I'm speculating that if higher frequencies are going to be a problem, they'd radiate out into the room (out the back of the outer cone) before reaching this damping material. Using it may still reduce the contribution of the inner driver, and whatever happens in the cavity for cases where they need to be used beyond typical sub frequencies.
Would setting an upper limit to these where possible achieve the goal instead?
(Could be worth a sim to see where the problems are?)
Would setting an upper limit to these where possible achieve the goal instead?
(Could be worth a sim to see where the problems are?)
Probably.
I've built many isobaric subs (with cones face to face) over the years and never put anything between the cones and never had any problems.
How high in frequency do you intend to run them?
I too am wondering about the intended value of this. It seems as though it can cause more concerns than it might solve when there might not be concerns to begin with.
Some messing around in the ripple tank shows that things aren't going to get modal until wavelengths approach and get smaller than the cone. Below this region, the damping will be ineffective as there is no pressure gradient outside of the primary coupling.
I did some homework and believe that you're all right, to some extent, and the outside portion of the cone is most likely the source of anything audible (I was musing that worrying what might be occurring in the space between the two cones reminded me of the paradox of Schrodinger's cat).🙄
Ironically, my concerns have vanished as I have a new focus- the left channel plate amp died (most likely a power supply cap, it's 25 years old). That's a REAL problem for me to tackle.
I guess I'll go with that old saw:
"If it ain't broke, don't fix it".
Thanks again to everyone for all the kind and patient input (especially you, Dave). 🙂
Good listening!
Ironically, my concerns have vanished as I have a new focus- the left channel plate amp died (most likely a power supply cap, it's 25 years old). That's a REAL problem for me to tackle.
I guess I'll go with that old saw:
"If it ain't broke, don't fix it".
Thanks again to everyone for all the kind and patient input (especially you, Dave). 🙂
Good listening!
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Stuffing some dampening material in between the 2 cones is a bad idea. It will fall apart and rattle at higher spls no matter what you do to contain it firmly. Id consider mechanically coupling the 2 cones together, sort of like KEF did with some of their older speakers, then fill the space with instapak foam just shy of the surrounds.