A possible SLOB variant design might allow a narrow baffle. If using four 8" woofers the view from the back:
- the baffle being narrow has poor resistance to lateral displacements, so the driver arrangement needs to suppress lateral translational and rotational forces
- the stacking lowers the height
- the slots are reversed front to back from the usual
- the rear slot is wide and central
- the front slots are dual narrow lateral slots - hopefully the long wavelengths allows them to seamlessly combine but that the compromise for an elegant frontal profile
Ahh, those are questions for the Director of Marketing to decide. We are still working the options for the manufacturing so should have some rough numbers shortly.
Availability of a commercial product will probably by typically 6-9 months from completed prototype. But sometimes availability of parts or drivers is a limiting factor.
Availability of a commercial product will probably by typically 6-9 months from completed prototype. But sometimes availability of parts or drivers is a limiting factor.
The paired drivers are horizontally opposed. They move symmetrically around the medial vertical line. In together. Out together. The aim is a pressure wave out the front slot. So both drivers work to compress or decompress together. This also cancels vibration. Its smart in many ways.
On Resonance Control/Abatement: you show absorbant cones in the interior of the U baffle on post #1 this thread. In the development thread, you show a horizontal brace at the rear on pg 21/#419 and on pg 6/#119, photo TI-6.jpg shows a similar baffle by Z Transform with braces and stuffing. Is the picture showing the cones in #1 the equivalent? On pg 26/#503 , you mention the placement of NOICO on the interior speaker baskets - can you elaborate where and how much?
There is discussion of buying various sub-compoents of your commercial design. I ask if the tweeter bezel will be made available for purchase because that is the only component really beyond the reach of the DIYA crowd and it dresses up your design and may be found attractive to all the DIYA users of PT2522-4.
My Thanks for such an intelligent design.
There is discussion of buying various sub-compoents of your commercial design. I ask if the tweeter bezel will be made available for purchase because that is the only component really beyond the reach of the DIYA crowd and it dresses up your design and may be found attractive to all the DIYA users of PT2522-4.
My Thanks for such an intelligent design.
Hi JHClark,
Thanks for your interest and kind words. I am looking into making the crossovers available as a kit and the bezel for the tweeter available for DIY’ers. Let me discuss with my partners about the XO. The tweeter bezels should not be a problem. I just need to get more made when I get a production run going. Right now they are single unit prototypes.
Regarding bracing, I built some braces and was prepared to install them but find the 1/2in BB ply mounted on 3/4in square ledgers plenty stiff. No need.
Regarding Noico on the woofers, I added strips on the basket legs and the frame next to the magnet. I also added some on the back of the magnet although I doubt that’s needed.
Like this:
Make sure you use a round tip tool to rub the foil to get good contact of the butyl and the frame. This cleaned up the 200Hz peak in resonance very well. This would probably be unnecessary for a cast frame woofer.
Here is the bezel:
You can see there is a lot of detail to make sure all the bolts and rivets have space. I am not sure what GRS (or B&G) was thinking when they designed the tweeter. There was like no thought paid to getting seal by providing a flush mechanical surface. We have instead a surface riddled with bumps and screw heads. How did they envision such a thing to be held in place with a tight seal? Well anyhow, the bezel also serves as a shallow waveguide and that actually improves performance substantially. Smoother response, improved lower bandwidth, and less distortion. CNC’d aluminum and satin black anodized finish.
It’s a much improved tweeter performance wise, visually, and practically in terms of mounting.
Thanks for your interest and kind words. I am looking into making the crossovers available as a kit and the bezel for the tweeter available for DIY’ers. Let me discuss with my partners about the XO. The tweeter bezels should not be a problem. I just need to get more made when I get a production run going. Right now they are single unit prototypes.
Regarding bracing, I built some braces and was prepared to install them but find the 1/2in BB ply mounted on 3/4in square ledgers plenty stiff. No need.
Regarding Noico on the woofers, I added strips on the basket legs and the frame next to the magnet. I also added some on the back of the magnet although I doubt that’s needed.
Like this:
Make sure you use a round tip tool to rub the foil to get good contact of the butyl and the frame. This cleaned up the 200Hz peak in resonance very well. This would probably be unnecessary for a cast frame woofer.
Here is the bezel:
You can see there is a lot of detail to make sure all the bolts and rivets have space. I am not sure what GRS (or B&G) was thinking when they designed the tweeter. There was like no thought paid to getting seal by providing a flush mechanical surface. We have instead a surface riddled with bumps and screw heads. How did they envision such a thing to be held in place with a tight seal? Well anyhow, the bezel also serves as a shallow waveguide and that actually improves performance substantially. Smoother response, improved lower bandwidth, and less distortion. CNC’d aluminum and satin black anodized finish.
It’s a much improved tweeter performance wise, visually, and practically in terms of mounting.
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Thank you for your full, prompt, and informative reply. If, as someone mentioned earlier, the bass manifold alone also becomes a purchasable item, it will be a "slam dunk", easy- peasy effort. Granting the favorable disposition of the "speaker gods", I'm planning for three sets; one for me and two for Christmas presents.
Again - Thank You !!
Again - Thank You !!
As stand-alone bass units I would like to keep the height about 24in and 8x 6.5in drivers is too tall. I am considering 4x 8in woofers and the cone area on that is about 20% less than the 8x 6.5in. But it might be fine. 6x 8in would be about 27in to 28in minimum with top and bottom panels.
What a neat design, full of cool ideas! I always love when I see force cancellation in a design. Phase and distortion look really excellent. Thanks also for the information you have given about the waveguide... It looked so mild I assumed it was essentially cosmetic. If you're comfortable sharing more info about it I'd love to know. I've got a pair of GRS slim 8's waiting to go into something. Now I have to wonder if they want a waveguide as well...
Good luck with the commercial aspect! I hope I can read a fancy review full of flowery prose about them some time.
Good luck with the commercial aspect! I hope I can read a fancy review full of flowery prose about them some time.
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Not meaning to hijack thread, just to follow up - Have attached a couple pics of current impedance and room resp at listening position from my XSD inspired build. Impedance was a little tricky using all 4 ohm drivers - will likely replace the top at some stage with another MA offering. Still work to go to tame response and has needed some EQ to lift low end and pull out some low mid. Sounding pretty good, although slight regret at not adding another pair of woofers 
Maybe a slot loaded sub in the bottom?
Maybe a slot loaded sub in the bottom?Attachments
Thanks xrk - I'm curious to know what difference you noticed (measurable/audible) from rear cavity absorption and woofer basket damping. Was it significant?