Solving the HD650 mystery

Dangeet, can't remember where I was hosting the images. There's a good chance they were on my old work google drive and maybe someone has killed it.

 

Wayback Machine (https://archive.org/web/) archived these images. You can download them and reinsert back into the post.

 

You the real mvp, @Metro

 

I was recently told by a reliable source that the hd650’s housing molds are using new tooling. The hd6xx’s are still using the old dies. I’m not sure if this might explain anything, just thought I’d throw it out there.

 

That explains just about everything ....

 

Recently Solderdude was sent a 'veiled' pair of HD650 to investigate, and his extensive measurements and findings are here:

https://diyaudioheaven.wordpress.com/headphones/measurements/brands-s-se/hd650/

His conclusion:

It looks like there is quite some spread in driver performance and Sennheiser matches drivers to sets that are then used in one headphone. This means that one can get HD650’s that sound darker or clearer depending on which matching set of drivers was used.
This also means that when replacing a blown driver and ordering a new one chances are you may be getting a driver that isn’t matched with the still O.K. driver.

summary

The silver/white screen HD650 performs closely the same as the older black screen driver when the same (new) pads are fitted.
The HD650 is a well known and capable headphone that does a lot of things right.
One of them is tonal balance. Also distortion is quite low and it shows why it had been the top model of Sennheiser for quite some time. It was considered an expensive headphone once. These days it is considered a cheap headphone…
Those that find the HD650 ‘veiled’ should look for headphones with more treble presence or audition another HD650 because not all HD650’s are created equal as shown above.​

 

Same driver, pads, headband, and clamp.



I don't know why it took me so long to try this, but I'm glad I did. Earlier in this thread, @Hands said, "My leading guess is that they're adhering the silver mesh material differently." and "But the new pair I heard looked to have more tightly adhered mesh." Also, @Lenroot77 said, "I was recently told by a reliable source that the hd650’s housing molds are using new tooling.".

After disassembling, visually inspecting the mesh, and swapping the drivers into the old housings, I believe you're both correct. The mesh on my 2019 pair was noticeably more tightly adhered to the housing, so much so that it was bulging into the gaps of the housing.

Simply putting the 2019 drivers in the 2016 housing improved/fixed the dip in the 6-9.5khz range.

I think we can say this issue, which is hopefully fixed going off of @Hrodulf's reports of later units measuring as they should, isn't caused by the drivers, but the housing and mesh.

So, If you have a darker sounding pair and have an older unit lying around, try putting the older housings in the newer pair. It might fix the darkness/ treble dip on your pair.

@Hrodulf, @Hands, & @Lenroot77, Thank you.

 

Not to resurrect this older thread, but I just purchased some HD600's from Amazon and yes they are Romanian. And I miss the marbled look, I found this response from Sennheiser on the other site:

"1. The final assembly of units and the enclosure molding is performed in Romania, following the same tolerance and quality assurance procedures and policies as always. Drivers are manufactured in Ireland, where they always have been. We may have shared comments on the HD 650 and HD 660S thread, and that could explain why you might not have found it. Essentially, there have not been changes to report, other than the external look.

2.The tooling for the old plastic molds was two decades old, and the new factory was an opportunity to use a new tooling with higher yield of in-tolerance enclosures. While the outer look is modernized with a few more angles than the rounded, almost bubbly look popular at the end of the 90's (also seen in cars of that period), the acoustic chamber has the exact same acoustic design as always... new or old enclosure, the sound should be within the same. We began using only the new tooling as of summer 2019, with the exception of the Drop exclusives... but again, the drivers are from the same Ireland factory as always, with the same acoustic design.

3. ABS plastic, often seen in keyboards and old game consoles, does yellow with age but is not the polymer we use in the HD 600. We still have HD 580 Precisions at KG (our headquarters) from the 90's that have only needed replacement pads for maintenance, and sound great!

4. The acoustic design and sound target have remained the same over the entire production history of the HD 600 and HD 650. Some minor changes such as the shape of the yolks or color of the screen have changed over the decades, but the tuning has been achieved in the same way throughout production."

I wonder if the "tighter tolerances" has something to do with the tightly adhered mesh. It seems super solid on these. Much more so than my older dark mesh 650's.

 

I am interested in the possible variation in production, but I must admit that I am impressed with the HD650 with my Asgard 2 close out. I’ve had it for about 2 weeks, with computer, and with cd transport through a Modius, and I think that it seems to offer plenty about what’s upstream.

The HD650 is new, unmodded, and has been tried with a Yamaha AV receiver for movies, and with a Rogue Sphinx V3, in addition to the Asgard 2.

Is there a break-in time? It has improved since first out of the box.

 

Earpads will change form slightly, making the seal better. Also you'll learn what listen for and how to appreciate the headphone better. Other than that - there isn't much in terms of measurable change in headphones.

 

So is the 2019 HD650 darker and bassier than the older ones?

 

From my experience with my particular pair, they didn't have more bass, but they were darker.

 

What about the uppermids and treble quality, is it as smooth as the older pair or more coarse/grainy?

 

I didn't notice any discernable difference or anything that stuck out in that regard.

 

I have just modded my Hd6xx yesterday. Now I understand that the HD6xx drivers really have an admirable technicality besides a good tuning and emotional mids. After the mod my hd6xx became much more detailed , to the point I think the new tiny sound I heard the first time from my fav track was caused by a broken driver. Yes I even thought I had broken the driver in the modding but it is not. And I feel my Hd6xx much more breathable. For now I don’t want to search for buying a HD800 anymore . But instead I got a deal on an used black silk HD650 for $230. May I ask if the deal is worth it? Tks

 

That is always a hard question to answer. 650's can vary in production, even with the same screen. However, you may find the BS a little less energy in the high mids and slightly more romantic. Go with your preferences. $250 is not a terrible price for those given if they are in good condition. Just remember that all the Senns have pad wear and need to be replaced almost yearly.

 

Solution: get an HD600 where extremely worn out pads are generally to the benefit of the sound signature

 

Try the ZMF pads if you don't want to have to replace them regularly.

https://www.superbestaudiofriends.o...zmf-earpads-for-hd6xx-series-headphones.12162

 

@TamHo Black Silk 650 for $250 is a great deal. Enjoy them. They should sound more full and relaxed than the silver, and will definitely get better as you feed them better and better equipment.

 

Sort of. The 650’s still have more more magic or soundstage or whatever going on.