Headphone speed and its effect

[ericj]

Quote:

Originally Posted by LostOne.TR /img/forum/go_quote.gif NICE. but what about relatively fast, dynamic phones when compared to other dynamic phones?

I'm no expert on high-performance dynamics. offhand, from my own collection, I'd say that the k240 sextett, monitor, and other AKGs that use the 600-ohm DKK32 capsule rate as "Not Bad".

 

[jellojoe]

Quote:

Originally Posted by LostOne.TR /img/forum/go_quote.gif NICE. but what about relatively fast, dynamic phones when compared to other dynamic phones?

To my ears, the Koss A/250 is faster than the 600 ohm AKG 240 series.

 

[Ragonix]

The way I understood headphone speed is that the faster the headphone the faster it plays the music. If you have very fast headphones it will sound like you are listing to the music on fast forward.

 

[billinkansas]

Here’s an example of speed at the bottom end of the spectrum:

This evening I was listening to a CD of the London Symphony playing Edward Elgar’s “Cockainge” – great recording BTW. About 5 minutes into the piece there is a soft section that as 4 very light deep tympani taps a few seconds apart - so soft that it would be easy to not notice tham. I listened carefully to this over and over for several minutes. Here’s what some of my different headphones thought about that passage:

Stax Lambda – These don’t go quite deep enough to capture the whole sound, but most of it was there crystal clear – the drum had a soft but fast and precise attack with a natural decay – just like real life.

Stax SRX-MKIII - Similar to Lambda, less deep response but even clearer.

I don't have my Stax SR303's set up right now, but I'll try them sometime as well.

Yamaha YH-1 Orthodynamic - dampened with thick felt – There it was, the entire sound of the drum tone, and just about as clear and quick as the Lambdas. Best of the bunch.

Yamaha YH-2 Orthodynamic stock – Similar to the YH-1, almost as deep as well. 2nd best of the bunch.

Denon D2000 – the depth of the tone was there ok as one would expect from these phones, but it the effect was neither clear nor precise.

Sennheiser HD600 – the bass drum sounded like someone down the street kicking a barrel. The attack was nebulous, and the whole thing was kind of just a thud. I really wouldn’t have been able to tell what it was with any certainty if I didn’t already know. Not good.

 

[b0dhi]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif A woefully underdamped ortho like the yh-100 in stock form - and damping here includes not only the resistive mechanical load on the driver in the form of earcup stuffing but the pliancy of the driver and the damping factor of the driving amplifier - can have terrible transient response. The classic example is a speck of dust on a vinyl record, which in a headphone with good transient response will go 'Tick!' and in a headphone with poor transient respone will go 'Thockkkk'.

EQ distortion aside, couldn't exactly the same effect be achieved in a "fast" headphone by EQing some attenuation at some appropriate treble band? Or more significantly, the inverse achieved in a "slow" headphone by EQing some extra treble in the right bands?

I guess what I'm saying is, does "speed" as you've described it actually change the sound in any way except altering the frequency response?

 

[smeggy]

Another way of looking at it is in the form of dynamics, not dynamic headphones, but the dynamic response of the headphones to the signal. My stats, as well as being precise and clear are also startlingly dynamic. It's that whole transient response thing mentioned earlier, a sound can be reproduced with such dynamism that it can almost make you jump. Much like the real thing if you've ever been close to a bongo drum or similar when whacked.

Dynamic phones generally have a voice coil, former, a ribbed plastic diaphragm that acts as both an air mover and roll surround/dampener. It's moving mass will generally be much higher than a planar, long voice coils and powerful magnets are used to overcome the inertia of the assembly. By contrast, a 'stat diaphragm is driven over most of it's surface area, is push/pulled by forces not in contact with the diaphragm, therefore the diaphragm can be incredibly light and thin with almost no mass or inertia. This makes their transient response very high and they can out accelerate and decelerate most other phone types with ease. That immediacy of signal conversion to motion is what makes a phone fast. I also have K1000s and my staxes cream them for speed and the K1k is itself a fast and dynamic headphone.

To me, this has nothing to do with sound preference or tonality or frequency response, only with how quickly a signal can be converted to sound waves of the correct level. That's my take on what a 'fast' phone is.

 

[PWilson]

Quote:

Originally Posted by b0dhi /img/forum/go_quote.gif EQ distortion aside, couldn't exactly the same effect be achieved in a "fast" headphone by EQing some attenuation at some appropriate treble band? Or more significantly, the inverse achieved in a "slow" headphone by EQing some extra treble in the right bands? I guess what I'm saying is, does "speed" as you've described it actually change the sound in any way except altering the frequency response?

Speed as I understand it and as explained by a few people in this thread has nothing to do with frequency response. It's about transient response.

The best way I could illustrate my understanding of it is this:
Imagine a signal with rapid switching of two tones, at extreme ends of the frequency spectrum. Assume we have two cans with the exact same freq response, but one is significantly 'faster' than the other.

The fast headphone will give you distinct, sharp, clean switches between the two tones. A slow headphone will give you a warble as it never gets to the lows of the low tones before it's being asked to play the high tone again. It's not that it's incapable of reproducing the tones, but it's that it hasn't sped itself up or slowed itself down enough to do so in time.

 

[b0dhi]

Quote:

Originally Posted by PWilson /img/forum/go_quote.gif The fast headphone will give you distinct, sharp, clean switches between the two tones. A slow headphone will give you a warble as it never gets to the lows of the low tones before it's being asked to play the high tone again. It's not that it's incapable of reproducing the tones, but it's that it hasn't sped itself up or slowed itself down enough to do so in time.

The warble effect (intermodulation distortion) you described (discussion here) exists in dynamic, piezo and electrostatic headphones at roughly the same level (give or take a couple of dB). You'd expect that if transient response was the cause, electrostatic and piezo drivers would do much better than dynamics at reproducing those samples without audible distortion.

 

[PiccoloNamek]

I remember that. It was noticeable on my HD650s but not drastic. It is unnoticeable at normal and loud volumes on my Lambdas.

Another thing about "fast" headphones is that they are extremely good at reproducing heavily textured bass tones, the kind you often hear in electronic music, whereas slower 'phones produce an effect that sounds as if the audio had a gaussian blur applied to it.

 

[ericj]

Quote:

Originally Posted by PWilson /img/forum/go_quote.gif Imagine a signal with rapid switching of two tones, at extreme ends of the frequency spectrum.

How about not.

Lets imagine that we have a headphone driver sitting at dead center on it's path of travel.

A single pulse arrives. It goes from 0v to 3v in 5uS, from 3v to -3v in 10uS, and then back to 0v.

No further electrical activity occurs.

Questions:

1: On the positive swing, does the driver arrive at the expected point of outward excursion in exactly 5uS, or does it not quite make it?

2: On the negative swing, does the incursion past dead center match the preceding excursion in distance?

3: After the return to 0 volts, does the driver stop completely at dead center or does it bounce?

an underdamped driver passes questions 1 and 2 with flying colors, and fails miserably at question 3.

an overdamped driver (such as an overtensioned 'stat) fails at #1, passes 2 and 3 easily, but has abysmal sensitivity, and may be bassless due to restricted excursion.

Further questions:

Lets say that the pulse was a single, perfectly formed sawtooth with nice sharp points on both the positive and negative ends, and that you have a sophisticated system of laser scanning that allows you to track the motion of the driver in real time, and graph it, much the same way that an oscilloscope graphs the electrical pulse.

Does the graph of the motion of the driver have corners just as pointy as the oscilloscope screen for the signal, or are the corners blunt?

 

[smeggy]

The Ety ER4 is also very fast, sadly it's also screechy and thin.

 

[PWilson]

Hrm, warble was a very silly word to use, in hindsight, as it already has an accepted defenition.

The illustration I wanted to give was of the slow cans eventually being unable to alter the frequency of the driver fast enough to resolve the details. You get to the point of hearing a rough sine wave (of frequency, I mean; not the sine wave of a constant pitch) rather than a distinct high/low pitch switch.

I'm still very much of the opinion that it's not frequency response related.

 

[wualta]

Quote:

Originally Posted by billinkansas /img/forum/go_quote.gif ...Sennheiser HD600 – the bass drum sounded like someone down the street kicking a barrel. Not good.

This description actually caused me to snortle and guffaw, and I own an HD 600.

This pulls the discussion away from the concept of speed (which is a subjective term the closest objective measurement of which would be rise time ((ericj's Question No.1 above)), but yes, both transient response and frequency response are involved too-- don't forget that you can Fourier the impulse response and derive the frequency response), but intermodulation (IM) distortion is a very interesting and revealing test. Amplifiers have it, which pretty much rules out poor transient response alone as a cause. Any transducer has many little nonlinearities (impulse response, frequency response, dynamic range response, etc. etc.) that can be excited by the classic two-tone test, and it would be revealing to run a bunch of our best-beloved headphones through the gantlet.

.

 

[PWilson]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif How about not. Lets imagine that we have a headphone driver sitting at dead center on it's path of travel. A single pulse arrives. It goes from 0v to 3v in 5uS, from 3v to -3v in 10uS, and then back to 0v. No further electrical activity occurs. Questions: 1: On the positive swing, does the driver arrive at the expected point of outward excursion in exactly 5uS, or does it not quite make it? 2: On the negative swing, does the incursion past dead center match the preceding excursion in distance? 3: After the return to 0 volts, does the driver stop completely at dead center or does it bounce? an underdamped driver passes questions 1 and 2 with flying colors, and fails miserably at question 3. an overdamped driver (such as an overtensioned 'stat) fails at #1, passes 2 and 3 easily, but has abysmal sensitivity, and may be bassless due to restricted excursion.

I have to admit my utter ignorance of the ways damping is actually achieved in a speaker/driver. I assume surround stiffness plays a part, but I suspect the important damping happens electrically, rather than mechanically...

Apart from damping, would a stronger magnet be able to control the cone better both in terms of propelling it to its desired extension faster while also preventing the flutter when it returns to 0? Would this then be a key player in what we call the speed of a driver?

When we (I?) talk about speed, we're not just talking about transient attack (though personally I value that higher), but also decay, which sit on opposite sides of the damping spectrum, and is why I believe there's another factor at play.

These are questions of curiousity and to further my knowledge, btw. Not to defend my rudimentary explanation attempts above or to attack what you've said.

Actually, I think you just said something similar, Smeggy, re magnet power/mass of driver.

 

[toxicsweet]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif The Ety ER4 is also very fast, sadly it's also screechy and thin.

Balanced armatures are much faster than dynamic headphones. All in all, dynamic headphones are the slowest type of headphones(AFAIK).