I remember when RU-vid wasn't even owned by Google😢 it was like tiktok. Just random stuff from people.. but I'm talking about the beginning of a tiktok. It's just pure advertisements niw
@@martingo2680back when every video was a gamble, would Rick be hypnotizing us with timeless vocals and bass or would a backyard scientist actually go critical with their smoke detector reactor. Good times.
their worthless trash actually. the only reason you can hear anything is because he ripped a speaker apart and jury rigged it to the back of that fan, but the actual rotary woofers dont output sound. they direct extremely high velocity pulsed air into a support column, which induces vibration through the entire foundation and walls, which is then perceived as sound, but still isnt. this idiot just ripped up a speaker and threw it in a window, but thats absolutely not how these devices work.
@@FingerinUrDaughter Look up rotary woofer on Wikipedia. It's an established thing for generating very low frequencies, the kind you can feel in your body.
You could still use car parts from a junkyard, grabbing a couple of identical flywheels from manual transmission cars to help keep the motors at a constant RPM while producing sound waves. Using Automotive flywheels like that, most of them are balanced for use at thousands of RPMs, speeds you'll never need with that setup.
They're balanced for thousands of RPMs, but they're also sized for thousands of RPMs which would make them less suitable for this application. They'd probably still work, but it would be pretty hard to integrate them.
I wish some company would make these for concerts and theaters. These subs are awesome, and I love to see more people making them, engineering them, and just experimenting to make them better.
Because these require a space outside the listening area to vent air into and out of. This means you either send a lot of noise pollution outside as seen in this video. Or, contain it in a second large empty room adjacent to the listening area. This is much less cost effective than using a standard reflex sub tuned to low infra sub frequencies. Also this can't be used for outdoor environments unless you made a very large wall that separates all the energy from the front of the fan from the back of the fan.
I've been an audiohead for years. I owned Bose, B&O, Pioneer and many others. I have never heard of this and honestly, I thought it was a joke. I researched and and wow. That is pretty amazing for the science involved vs concept and the application. Nice work
@@SoylentGamer you mean KHz, what they actually struggle with is anything below 60 hz and they’re boomy around 80-120hz to counteract it. By no means a flat response. Efficient design but useless if you want to hear what the producer wanted you to hear.
I wonder what would happen if you put a little big of fog in the room to see how the air was moving. I'd love to see a fluid simulation and see just how that little device is moving so much freaking air
This! Or something along these lines. I had never heard of these and I am very curious how well it works, something that is unfortunately not really easily captured through video. Best I could come up with was something like an air balloon on a string or perhaps a candle to Mahe the waves visible.
@@danielfajkis4952 as i was telling nathan i the 3" video... its not just the mass but the balancing of the blades. pivot them along the CofG, and the only load is the mass of them, air pressure equalising on either side of the pivot. im of the opinion they should be flaps cut from a solid sheet, cover the port when neutral. but despite knowing of them for at least a decade... havent made one! i just know theyre closer to a helicopter than anything. the power is required to spin them, not flap the blades. i really should put my money where my mouth is and have a go myself. effing keyboard warriors! got a bunch of RC swashplates hanging around... i was MEANT to be making a collective pitch quad! lol, the irony of subsonic speaker demonstrations on dodgy 8 inchers... with the bass turned down cus i hate voices all boomy.
Sounds amazing like driving down the motorway with one single window wide open. Nice using the room as a Helmholtz resonance chamber, depending on the things inside, it could rattle things like hell.
This sounds truly impressive even on video. I would love to experience it IRL, how does it feel in your body? I imagine this must feel more impressive than ordinary subwoofers!
That's incredible, I had to turn my bass down a bit. I was amazed at the lows this produced because I had to put my hand down and feel like 15hz since you can't hear it. Interesting how it seems a bit tame the way it's not rattle the doors or anything.
Well, unless you have one of these rotor subs…you wouldn’t hear it anyway unless your sub could plummet below 20 and that just doesn’t happen. Your sub may flop at 15hz or 18hz but isn’t loading the air.
I remember seeing a video a long time ago where a guy built this sort of thing in the space between his walls and said a similar system would run upwards of $25,000. You, sir, are magnificent.
I've got some old 700 size collective pitch helicopters. I've always wanted to put 3 tail servos (usually fast af) in place of the collective/cyclic servos, build an enclosure with a 700mm hole and modulate the servos to make some tones. Lotta power... one day
I remember seeing this being developed for commercial cinema use ten or so years ago. The commercial team used a DA converter and/or PPM/PCM to servos if I remember, basically a helicopter rotor head mechanism. it was sizable too. Definitely a digital drive. 10% distortion did not matter being that is was subsonics.
I'd love to see some of these in home theater use for infrasonic bass. Would be cool to experience the lung-emptying bass that some massive subs have down below 20Hz. Awesome setup, can't wait to see more!
Interesting. Would have been nice to see a frequency response curve. Also be nice to seen this vs the same coils, but used in the conventional way, also mounted in your window.
Ingeniously. Well done! What an approach. The besutiful thing is that the zero point will be found by the rotation rather than suspension. The volume of air moved by this way of bass coupling must be enormous.
It is interesting that subwoofers can be created like this, since technically that is what a subwoofer does, it moves air and thanks to the cajon it intones the air that moves it and creates that beautiful bass tone. It is something that they wanted to use a long time ago but for aesthetics it was never used
This is sick, first I've ever seen or heard of a rotary subwoofer. I'm in AZ too, glad there's cool stuff like this around. Also, Legion is an absolute banger..
This is some next level engineering. To take this from concept to reality is a huge accomplishment, endorphins would have been awesome when you heard your creation for the first time. I see you've made videos on how you did this, will be watching!
Definitely some of the highest frequency rotaries I've ever seen, probably due to the lightweight 3D print. Every other rotary sub I've seen doesn't play past like 15Hz before wanting to rip itself apart, nice to see them used for audible sub bass for once. Well done on this build, I'm super jealous! I can only just about appreciate infrasonic thanks to a Dayton Audio BST-1 I've strapped to my chair lol. Effective minimum frequency I can feel is ~26Hz, after which it rapidly rolls off to about 12Hz. Not too bad... But I've wanted to build a rotary for years. Shame my windows are not suitable for it :( I have a question though, what (if anything) would you do about the blade speed bogging under high excursion? Especially in that last test, you could tell the fans were slowing down significantly due to the the aero load. Only solution I can think of is using large BLDC motors with a high current ESC, but that'd definitely bump the power draw far beyond 80W and I don't think the ESC would like the rapid current spikes lmao.
I've had a lot of people on RU-vid saying the blade speed going down is a problem. The blade speed being slowed is however not an issue. This is because there is a large range of speeds that produce the same amplitude of sound. I found that running the blades so slowly that you can see the rotation (i.e. it's not blurry) produces almost the same amplitude of sound. Likewise, running it super fast (very terrifying and loud fan sound) produces the same amplitude. The only difference that higher fan speeds make is that the rotary can play higher frequencies (i.e. the rotary running on 24 volts rather than 12 increases its range from 50hz to 100hz). These low power motors are plenty strong enough. The ratio for coil power to motor power is 3 to 1. If your coil can handle 90 watts, choose a 30 watt motor. Does this answer your questions?
I guess lower fan speeds are quieter in terms of fan noise, which could be a benefit as usually these things are located away from the listening area, in which case frequencies you can hear are played by regular drivers.@@nathanbulle5782
@@nathanbulle5782 Ah. fair enough regarding the amplitude. It's hard to get a sense of the amplitude changes based on deflection through a video, but I'm inclined to believe you since you've got (literally infinitely more) real world experience with rotary subs than I do. Completely removes the need of using a BLDC motor and a dedicated driver, so yeah that answered my questions perfectly, thank you haha. My windows don't slide in any direction, they open outwards on a hinge. Unless I completely take off the window (impractical and unsightly since it's facing the front of the house), it's just not accessible sadly. I do have a wardrobe built into the wall and it has quite a large internal volume but nothing will even come close to the infinite baffle of having it point out the window. Thank you for your responses
WOW i'm impressed by the result already on the first song when the blades startet to spin. I thought that would just be nice little neat thing for demonstration but that would be useable for example in big Party rooms. Can you also hear that loudly from the outside or only on the inside? Could you please make a another video on how you build them and so on? Edit: I see you already made a video on how to build it haha
Its hard to judge performance from video, but its a cool idea. I do know that more blades produce less noise, whether from a fan or even a helicopter prop. Might be worth checking out to see if 5 or more is doable in your design.
Wow, thanks for sharing, I don't fully understand how this works, let alone how to hook it up to an amp and how to drive it, but I think it's amazing, I've seen a model installed in a door years ago and was blown away fascinated, do you intend to make a permanent installation?
@@coaber yeah, just one of the woofer fans can cause ear damage when played at 18 hz. I did this once at full volume and it felt like someone had connected a bicycle pump to my ears it was an insane amount of pressure.
I just drilled through the entire shaft. It is much easier than you would expect. First you turn on the motor and start the hole with a tiny drill bit (this centers the hole). Them you hold the desired size of drill bit with a vice grip and use the motor to drill itself the rest of the way. I recommend using cutting oil.
I'm also trying out different designs for this. If you see my video about the smallest rotary subwoofer you'll see another design I tried. It's quite different from the original.
@@nathanbulle5782 Actually no. I stand corrected. After doing research I see a few other DIY designs using the directional blades. I am used to the fixed blade rotaries that actually change rotation such as the Phoenix Gold Cyclone. Still very cool Yours was the first time I have seen the bearing with the coil method. I didn't even know it was a thing. I think the other method uses a type of DC motor running on AC current.
@@nathanbulle5782 The cyclone IS a rotary sub. That's what I am trying to tell you. Older rotary subs didn't have a coil and a spider. What you built is some kind of hybrid design. That's why it took me for a second. I looked them up on google and see a couple others like yours and they are DIY designs. Go look at older rotary designs and you will see what I mean. Theres a reason the original rotaries aren't in use anymore and that is efficiency and new technologies that allow our piston motor subs reach low frequencies. That is likely why the design you are using was created as sort of an in between. Still very inefficient however.
First off, thanks so much for the video and build! I absolutely love it, and it’s a shame people aren’t able to see or feel the amount of force something like this truly creates! If you ever wanted to level up from here, I’d recommend you’d use a rotary linear bearing attached to the woofers shaft, going to a rubber timing belt, connected to a remote motor and flywheel thus removing the need for as complicated woofer design , and spending more space and time on the voice coil design and prints. You could run some big ass coils (3” sundown or similar) and have more than adequate cooling, and use a Neodymium magnet and steel plate as the motor to save even more space and have more Bl (force). The final thing left would be making a mold for some carbon fiber fan blades, and maybe using brims joints with some lightweight carbon fiber rods from Amazon to connect it all. I just mentioned the flywheel in my last comment (weighs close to 200lbs) and is flat down to 0.05 microns 😂
What if you had two duct fans going in opposite directions? Add a T junction after the output, and solenoid or servo driven flap valves inside the junctions. The airflow comes into the junction from outside (= inside, for the other fan) after which the flap makes it either loop back outside (= back inside), or increase pressure in the house (= decrease pressure in the house). You could generate some huge SPL with this kind of setup!
Neighbor: "WHAT'S GOING ON IN THERE?!" Other neighbor "Oh, they must be doing laundry again!" Sweet device though, I've been fascinated with these for years!
RU-vid algorithm doings its job! I hope this blows up, it's an unique idea that I haven't heard of being done by anyone else, yet! After looking through comments I learned its not a new idea, still very interesting!
I have two of those Harmon Kardon speakers, I absolutely LOVE them. I've always been intrigued by Rotory subs, never seen them placed in a window before
Nathan's Mom: NATHAN! Turn that down! Mrs. Griffin, two houses down, already claims you broke three of her Precious Moments figurines. She doesn't like us, as it is.
