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Headphones that are the benchmark for objective measurements - Page 3

post #31 of 40
Quote:
Originally Posted by ultrabike View Post

 

Warning: Spoiler! (Click to show)

 

So it stands to say that if a headphone has better response at these two frequencies, it will at least appear to have good square wave response, correct?

Not necessarily. A square wave is made up of its fundamental frequency (30Hz or 300Hz in this case) and it's odd harmonics. If the headphone does not have a flat magnitude response and linear phase at the odd harmonics relative to the fundamental of the square wave, the square wave will not appear good. Here is a 300Hz square wave along with it's FR.

700

700


I notice that below 1kHz, there are two "major" notches. One at ~80Hz, and another at ~600Hz...

The HD598 80Hz notch is fairly close to the 90Hz component of a 30Hz square wave (third harmonic - first and most influential odd harmonic) and will influence the shape of the HD598 30Hz square wave response. Also note that, in the HD598 uncompensated FR at IF, the 30Hz component is down (on average) about 5dB from 90Hz. This difference will contribute to the shape of the 30Hz square wave response of the headphone. The 600Hz notch will probably have a lower impact on both the 30Hz and 300Hz square wave responses because these square waves do not have frequency components at that frequency (no even harmonics on a square wave).

 

Outside of the simple damping conditions, how much do other factors (such as earcups and positioning on the head) affect square wave response?

The response and limitations of the driver will more than likely contribute to the shape of the square wave as it contributes to the shape of the FR.

 

EDIT: Given that earcups and positioning on the head affect FR, they will affect square wave response... Based on the HD598 IF results, intuitively the 30Hz square wave would probably be more affected by positioning than the 300Hz square wave. My reasoning for this is that I believe the uncompensated FR responses are taken at different positions, and they show relatively large variation close to 30Hz (a little over 5dB) where as 90Hz, 300Hz and 900Hz show relatively small variations.

 

 

 

Thanks for the great reply ultrabike. I think I understand the concept better now.

 

So a headphone that performs poorly with odd harmonics would show bad square wave response regardless of the frequency that is tested, correct? Would a 50Hz square wave (and so on) look equally good (or bad) based on the headphone's prior performance? I'm guessing there will be variations if you tried to test square waves of higher frequency.

post #32 of 40
Quote:
Originally Posted by OJNeg View Post

 

Thanks for the great reply ultrabike. I think I understand the concept better now.

 

So a headphone that performs poorly with odd harmonics would show bad square wave response regardless of the frequency that is tested, correct? Would a 50Hz square wave (and so on) look equally good (or bad) based on the headphone's prior performance? I'm guessing there will be variations if you tried to test square waves of higher frequency.

 

Thanks smile.gif... (Edited a little bit of math mumbo jumbo)

 

So a headphone that performs poorly with odd harmonics would show bad square wave response regardless of the frequency that is tested, correct?

 

It still depends the square wave frequency because the odd harmonics of the square wave are relative to the square wave frequency. A 30Hz square wave has odd harmonics at 90Hz, 150Hz, 210Hz... while a 50Hz square wave has harmonics at 150Hz, 250Hz, 350Hz...

 

I'm guessing there will be variations if you tried to test square waves of higher frequency.

 

Agreed.


Edited by ultrabike - 11/19/12 at 1:10am
post #33 of 40

Even if the headphone can reproduce each harmonic at the same level, the square wave response still can look everything but like a clean square wave.

The reason for this is that there's also the phase response which has to be considered. For example a headphone that rolls off at 20 or even 10 Hz will cause a phase shift at 30 Hz, which makes the square waveform "descend" over time.

post #34 of 40
Quote:
Originally Posted by xnor View Post

Even if the headphone can reproduce each harmonic at the same level, the square wave response still can look everything but like a clean square wave.

The reason for this is that there's also the phase response which has to be considered. For example a headphone that rolls off at 20 or even 10 Hz will cause a phase shift at 30 Hz, which makes the square waveform "descend" over time.

Agree. This is why, in the case of the HD598, the headphone notch at 80Hz could cause some problems for a 30Hz square wave (90Hz harmonic). A 600Hz notch probably causes less problems to a 30Hz and a 300Hz square wave, but it could be problematic for anything close to 200Hz.

 

The bass region is very problematic for most dynamic headphones.


Edited by ultrabike - 11/19/12 at 9:21am
post #35 of 40

Yeah, well I guess the biggest problems are

a) excursion

b) completely airtight seal

 

Anyway, square waves are the last thing to look at imho.

post #36 of 40
Quote:
Originally Posted by xnor View Post

Yeah, well I guess the biggest problems are

a) excursion

b) completely airtight seal

 

Anyway, square waves are the last thing to look at imho.

 

What's first? I'm going to guess FR and distortion.

post #37 of 40
Quote:
Originally Posted by OJNeg View Post

 

What's first? I'm going to guess FR and distortion.

 

I would say 300Hz square wave and impulse response are pretty important... Look at the HD800 measurement from innerfidelity and you already know why they are so special in comparison to other dynamic headphones (I do prefer Audeze LCD-2 rev2 over all including LCD-3 though).

post #38 of 40
Quote:
Originally Posted by OJNeg View Post

 

What's first? I'm going to guess FR and distortion.

FR!

post #39 of 40
Waterfall plots too.
post #40 of 40

SRH840 for cheapy closed can I really like. ER-4S for FR no doubt. HE500 or HD600 for beginning into "reference" cans that spread far and wide.

 

If I'm just looking at a not wildly popular can, definitely the Paradox. For me, truly high level reference comes in the form of an occassionally ear-stabbing HD800.

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