what information an impulse response graph provides about headphones?Submitted by MEGA_AEOIU792 t3_10kgr8r in headphones
AtomikPi t1_j5r5hbl wrote
Reply to comment by No-Tune-9435 in what information an impulse response graph provides about headphones? by MEGA_AEOIU792
The reason why is that headphones are nearly entirely minimum phase. This means that phase domain and time domain are directly related, and the above impulse response is implied by the frequency response. (This isn’t true of room issues with speakers by the way.) This is not entirely the case at low frequencies and with certain weird designs. There is a Crinacle video and some Oratory1990 posts explaining this better that I can’t find right now. Fwiw I subjectively sometimes think impulse response corresponds with my sense of speed and decay (stats sound dry/ fast decay), but don’t claim that is objectively the case.
No-Tune-9435 t1_j5rety5 wrote
Two quick fallacies to call out here A) the one everyone misses: time domain = frequency domain if you have infinite time and infinite frequencies. But if I showed you a frequency response of a song on only 1-40,000hz (or whatever, limits exaggerated to make the point), there would be infinite different songs that have that exact same FR. Simplest way to understand this is imagine if I played a song in reverse. It’d have the same FR from 1-40khz. Imagine I took the first second of a song and moved it to the end of that song. Also same FR. You could absolutely take the Fourier transform of a song and convert it to frequency domain. But you’d need to go into the microhertz to fully represent it in FR. People like to cite the frequency & time domain equivalencies to say that the time domain doesn’t matter at all just because you have an FR graph that goes from 20hz-20khz. This concept gets misquoted and abused in lots of arguments about interpreting FR plots. It doesn’t conclude what people want it to, and if people want to claim time domain plots are 100% irrelevant, the onus is still on them to demonstrate this with controlled studies. We can do some fancier math to put some constraints around my argument, but the original point needs to be made that time and frequency domains are only equivalent if both are infinite. Source: I am a mathematician who studied signal processing
B) Nobody said anything about subjective listening or hearing impulse response. I know you cite it as your own experience, but that feels a bit like a straw man argument. Original post made a conclusive assertion that impulse response is irrelevant
AtomikPi t1_j5rhl45 wrote
Hi there. I don’t claim to be an expert on this branch of math and will believe you here. I would be curious to hear from someone like Oratory on the topic who has made similar arguments.
I’m only offering my subjective experience since I often find it hard to reconcile the subjective and objective side of things in audio. In the case of electronics and certainly cables, I’d rather largely ignore my subjective experience (also given the tons of failed ABT with speakers, which make it hard to believe electronics make any audible difference if not faulty). As you’ve stated, there have not been any time domain AB tests to my knowledge so the answer is ??? and people are trying to reason from the math rather than trials.
- also soundstage (partially not driven by FR) and FR smoothness (important in Harman’s experiments) are two reasons to consider higher end headphones.
Titouan_Charles t1_j5sjnk1 wrote
This is legit on paper, thanks to your Fourier transform but it doesn't help with actually understanding headphones here. The graph we see helps us seeing if something is wrong with the resonances/reflections inside the earcup, or if the open/closed back design manages what it intended to. No need to expand into theoretical Fourier transforms of "whole song FR" and Hz ranges outside of human hearing.
No-Tune-9435 t1_j5t7nd7 wrote
I don’t understand your comment that there is no need to get into the math. Do you realize the original comment was misunderstanding the exact math I was talking about?
To make sure you’ve read my post… I’m not saying the math tells us anything. I replied to a comment that claims that impulse response is exactly the same as frequency response, and therefore we could safely ignore impulse response graphs. The math says that isn’t true. Therefore I claim we need controlled studies to understand what an impulse response can or cannot tell us before anyone knows what to interpret from them.
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