First, I would like to thank gnarls for lending me his F111 to finally audition this great iem. I've been on the fence many times in the past year on purchasing it, but never pulled the trigger because of the correlation with the ER4S (owned 3x) and the huge price gap between the two let alone the relative scarcity of the F111. I wish I still had my ER4S for direct comparison. So, consequently, any comparison involving it is based on my audible memory.
In retrospect, what I always liked about the Etymotic sound is the ability to make me believe I'm at a comfortable distance to the music sources, and the ability to resonate a natural and realistic sound. You'll never find me in the first five rows of a concert or wanting to stand on stage with the performer(s). The perception of air is dry, dull, and over time a little claustrophobic, which is why I was never able to listen with the ER4S for more than an hour or two at time. However, I will tell you this, "The first hour of listening with the ER4S is magical with some of the best treble I've heard in a portable application." Then, the soreness and itch would set it, along with the unanswered wish for a little more low end impact on many of my tracks, and call it for the day.
Despite the use of identical drivers, the design specifications makes the two seem as distant cousins rather than siblings. If I had to quickly describe the experience between the two, the ER4S is like looking through a high definition (HD) monocular scope with just your good eye. The F111 is like looking through a a pair of Swarovski HD binoculars. For me the largest differences between the two is the widen soundstage with the F111 along with a slight increase of bass quantity. I believe the design of the titanium sound tube with a horn shape exit along with a shallower insertion are responsible for this.
I find both are highly detailed, but I would bet the ER4S is perceived to pull even greater detail due to its more narrow stage and the much deeper insertion. The F111 has a nice and warm touch over the cold ER4S, but never to the point of taking away from the flat and balanced sound presentation.
So, what does the F111 bring to the table over ER4S? One word - COMFORT. I have never worn a more comfortable iem or ciem. There must be some deliberation with company calling themselves "FITEAR." I appreciate the more shallow ear tip insertion depth over the ER4S triple flange and ear glider tips. I can see myself wearing the F111 with my Monster foam supertips for 24/7.
Both are robust in construction and first rate, but I give the Etys' a tip of the hat should they got dropped or stepped on. By design, I've always considered the ER4S professional grade and pretty much everything else professional and/or consumer/audiophile grade, which I would place the F111. The F111 stock cable construction reminds me of the Ortofon EQ5 cable.
From my short audition with the F111, Fitear's tribute towards the ER4S is evident by maintaining most of the Ety house sound, but improving upon it in terms of immediate and long term comfort, providing a little wetness to the dry, and really hitting it home for a very enjoying experience. If I had to provide a complaint, it would be the scant Grado-like approach with accessories, but at least you get a mesh bag with the F111; although, I find a small, hard zippered case much more practical.
Is the F111 worth the price over the legendary ER4S? I can wholeheartedly say, "Yes"; but my wallet says, "NO!"
Thanks again, gnarls. I look forward to your impressions with my Tzar 350.