I had very high expectations for these beautiful gems. They are super-comfortable and well-designed (obviously inspired by Audio-Technica), high-quality built, and have some of the most potent bass reponses around. That, however, is ruined by nasal overly loud upper-mids, rather weak treble, and overall dark and unnatural sound quality.
I'm very disappointed, and yet I'm all in hopes that I just got a defective pair...
Powerful and well-balanced bass response.
These are VERY loud. Anything can drive these earphones.
Probably the most comfortable earphones I have ever used. Getting a firm fit is effortless.
Excellent design and choice of materials. The 90° angled plug is top notch.
The cable was rolled perfectly in the package - you get a perfectly straight cable out of the box.
Disappointing sound quality when it comes to timbre and clarity.
Unbearably shouty caused by overemphasized upper-mids.
They look like they have an open-back design, but their backs are actually sealed behind the meshes.
Comfort & Fit
I was absolutely amazed how easy it is to wear these earphones. Without putting any pressure on your ear, these earphones go straight in and sit firmly, and are not easily pulled out. These earphones' design was quite clearly inspired by Audio-Technica's ATH-CKR9/CKR10, a brand that makes comfort a high priority. They're also similar in design to TIN Audio T2, Tingker TK200, LKER i8 and Remax RM-530, but are noticeably more comfortable than any of those, thanks to the unique angle used on the nozzle.
Lows / Bass
A whole lot of excellent bass. Strong presence of a warm mid-bass, but not muddy and not overbearing. The sub-bass is deep and punchy but not too ear-drum shaking. These earphones passed the bass shaker test without any noise or rattle and relatively minimal distortion on the sub-bass at full volume. Very impressive!
Mids / Vocals
That's where the earphones start to disappoint. Sure, I'm all for mid-centric earphones, but the F1 are just too upfront. The vocals are all too much shouty and in-your-face. It becomes unbearable on higher than low volume levels. Moreover, mids and vocalls have a dark, nasal and metallic timbre, which makes things even worse.
Highs / Treble
Although seem to be quite detailed, the highs are rather silent and underemphasized, with a few peaks in between, and are nowhere as tonally accurate as I expected them to be. They are dark and lack any light or transparency.