Monday, April 8, 2013

Harman Kardon Bluetooth Headphones

BestBuy has these HarKar-BT on clearance for $99, so I give them a try. They have over-the-ear cups; on-the-ear type always make me sick after about 1 hour. They support APT-X that's also available on my Note 2. The only alternatives that offer these two features are the Sennheiser MM 500-X and 550-X (NC) for $330 and $500, respectively.

Spoiled by the very comfortable and natural sounding Sennheiser RS160 wireless headphones, the BT was initially way too tight with much more bass. I changed to the included large metal band, still no enough improvement. Then I stretched it from about 5" span to 6", it felt and sounded better. But still too tight to me, because the square cups are not natural and too shallow.

I tried them on a bus ride, engine noise was still too loud; the RS160 does a much better job. I think the squared shape cannot provide an ideal seal. On the other hand, the BT can be turned into flat, much easier to carry in a bag.

Before the BT, I bought a pair of Emerson EM515 bluetooth headphones. There was interference noise on the right side of the EM515. The circuit board is on the right side and it is too close to the drive unit - the coil gets the RF noise. The noise is even louder during battery charging. I opened the EM515 and lifted up the circuit board away from the drive unit and the noise was totally gone but still some during charging.

Harman Kardon says the BT cannot be used during charging. What I found is: it actually works normally - it is still connected over bluetooth and all control buttons work, just no audio coming out of the headphones, they are muted during charge. Why HK would do this? Knowing my above EM515 story, it is not difficult to guess the reason. Yes, indeed, I can hear the interference noise on the left side where there is the circuit board. I guess this noise will become more audible during charging, like the EM515, so that the HK engineer muted the speakers to hide this issue.

To HK, simply cutting off any sound during charge is an easy trick to avoid bad reviews on these $250 headphones; but to me, slightly noisy music is still way better than no music at all.  My $20 Emerson can keep my music flowing like this:

To put salt on the cut, the USB charging port is non-standard. For those who want to make a charging adapter, here is the layout of the 2.5mm 4-pin plug:

One more very annoying thing: the square metal frame always rub against the collar, making horrible resonance.

Final Words:

Bluetooth is finally ready for music, but the Sennheiser MM 500-X and 550-X are currently the only alternatives to this Harman Kardon BT, if you require something that is comfortable and can still provide some noise isolation. If you're a DIY person, you can modify the Emerson EM515 to reach your goal. Otherwise, you either pay over $300 or wait.

Or, you can buy an APT-X receiver such as the Avantree BTTC-200X or Samsung HS3000, to make your favorite headphones wireless. Not so elegant, but doable if you don't want to pay more than $300 nor wait.

Either way, once you go wireless, you'll never want to go back to wired.

Abstract in Chinese

用蓝牙播放高音质的音乐在技术上已经可行了,但是目前除了这里介绍的海尔曼-卡尔丹HarKar-BT,也就只有森海塞尔的MM 500-X和550-X。海尔曼-卡尔丹虽然没有森海塞尔那么贵,但是在电池快耗尽时有很轻微的干扰杂音,而且充电时会更大,为了不让你听到这个杂音,充电时声音被完全切断。人耳朵上神经和经络非常丰富,那种压到耳朵上的耳机都是不行的,不到一个小时就会导致各种不适,必须是罩住耳朵的那种才行。

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