Thanks 64 Audio and Barra for the opportunity to demo the Tzar and Tia Fourte, it was really a treat. I've never done a review, so please consider this merely a recap of my impressions of the TOTL 64 Audio iems. Also, listening was done with old ears, so YMMV! I demoed the iems in various ways, using my iPhone 7, Sony ZX1, Hugo, and Liquid Carbon with SE connection. My primary playing time was with the ZX1 playing though my Hugo.
I only have one iem at the moment, the Obravo EAMT-1C, so I can only make draw comparisons to this at this time. I hesitate drawing comparisons to earlier iems I have previously owned, including the Fitear 334, Parterre, K10, and FA fi-ba-ss. My Obravo's bring a lot to the table, with an extremely wide and deep soundstage, natural (to my ears) timbre, and bass that extends very well into the lower sub-bass region. Treble is very detailed yet smooth and not overpowering.
I started with the U18, and was immediately struck by the impression of the upper mids and treble being pushed more forward than I have been accustomed to. Sounds stage was nice and wide, but lacked a litte depth. Bass was tight and fast, with slightly less decay than I would prefer, but was never overpowered by the mids and treble. The overall sound felt a little "in your face", but I came to realize after a few hours of listening time that I needed to become accustomed to the high clarity of the upper mids and treble. After some time for brain burn in, the sound became very coherent and balanced. I have to say that the detail and clarity of the treble is really top notch, and I never listened to a track that showed any trace of sibilance. I've never considered myself a treble head, and honestly always preferred a more organic, smooth sound more like the Audeze house sound, but with this iem I enjoyed a treble that is highly detailed yet smooth and comfortable to the ear. The mids were very well balanced and vocals were placed very well with instrumentation, neither too forward or too recessed. I ultimately did find it slightly lacking in sub bass, but the bass is very tight and lively and never bleeds into the lower mids.
Switching to the Tia Fourte, I expected to need some brain burn in with these as well, but immediately felt like these hit my sweet spot, and so I personally prefer these over the U18. Bass especially is more to my liking, going a little deeper and thunderous when needed in the music. Upper mids and treble are very similar to me to the U18's, but seemed to offer slightly greater instrument separation and placement. Bass, mids, treble; there isn't a real weakness in my mind with the Fourtes. They possess a wonderful balance throughout the spectrum, and I can't imagine an iem that provides better clarity from top to bottom. I have to say, that after reading other reviews stating that the Fourte's had mids that were slightly more forward than the U18's, that I honestly didn't find that to be the case with my setup. In fact, I felt that the mids where the vocals are placed might actually be a little more recessed than the U18. Keep in mind they are by no means recessed in the overall sound, but just enough to create, again to my ears, greater depth in the soundstage than the U18. I don't know if that makes any sense, but is this what Tyll Hertsens refers to as the effect of a slight recess in the presence region (as he described in his Ether Flow review)? I just don't know, but I felt that it made for a more 3d sound stage over the U18. Anyway, width and height are very similar to the U18 and overall soundstage and instrument placement is very impressive.
These are very cohesive and well balanced iems. Many use the term fun sounding, and I have a better understanding of that term now. Where my Obravo's give me the sense of wearing full size headphones with a rich, well textured and smooth sound, the U18 and Fourte dazzle you with the micro detail in the instruments. I do prefer the Fourte in terms of balance and space between instruments, but I'm certain it's a matter of personal taste. Fourte is more similar to my Obravo's in bass presentation, with great low end that has a tiny bit of bloom but does not bleed into the lower mids. Vocals with Obravo's are rich and natural, while the Fourte by comparison has a slight (but not unnatural) shimmer to vocals which can be a big plus in bringing out female vocals in particular. Both the Obravo and Fourte have really large soundstage and give you a great out of head experience. But I much prefer the treble presentation of the Fourte; it's just wonderful in the way it presents detail and clarity without being fatiguing. The Fourte's fit very well in my ears, and isolation, while not ciem level, is still very good. 64 Audio's top 2 iems are well done and now I want to buy the Fourtes!!