I can’t remember if I started a thread for this and couldn’t find one using search. A while back I sliced the slits in my pair of M180-8. I applied a little caulk to the backside of the slits. This morning I felt froggy so I carefully removed the porous dust caps with a new sharp X-Acto blade. Now I’m making pole piece extentions out of 7/8” oak dowel rod. When those are done and glued in place I’ll reattach the dust caps and apply a thin layer of caulk on the front side of the slits.
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you are not making phase plugs? I am not sure what pole piece extensions are and how they will help?
Tomayto tomahto.
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Pretty impressive slicing- thinking you chalked these lines out first ?
I made a templates out of construction paper then laid them on the cones and sliced through them and the cone material.
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I’ve got a quad of the PM180-8s, but hesitant to put a knife to them.
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I think the long throw 8” woofer from MCM/Newark would probably benefit from this treatment. I’m willing to donate my pair to science.
I made a couple of resonance cavity fillers out of some oak dowel rod. Blackness thanks to a King Sharpie marker. A little 5 minute 2 part epoxy and they are in place. I just need to glue the dust caps back on.
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Oh yeah and I also applied the latex caulk to the front side of the slits. It goes on pure white and dries completely clear. In the above picture it has only dried for an hour or two so somewhere in-between.
Ok I’ve run out of ways to say tomato.
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Good one 
would it help for a traditional 3 way - or only for 2 ways where you are trying to cross as high as possible - aren’t these resonances higher up in the frequency region?
Interesting symmetrical / spaced non-symmetrical groupings of cuts.
In Josh Bruner’s original thread, he reported that he could hear a resonance in the empty cavity under the dust cap. A wooden dowel alleviated it.
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^^^ This!
I’m just copy cat’n JBrunner’s posted work!
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Symmetrical with respect to the origin, just how SS does it in the Revelator series.
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I got the dust caps glued back on.
I used this little syringe from Hobby Lobby.
Worked great. Just wish I had better eyesight and steadier hands.
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I’m surprised no one mentioned or asked about these aperiodic vents (part of one shown in the first picture). I 3D printed them.
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They looked like regular aperiodic vents - that good!!! What did you stuff them with - looks like different material from the front/back.
Is there any way to measure or tune aperiodic vents or just sim with lossy box?
Set Ql to 3
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