[bigshot]

According to the studies temporal pre-masking has a duration of about 20 msecs and temporal post-masking a duration of about 100 msecs. Most of the waterfall plots I've seen have a duration of about 5 msecs, without claiming to have seen them all, there probably are exceptions. So this would make human perception between 4 and 20 times slower in theory and more than that in practice, the traces are usually at something like -90 dB after 5 msec and I defy anyone to hear that!

 
Oh look at that! Someone just brought the science to the table! I was waiting for that. Thanks Roly!
 
The threshold of perception for group delay is somewhere around 30 ms. You can't know what things sound like by looking at a nice colorful waterfall chart unless you know what those numbers along the sides represent in terms of human hearing.

 

[vid]

That seems saying frequency response is different from decay, yet it's easy to show they're coupled. If you hear a change in frequency response and decay changed as well, what are you hearing, really?

 

[bigshot]

Maybe you are just hearing frequency response and pulling the idea of decay out of thin air? Lord knows it's been done before around here!

 

[ProtegeManiac]

  That seems saying frequency response is different from decay, yet it's easy to show they're coupled. If you hear a change in frequency response and decay changed as well, what are you hearing, really?

 
Based on the replies to my clarifications (and what I've thought about that decay problem prior to that) I think it's safe to say that it's partly response of the headphone and partly distortion on the part of the amp. If a headphone has a boosted bass response, without considering at what level it can precisely do what, then you are likely to hear a bit more extension given a real instrument doesn't really "stop" vibrating immediately. The thing is -  let's take for example a bass drum - chances are you'd have to be standing pretty close to it or walls are very reflective for you to hear a long decay on the actual instrument. If you're in a fairly large venue and standing at a fair distance, all you hear is the "thump," even if the drummer doesn't follow up right away with another kick. In the same sense, consider a relatively small 2-way speaker - barring near field use tendency is that the bass drum sounds hollow on that as well. Of course, there's a way to overdo this; and ditto squished earpads (the HD6x0 regardless of what amp is driving it is screwed up with old earpads vs absolutely new earpads, the latter having a sound more similar to the HD800 than what the HD6x0 is popularly known for).
 
The amp then comes in (this is basically what I attributed more to prior to Page 3) only when it's already having a fair bit of trouble driving the transducers in question. Note though that even then I will still be one to question why one would need an exceptionally huge amplifier when amps along the size of the Asgard will have a large enough power supply to cope with dynamic drivers and even some other non-dynamic drivers.
 
-----
 
One other thing though: if frequencies can briefly cause variances in the transducer's impedance from its nominal rating, then does this explain what makes an amp "better" and does it have anything to do with the above distortion that causes a "slow" sound? (Again, it doesn't follow that one needs a huge-arse amplifier/power supply for everything) This was easy to determine with speakers given they're all around 6 to 8ohm, so just look for an amp that at least does 1.5x power at half the impedance (2x preferably), but obviously headphone impedance ranges don't work the same way (and neither do amp power ratings).

 

[vid]

  Maybe you are just hearing frequency response and pulling the idea of decay out of thin air? Lord knows it's been done before around here!

 
Hold on, you first say decay is too short to be noticed, now you say I thought it up entirely? You're also saying changes to the frequency response are salient, and I'm saying changes to the frequency response predictably alter measured decay. I've posted proof of this a bunch of times - if someone hasn't yet seen it, ask for it.
 
But what I asked for initially was proof that you can't hear decay. There's speculation but no proof.

 

[bigshot]

Decay exists, but if you want to be able to hear it, it has to exist at levels that are audible to human ears.
 
Frequency response imbalances can make bass sound thick and sloppy. The reason for that is auditory masking. The pluck of a bass note involves a range of frequencies covering two or three octaves. A boost down low can mask the pluck sound an octave or two higher. That results in a sloppy sounding bass. The attack of the note becomes invisible and the whole thing sounds like a muffled thump. But the problem isn't decay. It has absolutely nothing to do with time. The attack still exists and is being presented the same as always, it's just being buried under the frequencies below. It is a response problem, not a decay problem.
 
It isn't even correct to describe the effect as decay, because it's the attacks you are hearing get messed up, not the decay. Almost all music has some sort of reverb built into the mix that extends the decay time. That is part of the mix, not the headphones. And human hearing is VERY forgiving of variation in decay as opposed to attack.
 
Actual time issues in transducers manifest themselves as frequency response imbalances and distortion. But the problems start at the top in the high frequencies, not at the bottom. An 8kHz frequency is a lot more apt to be audibly messed up by a transducer that is "sloppy" than a 30Hz one. Why? Because a 30Hz waveform is as long as a mid sized car. It takes a LOT of time overlap to mess that up. But a high frequency is tightly packed together. A small section of time can cause frequency cancellation. The amount of that is measured in tens of milliseconds as cited above.
 
Define the problem. Measure it. Then apply your measurement to the thresholds of human perception. That will tell you if you are hearing what you think you are hearing, or just making it up.

 

[Roly1650]

That article doesn't seem to show or even claim that you can't hear decay. It establishes that temporal masking exists, but that's it, unless I misunderstood something.

As for different decay patterns, yes, if you change the frequency response, you change the decay.

Not strictly correct, the source quoted sets limits on human perception and what may or may not be audible. The original study was published in 1998 and hasn't been refuted, so hardly speculative at this point in time. Anyway, I was attempting to relate this data to waterfall plots, which, as you know, relate an impulse to the resonance and decay of headphones and what may or may not be audible, as a consequence of having some scientific insight. My error if that wasn't what you wanted.

If your playing around with frequency response, then aren't there only two choices?

a) tilting the fr moves the balance towards/away from any resonances in the headphone. The Wiki shows that we have a fairly generous tolerance to that, so it would have to be a pretty radical fr shift to make that happen.

b) tilting the fr moves the balance towards/away from the frequencies in the program material which contain the reverb and decay information, which by definition are going to be at low level, assuming of course that you are listening to music when you make the comparison.

Now of course neither is mutually exclusive but if I had to put money on it, I'd go with b) over a) as being the most likely, if only because the changes required are probably more subtle. But it is possible I'm talking a load of bollocks and I've misunderstood you again.

And thanks bigshot.

 

[vid]

  Decay exists, but if you want to be able to hear it, it has to exist at levels that are audible to human ears.
 
Frequency response imbalances can make bass sound thick and sloppy. The reason for that is auditory masking. The pluck of a bass note involves a range of frequencies covering two or three octaves. A boost down low can mask the pluck sound an octave or two higher. That results in a sloppy sounding bass. The attack of the note becomes invisible and the whole thing sounds like a muffled thump. But the problem isn't decay. It has absolutely nothing to do with time. The attack still exists and is being presented the same as always, it's just being buried under the frequencies below. It is a response problem, not a decay problem.

 
I say it is a decay problem, and make the case like this. Take a bass-hump headphone, measure its decay, EQ down the hump, and measure the decay again. You're going to see change in the decay that isn't simply the old decay pushed down by the number of dB you EQd down. You'd say it was the change in the frequency response and not the change in the decay that made the sound better, but which caused which?
 

Not strictly correct, the source quoted sets limits on human perception and what may or may not be audible. The original study was published in 1998 and hasn't been refuted, so hardly speculative at this point in time. Anyway, I was attempting to relate this data to waterfall plots, which, as you know, relate an impulse to the resonance and decay of headphones and what may or may not be audible, as a consequence of having some scientific insight. My error if that wasn't what you wanted.

 
Sorry, I didn't notice a study. If you don't mind linking to it directly?

 

[money4me247]

  Decay exists, but if you want to be able to hear it, it has to exist at levels that are audible to human ears.
 
Frequency response imbalances can make bass sound thick and sloppy. The reason for that is auditory masking. The pluck of a bass note involves a range of frequencies covering two or three octaves. A boost down low can mask the pluck sound an octave or two higher. That results in a sloppy sounding bass. The attack of the note becomes invisible and the whole thing sounds like a muffled thump. But the problem isn't decay. It has absolutely nothing to do with time. The attack still exists and is being presented the same as always, it's just being buried under the frequencies below. It is a response problem, not a decay problem.
 
It isn't even correct to describe the effect as decay, because it's the attacks you are hearing get messed up, not the decay. Almost all music has some sort of reverb built into the mix that extends the decay time. That is part of the mix, not the headphones. And human hearing is VERY forgiving of variation in decay as opposed to attack.
 
Actual time issues in transducers manifest themselves as frequency response imbalances and distortion. But the problems start at the top in the high frequencies, not at the bottom. An 8kHz frequency is a lot more apt to be audibly messed up by a transducer that is "sloppy" than a 30Hz one. Why? Because a 30Hz waveform is as long as a mid sized car. It takes a LOT of time overlap to mess that up. But a high frequency is tightly packed together. A small section of time can cause frequency cancellation. The amount of that is measured in tens of milliseconds as cited above.
 
Define the problem. Measure it. Then apply your measurement to the thresholds of human perception. That will tell you if you are hearing what you think you are hearing, or just making it up.

I don't really understand the point you are trying to make.
 
If a distorted frequency response hides the attack of the note... well obviously that headphones doesn't present attack well & the attack is not being presented true to the recording. There are other reasons this could happen such as bad damping or whatever, but the end result is the same: no poor attack.
 
So if the same phenomena applies to decay, and it's the recession certain frequencies that hide the decay or other frequency overwhelming the decay of a note... then you can hear the differences between how headphones present the decay. Regardless of the reasoning behind the change in decay/attack, you seem to say that it is possible for there to be variation in decay/attack quality... soooo...? Isn't that the opposite of your argument of not being able to hear differences in decay?
 
If decay is defined as the fadeout of a note... that is pretty easy to hear that on any pair of headphones. I don't understand your argument.

 

[Roly1650]

I say it is a decay problem, and make the case like this. Take a bass-hump headphone, measure its decay, EQ down the hump, and measure the decay again. You're going to see change in the decay that isn't simply the old decay pushed down by the number of dB you EQd down. You'd say it was the change in the frequency response and not the change in the decay that made the sound better, but which caused which?


Sorry, I didn't notice a study. If you don't mind linking to it directly?

It's in the Wiki, check the references at the bottom of the page and cross linked to the bracketed numbers in the text.

 

[bigshot]

  If a distorted frequency response hides the attack of the note... well obviously that headphones doesn't present attack well & the attack is not being presented true to the recording.

 
No, you're thinking about it backwards. Auditory masking doesn't exist in headphones. It exists in the human ear. The headphones are just presenting sound the way they always do. The frequency response imbalances are altering our ability to hear it. If I say hello to you normally, and then say hello again as a air horn on a truck blows, the reason you can't hear it isn't because I'm not speaking. It's because the air horn is masking your ability to hear me.
 
Again, sloppy bass has nothing to do with decay. It has to do with the masking of the upper bass... the pluck... that makes up the attack. The headphone is producing the pluck sound, but the loud lower bass is preventing you from hearing it.
 
Reverberation in music, also called decay, is part of the mix created by the engineers who recorded the music, It has nothing to do with the headphones that are playing back the music. If the engineer sets his reverb for a half second decay, it is a relatively short reverberation like a small club. If he chooses a five second decay, it sounds like a huge arena. Classical concert halls generally have about a 1-2 second decay. Decay is defined as the amount of time it takes sound to echo until it drops 60 dB below its original volume level.
 
Is this clearer?

 

[money4me247]

  No, you're thinking about it backwards. Auditory masking doesn't exist in headphones. It exists in the human ear. The headphones are just presenting sound the way they always do. The frequency response imbalances are altering our ability to hear it. If I say hello to you normally, and then say hello again as a air horn on a truck blows, the reason you can't hear it isn't because I'm not speaking. It's because the air horn is masking your ability to hear me.
 
Again, sloppy bass has nothing to do with decay. It has to do with the masking of the upper bass... the pluck... that makes up the attack. The headphone is producing the pluck sound, but the loud lower bass is preventing you from hearing it.
 
Reverberation in music, also called decay, is part of the mix created by the engineers who recorded the music, It has nothing to do with the headphones that are playing back the music. If the engineer sets his reverb for a half second decay, it is a relatively short reverberation like a small club. If he chooses a five second decay, it sounds like a huge arena. Classical concert halls generally have about a 1-2 second decay. Decay is defined as the amount of time it takes sound to echo until it drops 60 dB below its original volume level.
 
Is this clearer?

I still don't understand how that translates into headphones not presenting decay or all headphones presenting decay the same.
 
Different headphones do not all present the source material the same way due to a variety of factors. Regardless of what specific the cause behind hearing more decay or less decay on different headphones, if there is variability in the presentation of attack/decay, then you can talk about a headphones' ability to reproduce attack/decay. 
 
So you are saying that decay, defined as the reverberation a fading note, is always just recorded into the music. However, if you hear the decay being longer or shorter on different headphones, isn't it a valid sound quality to discuss when comparing headphones? You can even remove this confounding variable by playing a test tone that has not been engineered with additional decay, since that actual note will decay after it is produced by your headphones & you can judge how well your headphones present decay. 

There are "Cumulative Spectral Decay" graphs that measure the differences of the decay of a single note in different headphones.
 

edit: It's like saying there is no such thing as sound stage because the sound stage in determined by the source, but people can obviously hear differences in how headphones present the sound stage present in the source.

 

[Head Injury]

  I still don't understand how that translates into headphones not presenting decay or all headphones presenting decay the same.
 
Different headphones do not all present the source material the same way due to a variety of factors. Regardless of what specific the cause behind hearing more decay or less decay on different headphones, if there is variability in the presentation of attack/decay, then you can talk about a headphones' ability to reproduce attack/decay. 
 
So you are saying that decay, defined as the reverberation a fading note, is always just recorded into the music. However, if you hear the decay being longer or shorter on different headphones, isn't it a valid sound quality to discuss when comparing headphones? You can even remove this confounding variable by playing a test tone that has not been engineered with additional decay, since that actual note will decay after it is produced by your headphones & you can judge how well your headphones present decay. 

There are "Cumulative Spectral Decay" graphs that measure the differences of the decay of a single note in different headphones.
 

edit: It's like saying there is no such thing as sound stage because the sound stage in determined by the source, but people can obviously hear differences in how headphones present the sound stage present in the source.

He's saying the decay added by headphones, even "slow" ones, is insignificant compared to the amount of decay already added to the recording from the live performance or from studio magic. He's also saying the differences in "speed" between headphones is not because of delay, but because of differences in the volume of frequencies. Particularly, IMO, differences in bass and lower midrange which will cause masking of "detail" in the upper midrange and treble.
 
I tend to agree, but don't know enough to take a strong stance for it. Still, it makes a lot of sense when you think about it. Isn't it convenient that all the audiophile detail darlings like the HD800 have emphasized treble? Bright and detailed always go hand in hand in subjective impressions.
 
But then, so do cables and improvements 

 

[bigshot]

  So you are saying that decay, defined as the reverberation a fading note, is always just recorded into the music. However, if you hear the decay being longer or shorter on different headphones, isn't it a valid sound quality to discuss when comparing headphones? You can even remove this confounding variable by playing a test tone that has not been engineered with additional decay, since that actual note will decay after it is produced by your headphones & you can judge how well your headphones present decay. 

There are "Cumulative Spectral Decay" graphs that measure the differences of the decay of a single note in different headphones.
 

edit: It's like saying there is no such thing as sound stage because the sound stage in determined by the source, but people can obviously hear differences in how headphones present the sound stage present in the source.

 
To answer your first question... What you are hearing and calling "decay" isn't decay at all. It's frequency response imbalance. By far, the single most common problem among transducers is frequency response, followed by distortion. Dynamics are related to how much volume a transducer can take without seizing up and clipping. But if you take a pair of headphones that are able to reproduce a full spectrum of sound at loud volumes without clipping, you can EQ them to sound like just about any headphone on the market.
 
Sound stage is another issue entirely. That is placement of the instruments in three dimensional space. Headphones do that very poorly. They place instruments along a straight line in the middle of your head. Stereo speakers can present a clear soundstage in front of you. A 5:1 system presents it the best because it can do front to back as well as side to side. Dolby is working on a system called Atmos that adds the vertical dimension. I bet that will be even better than 5:1. There are also depth cues embedded in the mix (reverb, phase). Those are entirely due to the source.
 
Most of the descriptions you see in headphone reviews are totally made up. It's vague, flowery poetry designed to describe subjective feelings about sound, not describe the sound itself.

 

[money4me247]

  He's saying the decay added by headphones, even "slow" ones, is insignificant compared to the amount of decay already added to the recording from the live performance or from studio magic. He's also saying the differences in "speed" between headphones is not because of delay, but because of differences in the volume of frequencies. Particularly, IMO, differences in bass and lower midrange which will cause masking of "detail" in the upper midrange and treble.
 
I tend to agree, but don't know enough to take a strong stance for it. Still, it makes a lot of sense when you think about it. Isn't it convenient that all the audiophile detail darlings like the HD800 have emphasized treble? Bright and detailed always go hand in hand in subjective impressions.
 
But then, so do cables and improvements 

This is a good explanation. I can get onboard with stuff in the first paragraph.
 
second paragraph, I think emphasized treble correlates to more detail because emphasized bass will mask other frequencies & hide details. makes sense to me.
 
totally disagree with cables having any impact on sound what-so-ever. even if they did, any minute sonic changes are definitely not worth their sticker price.
 

 
To answer your first question... What you are hearing and calling "decay" isn't decay at all. It's frequency response imbalance. By far, the single most common problem among transducers is frequency response, followed by distortion. Dynamics are related to how much volume a transducer can take without seizing up and clipping. But if you take a pair of headphones that are able to reproduce a full spectrum of sound at loud volumes without clipping, you can EQ them to sound like just about any headphone on the market.
 
Sound stage is another issue entirely. That is placement of the instruments in three dimensional space. Headphones do that very poorly. They place instruments along a straight line in the middle of your head. Stereo speakers can present a clear soundstage in front of you. A 5:1 system presents it the best because it can do front to back as well as side to side. Dolby is working on a system called Atmos that adds the vertical dimension. I bet that will be even better than 5:1. There are also depth cues embedded in the mix (reverb, phase). Those are entirely due to the source.
 
Most of the descriptions you see in headphone reviews are totally made up. It's vague, flowery poetry designed to describe subjective feelings about sound, not describe the sound itself.

Decay is defined as the note fading. how is that frequency response imbalance? frequency response imbalance = coloration. both a colored or neutral pair of headphones can present decay. I can agree that frequency response imbalances affect our perception of decay, but those are definitely two separate things. I can agree with your thoughts about the primary issue with a pair of headphone's sound is frequency response problems. Differences in frequency response is the most obvious thing you notice when comparing headphones. With nice headphones, distortion in the headphones is usually caused by distortion in the source or distortion from interference in another component.
 
The last point of your paragraph about being able to tune one pair of headphones to sound like any other pair of headphones is simply not true. The earcup, damping, actual driver, and a variety of other factors besides frequency response affect how the headphones sound.
 
Your point about sound stage is not true either. Yes stereo speakers present soundstage better, but different headphones present the depth cues embedded in the mix better than others. This can also be affected by the physical headphone design.
 
your final point is well-taken. A lot of headphone reviews are just subjective & often biased impressions with cool audiophile jargon. However, the audiophile jargon actually does have very specific definitions and if the reviewer is legit and use the words correctly, it does translate into an accurate description of the sound. the thing is that most of these words are relative, so obviously it is hard to know what the reviewer is comparing the sound too. also, our biases translate into the reviews. you can describe the exact same sound accurately using a positive spin or negative spin.