[spritzer]

There is no crossfeed in any Stax headphone. 
 
Claiming the 009 sounds this way because of the arc is akin to the guy who claimed the MDR-R10 sounded so good because Sony used such a nice TRS plug. 

 

[arnaud]

Couldn't it be you're changing the clamping force / angle of the pad against your chick by using these dampers? I say this because, as you know, the bass response of the Omega 2 (and any stax for that matter) is severely affect by the leakage through the cushions and their level of compression. 

 

[edstrelow]

Quote:

There is no crossfeed in any Stax headphone. 
 
Claiming the 009 sounds this way because of the arc is akin to the guy who claimed the MDR-R10 sounded so good because Sony used such a nice TRS plug. 

There will  be crossfeed in an open back phone because some sound will cross the head and get into the opposite ear. I am suggesting some may also get through via the arc assembly too.
 
For some reason Stax ditched the 007 arc assembly when it went to the 009. My observations suggest that the 007 design was a poor one.  I am more convinced of the resonance issue but think crossfeed could be an issue.
 
 
Quote:

Couldn't it be you're changing the clamping force / angle of the pad against your chick by using these dampers? I say this because, as you know, the bass response of the Omega 2 (and any stax for that matter) is severely affect by the leakage through the cushions and their level of compression. 

The dampers I am now using don't seem to make any changes on the clamping force that I can see.  Pressing the pads by hand doesn't seem to give the same effects that I am hearing.

 

[n3rdling]

Noting that Stax changed the arc from 007 to 009 and then deducing that it's because the 007 arc had a negative effect on the SQ via vibration transfer is quite the leap.  If that were the case, why wouldn't they have noticed that in 007 prototyping?  After all, Stax used plastic arcs for decades on Lambdas, Sigmas, and the Omega.  Using your line of reasoning, one could easily say that Stax changed the arc system from those past models to the 007 because the old ones had a negative effect on SQ.  Just pointing out why your theory doesn't really make much sense.  I actually think it's much more likely they changed the headband either for aesthetic reasons (maybe they liked the look of black plastic more with the 009 cups), financial reasons (cheaper to produce the plastic headband, especially when the SR-507 shares the same headband), or reliability reasons (the elastic bands on the 007 headpad wear out, and the dual metal arc isn't possible with the slide adjustment system).
 
Also, if you're that paranoid about crossfeed in your headphones, you should just stick with closed headphones.  Even then audiophile nervosa may set in after a few years ("these closed HPs only isolate to -20 dB!"), so you'll have to eventually install drivers into some industrial grade sound-isolating ear muffs.

 

[edstrelow]

Noting that Stax changed the arc from 007 to 009 and then deducing that it's because the 007 arc had a negative effect on the SQ via vibration transfer is quite the leap.  If that were the case, why wouldn't they have noticed that in 007 prototyping?  After all, Stax used plastic arcs for decades on Lambdas, Sigmas, and the Omega.  Using your line of reasoning, one could easily say that Stax changed the arc system from those past models to the 007 because the old ones had a negative effect on SQ.  Just pointing out why your theory doesn't really make much sense.  I actually think it's much more likely they changed the headband either for aesthetic reasons (maybe they liked the look of black plastic more with the 009 cups), financial reasons (cheaper to produce the plastic headband, especially when the SR-507 shares the same headband), or reliability reasons (the elastic bands on the 007 headpad wear out, and the dual metal arc isn't possible with the slide adjustment system).

Also, if you're that paranoid about crossfeed in your headphones, you should just stick with closed headphones.  Even then audiophile nervosa may set in after a few years ("these closed HPs only isolate to -20 dB!"), so you'll have to eventually install drivers into some industrial grade sound-isolating ear muffs.

Not a leap if these metal arcs degrade sound. I think I have found a problem here and invite others to try some experiments to confirm, reject or modify these observations.

For many years Stax used plastic arcs (sigmas and lambdas especially) and then put steel bands in the then top of the line 007. Possibly they thought this would make the entire set-up more rigid. However then Stax dropped dropped steel in the next TOL, the 009. Clearly one can say that steel didn't work for them. Whether it was aesthetics, cost, sound problems or some or all is not clear, just that they ditched steel and went back to plastic.

If they realized it created sonic issues they sure wouldn't be bragging about it since it would hurt their reputation in general and sales of the 007 in particular.

Generally I prefer open back to closed phones so whatever whatever crossfeed is there and it's got to be 30-40 db down and I can live with it. If it's coming through the arcs, I'd rather do without it. I thought I saw crossfeed measurements on various headphones on Tyll Hertsen's site but I can't find them now.

However my point is that there is something odd about the 007A. I started out by pointing out that the metal arcs gave a ringing when tapped but this stopped if you you left a finger across the 2 bands. I then tried a couple of tweaks to to stop the ringing and found one that seemed to make the sound better, (sorbethane pads). I think my phones sound a lot better now so whether it's audio nervosa or not it makes me happy and didn't cost me any money which makes me even happier.

At this point I would be more interested in hearing that someone else tried a tweak like this and did or did not notice a sonic difference. So far no-one has even challenged me on the initial observation that the arcs give a ring when tapped.

 

[TheAttorney]

At this point I would be more interested in hearing that someone else tried a tweak like this and did or did not notice a sonic difference.

 
Well, better late than never:
 
On the basis of a very limited  few minutes trial, I would say this idea is definitely worth exploring further.
 
The metal arcs are very resonant when tapped. Simply holding the arcs with fingers dramatically reduces the resonance, and this does seem to translate to improved sonics. In particular, the sound images become slightly more focused and precise across the board, not just a tighter bass. As sometimes is the case with such tweaks, the resultant increase in musical enjoyment seems greater than the (probably) tiny objective difference.
 
Conversely, removing the tension is a bit like increasing a reverb control: Everything becomes a bit looser and splashier. It's possible the Stax designers knowingly left the arcs un-damped in order to give a more "euphonic" presentation, and some people might prefer that, but I don't.
 
The thing is though, I think the 007 is one of the least "dorky" looking high end phones around - when actually worn on the head. Those slim arcs contribute to a very unobtrusive look, particularly the brown version.  In comparison, the 009s look bulkier on the head  IMO, even though they look impressive off the head. 
 
The sorbothane pads in the earlier picture unfortunately do detract from that unobtrusive look, so I tried something very simple: I tensioned the arcs by wrapping round some paper-based brown masking tape. This did dampen the ringing  slightly, but nowhere near as much as when using the fingers. So now I'm looking for a solution that does the damping, but looks good too...

 

[n3rdling]

Sorry, but the drivers simply don't have the power to resonate the cup and arc.  Tapping on the headband will produce a few orders of magnitude more energy on the arcs than the drivers can produce at listening levels.  I'm chalking this up to imagination.

 

[TheAttorney]

n3rdling, I haven't discounted imagination at this point )
 
However, you are basing your judgment purely on an assumption that the tiny amount of energy (from driver to arcs) can't possibly affect anything.
 
The sound heard when tapping the arcs is affected by the whole structure of the headset (none of which is particularly well damped. If I can clearly hear the taps on the arcs, then it stands to reason that any sound that I can hear must also be able to get back to the arcs, even if in only a small way. No one here can be absolutely sure if that matters without either listening or measuring it - the latter probably requiring a lot of effort and specialized equipment.

 

[n3rdling]

I'm just using common sense.  Sure you can say I'm just assuming, just like I'm assuming that the tiny gust of air produced by my eyelashes when I blink isn't strong enough to resonate the windows of my house. 
 
In any case this isn't that hard to measure.  I have a dial test indicator good to about a thousandth of an inch.  I'll have the headphones clamped down, set the indicator tip on the headband arcs and play music super loud through the headphones.  If the needle doesn't move then I'm either good at assuming or I used common sense.

.

 

[TheAttorney]

Hmm, the eyelash analogy is few orders of magnitude difference, but that woukd be a circular argument, and we don't want one of those ).
 
I wouldn't know if a thousand of an inch resolution is enough to measure such things, but if you have the time and inclination, by all means give it a go.

 

[edstrelow]

  Sorry, but the drivers simply don't have the power to resonate the cup and arc.  Tapping on the headband will produce a few orders of magnitude more energy on the arcs than the drivers can produce at listening levels.  I'm chalking this up to imagination.

Any evidence to back this up?  Do you know of anyone who has actually measured how much power will caused resonance somewhere in a headphone, because without this you have no argument, or rather all you have is argument and no fact.
 
It is an extraordinarily simple matter to check my original observations.  The Attorney has and seems to agree with me. Anyone with an 007 can try this.  I suggest you do so before making further comments.
 
Re: the appearance of my tweak. I agree it is not attractive. But I put all of 10 minutes work to make and fit these dampers.  I already had whatever material  was needed. I really like the sound now and can't be bothered messing with it further.  

 

[edstrelow]

After considerable listening and some playing around with the 007 and other Stax phones, I  have changed my opinion somewhat as to the nature of the resonance issue and I realize this is not just a problem unique to the 007.  I still feel that Stax made a blunder in linking the arc assembly  tightly to the 007 earcups, because it passes energy from the earcup to the metal arcs.  As best I can tell none of my other Staxen (Lambdas, 003's SRX3, Sr005) show this effect i.e that damping the band changes the sound.  But the more important point is that there is so much energy floating around the earcups in the first place which is impairing reproduction.  The 007 bands benefit from damping by sorbethane pads but with the 007 you can do this on the earcup itself as I have recently done, by applying a sorbethane clamp  to the metal tabs at the top of the earcups of the 007.
 
 It is harder to find good locations to put dampers on other models, but I have also  been working on finding a place to apply sorbethane of the 003 (and I have a good spot there) and the Sigma Pro and Sigma/404.
 
The energy going  into the earcups is not negligible from the point of view of the listener.  There is as much energy floating around the earcups as is getting to your ears from the drivers.  Basic physics  tells us that the energy passed into the cups is equal to that going into the drivers (equal and opposite reaction- Newton's Third Law) and (a bit more high school physics) that it is conserved   (conservation of energy).   Also, most stats generate enough acoustic energy to broadcast their signals to all in the neighborhood.  In fact the Sigma's were sold with a  stand  with a resonating chamber so that they could actually be used as loudspeakers.
 
With loudspeakers, we try to minimize resonances by making them extremely rigid, general heavy ( my main speakers are 90 lb each) and by spiking them to the floor.   There are also some sorbethane speaker mounts.   It seems to me that in earcup design the resonance issue  is mostly not being addressed.  This is the first such tweak for this purpose that I have encountered.
 
My other change of opinion was that the use of an adjustable clamp holding the sorbethane to the phones is extremely beneficial. I have found that just sticking sorbethane on an earcup can actually make the sound worse.  You need to get the pressure right and the simple screw contraption noted above was a bit of serendipity.   
 
I should be putting up a separate posting with photos and observations about sound changes in due course.

 

[soren_brix]

One could suggest to place the 007 on a dummy head, and let only one channel play, then let a pick-up rest on the chassie on the other channel and listen to the what comes out (assuming non RIAA), if anything ... it should give a fair impression of the amount of cross vibration, and if placed onto the chassie playing it should give a fair impression of how much vibration that are absorb by the chassie ...

 

[edstrelow]

  One could suggest to place the 007 on a dummy head, and let only one channel play, then let a pick-up rest on the chassie on the other channel and listen to the what comes out (assuming non RIAA), if anything ... it should give a fair impression of the amount of cross vibration, and if placed onto the chassie playing it should give a fair impression of how much vibration that are absorb by the chassie ...

I am less concerned now about the possiblity  of crossfeed going through the metal arcs than about the amount of energy which seems to be floating around the earcups.  If you can reduce this, you would presumably also reduce crossfeed as well as  ringing of the arcs. However you are right to point out that measurements could help with this issue. I suspect that you might not get a clean measurement of crossfeed through the arcs, because there will be some airborne crossfeed (these are open back phones  which blast a fair bit of sound) and even possibly through the dummy itself.
 
The 007 is the only phone I have encountered which seems to have this type of problem.  I think this is  a result of the fact that the 007 arcs are directly screwed to the earcups.  However I see that cucera found it was useful to damp the arcs of the Stax 4070.  I am less familiar with these but the pictures I have seen suggest that it has arcs attached directly to the cups rather like the 007.

 

[edstrelow]

soren_brix thinks the arc resonance at about 150 Hz. That 's quite audible, as a fundamental tone that's a few keys below middle C on a piano. ( see thread on damping Stax)

"Attached a FG to one channel and swept through the lower fq's <200Hz.
Sounds like the arcs resonance is close to 150Hz.
What I noticed the most is that somewhere between 150-200Hz and below there is a clear resonance present in the opposite channel.
Putting the clamps on, or even just damping the arcs with a hand is enough to remove the resonance."