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Sonosub with Passive Radiators - Cylinder-PR united?

6K views 18 replies 8 participants last post by  Lucky7! 
#1 ·
A next diy sub might be ahead of me but now its a good time to figure out what is the next subsonic design I ll make. And so i would be glad and thankful if i could discuss with you an idea that swept me through :bigsmile:.

Even though I am very pleased with the cylinder enclosure with PVC tube I have and finally got the chance to hear that sub on max, and i actually had no clue of the limits of the this thing, it was gorgeous for a 20liter cabinet. I figure out the horizons were there, I mean its inherent rigid and not-vibrant to basses nature, a solution to the problem with the bracing, the simplicity and all in all and so I want to see how far this can go.
(Here is the previous sub http://www.hometheatershack.com/for...-my-transmission-line-ported-sub-its-way.html)

And here i am, How does it sound to you: Sonosub (PVC version I get it cheap 8$ per foot for a 15inch) with a passive radiator on top (instead of a port with noise)? Do you think that could be the kid taking the applauses?

A word to the passive radiators
I found a PR that can be loaded up to 1800gramms (think will withstand more) with stiffness Cms of 1mm/N, that worries me.. it is too much, for sure the excursion of the sub is more than that of the PR but they are acoustically connected to each other and the typical Cms of a sub is around 0.15-0.30 for the power range i deisire. Do you think the force the sub generates could oscillate the PR to its limits even at low power?
 
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#3 ·
with a passive radiator on top
I am not aware of any current PR's that can be mounted horizontally, the tube would need to be on its side for the PR to be mounted vertically.

Do you think the force the sub generates could oscillate the PR to its limits even at low power?

Modeling will show what the capabilities are of your sub and PR combination.

 
#5 · (Edited)
I am not aware of any current PR's that can be mounted horizontally, the tube would need to be on its side for the PR to be mounted vertically.


Modeling will show what the capabilities are of your sub and PR combination.

Thanx Mike, my initial thought was to place the PR at the opposite side of the tube,i.e bottom is driver and top is the PR, instead of a chuffing port and having no problems with air velocity as the Shiva X2 is powerful sub.
 
#6 · (Edited)
Dont you think with this design, actually the SPL from this double-driver sealed sonosub results in twice lower output compared to a single driver sealed one, cause as i can imagine the wave instead of hitting the non moving cap on top will continue as if it was open. In such way this comes very close to transmision line sub with very low to absent acoustic load ot both sides :doh:
 
#14 ·
yes my high fidelity dayton rss265hf waits for a enclosure upgrade, cause it is now undersized, i could tune it to 20Hz with a 3.5c.f. enc, and for the extra 4Hz with the maelstroms i need 12c.f.. i simply dont have the room for it
 
#16 ·
you are right that is the way to go:T, there would be 2 resonances, a moderately pronounced one for the small box and a determinative one from the sono tube.. and now who is looking at the Transmission Line web pages :bigsmile::hsd:, up there is open hehe. How do you thing about that Fabulous FR at the same web page for this TL?
 
#17 ·
there would be 2 resonances, a moderately pronounced one for the small box and a determinative one from the sono tube..
the box section is too small to have a resonance in the pass band of a sub. The TL section might depending upon length.
and now who is looking at the Transmission Line web pages :bigsmile::hsd:, up there is open hehe. How do you thing about that Fabulous FR at the same web page for this TL?
I'd rather see a true sweep than a 3rd octave RTA and to know what level it was done at. Still, not a lot of output capability with those (10") drivers.
 
#18 · (Edited)
I made a drawing for this case for one half period (for the next one the arrows reverse). The other two sides occupied by passive radiators. The speakers are so mounted to compensate the non linearity of the cone movement of both subs to achive low box vibrations.



Do you think the polarity of the subs connection is right? I think, if it would be the other way, it will be like a hole instead of speaker and the sound presure will be considerably diminished, or worse than a hole because there would be not only no resistance but also a pull force extracting the preasure out of the enclosure..
 
#19 ·
Connect the drivers that way to cancel some of the even order distortion. Not so sure about the PR's as I have never done it this way, but the suspension non linearity cancellation should be similar.

As long as both drivers are moving out into the room or into the box at the same time, you're fine. They will add, not cancel output.
 
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