This is a completely random thought: Assuming you modeled it correctly, what would happen if you had a passive radiator on all surfaces of a speaker cabinet? Essentially 5 passive radiators and one active subwoofer?
I guess I was wondering what it would do structurally. How would it affect resonances, standing waves, etc…
The whole random thought happened when I poorly braced my Ultimax 15 and there was a lot of vibration on the top panel. Since the panel was vibrating so much I wondered what would happen if all the panels were essentially radiators. You’d hardly have any MDF left at that point, lol
The whole random thought happened when I poorly braced my Ultimax 15 and there was a lot of vibration on the top panel. Since the panel was vibrating so much I wondered what would happen if all the panels were essentially radiators. You’d hardly have any MDF left at that point, lol
I had to interpret "what would happen" as best I could Brent. 🙂
So, the effect on enclosure resonances... let's think.
A passive radiator is effectively "closed" at frequencies above the tuning frequency.
So does this mean that enclosure resonances occurring at frequencies above the tuning frequency would not be suppressed by the PRs?
So, the effect on enclosure resonances... let's think.
A passive radiator is effectively "closed" at frequencies above the tuning frequency.
So does this mean that enclosure resonances occurring at frequencies above the tuning frequency would not be suppressed by the PRs?
Ah, that’s a good point. I didn’t think about them being closed above tuning. If anything, they would add more unwanted resonance. I thought they produced the same range of frequencies as the main driver, but it makes sense that they only reproduce the specific frequency they are tuned to.
The tuning resonance is supposed to be a wide band of frequencies so the passive radiators moving throughout the range of these sub frequencies shouldn't be a bad thing.
Assuming you decided you really wanted to do that, you might end up with a more balanced setup with two drivers and four passives. Unless you use one a them monster subs or wanted to use small passives for some reason..
That’s interesting and similar to my initial assumption.
I was hoping to get reinforced output from the build, but even more so, I wanted to alleviate the internal pressure of the enclosure. It seemed like a cool idea to have the box harmonically flex with the back wave.
I thought, “If the panel is going to vibrate so much, just get rid of the panel, lol”
TBTL, in college I bought a pair of JBL Lancer 44 speakers. Wonderful speakers!
The driver was an LE8-T, a legendary 8 inch driver.
It was mounted alongside a JBL 8 inch passive radiator.
I enjoyed that setup for more than a decade, and never had any problem with the PR being mounted vertically.
Seems to me that the cone mass of a passive radiator is pretty low, provided it's not mass loaded to lower its respnance.
The driver was an LE8-T, a legendary 8 inch driver.
It was mounted alongside a JBL 8 inch passive radiator.
I enjoyed that setup for more than a decade, and never had any problem with the PR being mounted vertically.
Seems to me that the cone mass of a passive radiator is pretty low, provided it's not mass loaded to lower its respnance.
Would the sole woofer even have enough energy to share with five PRs to be effective?
One subwoofer one box.
One subwoofer one box.
I don't see why not. While we talk of a passive radiator acting as a mass, it needs energy of a certain quantity to fulfil the interaction. Compare to the way a small short port becomes the equivalent to a wide port, only if the wide port is also long, which seems counterintuitive if mass were the only factor.
With passive radiators on all sides, if you were to ignore the sag factor, would it begin to act like an infinite baffle at some point?
Also, more radiators = more weight needed per radiator?
If I wanted to kill vibrations, I could probably build an enclosure and fire 2 subs directly at each other, but this is a fun thought experiment for me.
Also, more radiators = more weight needed per radiator?
If I wanted to kill vibrations, I could probably build an enclosure and fire 2 subs directly at each other, but this is a fun thought experiment for me.
![20230418_082532[6376].jpg](/community/data/attachments/1073/1073888-7274d6808a39b47d9cdfeeb29002aa08.jpg?hash=cnTWgIo5tH)
Some configurations cancel out waves, you dont want that. Why dont you try a push pull sub?
No, it will still behave like a ported cabinet.
Cone sag will affect the linearity of the output around Fb (box tuning) but won't affect the Fb. If the passive radiator has 10mm Xmax, and has sagged 3mm off center, it has lost 30% excursion on the down stroke.
Yes, to achieve the same Fb when passive radiator Sd (effective cone area) has increased requires added mass, similar to increasing the area of a port requires adding length.
https://www.diysubwoofers.org/prd/