Some speaker driver measurements...

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#2,403
The SB acoustics 6MW150D is another overlooked midbass. Its actually a very nice high sensitivity 6" which has a huge 2" vented fiberglass VC and machined pole plates.
 

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#2,404
With protruding/convex domes and nearby/close-up tweeters you will get a reflection from the dome midrange ... a suitable sculpted foam absorber could probably fix the reflection ... maybe this reflection is part of the reason why some expensive studio dome midranges have a short horn loading integrated so the reflection is only minor!

In case of doubt , compare responses of the tweeter with or without the neighbouring midrange dome (covering the mountig hole of the mid with some stable piece of cardboard) ... btw , in a MTM layout - the reflection is more pronounced!
 
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#2,405
@Marveloudio TRUE! And most designer seem to don't care. With my MTM layout for my last project I decided to print new frontplates for the Bliesma midranges to reduce this effect. The short horns etc are also introducing an unsteday front baffle and I also got influences with it. I belive it's more about protecting the domes.
 
#2,406
Marveloudio said:
Please let's not forget the Swans/Hivi-research domes DM7500 & DM7600 !!!

https://www.soundimports.eu/en/hivi-dm-7500.html

https://www.parts-express.com/HiVi-DM-7500-3-Soft-Dome-Midrange-Driver-6-Ohms-297-470?quantity=1

DM7600 is hard to get .... maybe price for a pair(?) :

https://de.aliexpress.com/i/1005004670093212.html?gatewayAdapt=glo2deu

https://www.swanspeakers.com/product/view?id=1174
Click to expand...
Are there ANY useful measurement sof this driver? FR from the manufacturer loks good but impedance ... not even this smoothing can even it out
https://www.swanspeakers.com/product/view?id=168
Looks like they would give a very compact package when the frontplate is removed.
 
#2,407
The latge domes from ATC and Volt need to be recessed due to large magnets. They also do this to get the flange smaller to decrease driver spacing. I've seen custom versions of the ATC and Volt domes with partially machined flanges.

Its always beneficial to recess the domes for exactly the reason you stated, which however isn't that significant of a problem, even at higher SPLs. Morel recesses their domes as well as Dynaudio.

I designed a 3 way with D76 and D330 esotar drivers on which the reflection of the tweeter output from the mid dome was repeatably measurable. It didn't however cause any audible issues being so close in time with the rest of the direct audio coming off the baffle. Im sure you'll see a minor disturbance in FR from it but its so small that you couldn't specifically say it causes some sort of acoustic signature.
 
#2,409
The height of the rubber surround is the problem please check with a thin but stiff disc having the appropriate diameter , lay speaker on the back so the disc touches the rubber surround and making any residuing gaps more air tight .

For me it is the main reason that SBA has recessed rubber surrounds integrated into their baskets like no(?) other manufacturer ..... for drivers without a dustcap but accessible center plug ("phase plug") one can cut a conical piece of acoustic foam (BASF/basotect in white or gray) to fill up the empty space , for absorbing any unwanted sound being reflected towards the microphone!

Now , where are the flat cone/disc drivers built by some heavenly creatures dancing in the moonlight 🙂
 
#2,415
Arez said:
Like this ?
from Japan too. sorry have no experience with them.
but there exist some drivers like that from different mfgs.

http://www.fal.gr.jp/products/flat-c90/
http://www.fal.gr.jp/products/flat-c60/
http://www.fal.gr.jp/products/flat-c40/
Click to expand...

maybe too expensive and too exotic

PE has recently introduced something similar more rectangle-shaped ...

But Dayton Sig120 4-inch is quite shallow so reflected energy should be less than typical ...

A compromise is a compromise is a compromise so please don't get crazy about it!

IT COULD BE WORSE .. 🙂

 
#2,416
You actually really don't want a flat membrane in circular mids and highs due to energy storage within the flat surface and the circular size. It will cause a peak in impedance like no other. I'm not saying you can't work around this, but it can create one huge thorny problem.

In bass it's fine as the wavelengths are long enough to be longer than the offending frequencies, and more often than not the Le rise reduces their effective properties.

The bending wave Tectonic drivers are not rigid flat diaphragms in the traditional sense and can get away with it.
 
#2,417
I am well aware of the design constrains but FLAT sounds so promising in the context therefor I kept it as an idol for the future!

The BMR is a can of worms 🙂

But the round 88mm unit designed by german tech designer and smart-ear KHF in Essen measures very good in the frequency domain! (not available for the public unfortuneable)
 
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#2,418
 
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