[Craftsman]

I am not sure if the mini cup over the driver in the 25 is an attempt to improve the sound, though. The driver cup could just be for cost saving (simple outer cup and simple inner cup, instead of a single complex shape with a partition wall in the middle. I suppose it is more difficult to add the partition wall in a metal mold).

Is there any damping material under the 25's driver cup?

If you look at some teardowns of the QC25, you'll quickly realize that adding a minicup over the driver and then gluing the minicup in place is not a cost savings as it would be very labour intensive just to glue the additional part in place... not to mention you need an additional part. They don't have to add a partitioning wall to the metal side of things... they could have molded a plastic partitioning wall to the chassis of the headphones and then add a bit of thin foam padding to the metal cup at the interface just like they did in the QC15 but in reverse (ie the plastic partitioning wall is on the cup and the foam on the chassis).

The reasons for the minicup is something that only Bose knows for sure but the results to the sound according to comparison testing by many online reviewers basically mirror the comparison between a sealed box speaker and one that is vented - ie Bose went from their Triport design (which basically has 3 vented ports) to a sealed box

There is no dampening material reported under the QC25's minicup.

And by the way, there's really nothing that is too simple with the QC15's cup if you look at it closely - it's a two piece mated cup with a thin partitioning wall and a metal mesh vented port. The assembly cost is up there.

 

[AudioCats]

Craftsman, do you have a link to your deadening/damping mod? Or would you mind re-post them in this thread? Thanks

 

[AudioCats]

Driver upgrade, Level-2, Nhoord-Red

The result of iGrado drivers made me curious of how higher grade drivers might sound in the QC2. And I have some Nhoord-red laying around....

The primary issue from the iGrado driver experiment was that the bass being too strong, border-line boomy. And it is arguably too warm to me, not enough bite. I wanted to see if Nhoord is any different.

First pulled the driver out of the aluminum grill (the grill is way too large to fit into the cup)



then trimmed off the little ridge, and cleaned off foam gasket so the driver can fit flush to the baffle



Held the driver in place using some hot glue;
trimmed off the partition wall on the underside of the cup;
added 0.75g Acousta-stuf under the cup and put back togather.....

Impression, quick A/B/C:
-- not as loud as either the stock QC2 or the iGrado-QC2
-- ANC is not as efficient, at maybe 80% of the QC2's.
-- not as warm as iGrado-QC2, but still on the warm side. Sharper sound.
-- a little better details than the iGrado-QC2. The improvement is less than the difference between iGrado-QC2 and stock, though.
-- very strong bass but tighter than the iGrado-QC2, no boomy-ness.

Overall nice results. The main issue with this mod is the cost of Nhoord Red drivers: at 70 euro (about 80 USD right now) they are more than 2x the price of the iGrado.... But since the aluminum grill is not needed in this mod, maybe Nhoord can offer special edition "bare" drivers (without the grill) at a lower price?

 

[Craftsman]

Craftsman, do you have a link to your deadening/damping mod? Or would you mind re-post them in this thread? Thanks

I just posted some pictures and observations in the other thread - https://www.head-fi.org/threads/bose-headphone-mods.503432/page-3#post-14513640