Heir Audio headphones: The new kings of clarity?

I'm a lucky guy; audio companies keep asking me to check out their gear, and that's not a bad way to make a living. Before you get too jealous, I have to listen to a lot of crap to find the good stuff. There's a lot of shipping to and fro, and that's not a fun part of my work. Every now and then something really special arrives, and that makes it all worthwhile.

The nice folks at Heir Audio sent over two models of universal-fit headphones, the 3.Ai and 4.Ai, and even before I popped 'em in my ears I thought they might be out of the ordinary. While the earpieces are made out of plastic, the "faceplates" have gorgeous real "Amboyna Burl" wood inserts. The wood looks classier than what you get with most in-ear designs. The 4.Ai is a "quad armature" design, meaning it has four balanced armature drivers -- two bass drivers, one midrange, and one treble -- in each earpiece. Balanced armature drivers produce clearer sound than conventional headphone drivers, which are essentially miniaturized speaker drivers. The 4.Ai comes with a user-replaceable 52-inch-long braided cable, terminated with a 3.5mm plug.

Heir was formed by two audiologists, John Moulton and David Tao, and Heir is a division of Micro-DSP, a Canadian company that builds headphones in China. North American distribution started last month.

The first thing that made the 4.Ai model stand out from the usual suspects was the way its sound changed from one recording to the next. That's a good sign: each recording's unique qualities could shine through. If the recording is bright and aggressive, the 4.Ai sound is bright and aggressive, and if it's muddy and thick, that's what you're going to hear. Bass is a different matter; while the 4.Ais' extreme low end is seriously solid and deep, it lacks the "slam" and weight of my Monster Turbine Copper headphones. The 4.Ais trounce the Coppers in every way but bass thump, and even there the Coppers' bass oomph is only slightly better. What consistently impresses is the 4.Ais' resolution of fine detail with great recordings. Isolation from external noise on the New York subway was average, nothing special there.

I thought the 4.Ais' sound would be close to the transparent Phonak Audeo PFE 232 ($599) universal-fit in-ears, but a quick shootout proved the PFE 232s were still the clarity champ in this price range. Even so, the 4.Ais' sound was richer and fuller, which I preferred overall. I'd rather listen to the 4.Ais than the PFE 232s.

With "VCR" by the Xx the sound was remarkably vivid and clear, well beyond what I hear from my Ultimate Ears UE 4 custom-molded in-ear headphones, which sell for the same price as the 4.Ai headphones, $399. The UE 4s do a much better job of isolating my ears from outside noise. The 4.Ais can sound a little bass-shy on the subway, precisely because the subway's rumble is masking the music's bass. Custom-molded earpieces have the edge down there, but you can buy a custom-molded version of the 4.Ai headphones to get around that problem. The 4.Ais I'm reviewing here today are universal-fit models that come with a nice variety of eartips; the 4.A custom-molded model is on sale right now and runs $450 until October 1.

Up to this point I listened to the 4.Ais with my iPod Classic, and the sound was great, but running the iPod through the ALO Rx-3-B portable headphone amplifier enhanced the 4.Ais' transparency, big-time. Bass definition radically improved as well. The ALO amp demonstrated the headphone's sound potential, and it was exceptional at low, medium, and loud listening levels.

The Heir 3.Ai ($299) model is pretty much the same headphones, but with three balanced armature drivers instead of the four in the 4.Ai. Sonically, the two models are very close, so if you can't get to $399 for the 4.Ai, buy the 3.Ai for $299 and don't look back.