Quote:

scuttle said:

It would help if you say what "those" are.

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Why is that important ? If you can really read from a square wave graph what the sound is like, then knowing what device is on the graph should not be necessary.
 
Anyway, the second square wave sounds the same as the first one, as it was processed with an allpass filter (it has a flat magnitude response, and only changes the phase - by 90 degrees at 60 Hz), but the low frequency delay (a few ms under 100 Hz) is either inaudible or at most it has a minor effect.
The third square wave sounds noticeably different, despite looking more similar, because a 3 kHz lowpass filter was applied.

Quote:

Originally Posted by jaddie /img/forum/go_quote.gif
 
 
I'd hardly call that graph a Dummy's Guide.  If the caption wasn't there, would you have reached the same conclusions for the Shure and Denon? 

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Please stop wasting my time asking questions I have already effectively answered: if you read the heuristic I gave, the Shure and Denon are "ins" and the Koss an "out".
 
 

 
Couldn't you have seen this from the FR plot, which assigns a magnitude to the FR variation?
 

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From the research I've done so far, the 500hz sqw is reasonably associated with FR variation - but when you reach 50Hz the speaker membrane is often poorly controlled and you need to look more directly at what  it is doing.
 
 
 

Why put such weight on a square wave test?
 
What, specifically does it show you (my examples are far simpler to analyze than any headphone, but if you can't do that...you get the idea)
 
How would the examples translate to what is heard?  You've said the first three are all good and hard to tell apart.  What about the fourth?  It looks pretty different to me. 

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All the questions except the last one about the fourth are already answered. Re. how the fourth will sound: if you read my heuristic, it's an "in". It's tempting to say that it will sound  less good than the squarer waves but that is outside my heuristic and a speculation. I've not been able to compare headphones with square waves like the first three you drew  - those waves were freakishly square and it could be the flatter tops and vertical descent are not important to how the ear processes sound.
 
 

 
Last question: would it be possible for you to just answer the questions without being demeaning, disrespectful or name calling?   

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If actually start reading what I write, stop trying to put strawman arguments in my mouth, and stop wasting my time asking questions I have already answered and which would have been unnecessary if you had read intelligently - then, yes, I will be less irritated with you. Oh - and you should start explaining your assertions at least once. 

Hey jaddie, could you explain the difference between the 4 types of square waves you posted?

Unfortunately I can only find this as a pdf, but for a really good example of poorly defined bass:
 
http://www.innerfidelity.com/images/MonsterBeatsStudio.pdf
 
- Note that the false peak/echo is about the same magnitude as the first peak! 

Ok: here is a much complete guide that goes way outside the heuristic I have actually tested:
 
http://www.innerfidelity.com/content/headphone-measurements-explained-square-wave-response-page-2
 

My heristic is much cruder: it blurs the third and fifth rows (ie bright-harsh and strongly-midcentric) into one case and says "Here will be found poorly defined bass." I'd say that in both these cases it is much easier to recognize the sqw than the fr because the sqw can be recognized by crossing the x-axis.
 
 
..And again, to indicate how ridiculous J's "three simple cases" are, with the y axis scaled sensibly, they'd all arguably be in the first row - so not simple to tell apart at all, and high unusual phones indeed to get there! (Three samples of LCD3s maybe?)

Quote:

scuttle said:

Unfortunately I can only find this as a pdf, but for a really good example of poorly defined bass:
 
http://www.innerfidelity.com/images/MonsterBeatsStudio.pdf
 
- Note that the false peak/echo is about the same magnitude as the first peak! 

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There is no false peak or echo. The headphone actually extends pretty flat to 30 Hz (the main frequency of the square wave).
In the FR you can clearly see the sharp roll-off just below 30 Hz, so there has to be quite some phase shift at the first harmonics of the square wave. You don't directly see that in the square wave. You'd have to have the data for further analysis (which is kinda pointless considering a single look at the FR and maybe IR for multi-driver headphones tells you everything you need to know).
 
Oh of course low THD is also important for clean bass.
 
I don't see "poorly defined bass" here.
 
Quote:

scuttle said:

Ok: here is a much complete guide that goes way outside the heuristic I have actually tested:

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Did you notice that the interpretation is based on the FR...?

chewy4 said:

Hey jaddie, could you explain the difference between the 4 types of square waves you posted?

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Sure. In the first group of three:

50hz unaltered, theoretically "perfect"
20hz 6dB/octave high pass
20KHz 48dB/octave low pass with 7KHz Q=.5, gain=3dB filter.

Graph 4 is phase shift, -90@20hz, +90@20Khz, linear.

I'm fairly sure I never claimed these to be actual headphones. They are all filters.

They all sound nearly identical with a 50Hz square wave, and absolutely identical with music. Even the rather nasty looking fourth one.

If you gotta have proof, suggest some audition material and I'll see what I can do. Or better yet, build these yourself in a DAW. I used Audition. That way I'm out of the picture as a "liar".

Guys, it's been a slice, but I got to bail on this one now. I think most readers got my point, and all I've done with scuttle is make him mad. And I'm fairly sure he'll be mad anyway.

Quote:

jaddie said:

Sure. In the first group of three:

50hz unaltered, theoretically "perfect"
20hz 6dB/octave high pass
20KHz 48dB/octave low pass with 7KHz Q=.5, gain=3dB filter.

Graph 4 is phase shift, -90@20hz, +90@20Khz, linear.

I'm fairly sure I never claimed these to be actual headphones. They are all filters.

They all sound nearly identical with a 50Hz square wave, and absolutely identical with music. Even the rather nasty looking fourth one.

If you gotta have proof, suggest some audition material and I'll see what I can do. Or better yet, build these yourself in a DAW. I used Audition. That way I'm out of the picture as a "liar".

Guys, it's been a slice, but I got to bail on this one now. I think most readers got my point, and all I've done with scuttle is make him mad. And I'm fairly sure he'll be mad anyway.

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Thanks.
 
I wouldn't have guessed that they all sound identical. I don't think I'll be judging a headphone by its square wave any time soon.

Quote:

xnor said:

There is no false peak or echo. The headphone actually extends pretty flat to 30 Hz (the main frequency of the square wave).
In the FR you can clearly see the sharp roll-off just below 30 Hz, so there has to be quite some phase shift at the first harmonics of the square wave. You don't directly see that in the square wave. You'd have to have the data for further analysis (which is kinda pointless considering a single look at the FR and maybe IR for multi-driver headphones tells you everything you need to know).
 
Oh of course low THD is also important for clean bass.
 
I don't see "poorly defined bass" here.
 
Did you notice that the interpretation is based on the FR...?

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Now I'm genuinely puzzled, as it is readily apparent from the plots that phase is rock solid. So what makes the square wave behave the way it does?
Some flexing/resonance of the diaphragm itself? In a way it looks as if the diaphragm is too soft and kind of 'lags behind' the pulse.
 
 

That's a plot of electrical phase, not acoustic.
 
Most single-driver headphones are pretty close to minimum phase I think, so the phase response could be calculated through the frequency response magnitude through the Hilbert transform and so on.

Isn't electrical phase what Jaddie has been talking about all this time?

No, it's acoustical.

Well, if you altered the input electrical phase, this will be reflected on the acoustic output.
 
Just because the electrical load of the headphone is a certain way, doesn't mean that the headphone's electrical -> acoustic response is linear phase.

No, I don't think he was talking about any kind of phase shift. I was bringing up the problem of (acoustic) phase shifts (which are usually not audible) messing up square waves.

I'm just getting more confused.
First of all: how does Tyll measure a headphone's phase?