Originally Posted by gatucho
I see a lot of talk regarding FR design goals. Nonetheless it seems that at this point defining a single FR profile as THE ONE is just silly, considering that there are a LOT suggested by different sources.
Not exactly on your point, but let me first say that FR is *the* most important measurement. Yes, you could deliberately manufacture an audio component with nice enough FR that is screwed up in other areas but in practice those are rare cases.
I don't see why you wouldn't want one target FR. High fidelity means accurate reproduction, so we have one target FR for speakers (flat). The user or manufacturer may add a smooth downwards tilt of the FR curve or even a loudness function, but that doesn't change the flat target curve.
Why should it be different for headphones? Research by Harman and the NRC tries to come up with a better target for headphones that takes human perception into account. The other old curves were based on different sound fields, not perception.
Precise measurements are only half of the equation, the author of the original articles points himself that it is possible to predict whether a speaker will be PERCIBED to sound good or not using a set of measurements similar to those he proposed. So PERCEPTION is still at the center of the issue. We would have to agree that different manufacturers have different ideas of which FR is ideal.
Setting a better target curve does not mean manufacturers cannot produce different sounding headphones anymore. Something like +/- 3 dB leaves *a lot* of different sound signatures to be realized. And there's also still some "specialty" frequency responses like extremely boosted bass for bass-heads.
The listeners will still have different head shapes and ears, ear canals.. so headphones will still be perceived slightly different. Different people will prefer different types (on/over/in-ear, closed, open, semi..) of headphones, different frequency responses, etc.
BUT, all of these headphones with similarly accurate FR would score similarly.
At this point measurements are only useful to predict the character of a given HP. Under this consideration and assuming that each FLAGSHIP closely represents the corresponding manufacturer FR ideal, well performed measurements only allow an insight of the characteristic Sennheisser, et Al sound.
Here's an interesting idea: there is no "manufacturer FR ideal". Re-using the same construction (cup, ear pads etc.) and drivers will often lead to similar sound. That's the main reasons you see similar sound from different products by the same "manufacturer".
Examples: Take an HD650 and compare it to an HD800 - completely different sound signatures. Why, because the HD800 is completely different. If Sennheiser had a "house sound" then they would have tuned the HD800 to sound like a HD650 or 600.
Grado: all the same, hence they all sound the same.
Beyerdynamic: OK, they seem to strive for "taunus sound" (boosted bass and treble), but they don't manage to do that with some of their headphones either.
An example of how, ironically, subjective this FR measurement comparison can be is the FR of the hd800 vs the t1. I will say it again, since it seems that the t1 is not very liked around here, comparing the RAW uncompensated FR responds of these HP (see headroom measurements) THE HD800 HAS MORE RESONANCES. In this regard the author proposes that resonances are indicative of a poorly designed diaphragm. So, is the hd800 more poorly designed than the t1?
This is an example on how objective measurements can be used to support ANY argument if a subjective interpretation of such measurements is used. The sciency folks around here dont seem to understand this simple fact (a thing which I know, suffer and exploit for a living)
I disagree strongly.
First of all look at: http://www.innerfidelity.com/images/BeyerdynamicT1SN3964.pdf and http://www.innerfidelity.com/images/SennheiserHD800.pdf
You can compare the raw FR and also the impulse responses. The T1 does have more ringing => more peaks and dips. Also see CSD measurements at the headphone pirates site. The HD800 is extremely clean.
While I like Beyerdynamic for trying to re-invent the dynamic driver, the "fullmetal housing" of the tesla drivers seems to do more harm than good.
Headroom graphs give you a rough idea of how the headphones will sound, but beyond that I'm not sure they're that useful. (Still a wonderful effort though.)
Edited by xnor - 12/28/13 at 9:32am