[Kodhifi]

I often wonder if the Beyerdynamic Custom One Pro have the adjustable ports because they realized that no matter how they make headphones sound, people will want to mod them to get better bass or flatter response.
 
Look at all the sennheiser modding threads for instance. They give you a bass heavy version of one headphone, and people modify it to make it have a flatter response. They make a flatter response version of a bass heavy headphone and people mod it to give them more bass. Hehe.
 
I forsee a lot more of this 'customize the enclosure' type of tech that the COP's use.

 

[tommy321]

Quote:

 
 
Well, yes, sort of. The best possible sound would be if only the sound waves produced directly by the speaker drivers would reach your ears, without any additional interference from sound waves that are reflected away from others parts of the headphone enclosure. That should in theory give the purest sound.

like this?

 

[MarcoGV]

Quote:

 
They're almost superimposed on each other.  So I figured there was a good chance they used the same driver.  I finally got a chance to take mine apart, and I snapped a picture of the driver's part number:

 
Compare the part number (93481B) to the part in Headphonia's review.  Exactly the same!  That's pretty exciting.  So even if you assumed the HD 518 had a different driver like the HD 515, maybe don't tell people that as if it's a fact.  Just saying.  

 
So what about modding potential?  Here's the inside of the earcup:
 

 

 
My message is a followup motivated by the observation at http://www.amazon.com/review/R1HXKDUQ4TH5VE (An in-depth comparison [of the HD 598] to the HD 595, October 15, 2011, by Anthony Miceli

) that the part number in photos above refers to the PCB holding the drivers and not of the drivers themselves.  The posting by A. Miceli even notices that the PCB housing number is the same as for the HD 595, while the drivers are different:
 
 
Quote:

The HD 598 uses a new driver (part no. 533392). The damping element material is slightly darker and has a bolder outline of the asymmetrical frame behind it. The driver has 4 small holes in the cellulose portion and at the rear, a black plastic ring on the pole piece. The driver's PCB remains the same (part no. 93481B).

 
 
 
To resolve the issue, I contacted Sennheiser with the following request:

Dear Sennheiser Technical Support Specialist, I own a set of 
 :    Sennheiser HD 518 Audiophile Headphones and am pleased with  
      their performance. In a discussion with friends, we were     
      trying to ascertain whether the HD 5X8 series uses the same  
      driver. Could you please confirm or deny that the Sennheiser 
      HD 518, HD 558, and HD 598 all share the same driver? If you 
      cannot answer directly, could you please let me know the part
      numbers for the HD 518 and HD 558 drivers? Thank you for your
[size=11pt]      consideration of this request.[/size]

 
Sennheiser kindly replied on 2013-01-09, as follows:
 

Hello,
 
All of the headsets you listed use the same drivers.  Let me know if I can help further.
 
Regards,
Jason Kelly
Sennheiser Technical Support Team
(P): 860-434-9190 EXT3
Email:techsupport@sennheiserusa.com
www.sennheiserusa.com
 
.....
 
Same replacement drivers.
___________
Gabe Panko
Service Technician
+1 860-434-9190 x109
 
Service Portal: sennheiserusa.net
 
SENNHEISER ELECTRONIC CORPORATION · ONE ENTERPRISE DRIVE · OLD LYME CT 06371
 
“WE SHAPE THE FUTURE OF AUDIO · BASED ON OUR HERITAGE · INNOVATION CULTURE · AND PASSION FOR EXCELLENCE”
 
 

 
So, now we are sure that the three 5x8 models use the same drivers.

 

[Kodhifi]

Quote:

 
My message is a followup motivated by the observation at http://www.amazon.com/review/R1HXKDUQ4TH5VE (An in-depth comparison [of the HD 598] to the HD 595, October 15, 2011, by Anthony Miceli

) that the part number in photos above refers to the PCB holding the drivers and not of the drivers themselves.  The posting by A. Miceli even notices that the PCB housing number is the same as for the HD 595, while the drivers are different:
 
 
 
 
 
To resolve the issue, I contacted Sennheiser with the following request:

Dear Sennheiser Technical Support Specialist, I own a set of 
 :    Sennheiser HD 518 Audiophile Headphones and am pleased with  
      their performance. In a discussion with friends, we were     
      trying to ascertain whether the HD 5X8 series uses the same  
      driver. Could you please confirm or deny that the Sennheiser 
      HD 518, HD 558, and HD 598 all share the same driver? If you 
      cannot answer directly, could you please let me know the part
      numbers for the HD 518 and HD 558 drivers? Thank you for your
[size=11pt]      consideration of this request.[/size]

 
Sennheiser kindly replied on 2013-01-09, as follows:
 

Hello,
 
All of the headsets you listed use the same drivers.  Let me know if I can help further.
 
Regards,
Jason Kelly
Sennheiser Technical Support Team
(P): 860-434-9190 EXT3
Email:techsupport@sennheiserusa.com
www.sennheiserusa.com
 
.....
 
Same replacement drivers.
___________
Gabe Panko
Service Technician
+1 860-434-9190 x109
 
Service Portal: sennheiserusa.net
 
SENNHEISER ELECTRONIC CORPORATION · ONE ENTERPRISE DRIVE · OLD LYME CT 06371
 
“WE SHAPE THE FUTURE OF AUDIO · BASED ON OUR HERITAGE · INNOVATION CULTURE · AND PASSION FOR EXCELLENCE”
 
 

 
So, now we are sure that the three 5x8 models use the same drivers.

 
 
Speakers don't produce sound in a vacume. (actually that's true in other ways too)
 
The driver is one part of what makes a speaker sound a particular way, the other half is the enclosure and it matters as much as the driver for final sound characteristics. When a driver is enclosed, it creates a resonant chamber which deadens some frequencies, enhances others, and the enclosure itself oscilates sympatheticly to the driver causing secondary sound to be transmitted through contact with surfaces, and the outside of the enclosure through air.
 
This is doubly so in headphones where the enclosure is actually strapped to your head. It's not a surprise at all that these cans share the same driver. The difference in sound is the enclosure, they can be tuned in different ways and that tuning is what makes it win or fail.

 

[streetdragon]

i knew the HD558 and HD598 have the same driver but but i didnt expect the HD518 to have the same driver as well. probably the more closed shape of the earcups causes it to sound more bassy and less refined

 

[derbigpr]

Quote:

i knew the HD558 and HD598 have the same driver but but i didnt expect the HD518 to have the same driver as well. probably the more closed shape of the earcups causes it to sound more bassy and less refined

 
 
Lower quality plastics, not as stiff, not as good acoustically used, as well as different mesh design on the back of earcups, much lower quality ear pad material, etc. All of those things play a big role in how the headphones will sound, maybe even bigger than drivers themselves. Just imagine strapping those same drivers into a ear cup made of cheap card board, it would sound horrible. But them into a very solid, well engineered cup like the HD558 and especially 598's have, and you transform the sound to something completely different. Despite having same drivers, HD518's and 598's dont sound like they come from the same planet. The difference between the two is as big as the difference between 598's and 650's.

 

[XxDobermanxX]

I've read the Beyerdynamic dt series uses the same drivers too 

 

[streetdragon]

all the way from DT440 till DT990?

 

[Catchytune]

@streetdragon Yes, same drivers for DT440, 660, 860 and the 32 ohm version of the DT770 and 990. Then the same again for the 250 ohm and 600 ohm DT-models.

 

[Dongle]

Quote:

 
 
Lower quality plastics, not as stiff, not as good acoustically used, as well as different mesh design on the back of earcups, much lower quality ear pad material, etc. All of those things play a big role in how the headphones will sound, maybe even bigger than drivers themselves. Just imagine strapping those same drivers into a ear cup made of cheap card board, it would sound horrible. But them into a very solid, well engineered cup like the HD558 and especially 598's have, and you transform the sound to something completely different. Despite having same drivers, HD518's and 598's dont sound like they come from the same planet. The difference between the two is as big as the difference between 598's and 650's.

Interesting point, but here's a wrinkle you may not have considered: what makes a material "lower quality"? The acoustic properties of a lower-cost polymer might actually be beneficial for a desired sonic characteristic. You could make the inverse argument: Imagine that the HD518s were built out of solid platinum. Do they now sound better or worse? 

This "lower quality" plastic may flex in such a way that amplifies lower frequencies, hence the perception of deeper bass. To a bass head, "cheaper plastic" may be more desirable.

The only real way to know is to run the experiment, which the OP did when he showed waveforms of the 518, 558, and 598 that showed very slight variation. That slight variation is exactly the difference in enclosure -- no more, no less. We were wondering what the difference an enclosure makes and the data tells us right there. Now, if you measure the "area under the curve" of the net deviation from one curve to another I can already tell you just by eyeballing that the difference is going to be less than a fraction of 1%. The frequency response of these headphones are 99% similar.

Of course, the microphone used to generate this waveform data won't tell the whole story -- psychoacoustics are not modeled in that data. And it's up to you how much stake you put into the subjective experience. 

I read an interesting scientific paper recently that demonstrated that people who drink hot chocolate out of an orange mug report that it tastes better than in any other color mug. The molecules that run across the tongue haven't changed, yet for reasons unknown, the sight of orange as you drink chocolate enhances the subjective experience.

I'm not claiming to know either way, but it's not outside the realm of possibility that the cream & oak color of the HD 598 is entirely responsible for it's perceived difference, despite fact that the air molecules are vibrating in a way that is 99% similar to the HD 518. The hot chocolate didn't change, but the taste did, so to speak 

 

[derbigpr]

Quote:

Interesting point, but here's a wrinkle you may not have considered: what makes a material "lower quality"? The acoustic properties of a lower-cost polymer might actually be beneficial for a desired sonic characteristic. You could make the inverse argument: Imagine that the HD518s were built out of solid platinum. Do they now sound better or worse? 

This "lower quality" plastic may flex in such a way that amplifies lower frequencies, hence the perception of deeper bass. To a bass head, "cheaper plastic" may be more desirable.

The only real way to know is to run the experiment, which the OP did when he showed waveforms of the 518, 558, and 598 that showed very slight variation. That slight variation is exactly the difference in enclosure -- no more, no less. We were wondering what the difference an enclosure makes and the data tells us right there. Now, if you measure the "area under the curve" of the net deviation from one curve to another I can already tell you just by eyeballing that the difference is going to be less than a fraction of 1%. The frequency response of these headphones are 99% similar.

Of course, the microphone used to generate this waveform data won't tell the whole story -- psychoacoustics are not modeled in that data. And it's up to you how much stake you put into the subjective experience. 

I read an interesting scientific paper recently that demonstrated that people who drink hot chocolate out of an orange mug report that it tastes better than in any other color mug. The molecules that run across the tongue haven't changed, yet for reasons unknown, the sight of orange as you drink chocolate enhances the subjective experience.

I'm not claiming to know either way, but it's not outside the realm of possibility that the cream & oak color of the HD 598 is entirely responsible for it's perceived difference, despite fact that the air molecules are vibrating in a way that is 99% similar to the HD 518. The hot chocolate didn't change, but the taste did, so to speak 

 
 
Well, there's always a possibility for such effects, but the differences between the 518, 558 and 598 are definitely too obvious and too great to be just a placebo effect. They truly don't sound like headphones that have identical drivers. Firstly the HD518 feel cheap compared to the other two. The fabric and foam used on the earpads is similar to that used on the HD4xx series models.  Fabric and foam on the 558's and 598's is similar to the HD600 and HD650.  Different fabric affects the sound as well. Then you have the clamping force, which is the lightest on the HD598's and tightest on the 518.  It brings the drivers closed to the ear, reduces the overall volume in which the sound waves can move between the drivers and your ear, etc.  It has a great effect on the sound, which you can clearly hear when wearing any headphones and pressing them towards your head, it usually makes the sound darker, more bass heavy and muddy.

 

[streetdragon]

Quote:

 
 
Well, there's always a possibility for such effects, but the differences between the 518, 558 and 598 are definitely too obvious and too great to be just a placebo effect. They truly don't sound like headphones that have identical drivers. Firstly the HD518 feel cheap compared to the other two. The fabric and foam used on the earpads is similar to that used on the HD4xx series models.  Fabric and foam on the 558's and 598's is similar to the HD600 and HD650.  Different fabric affects the sound as well. Then you have the clamping force, which is the lightest on the HD598's and tightest on the 518.  It brings the drivers closed to the ear, reduces the overall volume in which the sound waves can move between the drivers and your ear, etc.  It has a great effect on the sound, which you can clearly hear when wearing any headphones and pressing them towards your head, it usually makes the sound darker, more bass heavy and muddy.

Also,the earpads of the HD518 are WAY different from the HD558 and 598. The surface material is cloth, the shape is different,flat and it's much stiffer. The HD558 and 598 have almost identical soft rounded valour earpads. Just that the HD598's one is brown and softer.
Also the grill in the HD518 is mostly closed with lots of needle holes while the 2 bigger brothers is mostly a very porous grill. 

 

[johan851]

Quote:

Interesting point, but here's a wrinkle you may not have considered: what makes a material "lower quality"? ...

I really like your post.  And don't forget that the higher model number may be as much an orange cup as anything else.  
 
In case anyone's interested, I purchased the 558 pads for my 518.  They're about $20 from Sennheiser.  The headphones are a lot more comfortable now (I got tired of wearing them before) but otherwise I didn't pick up any big differences in sound quality.

 

[baconbriefs]

I love my 518.

I picked it over the 558 and 598 because its bass would be handy in movie watching, which would be 50% of what I would use it with.
 
Wouldn't being less open and having a higher clamp be why it is the bassiest of the three?

 

[Dongle]

Quote:

I really like your post.  And don't forget that the higher model number may be as much an orange cup as anything else.  
 
In case anyone's interested, I purchased the 558 pads for my 518.  They're about $20 from Sennheiser.  The headphones are a lot more comfortable now (I got tired of wearing them before) but otherwise I didn't pick up any big differences in sound quality.

Cool, man. Science in action.
 
 

Baconbriefs
 
I love my 518. 

I picked it over the 558 and 598 because its bass would be handy in movie watching, which would be 50% of what I would use it with.
 
Wouldn't being less open and having a higher clamp be why it is the bassiest of the three?

Have either of you compared your 518s to a decent closed headphone in a similar price range like the M50? I only have closed headphones and I'm thinking of getting something like a 518 for better soundstage and instrument separation. I'm really happy with my Z02 + M50 setup though; I wouldn't want to lose any of that incredible sub-bass.