Here are my impressions for the FiR Audio M4 and M5. I was also part of the HeadFi tour, so I got to try both of these IEMs for free.
The sources used with both IEMs are the iFi Micro Black Label and Sony NW-WM1A. Both models were fairly resistant to hissing, which makes them more versatile with sources. They were also very comfortable for long periods. No pressure build up whatsoever. Stock cable is quite good. It is pliable, but not the softest. Feels good on the ears, it doesn’t itch or anything.
The music I listen to tends to be quite vast, but it mostly revolves around metal, rock, instrumental and soundtracks. Here is a non-exhaustive list of the bands I used to gather my thoughts : Dream Theater, Haken, Jinjer, Opeth, Tool, Gojira, Killswitch Engage, Lamb of God, Breaking Benjamin, Chevelle, Soen, Karnivool, Andy Timmons, Marco Sfoli, Anup Sastry, Intervals, Plini, Animals as Leaders, Hans Zimmer and Ramin Djawadi.
FiR Audio M4 impressions
Best genres : rock and metal, if you don’t mind the reduced treble presence.
Some things sound amazing, some things don’t sound really good. Relaxed sound signature.
Excellent bass (sub bass is excellent, mid bass is good)
Lower mids are nice, distorted guitars sound amazing
Vocals are definitely laid back, they sit a bit at the back when compared to everything else in the mix.
Not the best detail out there, can lack definition on more complex and complicated tracks.
Some instruments just aren’t well reproduced (piano, bass guitar), due to speed mostly. Seems like the drivers can’t keep up. Much better at higher volume, but performance is quite poor if you keep the volume fairly low.
Recommended for the price? If you really just want to “chill” and relax while drinking some whiskey, then sure. If you want to do some critical listening, then no. A bit on the pricier side of things, would be more competitive at a lower price point (something around 1.2 - 1.3k usd), cause I would definitely take the Solaris or U12t over the M4.
FiR Audio M5 impressions
Exciting sound signature, with decent bass (not the best, even though it’s a DD, but gets the job done). The sub bass extension and mid bass are about average for a DD (still better than most full BA setups).
Treble does not feel exaggerated, even though most EST implementations tend to have a bit too much energy. Can definitely be a little hot for some people, but I did not hear unbearable peaks.
Mid range is quite good ! Definitely goes for something balanced. Vocals and instruments are not emphasized, they just sit a little back compared to the rest of the mix. Detail pickup was a little disappointing for a flagship. It could not keep up with some of the other models I’ve tried (namely, the Anole VX and U12t, which are both cheaper). Still decent overall, but nothing to write home about considering the price.
Recommended for the price? Definitely not at retail. The price is higher due to the technologies used (trybrid with EST, DD and BA drivers), but the actual sound does not feel improved per se. The price would be fair at around 1.5-1.6k usd, so I consider MSRP to be very overpriced. Would probably look at alternatives from 64audio instead, although the bass response probably won’t be as good. The techs used are similar (LID, APEX, etc.), so you can something comparable if that’s something you care about.