After just sitting back in admiration of detailed beauty in the design and artwork, I decided I would pencil in some thoughts regarding the sound.
An overall summary of the signature would be balanced, precise with a natural tone and timbre. Created with long listening sessions in mind.
The bass is present with the mids being a touch in front however the bass certainly assists in creating the full sound that the F7 delivers. The bass has impact and is more quality focused than the F6 which has quality, almost DD like bass, but the F6 has more indulgent quantity. The F7 is mid bass rich with sub bass rumble that is heard and if heavy bass is in the music, felt.
The stage is precise but offers more of an excellent stereo separation as opposed to a holographic presence.
The mids deliver a dynamic soundpainting. The canvas is large and the art is displayed from edge to edge due to the detail and forwardness that the F7 renders. Forward does not mean abrupt and in your face, it refers to how the clarity and detail is pushed at you.
The F7 has garnered about 90% of my ear time since receiving it. I love long sessions with this great all-arounder. Long listening sessions are the norm as the treble is so vibrant but never sharp or harsh.
Great job Custom Art. The overall balance and tone deliver your consumers an A+ experience, and of course you have offered a TOTL IEM without astronomical pricing.