dynamic, balanced well, detailed yet not irritatingly so, but sound (to my ears) a little distant or "dark". Compared to my K701, D5000, or especially my HE-5LE, they cannot compete in resolution and sound soft in the top octave. You don't get the sense of "air" or room acoustic compared to the top headphones. Comfort-wise, the N650 has softer earpads but they sit more on the ears rather than around the ears like on the HD668B. Both headphones are initially comfortable but I find my ears need a rest with either one after 1 – 2 hours.

I have listened to these headphones for roughly 24 hours accumulated over a month. I initially burned them in for half a day. The headphone still sounds the same, maybe just a very slight decrease in treble. Volume is quite soft, I need to turn my Xiaomi 4X volume up to around 30-40% to be as loud as my Sony MDR-ZX600 at 20%.