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Of course getting mitts on the T2+ was only half the job. Whilst Sasa had a loaner pair of H2+ from Norwegian importer Moiz Audio, "the problem is that I can't test my amps without headphones. It's not possible to do proper measurements with load resistors as I could for any normal amp. You might want to get with Moiz or Fred Crane. Or perhaps Takei San in Japan." The designer had no stock but was "working hard to prepare the next lot of H2+ to ship to our distributors by the end of the month." Ditto for Fred Crane who was "under the same prohibition of H2+ as most until April. However three units I sent out were to manufacturers and two of those went to Audience. I've emailed Roger Sheker to send back one which I'll forward to you."
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With at least two moons aligned, I was in business. But something was still cloudy: the AMT connection. Oscar Heil's air-motion transformer technology depends on folded or pleated diaphragms. Those 'squeeze' air like accordion bellows, hence the oft-cited 5 times propagation velocity advantage over standard drivers which merely 'push' the air. Except that published photos of the BatPure tweeters didn't show any pleats. Was their geometry different from what's inside the H2+? Whilst I had Takei-San's attention, I asked about this and the impedance behaviour plus the 10% inter-channel discrepancy Sasa had measured. I capped off with the opinion that this didn't exactly suggest a finely tweaked tight-tolerance design such as price would warrant. One hates to be fresh but some words from the designer seemed in order to hear from the other side.
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"In the Heil driver's basic composition, the pleat isn't fixed though there are fixed examples based on easier manufacture. We fold our film with our vibration board, a square frame which supports the folds from the lateral edges for sonic stability and ease of fabrication. The Batpure unit on the other hand doesn't fix the foil's side edges. That's because for bass it's necessary to increase the pleat size. For very high frequencies like in the Batpure one must use a very shallow pleat instead. Hence the Batpure is shaped like a shoal wave."
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Progressively diminishing pleat size suggests a 'bass end' on the bottom and a 'tweeter end' on the top.
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"Re: impedance, our piezo film presents a capacitive load. At DC its impedance is actually infinite and impedance then progresses in inverse proportion to frequency, i.e. decreases with HF. Hence don't use a high-amplitude high-frequency test signal as the thermal protector inside the H2+ will shut down. This protection removes itself once the temperature of the protector falls. With normal music signal the protection will never be triggered as treble signal voltage is minute. About response variations, the H2+ might certainly vary a little as does the impedance of the right and left channels compared to mass-produced headphones. Hence we don't recommend the H2+ as a monitor headphone. But the taste of a mass-produced cookie is secondary to its shape and colour consistency. With the H2+ the minor unevenness creates a fantastic taste that's not available elsewhere.
Of course we do want to advance the H2+ too so that it may approach a monitor headphone on specifications as well."
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I'd say altogether more is required.
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In the flesh—or hard plastic as it were—the H2+ exuded absolutely nothing of the luxurious build quality of a current Audeze or Sennheiser's now older HD800. Whilst the 'wings' were an obvious nod at audiotechnica, their execution was outright flimsy by contrast. Think basic wire loops with leather sleeves terminated in shrink wrap. The plastic bridge sported four screws to adjust width. That's a vital provision for comfort since the ear cups themselves barely swivel whilst the overall contraption affords very little give to offset the contact pressure of the narrowest setting. Then there was the hardness of the leather-clad pads and their bizarre geometry with deliberate air gaps in the front and downward.
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Adjustment screws on the bridge fix overall width
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To be blunt, on looks and physical handling the H2+ priced to compete with an LCD-XC, HD800, K812, Raffinato & Co. felt completely outclassed. Think ex Soviet chic or former DDR ware. Sliced bread but of the decidedly white very stale variety. I would consider it a laboratory prototype ready for beta testing. I'd not call it up to par with 21st-century standards in this price class. Yet. Hopefully announced revisions would address this satisfactorily. A good thing of the current non-metal assembly was its very low weight conducive for comfortable longer listening sessions once the ideal bridge spacing is locked in.
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