Anyone that doesn't believe in evolution has never seen me working on a speaker project...
Today's report on that involves the frustration that Steve and I have when we find that the data sheets for speaker drivers don't accurately report dimensions and leave some out completely, and that I figure that out for one project (Saint-Saëns Planar) and forget some of the details and urgency in another- this one specifically.
The driver frame I'm blaming is one that neither Steve nor I are especially fond of, the RSS210 series, whether speaker or driver, it's just that the parts themselves work so nicely once you get them sorted out...
So I went to mark the PR threaded insert holes this weekend, and ended up concluding the baffles need a little more "meat" around the inserts... must push the inner pass through hole to the max, snug as a bug in a rug, as some might say...
After finding my thinking cap underneath the coffee maker, what I decided might work was to drop the base for the PR rebate even further, and to see about fabricating a new "mounting collar" so to speak- and the gods must be looking out for me, because the Boise Woodcraft had two pieces of 30" by 30" by 1/2" BB ply, yes, the last left overs from before the Russian invasion of Ukraine. (have Ukraine friends locally, so that is a touchy subject!)
Of course, one mandatory item for this plan to work was having a VERY accurate number for the actual frame inner pass through diameter, not just some "sort a close" number from the data sheet. This of course required a fixture of sorts and the use of two of the RSS210PR elements.

Having a cool looking black ruler is optional...
This showed that something like 7.25" should be achievable, and no jiggle room allowed.
It was short work to cut the BB ply into 15" square pieces, and setup my favorite Porter Cable circle cutting router. Note again, the pivot pin in the fixture has been replaced with a solid pin with a very slight taper.
In this case we have to setup to make two cuts, one sized for the outer dimension of the rebate (8-1/2" diameter) and the other for the inner dimension that the driver passes through. My standard solid 1/2" solid carbide bit was used.
The router tracks were cut 1/4" deep, an easy cut for the follow up with Bosch jig saw.
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Today's report on that involves the frustration that Steve and I have when we find that the data sheets for speaker drivers don't accurately report dimensions and leave some out completely, and that I figure that out for one project (Saint-Saëns Planar) and forget some of the details and urgency in another- this one specifically.
The driver frame I'm blaming is one that neither Steve nor I are especially fond of, the RSS210 series, whether speaker or driver, it's just that the parts themselves work so nicely once you get them sorted out...
So I went to mark the PR threaded insert holes this weekend, and ended up concluding the baffles need a little more "meat" around the inserts... must push the inner pass through hole to the max, snug as a bug in a rug, as some might say...
After finding my thinking cap underneath the coffee maker, what I decided might work was to drop the base for the PR rebate even further, and to see about fabricating a new "mounting collar" so to speak- and the gods must be looking out for me, because the Boise Woodcraft had two pieces of 30" by 30" by 1/2" BB ply, yes, the last left overs from before the Russian invasion of Ukraine. (have Ukraine friends locally, so that is a touchy subject!)
Of course, one mandatory item for this plan to work was having a VERY accurate number for the actual frame inner pass through diameter, not just some "sort a close" number from the data sheet. This of course required a fixture of sorts and the use of two of the RSS210PR elements.
Having a cool looking black ruler is optional...
This showed that something like 7.25" should be achievable, and no jiggle room allowed.
It was short work to cut the BB ply into 15" square pieces, and setup my favorite Porter Cable circle cutting router. Note again, the pivot pin in the fixture has been replaced with a solid pin with a very slight taper.
In this case we have to setup to make two cuts, one sized for the outer dimension of the rebate (8-1/2" diameter) and the other for the inner dimension that the driver passes through. My standard solid 1/2" solid carbide bit was used.
The router tracks were cut 1/4" deep, an easy cut for the follow up with Bosch jig saw.
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