[The Monkey]

Quote:

Originally Posted by hwc The only problem is that the reviewer may not know what he's talking about. He mentions aluminum voice coils as a major change to the driver, but the 600, 595, 580, 555, 515, 485, and 465 all have aluminum voice coils. The damping materials they are talking about are external to the driver itself. They are the white "fabric" sheets glued to the front and back of the driver.

Good points, but what do you make of the comment about the new diaphragm material? Does that refer to the damping? Also, I pm'd Tyll about this earlier and he replied that he thought the drivers were the same, but was not positive. I suppose the mystery continues...

 

[euclid]

the best way to know is contact sennheiser for replacement driver inquiry, first tell them you have a 650, then a 600. compare part numbers.

the headphones are identical in construction, my opinion is somehting about the drivers has to account for the sound difference.

 

[hwc]

Quote:

Originally Posted by The Monkey Good points, but what do you make of the comment about the new diaphragm material?

I don't make much of that. The material, as far as I can tell, is from the category of mineral-filled polypropylene. Every tweeter manufaturer in the world uses it -- from Europe to the US to Japan to China. There are, almost certainly, several suppliers of the raw sheet material and several variations. Whether Sennheiser made a running change to their flavor, I don't know. If they did, it would only make sense from a manufacturing standpoint that they would change it across the board. It's not a big deal.

BTW, the material starts as a thin sheet. It is laid on top of a machined aluminum former and vacuum formed -- heated and pulled down on the former. You then have a sheet of 4, 8, 12 or however many diaphragms per sheet, ready to be cut out of the sheet and used. One of the quality control mechanisms is to weigh each diaphram after it is cut out of the sheet. If the weight varies from your standard, you are tipped off to forming it too thick or too thin. I recall that it takes a little fiddling with heat settings, vacuum pressure, and time to get the desired process nailed down.

There may be a secondary operation -- I can't tell for sure, but little venting slots may be stamped near the outside edge of the dome.

The damping stuff is all external: the white fabric-like sheets glued to the front and back of the drivers, the foam sponge wedged behind the vented magnet opening.

If you want my educated guess (knowing a little bit about how speakers are built), I would be surprised if there is a any signficant difference in the driver. More likely, within the normal manufacuring tolerances, they have certain parameters that they know sound better, so they select those parts for the 650. I've seen that done in speaker manufacturing where several models use the same tweeter, but the best 10% out of QC get earmarked for the top-of-the-line model. These would, of course, get a different part number on the sticker and would be more expensive as a service part as befitting the top of the line model.

I think Sennheiser uses two basic drivers: the larger one for the 580, 595, 600, and 680 and a slightly smaller one for the 515, 555, and lord knows what else. The mounting frames for these drivers may change: for example the wires come in from the end on the 580-650 series and from the side on the 595 series. But, that's irrelevant to the acoustic design of the driver -- those bits and pieces would be part of the tooling for each new series. Just like a speaker manufacturer may change from a round tweeter mounting plate to a rectangular one. That's a styling issue: it doesn't fundamentally change the driver.

 

[The Monkey]

I posed my question to Senn USA and received the following reply:

Quote:

Thank you for your inquiry and interest in Sennheiser. The driver used is the HD650 is exclusive to the HD650 only; you can expect an increase in detail, resolution and bass response (and accuracy) with the HD650.

So I guess it's different.

 

[bonethugz]

i'll try to find the thread if i can. i never heard of those cans but from i've read. 650 and 600 use different drivers but not 580 and 600.

 

[bonethugz]

Quote:

They're still on Sennheiser's Site and sold New at places like Amazon, so I suspect that they're still in production. They use the same drivers as the HD600, so it's not like it's a huge extra cost for them to produce them.

that's from the first page post #6


http://www6.head-fi.org/forums/showt...ighlight=hd580

 

[Beagle]

Quote:

Originally Posted by JaZZ Sennheiser announced the HD 650 to have newly developed drivers in their then press release. New membrane geometry and damping measures, IIRC. .

Something to do with acoustic silk. I was looking at an older Sennheiser brochure from 1990 and they point out all the headphone parts and a description of each. On their top end models, they had a small round piece of black damping silk on the center of the driver. They called it "Dome Damping feature, made of silk; controls the attack and decay characteristics in diaphragm oscillations". I wonder if they engineered the same sort of thing on the 650. I never opened up my 650 (since traded in for Stax) to look at the drivers.

So I think their driver design is basically the same as it's been for 15 years. The improvements seem to have been made in the housings and cable. They also used to have this coffee filter-like paper covering the front of the driver area. They called it a "resonator". It also blocked all the top end.

Quote:

Originally Posted by hwc The only problem is that the reviewer may not know what he's talking about.

He doesn't. The 580 and 600 also had aluminum voice coils. Same reviewer even mentions this in his previous reviews of the 580 and 600 in Stereophile. In fact, aluminum voice coils were used by Sennheiser since the HD480 Classic II, around 1991.

 

[robm321]

Quote:

Originally Posted by Beagle Something to do with acoustic silk. I was looking at an older Sennheiser brochure from 1990 and they point out all the headphone parts and a description of each. On their top end models, they had a small round piece of black damping silk on the center of the driver. They called it "Dome Damping feature, made of silk; controls the attack and decay characteristics in diaphragm oscillations". I wonder if they engineered the same sort of thing on the 650. I never opened up my 650 (since traded in for Stax) to look at the drivers. So I think their driver design is basically the same as it's been for 15 years. The improvements seem to have been made in the housings and cable. They also used to have this coffee filter-like paper covering the front of the driver area. They called it a "resonator". It also blocked all the top end.

LOL that sounds about right.

 

[Meyvn]

The HD650 and HD600 sound far too different to have the same drivers, given the similarity of their enclosures; the damping difference would have to be HUGE in order for that to be the principle difference.

 

[hwc]

Quote:

Originally Posted by Meyvn The HD650 and HD600 sound far too different to have the same drivers, given the similarity of their enclosures; the damping difference would have to be HUGE in order for that to be the principle difference.

Not really. The damping materials and earcup design probably accounts for almost of the difference in sound between the various Sennheiser models.

 

[Sovkiller]

Do you have tried ot get the parts numbers asking them, or maybe online...???

Does any member had to order drivers for any of the two heapdhones, it is hard to believe that any owner of a HD600/580 had not blown one driver away yet, those part numbers if different should be different as well.....to the ones on the HD650...