Rotary Subwoofer

We don’t usually go for commercial products, but this one (try the Internet Archive version) caught my eye. This fan is actualy a subwoofer. The blades spin at a constant rate and the blades are servo actuated to produce sound from 0Hz(don’t look at me like that) up to 40Hz according to the spec. I don’t know if I’d want one too badly, it might be dangerous in the wrong hands.

48 thoughts on “Rotary Subwoofer

  1. So accoding to the website, the advantage of this thing is that it produces sound in the infrasonic range?

    infrasonic sound is, by definition, to low a frequency for the human ear to hear.
    I’m so dissapointed my system can’t produce sounds I can’t hear.

  2. Pretty slick, but I have a hard time believing it’s worth nigh onto 25 grand. I’m sure they’ve put a helluva lot of thought and work into it, but it’s basically an AC motor with a microcontroller-ed dynamic pitch fan blade.

    To frs, ya, you can’t hear it, you feel it. Basically you “hear” it in your gut. The sound you hear during an earthquake for example isn’t all sound, it’s feeling. This idea can more accurately reproduce things like earthquakes, helicopters, explosions, etc… in theater situations.

    See for this and a couple other, earlier ideas along these lines. And for a (stagnant looking) DIY version of a baffle sub.

  3. this was featured on Slashdot some time ago…

    As i recall the demo setup at some audio show in Nevada or somewhere almost destroyed the temporary enclosure it was installed to. I seem to remember the description saying that the walls were pulsing slowly as the pressure increased and decreased.

  4. This will go great with my cable elevators, sound panels, and acoustic wood volume knobs.

    There should be a study on the mysterious effect silly audio gear has in making money disappear from the pockets of gullible audiophiles.

    (At least this one has a scientfically measurible effect. I still don’t see how listening to sounds the movie audio designer left in by accident because he couldn’t hear them makes for a better home theater experience. Most movies with good sound quality probably clip everything below 20Hz anyway.)

  5. all i’m saying is 2 of these in the back of a 84 olds and then you know what i am talking about………………. THUMP IN THA MAHFUKKIN TRUNNKKKKKKKK umpbhhhh umpbhhhhhhhhhhh blapp blapp ummmmmbbbbhhh

    that is all

    but really


  6. I am going to say that there is no way in hell that this is going to make you home theatre sound any better when listening to any recorded media (well just maybe a record player might have had something below 20hz, but I doubt it) because there is nothing recorded down there… Even your prized collection of cd’s has absolutely nothing down in the the 10’s of hz.

    This would help some bands tho, as you can certainly make stuff vibrate at 20hz, and synthesize it down as low as you want… (I imagine this being hooked up to a syth that lets you play a 5hz tone to give a little more umpf) d^_^b

    But for home theatre… no

  7. The traditional theory that humans can only hear “20hz – 20khz” is flawed as it doesn’t account for a volume level throughout the range. Humans can hear below 20hz, it just takes a significantly louder source than is normally available to allow humans to hear that low, simply because our ears are so insensitive in that area.

    I have read articles written by Dan Wiggins (founder/owner of Adire Audio and, essentially, an audio genius) on the subject, which is quite fascinating.

  8. If I’m reading the site correctly, it’s not a servo that actuates the fan blades, but an ordinary voice coil, sans feedback. That means a) it shouldn’t be *too* hard to make your own, if you have a traditional subwoofer coil and an annular magnet you can set on the fan, and b) it would likely be too heavy for a helicopter, and adding directional control would cause a huge amount of drag on the propeller.

  9. for al the doubters, who’s seen master and comander? or the patriot? you dont hear the canonballs, you feel them. this is an extention of that effect. now, 25 large, thats an issue…

  10. The Mythbusters had a box fan for some myth and to oscillate the air at around half a hertz. They simply blocked it out with some spinning plywood. Theoretically, if their setup wasn’t flawed, if you spin that piece of plywood faster, you could get some audible frequencies.

    Just a thought.

  11. really cool find i did not know that the company that makes this is still around — i dont know if they still make the planar ribbon speakers — im from tallahassee and have seen what products they used to make — really great stuff sounded the best i did not know they were still around this seen cool but im sure that in the next few weeks we will see a diy unit up on makezines blog!!!!


  12. These always struck me as cool! Practical… well probably not. There isn’t a lot of material that will really use its VERY low end and you can buy or build a sub-bass system (say down to 20 Hz or so) for much less (I think you can get a REL that does that for 1k or so). But then again if you can spend 25k on a subwoofer… well… it might be worth it to you.

    What I want to know is what is the rest of your system like if you can spend that much on a sub? EEEK! Though honestly, I think this is more for special art installations etc. than for home use.

  13. So i take this will be able to produce the ‘Brown note’?

    If so it would be $25,000 well spent. Hook it up to the roof of your car and drive through a busy town/city with the brown note playing. (^_^)

    I just hope I win the lotto on friday and the manufacturer ships to the UK….

  14. hmm, I’ve got a CS Basscube 15, the documentation I have with it says it can reproduce sounds accuratly as low as 25Hz. Having sent it sound from a wave generator on my HTPC I can still “feel” it working as low as about 14Hz but it does dramatically drop off below 25. Even still There are a number of movies I own that seem to reproduce inaudable sounds at the very low end… I’ve never measured it so I don’t know how low but definitly low enough that I can feel it rather than hear it. More often then not stuff encoded in DTS as opposed to DD is better for that sort of thing. I’ve NEVER heard/felt stuff from the low end that I thought might have been data accidentally left in the audio… excluding some homemoves I’ve played.

  15. This looks really cool. And in response to nay-sayers who point out that you can’t hear infrasonic sounds, do you have -any- idea how much subconcious things influence you?

    while I’d absolutely love to have one of these (being a fair audiophile myself), the cost is outrageous. Something similar (though not as refined) could probably be built for a few hundred, you’re just dealing with a servo to modify the angles, a motor to spin it, and a small processing unit to tell the servo how much to move.

  16. oy yoy yaoi.
    Message to everyone who thinks infrasonics are a bad thing:

    The world doesn’t restrict itself to 20hz-20Khz frequencies, why should our reproductions of the world’s sounds? It’s not going to kill you, it’s going to make things seem more real by creating sounds that -should- be there, but aren’t.
    If anything, not having those sounds is more dangerous than having them. You’re screwing with your brain by feeding it incomplete information.

  17. dave said: “Come on, don’t you like to feel the music sometimes?”

    Well, I don’t know if I want to feel it THAT much. I think a repairman might mistake it for an old attic fan, not a 12,000 dollar ultra-low high fidelity subwoofer…

  18. If anyone can find me an equalizer or anything else that can even remotely proscess 0Hz, let me know… because, well, I call it crazy. But to those that are saying no recorded media has sounds that low, I think there is probibly a way one could write a computer program to trigger infrasonic frequencies when like 10 to 20 Hz is played.

  19. Has anyone noticed that the specifications/information provided on the website doesn’t quite add up.
    I’m not saying it doesn’t work, but its performance may not be quite as they say. It is not necessarily the most elegant solution for a servo/rotary driver either….

  20. There is plenty below 20Hz on most material, hell, even the AC3 versions of 24 I have downloaded had loads of stuff down near that.

    Sure, most currently mastered CDs have had anything resembling bass removed and replaced with phase rotated harmonics much like radio station type processors do, this is just to give them more headroom. Movies with the LFE channel dont suffer from this and have plenty of room to shake the house.

  21. “I’m so dissapointed my system can’t produce sounds I can’t hear.”

    You sound like a real audiophile. That is why they pay $400 for 1 foot power cords (not realizing that there is many feet of 25 cent per foot power wire in the walls). Or thousands on special DACs because of “jitter” in between the bits.

    If only consumers in all markets were that gullable. There would be many more millionaires.

  22. Wouldn’t it make sense that you could get a similar effect by rotating a conventional speaker basket? The only real difference here is that the signal is coupled with the air differently.

  23. Much more spactial information is contained in the low freqs. than is usually thought. I used to own one of the old EV 30″ drivers that lived in a roughly 7′ x 3″ x 4″ cabinet Being driven by various Carver and Marantz power amps and it provied all sorts of information in the 16 to 40hz range. Stuff recorded in studios in the sixtes in NY where you can hear the subway, rumbling underneath the studio during a take, that the engineers couldn’t hear on tape and assumed those Neuman’s weren’t picking it up. Instruments, especially acoustic, had more life, weight. So yeah, I could see this fan/sub working, and would really like to.

  24. Real neat product. I must say that this bruce figure has found quite a nifty solution to controling the variable pitch propeller. I am sure he spent some time pondering on that one quite simple solution!

    I wonder if there is any room for improvement by adding some electronic control circuitry for more precise control of the propeller pitch at different frequencies, therefor flattening out the frequency responce.

    I wouldn’t mind building something similar just for the hell of it sometime!

  25. to …: you’re so wrong, its not even funny. there are plenty of DVDs with content below 20Hz, if you dont believe it just use a audio editor with spectrum analysis and look at something like Titan AE, which has scenes having plenty of energy down to 4Hz (!).

  26. Great thread. I’m really keen to make a very small-scale rotary subwoofer, if for no other reason than to demonstate the principle to myself. I’m currently playing with a 6″ diam long excursion sub & a slim 150mm 12 PC cooling fan… Looks promising so far :) Anyone else here inteseted at having a go at making one ?

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