Group Buy: custom SB Acoustics pure midrange or coaxial

What midrange would you buy?

  • 5” midrange based on SB15CAC

  • 6” midrange based on SB17CAC

  • 5” coaxial midrange based on SB15CAC

  • 6” coaxial midrange based on SB17CAC

  • I like the CAC cone

  • I want black (NBAC)

  • I want one of the soft cones eg. Norex, polypropylene, carbon

  • I want a bigger coaxial (8-10”)

  • I don’t need a 5-6” midrange… what SB currently offer is fine.

  • Is this really happening?! When’s the ETA? Shut up and take my money!

Results are only viewable after voting.
Joined 2005
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Suppose for a moment that much of the R&D is done; thanks to the hard working folks at SB Acoustics, @USXX and @5th element

What custom midrange would you buy from SB Acoustics?

The basics-
This will be a 4 ohms, high sensitivity pure midrange.
The sensitivity will be ~93dB/2.83V.
It will capable of ~200Hz to over 8KHz.

Here’s how you can play a part in making this a reality.

First, put ONE vote to nominate the size of your midrange, or coaxial, custom made for you.
(Options 1-4)

For your second vote- please choose an alternate cone eg. NBAC (black aluminium cone), or if you prefer, one of the other cones eg. paper, Norex, polypropylene, carbon.

And finally- add any comments and queries after you vote. All are welcome!

Edit 1:
-If you want to get in the group buy, then vote!
-But if you have no intention of buying, please refrain from voting.
-Please place only 1 vote from options 1-4. The forum software doesn’t stop you from making dummy votes eg. 2 votes for options 5 and upwards. But then your vote doesn’t add any strength towards the group buy. This is an Expression of Interest to buy, NOT a Wishlist!
- I don’t make promises I can’t follow through on. But I am practical- will a manufacturer make 10 pairs with exclusive gold plated cones? Err…
But a single product that hits hundreds of votes? This is very possible. So talk to me if you have a need for 300 13” subwoofers…
— pricing and pre-orders will be announced at a later date…
- will you get to see some pretty graphs? Of course!
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Joined 2005
Paid Member
Geometry is of vital importance.

Suppose the smoothness matches the catalogue standard SB15… or SB17…
This is where you vote your favourite model.

And assume for a moment; that without the dustcap, the response is NOT negatively. affected.

And the tweeter that takes over the spot of the dust-cap doesn’t affect the midrange response.

And we want a nice and smooth treble response- we don’t want the midrange to negatively affect the treble’s response.

Furthermore, we want the treble’s directivity to match the midrange, because controlled directivity is what we want- a smooth on-axis response AND smooth off-axis responses.

A midrange-treble unit whose polar response is controlled, and is matched in both vertical AND horizontal directions.
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Given they have the MR satori range ha most of this already covered except the sensitivity then my vote would be for a 3” dome that can go from 500-4000hz with 2nd order crossovers and has the stated 93dB/W/m sensitivity but priced around $200 for a soft dome or $300 with a Textreme dome (I set my hopes high!). Think of it as an ATC Dome lite or a Morel EM1308 on steroids.

A WO24TX, this dome and the TW29TX would be one revealing speaker. Oh, and whilst they are at it give the option of an oval faceplate combining the mid and tweeter to reduce spacing (like the TM4055).
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The SB17CAC is already a really great driver above 200Hz (see testing by Erin Hardison at link below). I own a pair. Changes in the motor to reduce the gap and increase sensitivity would probably make it a top performance, high sensitivity midrange.

Measurement data:

TBH, unless you are going to design a coax driver from the ground up a la Andrew Jones and the drivers in the MOFI Sourcepoints, you will not end up with a very good result. Not worth it unless you are very good at that game, IMO.
Ugg Doesnt such a dome already exist?

Not that I am aware of, ATC is unobtainable for DIY, the Volt 752/753 are expensive (as used in the Diyaudio OSMC), Bliesma M74 is available but again expensive and the BE version will soon be NLA, the MD60N - like the Morel domes and Scanspeak D7608-920010 is only good for 700hz plus and the TangBand 75-1558 seems to be difficult to get hold of. So basically I would like a proper dome mid with most of the reach of the ATC, a Textreme dome for detail, 93+dB sensitivity and all for $300, I can but dream.

P.S. I have built a speaker with WO24P, Morel EM1308 and ET448 which sounds great, especially that it produces voices so realistically.
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The midrange dome HiVi DM7500/7600 has not been tested yet! (why?)

SBA - the 5 inch driver should be equipped with the 35mm coil of the bigger brother for even better cone control!

The MD60-N (hand-built? really?) is underwhelming me regarding Xmax/one way , is it an unlucky combination of key elements in the motor? (also I don't like the highly conductive aluminium coil former and it's weight)

Dayton OEM is hiding in the background watching this thread keenly :)

The Signature stuff makes SBA quite nervous! (price-wise too)

Btw - I have heard the midrange inverted dome of Usher Audio (Taiwan) costs only $200 as a replacement driver! (Tech PDF is very promising!)

What the audio world also needs is a true dipole radiating ribbon tweeter that doesn't costs a fortune! (Hello Fountek come back to life ..)

gimme some hot stuff man :)
I voted for the 5 and 6" NBAC based coaxes, but would prefer a CRC or textreme-based coax.

I would think definitely black, a white driver coax almost precludes use as a center channel, which to me is one of the most interesting applications.

I don't know where this is going, but if it comes to fruition it has a lot of potential!
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Charlie I dont think designing himself is the plan.
What is the "plan" exactly? So far details are scant to none.

The title says it will be a "custom" driver, and to me that means with some modifications, so I suggested one.

I am definitely not a fan of co-ax drivers but I could definitely use a souped up SB17CAC.
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A s long as a conventional half-roll surround is used, you'll never get optimal termination of the cone acting as a waveguide. Why not persuade KEF to make a few hundred Uni-Q drivers available for the d.i.y. market if a state of the art coaxial 5.5/6.5" is the target?
6" coax for me. I would like an even larger coax but I don't think a reasonable tweeter would be able to handle going down low enough to cross while the woofer is still in omni radiation.

The tweeter would have to be really good for this to make sense to do, though. A smooth top end and uniform directivity up to ~18-20 kHz is mandatory for me. That would typically mean a 3/4" tweeter but Bliesma seems to be doing some magic with larger format domes that don't beam significantly in audible HF, and without any excess diffraction (?) to boot. And the PTT 33 too.