Originally Posted by SilverEars
I looked at Tyll's graphs of BA iems. They seem to have significant distortion. How come to my ears they sound tight and clear, and joker rates them so high? Does the fit have lot to do with it? My CIEM sound very clear and tight.
BAs' time domain characteristics behave a bit differently from those of dynamic coils, so they sound crunchier. In general, with the exception of certain types such as Sony's proprietary BAs, balanced armatures exhibit higher levels of odd order distortion than do dynamic moving coils. Odd-order distortion is said to be "less pleasant" than even-order distortion. While multiple BA earphones squash down the distortion, distortion is fairly audible in many single driver models and some dual driver models. The rule of thumb is 1% THD at 100 dB is audible, but I find that I can hear 0.8% (when measured at 100 dB, but not necessarily listened to at that loudness) with no problem if it's in the most sensitive band of human hearing (~500 to 5000 Hz) --- I've heard a lot of BA earphones, though, and have honed myself to recognize the kind of distortion they exhibit. So you'll need to train yourself to recognize the distortion, though with enough training it shouldn't be a problem; it's not like I have golden ears, I just have more experience. Even so, I don't think it's a huge deal. It doesn't sound that bad, but some people may insist on a cleaner distortion profile. In that case, they'd want to go with a high-quality coil driver such as the liquid-crystal polymer diaphragm used in the Sony EX1000, or the Titanium-coated Mylar diaphragms used in HiFiMAN IEMs. Regular ol' Mylar works too, but the QC has to be done well, or else the distortion profile is no better than that of a BA.