Summary: So, I bought these during my birthday, though I first thought of buying the 688B and I thought the headphones were the size of a small pair.
But I was wrong. Instead of an HD668, I bought these. A really big pair of cans that you can't take out of a studio or a house.
Anyway, the first time I wore these, I already liked them. Though it takes some time to getting used to if you're used to small sized headphones or if you're not used to a sharp treble.
Pros: Not too expensive, Flat, nice build quality, good bass
Cons: The materials are cheap, sharp treble, these cans are huge, not very portable if you want to use it outside.
Summary: I've been using this can for a week now, and I can tell I'm really happy with it. I wanted to buy another model (Superlux HD-681 EVO) but it was unavailable in any retail shop in my country.
I'd prefer a semi-open build, because isolation could be a problem after prolonged use for me, but in the other hand it's great because you can listen music fairly high volumes without any sound leakage.
Summary: I received these when I ordered the 688b But still, I'm happy with them. Bass is somewhat subdued but still present. Highs and mids are very nice. I am listening to them now with a portable amp, tcg t-box, and they have benefitted from this. They draw me into the music.
Pros: Neutral, fast, wide and engaging
Cons: Earpads are not nice, you need to tweak the headpads
Excerpt: Hola compañer@s. Hoy os voy a hablar de unos cascos que le compré hace tiempo al primo de mi novio,ya que esta con la moda esta de llevar los clásicos cascos grandes por la calle estuchando música.Para mi gusto no me gusta para nada esta moda de los chiquetes de hoy dia,pero en fin,era un regalillo.
Excerpt: J'ai acheté ce casque fermé pour l'enregistrement au microphone. Il serre très fort la tête et c'est bien étanche. Il isole suffisamment pour éviter la repisse. Toutefois le câble transmet mécaniquement des bruits parasites si il frotte sur la chemise. Ce casque est bien conçu et de fabrication correcte. Les tampons du sommet se règlent, çà coulisse sur deux tiges élastiques en fer.