One word: Clarity.

These are not for everyone. These are neutral monsters - no warmth, no bass boost, no mercy.

The Heir Audio Tzar 350 is a dual-driver, 350Ohm(!) universal IEM tuned for neutrality and transparency. It is hand built using the same, compact type of housing as Heir’s popular 3.Ai and 4.Ai. The Tzar is made using black acryllic where the Ai models are a dark shade of purple. 9 sets of tips are included in the sturdy Otterbox case, along with a detachable Westone-style cable and a cleaning tool. Tip rolling is recommended, try out all the tips to get a nice, tight seal. I first thought these a bit harsh and sibilant but a change of tips and following deeper insertion really helped.

Left to right: Tzar 350, 4.Ai, 3.Ai

If a recording has flaws or is overly compressed, the Tzar will tell you. Why would I want them, you ask? Because if a recording is done right, the Tzar will tell you. Listening to Lady Gaga - Judas on these can be most politely described as “an aquired taste”. I’m not talking about musical preferences here - Lady Gaga is a bit of a guilty pleasure for me. Her music is mastered to sound good from iBuds, car radios and huge towers of bass speakers in da club. When you play that music from a neutral source through a neutral amp to a neutral set of IEMs you get something rather unpleasant. Everything sounds incredibly artificial, reminding me of bad robot voices in 80’s movies. The bass sounds like angry gnomes beating up trash cans with spades - not that the Tzar 350 can’t do bass, it can - but this overly compressed, EQ’ed artificial bass is best played on something else. My very-close-to-neutral Heir 4.Ai with it’s slight warmth and very gentle bass boost is a lot kinder to that sort of music.

Tzar 350 w. O2 amp and iPod Classic

But what happens when we feed them the good stuff? The perfectly (or just not crappily) mastered recordings? That is where the Tzar really takes off. They are very, very neutral and with tons of details presented clearly they will award you with an amazing sense of presense and soundstage. Well-recorded vocals and strings are spectacular on these IEMs. “Spanish Harlem” performed by Rebecca Pidgeon is an absolute delight on the Tzar 350. Her voice so clear, right in front of you... Then you notice the sound of the studio. How her voice is reflected off the walls and you get a clear sense of the size of the studio. The strings, piano and maracas each have their own clear space and allow you to really pick apart the recording. The same thing goes for “Comes Love” by Louise Rogers, one of my regular test tracks from HDTracks in 24/192. Crystal clear vocals (and breathing) on top of the sound of that big, lazy bass. However, I believe that either the bass player has asthma or he really needs to get in shape. And Louise should stop turning pages while recording. The Tzar 350 is merciless. Sticking with the female vocals, the song “Me And A Gun” by Tori Amos, from the album “Tales of a Librarian” is a stunning experience. Even the slight background noise or hum on the recording cannot take that away, the feeling of presence and intimacy is overwhelming. The same goes for “Behind The Wall” by Tracy Chapman. Both are a capella performances and if it wasn’t for the slight noise on the recording you’d swear they were standing in front of you. I don’t know if I’m allowed to use the word “Eargasm” here on Head-Fi, but try listening to Allison Krauss (and a huge choir) performing “Down To The River To Pray” on the soundtrack from “O Brother Where Art Thou” (in 24/96 from HDTracks) with the Tzar 350 and see if you can come up with a better word for it.

Portable joy: Ibasso DX100 -> Heir Rendition 1 -> Heir Tzar 350.

Moving on to male vocals and live recordings, the amazingly detailed sound of the Tzar will let you hear the size of any given live venue. On the album “Unplugged”, Eric Clapton is clearly performing “Layla” in a smaller space than the one Fink was at when he recorded “Trouble’s What You’re In” on his (brilliant) live album “Wheels Turn Beneath My Feet”. Sadly, Clapton had a better sound technician - Fink’s acoustic guitar borders on clipping and his voice can get ever so slightly sibilant at times. Exactly like it was when I heard him perform live on the “Wheels...” tour. Still a brilliant album, but my 4.Ai and 8.A makes for a more pleasant listening session. The Tzar 350 tells it like it is. This can be a good thing or a bad thing, depending on the technical quality of the recording as well as the performers. Zach De La Rocha of Rage Against The Machine sounds exactly as pis... aggrevated as he should, but with the Tzar you almost want to wipe his spit off your face. “Take The Power Back” from their first album is another of my regular test tracks for it’s punchy drums and bass and the Tzar doesn’t disappoint. Less bass than the 4.Ai, a lot less than the 8.A, but a nice, dry punch. Guitars shred FAST, the cowbell (yes, that track has cowbell) is crystal clear... and then it gets bad. While the right tips will control the highs, this recording has some downright piercing cymbal hits. Lots of well controlled brass percussion as well, nicely ringing out in the studio. But beware of the hard hits to the cymbals, the Tzar will not shield you like the 4.Ai and it’s much debated 3.7Khz dip does.

As a Rammstein fan, I must admit that the unbeatable clarity of the Tzar 350 is a double-edged sword. “Wait, did you just say unbeatable clarity?” I hear the voices in my head asking. Yes, yes I did. “But what about the mighty Ety ER4, the IEM king of clarity?”. Alright, I’ll need you to sit down for this: The Tzar 350 beats the ER4 when it comes to detail and clarity. At least to my ears and those of a fellow head-fier and ER4 fan. He still preferred the ER4, but had to admit that the Tzar 350 had more detail. One could argue that they’d better have, at twice the cost and requiring an amp, but it doesn’t change the fact that they win on detail retrieval and clarity.

Anyways, back to Rammstein. On their latest album “Liebe Ist Für Alle Da” (Love is there for all) seems to be better mastered than the older “Reise, Reise”. While listenable on the Tzar 350, tracks like “Moskau” and “Mein Teil” sound better on the 4.Ai - to me, at least. Sticking to rock, but changing languages, the Tool album “Lateralus” has a couple of gems on it. “Ticks And Leeches” is a brilliant way to test if a headphone will keep up with fast drums without making a muddy mess of it all. The Tzar 350 handles this just fine, drums sounding like they should and easily distinguisable. The title track “Lateralus” has a lot going on, all of which is clearly etched out, but without ever sounding artificial. I must admit I like a bit of added warmth and a bit more weight to the bass and drums than what the Tzar gives me, but to get that and maintain (close to) the same level of detail, I have to reach for my 8.A, an 8-driver custom flagship clocking in at almost 3 times the cost of the Tzar 350.

Slightly less portable joy: 27" iMac -> M2Tech Young DAC -> Woo Audio WA6 SE.

Almost needless to say, if you like classical music the Tzar 350 could be just the thing for you. If the recording is well made, it almost becomes a sport to pick apart the groups of intstruments. Not sure if your favourite recording is up to snuff? Don’t worry, the Tzar will tell you. That brings us back to the first statement of my review: These are not for everyone. These are for those who want to hear exactly which members of the philharmonic orchestra turn the pages too loudly, for those that want to hear exactly how much a singer whets her lips before letting her voice be heard. This immense level of detail can be a blessing and a curse. It can ruin a recording for you or it can take your enjoyment to a whole new level. The former happened to me with Rage Against The Machine, the latter with Allison Krauss, Louise Rogers and The London Philharmonics. If you’re worried about these sounding too cold and analytical, use them with a warm-sounding full size tube amp. Their 350 ohm impedance will let you enjoy your home rig with iems in case your family doesn’t feel like listening to Debussy at 2 AM. The downside of that impedance is that you will need an amp to feed these properly on the go.