Dry hump mod.

[chinsettawong]

I think it is possible to use some resistors and make a low pass filter for the second driver. The diaphragm on this one can also be much thicker so that the bass can be more aggressive.

Wachara C.

[Tyll Hertsens]

Also, was just causing trouble,

Totally understood and appreciated.

[Dusty Chalk]

Yeah, I knew you'd get it, but then spritzer went and was like "yeah, I been thinking about that"...which of course meant the concept had some serious merit behind it, even if it was an "out there" concept (Jude -- take note -- that is an "out there" concept; iPodPJ's was beyond "out there").

I think it is possible to use some resistors and make a low pass filter for the second driver. The diaphragm on this one can also be much thicker so that the bass can be more aggressive.

Actually, the concept of Isobaric would require two bass drivers, so at least 3 drivers, total. link

[arnaud]

I forgot all about this stuff and was confising isobaric with push-pull. In any case, it would seem like these concept only apply for dynamic transducers in piston regime, so again, hard to see the meaning for estat.

On the the other hand, having two diaphragms with different tensioning and mass sounds interesting. Like a concentric dual diaphragm between the same stators (or at least each pair of stators getting the same signal). The high frequency diaphragm is much lighter/thinner, and smaller in size (center). The two diaphragms have the same polarization bias but the spacers are different so that the sensitivities are adjusted to get satisfying blend of the two concentric drivers. No xover, the center diaphragm is inherently highpass and the heavier diaphragm on the outer rolls of at HF. You could also adjust the perforations on both stators to get the right amount of damping for each transducer.

Nonsense?

[spritzer]

The isobarik was designed to compensate for the inherent non linear nature of piston drivers but will naturally bring it's own issues. No use for this with electrostatics as the issues with dipoles are more to do with baffle size and the bleed between the sides.

The idea of using essentially a tweeter and woofer is intriguing but I'm worried about the backwave of the smaller driver collapsing with the back driver and cancelling out part of the range. Only real way to deal with that is a small time delay but even that isn't a perfect solution. Quad's PJW's Egg speaker springs to mind as a neat way of stacking diaphragms but we would need a time delay there as well.

[El_Doug]

aww, the thread got locked, and those GLORIOUS pictures of a dozen senn headphones over pj's head was removed

that guy has some SERIOUSLY thin skin

[rhythmdevils]

Here's the picture. This is next gen dry hump technology right here.

[El_Doug]

thanks!

[arnaud]

Spritzer, what I imagine is that both diaphragms are in the same plane and there are really only two stators. The tweeter is in the center and the woofer around it.

I guess you're implying that the woofer has to cover the whole surface because you'll get way too much acoustic cancellation between the front and backwave? At least, I could simulate both responses assuming a constant velocity over each respective surface and see what it gives...

[livewire]

@arnaud - That would be divine!

@ rd - Thanks for the updated pic, I missed out over there. Audio nirvana!

[Dusty Chalk]

It's like surround sound, only...surroundier.

[Synchro Belt Drive]

Dry hump mod completely closed. A few minutes ago page 8 was accessible but after that it closed completely...

Edited July 16, 2012 by Synchro Belt Drive

[Nebby]

I think it was his talk about his "Beta Twenty Two" that did it for him

[nattonrice]

The guy is a self important arrogant prick.

At least we saved the photos.

[spritzer]

Spritzer, what I imagine is that both diaphragms are in the same plane and there are really only two stators. The tweeter is in the center and the woofer around it.

I guess you're implying that the woofer has to cover the whole surface because you'll get way too much acoustic cancellation between the front and backwave? At least, I could simulate both responses assuming a constant velocity over each respective surface and see what it gives...

Given the distances involved it would be very hard to use only two stators. Stax pro bias diaphragm to stator gap is 0.5mm so if you want to use two diaphragms then the bias has to go down quite a bit and with it, sensitivity and the "grip" the stators have of the diaphragms. The breakdown voltage of air is around 100V/mill (not mm mind you and can be much higher depending on external factors) so there isn't a lot of room for error here. Now if we were to just layer one diaphragm on top of the other with just the thickness of the glue separating them then that will make the driver less linear (the diaphragm is never exactly in the center) and just add distortion. I also wonder how much an effect the vibration of one diaphragm will have on the other.

[Wmcmanus]

@ rd - Thanks for the updated pic, I missed out over there. Audio nirvana!

Priceless! I missed it as well. Thanks for the pic.

[notmuchcash]

Did anyone see a post after mine? I think my theory on Sennheiser's next flagship being a HD25 driver in a HD800 chassis might have been the reason for the delete. Sennheiser didn't want their evil plans to be revealed.

[grawk]

indeed. Have you read your welcome message?

[arnaud]

Given the distances involved it would be very hard to use only two stators. Stax pro bias diaphragm to stator gap is 0.5mm so if you want to use two diaphragms then the bias has to go down quite a bit and with it, sensitivity and the "grip" the stators have of the diaphragms. The breakdown voltage of air is around 100V/mill (not mm mind you and can be much higher depending on external factors) so there isn't a lot of room for error here. Now if we were to just layer one diaphragm on top of the other with just the thickness of the glue separating them then that will make the driver less linear (the diaphragm is never exactly in the center) and just add distortion. I also wonder how much an effect the vibration of one diaphragm will have on the other.

What I meant was that the diaphragms don't share motion, the "woofer" and "tweeter" common rim is a circular spacer which pins both membranes (one on the outer edge, one on the inner edge. This probably makes no sense from a manufacturing point of view, that wouldn't be a first coming from an acoustics guy .

Also, from your post above, it would seem like that stator-diaphragm gap is essentially fixed by the polarization voltage. I somehow though it was adjusted based on the diaphragm tensioning and thickness (it really has to elastically deform to get shorting and my guess was the max excursion occured at the tuned LF resonance frequency, e.g. 50-75Hz for stax estats).

Anyhow, at the very least I am curious to see the effect of having two independent membranes. I "just" need to find time to update the model I made.

[notmuchcash]

indeed. Have you read your welcome message?

Now I have. Went searching instead of looking at your sig, but I found it. I was already a bit aware of the general feel of head-case.

Head-fi's delete of that thread was weird. Normally they just lock threads to prevent that sort of thing(been a while since I'd been there tho). I will therefore take it as conformation that my crazy theory on Sennheiser must be true. They designed the HD800 and HD650 to dry hump, and the next flagship will just be snake oil soaked HD25s.

[RudeWolf]

They designed the HD800 and HD650 to dry hump, and the next flagship will just be snake oil soaked HD25s.

Please elaborate. And don't forget to add for how long and on what equipment have you heard the said headphones.

[grawk]

He can't answer that for 2 weeks

[Nebby]

It was weird how he said he read it, then proceeded to ignore what he had read.

[grawk]

it's not weird at all. It's typical.

[RudeWolf]

I guess that's the price of doing these rational interventions.