[Parall3l]

Just wondering if its possible to measure soundstage in a headphone ? Almost everything else can be measured but I've never seen something measuring a headphone's ability to reproduce huge soundstage. Since humans detect the direction of a sound by the delay between the two ears, there is no reason that measurements of the delay can't be done ? Maybe its because we don't have equipment that can do this ? 
 
Edit: If we were to play the same sound out of both the right and left side of the headphone with X seconds of delay between the two channels and measure how much delay the headphone had compared to the set X seconds of delay at certain frequencies (Perhaps all of them, although that could take a long time), shouldn't that tell us how accurate the headphone is and therefore measure a headphone's soundstage ? A dummy head used for binaural recording should be perfect for this task.

 

[Head Injury]

The delay itself is in the recording and independent of the headphones. If a headphone is introducing a delay between channels that's not in the recording, it's a flawed headphone. Delay alone isn't enough to create soundstage, either. That would just make it sound funny. There needs to be attenuation of specific frequencies to mimic the effect of air between ears, variations between delay at different frequencies (bass wouldn't be delayed, for example, because it's felt as much as heard), and the length of delay has to match the listener's head. Everyone will hear it differently, which is why crossfeed plugins never work for everyone. I haven't found one yet that I like.
 
Soundstage in headphones is the result of lots of things. Here's some I think make sense:

1. Driver placement (distance from the ear, angle of the driver)
2. Driver design (size, shape, type like planar or dynamic)
3. The cup itself (resonance, damping, shape, variations in sound pressure at different points)
4. Frequency response (evenness, peaks, free field vs. diffuse field equalization, how closely it matches the ear of the listener)
5. Speed of the driver (responsiveness, driver ringing that obscures details)

 
Simply put, measuring delay shouldn't tell us anything. It should tell us only how the recording's soundstage looks. Soundstage in headphones is complex and affected by almost everything, and it would take a lot of effort to measure it.

 

[jcx]

remember in most close miced commercially produced music the soundstage is "painted on" by the sound engineer at the mixing board
 
in the recording studio R-L placement of instrument mic feeds is often done with "pan-potting" - just relative amplitude not delay, phase - today's DSP based tools could mix with phase/delay modeling but I don't think many do

 

[SP Wild]

Some of the top sound stereos on luxury cars use delay processing to center the image to the driver, this cannot be achieved by simply twirling the balance knobs.
 
I believe looking a Tylls measurement of Isolation VS Frequency correlates very well to the subjective imaging performance of experienced members with different top end headphones.

 

[Tyll Hertsens]

Quote:

I believe looking a Tylls measurement of Isolation VS Frequency correlates very well to the subjective imaging performance of experienced members with different top end headphones.

Interesting. I'd like to hear why you think that.
 

 

[SP Wild]

Quote:

Interesting. I'd like to hear why you think that.
 

Using my personal experience with the HD800s, K1000 and the LCD-2s, along with subjective impressions of respected members, including yourself in your Inner Fidelity articles, where STAX 009 and 007 seem to outperform the LCD2 in imaging.  Then to look at the Isolation graphs, we find that the isolation of HD800 and the STAXens are significantly different to the LCD2s after 1 khz, where location cues are generally found. 
 
Unless I am looking at the graphs incorrectly, the isolation of those frequencies above 1 khz inhibits the imaging capabilities of the LCD2 - channel separation above 1 khz is extreme on the LCD2, whereas the others would allow the noise floor of each channel to be raised at frequencies above 1 khz due to crosstalk contamination with the contamination being delayed by the distance between the ears.  Creating a similar effect as speakers, albeit to a far lesser degree.
 
With the K1000 and HD800 having a subjectively stronger center phantom channel presence and frontal imaging than the LCD2 on many recordings IME.  I believe that delayed crosstalk is the defining factor.
 
IMO of course.

 

[Parall3l]

So is there a way to measure soundstage ? Very interesting explanations so far 

 

[astroid]

Very simple way, get remastered  let it bleed by the Stones, play let it bleed , 14 seconds in drum starts in left channel. On my Ultrasone Pro 650 it sounds like it is around 15 ft away and on my Sony zx700 around 5ft away.

 

[Head Injury]

Quote:

Using my personal experience with the HD800s, K1000 and the LCD-2s, along with subjective impressions of respected members, including yourself in your Inner Fidelity articles, where STAX 009 and 007 seem to outperform the LCD2 in imaging.  Then to look at the Isolation graphs, we find that the isolation of HD800 and the STAXens are significantly different to the LCD2s after 1 khz, where location cues are generally found. 
 
Unless I am looking at the graphs incorrectly, the isolation of those frequencies above 1 khz inhibits the imaging capabilities of the LCD2 - channel separation above 1 khz is extreme on the LCD2, whereas the others would allow the noise floor of each channel to be raised at frequencies above 1 khz due to crosstalk contamination with the contamination being delayed by the distance between the ears.  Creating a similar effect as speakers, albeit to a far lesser degree.
 
With the K1000 and HD800 having a subjectively stronger center phantom channel presence and frontal imaging than the LCD2 on many recordings IME.  I believe that delayed crosstalk is the defining factor.
 
IMO of course.

I don't think pseudo-crossfeed has much of anything to do with soundstage or imaging. Does the effect disappear rapidly at low volumes? How would you explain closed and semi-closed headphones with decent soundstage, like Denon D2000-7000 or Sony R10? How do you explain Grados, which are very open but are known for lackluster soundstage? How would they compare to Sennheisers in the same price range, just as open but with much larger soundstage?
 
Also, isolation is how much it isolates from outside noise, and has no effect on the volume of sound the headphone is putting out into the air around you. The LCD-2 may have higher isolation after 3kHz than other open headphones, but it also puts out a LOT of volume into the air around you (presumably because of its push-pull design). I reckon it's nearly twice as loud as my Grados from a few feet away at the same listening volume. I'd expect it to be louder than the HD800, maybe the Stax.

 

[Tyll Hertsens]

^^^ Yeah, I don't think I buy it.  But I do think there may be something psychological about having a pair of headphones that are so transperant to outside sound that you don't think your wearing them .... maybe.  Crosstalk between ears is probably not at a high enough level, and I think would be too long a delay to be effective. IMHO.

 

[SP Wild]

 
Quote:

I don't think pseudo-crossfeed has much of anything to do with soundstage or imaging. Does the effect disappear rapidly at low volumes? How would you explain closed and semi-closed headphones with decent soundstage, like Denon D2000-7000 or Sony R10? How do you explain Grados, which are very open but are known for lackluster soundstage? How would they compare to Sennheisers in the same price range, just as open but with much larger soundstage?
 
Do speakers reduce staging effects at lower volumes?  My D7000s have the best channel separation in my collection, and was the can most noted to change in this regards when moving to an amplifier with better channel sparation than my Lehmann amplifier.  My other open cans also improved, but to not that much extent.  Driver distance is a contributing factor for its "wide" staging as is the excellent detail retrieval of ambient cues at the top end, due to a bright treble and quick speed, unfortunately if you listen closely, the midrange seem to lack staging.  EQing the bass out reveals why, the cup colors the mids excessively masking ambient cues at the mids.  Center image is poor compared to my other cans.  My HF2s sit a lot closer to my ears and are not as wide, imaging is good.  R10s I cannot comment on as I have never heard.  The drivers in the HD800 sit further from the ear than the HF2 which explains soundstage size.
 
I was only speaking of "imaging" my previous post and made no mention of "soundstage" size, but now that you mention it - that is my conclusion to all your questions.
 
Also, isolation is how much it isolates from outside noise, and has no effect on the volume of sound the headphone is putting out into the air around you. The LCD-2 may have higher isolation after 3kHz than other open headphones, but it also puts out a LOT of volume into the air around you (presumably because of its push-pull design). I reckon it's nearly twice as loud as my Grados from a few feet away at the same listening volume. I'd expect it to be louder than the HD800, maybe the Stax.
 
What is your point?

 
All you need to understance is what the effects of  a better channel separation sounds like on headphones.  What it sounds like to have a very low noise floor, and if an audible noise floor is heard, how might it affect the psycho perception of sound?  If there is an audible noise floor, where is the most likely source?  Simple diagnostic procedures to me.

 

[Head Injury]

Speakers are different, SP. Two speakers are heard at nearly the same volume with one ear. One is slightly quieter because it's slightly farther and turned away. With headphones, the other ear's canal is something like five times further away, and turned in the completely opposite direction. The volume difference is much larger. So at low volumes the crossfeed effect will be greatly reduced, indistinguishable from background noise. Not so with speakers.
 
My point with the second thing is that you can't use isolation to determine strength of this crossfeed effect, because it has no bearing on how loud the driver plays on the opposite side.

 

[SP Wild]

Quote:

Speakers are different, SP. Two speakers are heard at nearly the same volume with one ear. One is slightly quieter because it's slightly farther and turned away. With headphones, the other ear's canal is something like five times further away, and turned in the completely opposite direction. The volume difference is much larger. So at low volumes the crossfeed effect will be greatly reduced, indistinguishable from background noise. Not so with speakers.
 
My point with the second thing is that you can't use isolation to determine strength of this crossfeed effect, because it has no bearing on how loud the driver plays on the opposite side.

Agreed.  Speakers are different.  Your explanation is a plausible theory of why speakers stage significantly better than headphones and is not for me to dismiss.  What is this backround noise you speak of and where is the likely source?  I'd imaging the lower the volume of a sound the more difficult it would  be to locate, no?
 
Where did it say that I determined the "strength of crossfeed".  This is not possible with the absence of testing.  I didn't even mention crossfeed. 
 
You gave your hypothesis of possible contributors of headphone staging - I am in no position to dismiss your hypothesis.  I merely added one other possible contributing factor with an explanation of how this variable might contribute to the subject.  My hypothesis satisfies my curiosity, and is valid until proven otherwise.  I like my hypothesis, I like this one very much...
 

 

[Head Injury]

Agreed.  Speakers are different.  Your explanation is a plausible theory of why speakers stage significantly better than headphones and is not for me to dismiss.  What is this backround noise you speak of and where is the likely source?  I'd imaging the lower the volume of a sound the more difficult it would  be to locate, no?
 
Where did it say that I determined the "strength of crossfeed".  This is not possible with the absence of testing.  I didn't even mention crossfeed. 
 
You gave your hypothesis of possible contributors of headphone staging - I am in no position to dismiss your hypothesis.  I merely added one other possible contributing factor with an explanation of how this variable might contribute to the subject.  My hypothesis satisfies my curiosity, and is valid until proven otherwise.  I like my hypothesis, I like this one very much...
 

Background noise as in ambient noise. A computer or a fridge.
 
Let's set up a thought experiment. You have one speaker, and one headphone cup, in a room with dead silent background noise. You place the speaker to your right and in front of you. We'll ignore delay for now. You play music from it at 80dB measured at the right ear. Let's just assume that the left ear hears the same signal at 70dB, though that might be a bit quiet. Now you place that headphone cup on your right ear, and play it at 80dB. How loud do you expect the left ear to hear it? Let's say 50dB, but I think that's optimistic. So we can presume that the effect is much weaker on the headphone, and imaging is weaker as well.
 
Now increase the background noise, ambient volume, whatever to 50dB. The speakers still have a crossfeed effect 20dB louder than it. The headphones have a crossfeed effect equal to background noise. It's not just weaker, it's potentially gone. Turn the volume down 10dB, and the speakers still have 10dB of crossfeed but the headphones don't have anything. If imaging relied on this, low listening volume with high ambient volume would have little or no imaging, and it would increase dramatically if the difference increased.
 
What you're implying is pseudo-crossfeed. One ear hears a delayed and quieter version of the other channel. That's crossfeed. This is what creates imaging. You implied that headphones will low isolation image better. I presumed that was because the crossfeed effect would be stronger. What did you mean otherwise?
 
Your hypothesis is just a hypothesis, just like mine. It has to stand up to testing, reason, and logic. You have to be able to defend it.

 

[SP Wild]

 
Quote:

Background noise as in ambient noise. A computer or a fridge.
 
Let's set up a thought experiment. You have one speaker, and one headphone cup, in a room with dead silent background noise. You place the speaker to your right and in front of you. We'll ignore delay for now. You play music from it at 80dB measured at the right ear. Let's just assume that the left ear hears the same signal at 70dB, though that might be a bit quiet. Now you place that headphone cup on your right ear, and play it at 80dB  (At this stage do you still have the speaker on? if so this test is not valid) . How loud do you expect the left ear to hear it? Let's say 50dB, but I think that's optimistic. So we can presume that the effect is much weaker on the headphone, and imaging is weaker as well. (Even with the speaker turned off, the "imaging" is not "weaker" it is skewed too much to the right from the engineers intent, if the speaker is still on - this will be too many concurrent variables and is not valid)
 
Now increase the background noise, ambient volume, whatever to 50dB. The speakers still have a crossfeed effect 20dB louder than it. The headphones have a crossfeed effect equal to background noise. It's not just weaker, it's potentially gone. Turn the volume down 10dB, and the speakers still have 10dB of crossfeed but the headphones don't have anything. If imaging relied on this, low listening volume with high ambient volume would have little or no imaging, and it would increase dramatically if the difference increased.(This doesn't need any thought experiment if you want to introduce significant backround noise, use any open headphone out on busy traffic regardless of isolation - I doubt soundstage or even imaging can be reproduced without compromise.  Also absolute fidelity is significantly compromised when playback volume strays too far from initial performance volume - volumes should be matched with a decibel meter to maintain accurate referencing)
 
What you're implying is pseudo-crossfeed. One ear hears a delayed and quieter version of the other channel. That's crossfeed. This is what creates imaging. You implied that headphones will low isolation image better. I presumed that was because the crossfeed effect would be stronger. What did you mean otherwise? 
 
Crossfeed is when a delayed crosstalk is introduced into the signal in a manner like speakers do - this requires a crossfeed circuit or crossfeed algorithm.  I do not know, in the above scenario, if this difference in an order of magnitude lower can still be described as crossfeed.  It is definitively a delayed crosstalk, and in my opinion, of a level that will perceptible by a perfectly healthy individual.
 
Your hypothesis is just a hypothesis, just like mine. It has to stand up to testing, reason, and logic. You have to be able to defend it. 
 
For me to defend it, you need to come up with a flaw in my reasoning and logic, for which you have not demonstrated.