How much does frequency response actually matter?

I'm working through the thread and I'd say this is pretty concise



I'd be curious to know whether all the time domain elements that the like of burst decay et al DO manifest differently at the eardrum level, what sort of minutiae are changed in frequency domain. I really am willing to accept that it IS all FR if there are good, definitive rebuttals, but "it's absolutely FR at the ear drum that's responsible" is a bit curt.



This one offers a bit more context and I do see how shaping overtones of instruments and voices via EQ at the mixing stage can change the character of a thing, I've been mucking about with that more recently, but I still don't necessarily see how this would translate to one transducer being able to resolve texture more evidently than another given the same signal input and presuming both are well-amped out of the same source.



But later on they do disclaim that FR isn't everything, simply that it encompasses more than we give it credit for.

 

I get where Resolve is coming from saying that there's a difference measuring things *at the eardrum level of the listener* as opposed to on any standardised coupler, whether the latter be a flat plate coupler, a free-air coupler (@purr1n non sequitur could we get free air measurements of the R70x? Forgot I meant to ask too), a cheapo MiniDSP EARS rig, or a 5-digit HATS. None of those perfectly replicate the full human hearing system which include neurochemical pathways and all THAT fun stuff, never mind hoping to come within sniffing distance of an individual's personal hearing system.

But I do wonder whether these factors somehow DO manifest later on in terms of the signal that actually strikes our tympani. I don't see how that'd be the case in terms of how it'd function as a matter of FR and not time-domain. I had a random half-awake thought yesterday that basically amounted to: "wait, if sound waves bounce and it's sound waves that strike our tympanic membranes, what happens to any excess energy that gets pushed back, does it muddy the incoming signal any?". Likely a dead-end ponderance there, but yeah this is all just weird and curious stuff.

 

FR at the eardrum is really verging on unfalsifiable statement territory. I mean, is there any headphone measurement rig out there that's ever been able to take a measurement across the entire audible range that would accurately reflect the soundwaves hitting a specific person's eardrum? Is it even possible to make one and verify that this is what it does?

 

See that's why I think the narrative getting shifted to "it's all FR" when the original position by Resolve and Listener was always "it's all FR at the eardrum level" is a bit gross of the headphone community at large because it's a disservice to genuine research.

Even then though, just speaking from a non-physics degree perspective EVEN IF there were massive shifts in FR after going through all our physical hearing hardware (which as @Wilewarer pointed out seems rather difficult to prove), that's just true of FR at ONE POINT IN TIME. Sound is dynamic, and similar to how you can get frequency masking effects playing two stimulus tones together (never mind that music often has WAY more than two things going on, no?) the nature of the incoming signal can often change wildly in just the span of a few milliseconds-- if anything, this just reinforces how important time domain elements ought be, no? That's also not to mention how you feel (and I agree,though mind I stick to much lower-tier gear) part of why planar headphones tend to have overly smooth and plasticky treble timbre is because of how those massive diaphragms are more of a beast to move and might actually self-dampen a lot of those fine textures and such.

But yes, research funds and time. Bah.

This seems like it'd be easy to disprove because of mechanical limitations of the A-T driver, but just to make things more interesting is there an EQ profile that can make the Atrium Open sound as pillowy and bouncy as most A-T headphones? I feel THAT would be a more fun challenge and theoretically feasible for the folks who say it's all DSP.

 

This post, I think.

Also the link in this one. Fig. 5 (variations in "real ear unaided gain") is the interesting result for this discussion.

 

I’m just a caveman. Your world frightens and confuses me.

An FR plot tells my eyes what the headphone voice is, so to speak. The contour plots and distortion stuff and decay tell me a lot about how the voice is projected.

*porkers* who measure things at >5 volts and >100db and produce a single number do not have anything interesting insights for my simple mind to comprehend. Sorry, I’m not that evolved.

“Fantastic FR” can sound like ass if everything else is ringing and fuzzy and stuff. I think that’s the edge sbaf discussions have, tbh. More (and more useful) dimensions to consider and describe. For instance, I really like the plots of the usable region @atomicbob produces because that’s where my listening happens most of the time, while the decay stuff that @purr1n puts out (very good for telling Grados apart in terms of attack and “naturality”, for me). Harmonics and shit above the hearing frequency are also interesting (that’s why the Yggdrasil MIL irritated so much folks it seems!)

Back to my Eric Clapton Sunday binge.

 

A couple thoughts:

Yuck! You don't want destructive interference like that in the upper midrange. That will definitely sound weird.

REW sort of calculates this from the sweep. Step response is key here. You can also plot the FR and only include the first 5 cycles. With headphones it won't be too interesting, but with speakers it's very interesting.
This is because headphones have basically zero excess phase when measured on a coupler that doesn't introduce nulls.

This also means that your regular old PEQ peaking filters can fix the burst response.

One important bit here is that the recordings don't have a microphone FR filter, while the step response can take the microphone FR into account, something that should always be done. If the mic is peaky in the top octave like most electret measurement mics are, then the ideal response has some overshoot and ringing.

Basically I think FR magnitude and excess phase are the most important determiners to how something will sound along with distortion behavior.

As for distortion: measuring at different levels to check how it handles medium to high SPL is key.
This way I found interesting stuff like how some speakers which "come alive" at higher SPLs have relatively high-ish distortion at lower levels, yet the distortion doesn't change as much with different levels.
Other speakers which still sound vivid at lower levels may have a very low baseline distortion that rises for higher levels. At 90dB those two speakers may be similar, but at 70dB the 2nd is much lower in distortion. This mostly happens for the odd harmonics. Another data point for BA IEM timbral weirdness.

 

The worst thing we can do is to reify the frequency response or any other kind of measurement. Any measurement is a simplification of the infinitely complex for the benefit of the beholder.

We don't listen to the frequency/phase response, THD, or IMD. We listen to the physical phenomena of which a facet is illustrated (or not) in these measurements. Claiming that any of these measurements show everything of anything is grossly unscientific. They are incredibly useful but they are NOT the reality.

 

Correct me if I'm wrong, but basically there's more difficulty reproducing the 60Hz signal as designed when pushing SPLs higher? Never thought to measure that, damn. It'd basically look like a within-variance difference if looked at within the full scope of FR, but you're thinking it could be something indicative of difficulty achieving slam?

 

Yeah I'm a dumbass but with how headphone drivers are often *significantly* smaller than most speakers (besides the ones you get in phones anyway) I'm wondering how pronounced a difference there'd be here. Is this going to be something primarily evident in low bass or will it also affect higher-freq content?

Would be curious to see the HD600 and Focal Elear/Elex/Clear/whatever for comparison here mainly. Wondering if this is a matter of tech (planar/dynamic/estat) or similar. Grados are basically open baffle so would theoretically be sensitive to minute changes.