Fir Audio M4 UIEM
Fir Audio brought M4 out to party, employing innovations by industry luminary Bogdan Belonozhko such as Tactile Bass, ATOM Vent System and tubeless Direct Bore to get the most out of the dynamic driver and triple balanced armatures. That delivers a fun 'V-shaped' tuning with bass and treble emphasis, and gobs of space in the midrange.
Twister6 resultantly praised Fir for building M4 "with a well-balanced bit of excitement coming from the bass and treble, while performing at a very high technical level", Headfonics agreeing about its "excellent stage presentation, high amount of detail regardless of its warmth, and very well-balanced output".
Headfonia say the "M4 has the ability to get me off my feet ... its authoritative and energetic bass, coupled with its full mids and lively treble is something that can be quite versatile in the end".