Sennheiser HD650 & Massdrop HD6XX Impressions Thread
Oct 24, 2023 at 9:24 PM Post #46,201 of 46,648
To increase HD650 highs I tried removing the part of the silver metal baffle filter that covers the edges of the drivers. Didnt go so well… Too difficult to simply cut with a knife, so accidentally ended up pushing the entire silver material off in one piece (its glued on).

IMG_1113.jpeg

IMG_1115.jpeg
^ back-side after putting back together without baffle filter

Now I am experimenting with replacement baffle material… Good news though, there is more highs.
🙂…so what is the bad news…😒?
 
Oct 24, 2023 at 9:35 PM Post #46,202 of 46,648
🙂…so what is the bad news…😒?
Bad news is that I have to suitably replace baffle material, AND I've destroyed resale value. Guess this one's a keeper.

=================

First attempt at replacing baffle material is wedging a spare Geekria Grado donut foam pad into cups. The foam pad covers the baffle vents, but the inner hole of pad does not cover any portion of driver. Nice!

Anyways, sounds better than expected. Lucky! lol
HD650 accident mod VS HD650 stock.jpg

^ EARS

I couldve took a better pic.:
IMG_1122.jpeg
 
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Oct 25, 2023 at 9:33 AM Post #46,205 of 46,648
Bad news is that I have to suitably replace baffle material, AND I've destroyed resale value. Guess this one's a keeper.

=================

First attempt at replacing baffle material is wedging a spare Geekria Grado donut foam pad into cups. The foam pad covers the baffle vents, but the inner hole of pad does not cover any portion of driver. Nice!

Anyways, sounds better than expected. Lucky! lol
HD650 accident mod VS HD650 stock.jpg
^ EARS

I couldve took a better pic.:
IMG_1122.jpeg
I also removed the silver mesh, but in my case I wanted it off to experiment with different baffle materials to increase the bass and make the highs less edgy. I ended up with micropore tape around the driver edge and felt tape on the baffle.

That did the trick.
 
Oct 25, 2023 at 9:40 AM Post #46,206 of 46,648
and make the highs less edgy
Whaaaat? I agree! Something in the highs is a tad sharp (4kHz?, reminds me of HD800 driver but much less severe) and I was hoping a more v-shaped signature would diminish audibility of this possible lower treble peak. Can the possible sharpness be related to the metal mesh filter? So far, this mod sounds smoother to my ears. Perhaps we share a similar sensitivity in treble? Anyways, need more time listening and experimenting.

HD600 eta Thursday
 
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Oct 25, 2023 at 9:56 AM Post #46,207 of 46,648
Whaaaat? I agree! Something in the highs is a tad sharp (4kHz?, reminds me of HD800 but much less severe) and I was hoping a more v-shaped signature would diminish audibility of this possible lower treble peak. Can the possible sharpness be related to the metal mesh filter? So far, this mod sounds smoother to my ears. Perhaps we share a similar sensitivity in treble? Anyways, need more time listening and experimenting.

HD600 eta Thursday
Yeah the metal mesh filter certainly makes it worse compared to absorbing materials. But from my experience having heard like 7 different 650s, there's also product variance in that some are smoother and bassier etc.

This 650s model I have now was particularly edgy, so the mod made a welcome improvement. I used 2 CC copper rings (2nd one adhered with ducttape on the first one) and this increased bass and made it even more smoother than just 1 ring.
 
Oct 25, 2023 at 10:00 AM Post #46,208 of 46,648
Yeah the metal mesh filter certainly makes it worse compared to absorbing materials. But from my experience having heard like 7 different 650s, there's also product variance in that some are smoother and bassier etc.

This 650s model I have now was particularly edgy, so the mod made a welcome improvement. I used 2 CC copper rings (2nd one adhered with ducttape on the first one) and this increased bass and made it even more smoother than just 1 ring.
Product variance is definitely a cause. My current HD 650 (2022/2023 production) is silky smooth and doesn’t have the upper mid abrasion all other HD 650’s I had did. Every other HD 650 I had some sort of edge or grit to their sound.
 
Oct 25, 2023 at 10:40 AM Post #46,209 of 46,648
Product variance is definitely a cause. My current HD 650 (2022/2023 production) is silky smooth and doesn’t have the upper mid abrasion all other HD 650’s I had did. Every other HD 650 I had some sort of edge or grit to their sound.

I'm pretty sure on one of the Sennheiser panel talks they spoke of the great challenge of getting matched drivers and also the precision of that metal mesh in consistency and thickness.

And that they would have to be extremely careful to match it all together to get within their desired frequency response target.

Really that's what you pay for... The precision and measurements testing... And IIRC there would be slight variation between sets so when people try 10 different sets and pick the "best" one, there must be something to it


Though the 660S/S2 IIRC they have more advanced manufacturing techniques perhaps with automation where there is more precision than prior techniques with hand assembly. Perhaps why tolerances are so much tighter now than on HD580 with drivers and paper baffle
 
Oct 25, 2023 at 10:46 AM Post #46,210 of 46,648
I'm pretty sure on one of the Sennheiser panel talks they spoke of the great challenge of getting matched drivers and also the precision of that metal mesh in consistency and thickness.

And that they would have to be extremely careful to match it all together to get within their desired frequency response target.

Really that's what you pay for... The precision and measurements testing... And IIRC there would be slight variation between sets so when people try 10 different sets and pick the "best" one, there must be something to it


Though the 660S/S2 IIRC they have more advanced manufacturing techniques perhaps with automation where there is more precision than prior techniques with hand assembly. Perhaps why tolerances are so much tighter now than on HD580 with drivers and paper baffle
Yeah I got lucky with this HD 650 so it’s not going anywhere. First one I actually wanted to keep long term.

Yeah but I also experienced variation with the S and S2. The first 660S2 I got had a void in the upper mids, creating a distinct feeling something major is missing, it’s why I had to let go of it. The second one upper mids are basically as present as my S and I never felt it was missing or lacking anything in the mids. Maybe there was a problem with some of the early S2’s as I wasn’t the only one to note an upper mid void/cut.

I’ve oddly found a lot of variation in Sennheisers, despite the common sentiment to the contrary I actually found Beyers to be more consistent and less noticeable in their variance unit to unit.
 
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Oct 25, 2023 at 11:06 AM Post #46,211 of 46,648
Whaaaat? I agree! Something in the highs is a tad sharp (4kHz?, reminds me of HD800 driver but much less severe) and I was hoping a more v-shaped signature would diminish audibility of this possible lower treble peak. Can the possible sharpness be related to the metal mesh filter? So far, this mod sounds smoother to my ears. Perhaps we share a similar sensitivity in treble? Anyways, need more time listening and experimenting.

HD600 eta Thursday
Just wanted to make clear that this treble sharpness became readily apparent after I removed the spider cage + foam. Perhaps the effect of reducing 3kHz made a possible highs peak more prominent. Or perhaps reducing acoustic impedance allowed some increased driver resonance. idunno. Will update later with more impressions and hopefully final mod.
 
Oct 25, 2023 at 11:10 AM Post #46,212 of 46,648
I'm pretty sure on one of the Sennheiser panel talks they spoke of the great challenge of getting matched drivers and also the precision of that metal mesh in consistency and thickness.
I wonder why they are insistent on metal mesh in spite of the difficulties in consistency. HD800 driver uses a fabric mesh like some older HD6X0 variants with their “black silk” mesh.
 
Oct 25, 2023 at 11:12 AM Post #46,213 of 46,648
I wonder why they are insistent on metal mesh in spite of the difficulties in consistency. HD800 driver uses a fabric mesh like some older HD6X0 variants with their “black silk” mesh.
I read it was to help get better consistency than using the black silk which had more variation. Probably also cheaper as there is likely less material waste.
 
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Oct 25, 2023 at 12:50 PM Post #46,215 of 46,648
It's fortunate that you have the E.A.R.S and manage to use REW, because whatever you do, you can directly check for the consequences. So I'm not too worried about you. Damping material(beside probably interfering with high freqs) is often used to calm resonance frequencies, I'm guessing the bass bump could be most of it here. On this headphone, that's not even dangerous for the frequency response. I don't recommend doing it on purpose, but you could have picked a much worse headphone to go kill the damping material IMO.

I'm curious about low end distortions without any damping material. They're usually high enough for even the E.A.R.S to get somewhat usable data in the sub.
 

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