[leeperry]

There's a lot of ppl deeply into headphones cups damping on this forum...how do you guys work out whether your're listening to the cups resonances "back-wave distortion" or to the music "untouched" reverb?
 
Ideally it'd take a very dry reference recording and judge by ear?
 
There seems to be a very thin line between perfect damping and overdamping. The latter will sound muffled and claustrophobic(like a tiny anechoic room), and a lack of damping will sound like a massive amount of nasty sounding "back-wave distortion" that colors the sound in a pretty unbearable way, killing the smallest details due to the increased THD...picture what an aluminium lined cup does(very metallic/agressive trebles) and you'll get an idea of what I'm trying to convey. OTOH, AT regularly use metal cups...hopefully they're damped 

 
Many legendary headphones are based on those very cups resonances, and Beyer uses ABS on its Premium line(and so does SONY on the sa3k/5k)...that is widely used in music instruments due to its great sounding resonances, which leads to my real question: cups act as room walls, don't they? Or should we damp them to suppress those resonances? Which leads again to the fact that Beyer/SONY use ABS, and Sony used some vegetal/plastic hybrid cups on the cd3k.
 
Wooden cups have a god-like magical aura on this forum, but wood often has a very poor damping factor: http://qualia.webs.com/dampingfactorvalues.htm
 
I believe Dynaxorb does exactly what we want:

DynaXorb absorbs, diffuses and attenuates the sonic energy directed towards it

[size=xx-small]Back wave distortion, a common problem with every speaker, occurs when your speaker sends the same sound out the back as it does out the front!   If this rear sound wave energy is allowed to bounce back and return to the speaker, it interferes with the speaker’s ability to operate properly causing back-wave speaker distortion. [/size]​

 
It seems that you can't really beat petroleum based matters for acoustic damping, as they both absorb a great deal of energy and break the back-waves all at once. Wood cannot do that as effectively IMO.
 
I don't think any sane loudspeaker designer would decide to keep inner-cabinet resonances on purpose? But do loudspeakers and headphones aim at the same goal? Can all reflections be considered as parasiting the SQ? Music instruments need to resonate, it would appear that headphones do not..except if the cups are supposed to act as room walls do for loudspeakers..I'm sure listening to music in a true anechoic room must be a tad disturbing to the human brain?
 
Talking about anechoic rooms, this crossfeed plugin tries to mimic one...it's not really a "mono-izing" DSP and it's not a reverberating room simulator either. It's a "dry" reverb so to speak...it does sound kinda weird, yet you can read this kind of (supposedly) end-user testimonial:

I have reached a point with Redline Headphone Monitor that I can no longer do headphones without it. It just sounds SO much more like my speakers.

Need to chew on this, feel free to share your thoughts if you like 

 

[leeperry]

And talking about killing two birds w/ one stone, we can also finetune our damping to counterbalance our physiological limitations.

 

[InnerSpace]

Quote:

...how do you guys work out whether your're listening to the cups resonances "back-wave distortion" or to the music "untouched" reverb?
 
 

I have found you can learn a little by wearing the phones unplugged for an hour or two.  Watch TV, listen to your speakers, talk to people (if they're not laughing at you) ... just go about your normal business.  There may or may not be significant attenuation (probably less than you think) and the coloration signature you hear on incoming sounds will be at least suggestive of the colorations the cup will add to the reflected wave.

 

[leeperry]

Good point, but I think I've mixed 2 things:
-the back-wave reflections, that Dynaxorb aims at minimizing..all they do is bloat the sound.
-the cups resonances, much like a music instrument
 
It might very well be that the former must be tuned down as much as possible, but that the latter could be sought after(hence the wooden cups cult).

 

[haloxt]

I view all cups as different rooms. Some rooms are better for some instruments, none are perfect even assuming all recordings you use are "perfect". I think a big offender of using cup resonance to give more texture to the sound is Ultrasone, at least with the zino, hfi-2200, and pro 900. When I listen to the same albums on different setups, headphones and speakers, I can always isolate colorations for Ultrasones I have tried, namely warmed over and artificially richer bass. Euphonious and acceptable for low and mid-fi, but obvious coloration and limited accuracy with high fidelity gear. I consider both sony pfr-v1 and sony sa5000 a lot more faithful in bass than Ultrasones I have tried, but you have to go beyond mid-fi to really see how it is more life-like than Ultrasones.

 

[leeperry]

an obvious hardcore example is the dx1k: http://www.head-fi.org/forum/thread/391515/jvc-hp-dx1000-mod#post_5150715
 
a separate sound chamber to let the driver resonate like hell, some foam at the back to kill a bit of back-waves...and that's it!
 
many ppl describe this phone as utterly bloated...this would make an ortho-head collapse for sure

 
and the OP of that thread I just mentioned is about adding a coin to create nasty metal sounding back-wave distortion...on top of the cavernous cups resonances 

 
http://www.head-fi.org/forum/thread/391515/jvc-hp-dx1000-mod/30#post_6522298
 
"I recently got a third DX1000 that is still stock - I don't know how people can listen to those things [..] - it's so muffled, coloured, and boring."

 

[xnor]

As the OP of that thread describes, stock it has an 'empty-hall' like sound. That is most likely due to the weird mids dip followed by a peak in the frequency response of the DX1000's - if he'd used a parametric EQ and used it properly I'm sure the result would have been alot better than what he got there.
Sure, if one prefers to mess around and try to introduce some additional resonances that hide other flaws of the cans/cups/drivers, why not.
 
Anyway, the cup design looks like that of a more expensive product, but the result seems to be .. 'subpar'.

 

[GreatDane]

IMO, the DX1000 is not "utterly bloated". I think the "empty hall" description and general thinking this way is an exaggeration also. I feel no need to use my PEQ.

 

[xnor]

You don't notice anything weird around 300 - 500 Hz?

 

[leeperry]

I think every ortho ninja will agree that once you've listened to a fully damped phone, inner-cup reflections become unbearable...acting as "noise" parasiting the original waveforms.
 
The quote I posted above about the dx1k says it's "muffled, coloured, and boring". OTOH, many headphones rely on the cups resonances color...and each to his own after all. I personally got sick and tired of having a cavernous SS after a while on the cd1k(same story as on the cd3k). The "big hall" effect gets odd after a while...when nothing can be narrow and dry, you've got a problem: not all recordings are uber-wide.
 
The cd1k/cd3k use their big cups to project a very wide and deep SS: http://www.headphonereviews.org/headphone/Sony/MDR-CD3000
 
"The highlight of the CD3000 is most certainly its cavernous soundstage that separates instruments into their own locations better than all but only the very best headphones. The first time I heard these cans, I was mesmerized by the expansiveness and surrounding nature of the soundstage. The angled drivers undoubtedly help these cans project a frontal soundstage better than many competitors. The drawback of the soundstage is almost a philosophical one, in that the CD3000 makes virtually any recording sound expansive and airy, which while very interesting and entertaining, is hardly transparent or natural. It is great for giving live rock albums that stadium ambiance and feel."

 

[leeperry]

After more tinkering on my favorite Ortho, I've come to the conclusion that the only way to get rid of cup resonances/inner reflections is to fully damp the inside of the cups w/ acoustic foam, and fill the baffles w/ an high mass acoustic deadening clay.
 
Just like they say it here:

The purpose of acoustic foam is to reduce reverberation time and to generally improve the acoustic of the room

 
Once your phone doesn't add a nasty coloration of its own anymore, you clearly get to hear the acoustics of the room where the recordings took place...or at least what the mixing engineer heard in his soundproof cabin. You're not listening to your cups anymore. Very often ppl get bored of the coloration of their DAC/amp, when the cups of their headphones actually color the sound to death.
 
I know Germania fully damped her cd1k w/ this foam, I guess I shoulda tried...but it's not available in Europe, and it seems rather similar to the Akasa noise reduction foam I'm currently using.
 
And I believe that the whole "middle ears resonances EQ" story can be made history when using fully damped cups. I've got no EQ atm, and nothing resonates AFAICT.

 

[milosz]

Don't forget that besides resonance and reflection behind the driver inside the earcup there is also a resonant cavity and some reflection IN FRONT of the driver, in the chamber created between the driver and your head / ear.  
 
I think if you filled this space, including your ear, with  Dynaxorb or sculpy, you wouldn't hear ANY reflections or resonances....
 
 
(...or any sound.)  

 

[leeperry]

oh sure, and Beyer's answer to this problem is to drill holes at the back of the earpads, but that also weakens the isolation from outside noise...reason why their DT770/Pro is clamping like hell, and their "aviation" grade earpads don't have those holes.
 
I currently use sa5k earpads on my Fostex Ortho and they clearly provide a SONY'ish color the sound, very tight bass and very deep and wide SS(once angled). They're made of pleather at the back, and it is my understanding that SONY like to play around with earpads reflections to project their famous SS...There's a family sound to the cd3k, that's for sure.
 
I can only confirm that w/ drastic damping, I don't hear the cups "singing" along anymore(as wualta woud say):
I'm also using a thick disc of felt before the drivers:
 
And I don't get those two whiney peaks at 6400 and 9700Hz that I always get w/ other headphones...it's all about controlling reflections

 

[Omega17TheTrue]

I once damped my akg k271 with patafix and cotton and the high was tamed but the sound was too much dull,dark and without spark/musicality, i believe inner resonances are calculate to artificially extend high frequency.
 
IMO the best solution is open cups to avoid reflection/coloration and let the air move freely like in open baffle speakers.

 

[leeperry]

blutack has a poor damping factor, and all drivers are not born equal...so YMMV may vary indeed. You need very strong magnets otherwise the damping will muffle their sound IME.
 
I personally prefer semi-closed designs, best of both worlds to my ears...a bit of air breathing to beef up the SS, and still good bass/isolation.