i was daydreaming today. planning (once my big FAST system is finished) to build a little beachside bluetooth jobby, and expecting to use passive radiators.
i envisioned a tiny cube, with a long excursion fullranger on top ( or maybe a woofer and tweeter mounted coaxially in some way) with one of those (my brain has stopped working) conical metal jobbies above to provide 360 degree sound.
anyway, while thinking, i pondered wether a small cube with one or two sides open, and a piece of "inner tube" style rubber sheet stretched over the open sides could be tuned for use as a passive radiator?
im imagining tuning it would be a pig, (sewing weights on? adding layers of rubber? changing effective radius? tension of sheet?) and probably the non linear motion of a rubber sheet with no surround would just mess everything up royally.. ?
in my mind the benefits are maximum passive radiator area and minimum cost... im also (whilst in fairyland, its a nice place to be) imagining it could be in some way collapsible when not in use, due to the flexible rubber.
who wants to be first to shoot me down in flames?
i envisioned a tiny cube, with a long excursion fullranger on top ( or maybe a woofer and tweeter mounted coaxially in some way) with one of those (my brain has stopped working) conical metal jobbies above to provide 360 degree sound.
anyway, while thinking, i pondered wether a small cube with one or two sides open, and a piece of "inner tube" style rubber sheet stretched over the open sides could be tuned for use as a passive radiator?
im imagining tuning it would be a pig, (sewing weights on? adding layers of rubber? changing effective radius? tension of sheet?) and probably the non linear motion of a rubber sheet with no surround would just mess everything up royally.. ?
in my mind the benefits are maximum passive radiator area and minimum cost... im also (whilst in fairyland, its a nice place to be) imagining it could be in some way collapsible when not in use, due to the flexible rubber.
who wants to be first to shoot me down in flames?
For reference as to how you might succeed: square or rectangular passive radiator - Google Search
GM
GM
Not my point; in short, you need variable rigidity, so once massive enough it won't have sufficient flexibility to act as a PR, just at best turn it into a lossy sealed alignment.
FWIW, when I sent the link I had a thin rubber 'wall', tightly stretched, in mind with a plate bonded to it, then add lead as required.
GM
FWIW, when I sent the link I had a thin rubber 'wall', tightly stretched, in mind with a plate bonded to it, then add lead as required.
GM
Ok i thought you were just suggesting i buy one!
Anyway im not 100% clear on the "you need variable rigidity" and "once massive enough it wont be sufficiently flexible"
If i understand correctly, couldnt the mass be added at a central point, with the rest of the membrane thin enough to be flexible? Or will i have to accept that a rigid panel and flexible border is a necessity? If i could keep the whole thing flexible i could probably design a collapsible speaker.. My daydreaming has arrived at a rigid circular top and bottom panel with a mechanism which allows them to collapse together, or clamp rigidly apart, with a strip of flexible rubber forming the side of a collapsible,Cylindrical speaker, with the sides acting as a PR.. Impossible of course, if a rigid diaphragm is a necessity..
Thanks for the advice by the way
Anyway im not 100% clear on the "you need variable rigidity" and "once massive enough it wont be sufficiently flexible"
If i understand correctly, couldnt the mass be added at a central point, with the rest of the membrane thin enough to be flexible? Or will i have to accept that a rigid panel and flexible border is a necessity? If i could keep the whole thing flexible i could probably design a collapsible speaker.. My daydreaming has arrived at a rigid circular top and bottom panel with a mechanism which allows them to collapse together, or clamp rigidly apart, with a strip of flexible rubber forming the side of a collapsible,Cylindrical speaker, with the sides acting as a PR.. Impossible of course, if a rigid diaphragm is a necessity..
Thanks for the advice by the way
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