Superlux HD-681

I installed ear pads from Superlux HD660PRO, it greatly improves comfort. I hate leatherette.
660 more than 681 velor and more than 681 leatherette.
The speaker grill protrudes forward, due to this, the ear touches the speaker, but you can put something in the ear pads and the problem will almost disappear.
The headband unbends without problems and does not put pressure on the ears.

These are semi-open headphones and there is no hum here.
There really is bass here.
Sub-bass starts somewhere around 27 hertz.
Upper frequencies are of disgusting quality and there are sharp dips.
At first glance, the sound is close to natural, but made to please.
In general, this is a sharp sound.

Theoretically, this is a good option for a beginner.
BUT, I had 2 copies and both pairs had a different, but very serious frequency response imbalance (disagreement between the left and right speakers). Hence this assessment... The manufacturer needs to increase quality control, despite the fact that these are one of the cheapest headphones.

I prefer the comfort, quality and sound of the DT770 and DT990.

Thomann, my favorite store, I recommend it to everyone!
Addicted to Thomann all my friends)

I bought them for use on my small guitar amp for practicing, but tested them with some easy listening across more or less many genres (classical, jazz, metal, rock, electronica).

TL;DR: Sound OK-ish, comfort should be OK - for small ears.

The sound is better than expected, but I didn't expect too much. Maybe I'm just getting deaf enough, but I think they are acceptable -- slightly shrill at the high end, and too intense for the bass, but OK. (I don't do any mixing at all, but I doubt they would be usable for this.)

Comfort is a mixed bag. High pressure on the head (higher than Beyerdynamic 770, for instance), and not adaptable. For me they are slightly on-ear, not over... This is exacerbated due to me having glasses, so the (high) pressure on my ear is felt more strongly as well. So, not really usable for extended listening sessions, though for an hour it's good enough. For smaller ears this should not be any problem at all.

I bought this headphone as I was trying to learn mix some of my band's music. I wanted a cheap studio headphone and gave the Superlux HD681 a try.

Out of the box the Superlux comes with a simple nylon carry bag and a 1/4" jack adapter. The headphone is made out of plastic and looks cheap. I plugged it through a focusrite sound module to hear the sound quality and was astonished with the clarity of the sound and the details that I could hear.

However, while mixing I realised that the headphone has a bit more treble. My mix were always had too much treble when I listened to them on hi fi speakers and headphones.

I encountered the same problem while programming tones for my guitar on my multieffect units. The tone that I hear on the Superlux always had more treble when I plugged my guitar multieffect on full range speakers.

I'm still using the Superlux to listen to music from time to time and it still holding well. However, if you want to buy a headphone for mixing I would suggest that you look for something else.