Originally Posted by mnarwold
Ethan Winer has a good write-up about comb filtering here and blames it for the differences people hear between cables, power cables, etc. When it comes to speakers, I think he makes a great point. Of course, that doesn't really effect headphones does it? I mean, I guess its possible that the sound changes a little bit every time you put your cans on since they will never be in the exact same place twice in a row.
Yeah, placement changes the frequency response. Worn pads change the frequency response. I guess a lot of hair also reduce seal and therefore negatively effect low-end response. And so on..
Anyway, the article gave me a couple other ideas about HPs. First I thought, "yet another reason I'm glad I've gone the headphone route rather than the speaker route," but then I wondered if this somehow ends up being a practical disadvantage. Could part of (not all) the "unnaturalness" people talk about with cans be contributed to a lack of comb filtering?
Unnaturalness in headphone playback stems from two major things: a) unnatural stereo separation and b) fixed positioning on your head.
a) If someone stands to the left of you and speaks to you your right ear will also receive sound pressure, just at a lower level and slightly time delayed. This is what our hearing expects. With a headphone, sound in one channel (usually a result of hard panning instruments to one side) will only reach the same ear, not the other. A possible remedy is crossfeed.
b) You unconsciously move your head slightly to precisely locate sound sources, but your headphone is fixed on your head so a sound source doesn't move with head movement. The Smyth Realiser uses a head tracker (sensors that track head movement) and processes the audio accordingly in realtime.
Of course there's a lot more to it, this is just a simplistic explanation. Research HRTF, sound localization if you want to know more.
I don't think a lack of comb filtering has a negative effect, because comb filtering itself is bad.
Real life doesn't have a flat frequency response. According to the article, we're used to comb filtering and each ear receiving a different frequency response.
I've read the article but it was a long time ago. Does it really say that?
It says: "We don't usually notice these changes when moving around because each ear receives a different response, so what we perceive is more of an average." The important thing here is the averaging I guess, not that each ear receives a different comb-filtered response.
Back to frequency response: at low frequencies, headphones can provide a flat frequency response, but at higher frequencies it gets complicated. There's pinna, ear canal reflections and resonances. This is why we see very erratic high frequency responses in dummy head measurements. So I guess one could argue that at high frequencies there is comb filtering with headphones..
Edited by xnor - 3/23/13 at 12:26pm