The “LG Tone Pro HBS-750″ Bluetooth Headphones differ from the newer “Infinim” Headphones, partially in that the HBS-750 still have a thin cable connecting each ear-piece to either side of the collar-piece, that cable being on the outside of the collar-piece. I read that with the Infinim series of headphones, there is an even thinner cable on each side, which retracts inside the collar-piece. A review by other testers suggested doubt, about the longevity of these ultra-thin cables, of the Infinim-series headphones. The thin cables of the HBS-750 are at least not quite as thin.
But after only owning my HBS-750 for a few days, I made a foolish mistake with them. With the ear-pieces of mine, held in place in each of the magnets on the ends of my collar-piece, I lay down on a cushion, even though I had my collar-piece around my neck. I lay down on my left side while watching television, with my actual phone placed safely on a table in front of me.
What has happened as of yesterday evening, is that the very thin cable on the left side, has developed a slight kink.
There is a hypothetical possibility of such a kink affecting sound quality. In general, headphones should operate with the sound balanced perfectly between left and right. A kink in a cable on one side can do two things:
- It can short-circuit the cable.
- It can insert some small amount of resistance, in series with the ear-piece in question.
The problem lies in the fact, that even if HQ ear-pieces are just stated to have ’32 Ohms’ of impedance, in reality their impedance curve is frequency-dependent. Ideally, this impedance might then be equal to 32 Ohms – neglecting any imaginary component – in the middle of the audible spectrum. But on the low-frequency end, as well as on the high-frequency end of the spectrum, it is likely that their impedance is much lower. This is due to the fact that a certain part of this impedance is actually due to the resistance of the wire in their coils, while most of it is due to the fact that their coils move, within the static magnetic field of their magnets.
Hence, to insert maybe ? 1/2 Ohm ? in series with one of the ear-pieces, will not affect performance much in the middle of the spectrum, but may affect performance at either end of the spectrum, where these hypothetical 1/2 Ohm will be in series with much lower impedance, due to the ear-pieces themselves.
What I have found, thankfully, is that for now, the actual kink in that cable, has not affected the sound coming out of the left ear-piece one iota. Yet, over time, these thin cables may deteriorate below the condition they are in right now. In fact, they may receive more kinks and blemishes in the near future. All of which prompts the question, of how long blue-tooth headsets are expected to last in general, with normal wear and tear.
One lesson learned: Do not lie down on one side of the head, while wearing them… The next time, I may not be so lucky. Right now, my sound still seems to be perfectly-balanced, and not in any way that favors specific frequency-ranges on one side. I also still get good, rich bass and treble on the left side…