Rotary woofer - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 282 Old 12-27-2010, 05:46 AM - Thread Starter
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When it comes to producing sub-sonics conventional subwoofers are incapable of pushing enough air; they produce low bass by high pressure, going back and forth madly which produces very high distortion. The rotary sub produces bass with low pressure, very low distortion, and transient response that is real sounding. Having response to below 1 hz is the key to transient response and this is the reason the rotary woofer is so accurate at producing bass below 25 hz with real authority. One can use many drivers to push enough air to produce sub-sonics but they still have trouble with transient response and lots of distortion, not to mention the power needed. As with any new technology cost is a major factor and the rotary woofer is expensive, but if ones builds the necessary enclosure and installs it, the cost is half that amount. I built the enclosure which is 8' long by 4' wide by 4' high. Power comes from the ac voltage the drives the fan utilizing a motor controller to control the speed; a modulating amplifier is used to pitch the blades (a small amount, 200 watts). This is my second post on AVS and I just want to make it clear about the facts of the rotary woofer. A state of the art in sub-sonics; once one hears the results, there is no going back.
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post #2 of 282 Old 12-27-2010, 05:47 AM
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Are you saying you did this DIY?? You still had to buy the Rotary sub and modulating amp, correct?

I have been waiting a long time for a DIY rotary design.

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post #3 of 282 Old 12-27-2010, 06:04 AM
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Let us kill the fatted calf if you do a DIY rotary sub, with pics, connections and a nice BOM so we don't go crazy buying the wrong stuff.

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post #4 of 282 Old 12-27-2010, 06:47 AM
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This is probably Vas or some other troll . He has 2 posts and both are worshiping his almighty rotary.

If at first you dont succeed , get a bigger hammer !
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post #5 of 282 Old 12-27-2010, 07:11 AM
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Quote:
Originally Posted by rwaaudio View Post

When it comes to producing sub-sonics conventional subwoofers are incapable of pushing enough air; they produce low bass by high pressure, going back and forth madly which produces very high distortion. The rotary sub produces bass with low pressure, very low distortion, and transient response that is real sounding. Having response to below 1 hz is the key to transient response and this is the reason the rotary woofer is so accurate at producing bass below 25 hz with real authority. One can use many drivers to push enough air to produce sub-sonics but they still have trouble with transient response and lots of distortion, not to mention the power needed. As with any new technology cost is a major factor and the rotary woofer is expensive, but if ones builds the necessary enclosure and installs it, the cost is half that amount. I built the enclosure which is 8' long by 4' wide by 4' high. Power comes from the ac voltage the drives the fan utilizing a motor controller to control the speed; a modulating amplifier is used to pitch the blades (a small amount, 200 watts). This is my second post on AVS and I just want to make it clear about the facts of the rotary woofer. A state of the art in sub-sonics; once one hears the results, there is no going back.

Rotary, meet matterhorn.

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post #6 of 282 Old 12-27-2010, 07:52 AM - Thread Starter
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post #7 of 282 Old 12-27-2010, 08:03 AM - Thread Starter
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post #8 of 282 Old 12-27-2010, 08:11 AM - Thread Starter
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post #9 of 282 Old 12-27-2010, 08:30 AM
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Thanks for the photos! Looking forward to hearing more about your project.

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post #10 of 282 Old 12-27-2010, 08:34 AM
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Thanks for posting the pics, I'm not ignoring your email, I wanted to take my time and go through every pic...as you see, it's time consuming! You saved me the trouble. Again, beautiful work! I love the art you bring to it.
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post #11 of 282 Old 12-27-2010, 08:44 AM
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Wow, nice to see someone still using those CRT projectors. I use to have a NEC XG LC 8'' a couple of years ago and it was awesome. If you could live with the size and were able to properply set them up they produced some of the best images even against some of the top digitals today. The fact they lasted forever was another big plus.
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post #12 of 282 Old 12-27-2010, 10:14 AM
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Wow! Really cool!

Heh, totally not surprised that Phil Marchand made the audio filters for this bad boy. Mhmmm.
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post #13 of 282 Old 12-28-2010, 10:19 AM
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You had me at Rotary. Do tell us more!

Did you do buy some sort of kit? That frequency inverter looks awful familiar to me...that is what you are referring to as the motor controller correct? And the modulator is the box in your rack right?

A bigger hammer is only better until you hit your thumb with it.
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post #14 of 282 Old 12-28-2010, 10:36 AM
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The full TRW-17 package runs ~$23,000. This includes the setup fee for them to come out to your location, and build/set everything up for you.

You can choose to buy the hardware only from them, and install it yourself for ~$14,000.
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post #15 of 282 Old 12-28-2010, 11:04 AM - Thread Starter
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That is correct
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post #16 of 282 Old 12-28-2010, 11:08 AM
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Ouch. Some of us need to brush up on our R/C helicopter skills to bring these costs down.
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post #17 of 282 Old 12-28-2010, 11:14 AM
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Is this thread an ad? Where is everything of interest, you know, science related

Pictures are great and all, but c'mon.
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post #18 of 282 Old 12-28-2010, 11:22 AM
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Scott--I was looking into the feasibility of a rotary a while back. The swash plate would be an excellent place to start. It both spins and allows for linear motion, so it's pretty much perfect for the intended application.

With one little issue--they require maintenance. So unless you're planning on replacing plastic pieces every several hours of runtime, not the most practical solution in the world.

But who knows, maybe you could find a specialty supplier with a swash plate that doesn't require maintenance.

Ultimately I chickened out--the prospect of spending $600-800 with no firm promise of success was a tad much for me.

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post #19 of 282 Old 12-28-2010, 11:27 AM
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Yeah, idk if I am ready to take the plunge into the unknown either. Developing something like that is waay past my paygrade but I'd love to follow up on something like this if there was a feasable DIY design that wasn't too hard to replicate.
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post #20 of 282 Old 12-28-2010, 01:19 PM
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Quote:
Originally Posted by notnyt View Post

Is this thread an ad? Where is everything of interest, you know, science related

Pictures are great and all, but c'mon.

ya, throw some vids in here and make it legit

$14,000 can buy LOTS of IB3 18's and EP4000's

sorry, had to
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post #21 of 282 Old 12-28-2010, 02:16 PM
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Originally Posted by rwaaudio View Post

That is correct

So you just bought a package?? Installing it on your own does not really make it DIY does it?

Anyways, Im still waiting for a real DIY solution until then there are 100s of things I will spend $14K on.

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post #22 of 282 Old 12-28-2010, 03:07 PM
 
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Anyways, Im still waiting for a real DIY solution until then there are 100s of things I will spend $14K on.

You can get a lot of horn into a 128 cu ft box.
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post #23 of 282 Old 12-28-2010, 03:40 PM
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So you just bought a package?? Installing it on your own does not really make it DIY does it?

Anyways, Im still waiting for a real DIY solution until then there are 100s of things I will spend $14K on.

did you build your subwoofer from scratch? did you build your amp from scratch? your receiver? Or did you make a box and screw your subwoofer that was built by someone else into it?



jus sayin

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post #24 of 282 Old 12-28-2010, 03:41 PM
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You can get a lot of horn into a 128 cu ft box.

well design me one bill, I got to 128 cu ft boxes that I wanted to horn
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post #25 of 282 Old 12-28-2010, 04:04 PM
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Bill is quite expensive Kryptonitewhite!!

Max could design you something or even Lilmike depending on which horn design you want.

I cant remember but I thought there was a forum member from this forum or it could be from another one(I belong to too many) that was designing a rotary woofer. I think he was quite the electronical guru and it seemed really just a matter of time till he made one. I cant remember if he worked on helicopters or what but he seemed very promising to others that he could figure it out. I am not saying the guy promised anything just that when reading what he was attempting I would be willing to bet he could do it.
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post #26 of 282 Old 12-28-2010, 04:25 PM
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Quote:
Originally Posted by kryptonitewhite View Post

did you build your subwoofer from scratch? did you build your amp from scratch? your receiver? Or did you make a box and screw your subwoofer that was built by someone else into it?



jus sayin


You buying a $14K fan???

I get the point but usually we DIY because of 2 reasons.

1. We build designs that are not sold.

2. We build to get great value and ignoring time/materials/overhead. Even $500 worth of parts still costs over $1K in total because of materials, equipment depreciation and time all do matter (Well for me its $10K worth of time if I was actually to consider what my $/hr rate is).


I will be waiting for a DIY fan/motor option that should costs less then 1/10th what the Rotary costs. I have many, many motors to choose from many prototype automated stacker projects at a clients facility.


I already have 6 18" woofers, 6 15" woofers used/unused in the house. Time for something different

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post #27 of 282 Old 12-28-2010, 04:57 PM
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6 18" woofers, 6 15" woofers used/unused in the house? wtf? What are you currently running?
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post #28 of 282 Old 12-28-2010, 04:59 PM
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Quote:
Originally Posted by kryptonitewhite View Post

6 18" woofers, 6 15" woofers used/unused in the house? wtf? What are you currently running?

Remember I said used and unused. You know I have an IB array (4x18) in my family room and twin ported subs in my HT room? Just added two LMS5400s to the HT room. I also adding AV15X woofers as part of my new 3-way full range mains.

Im going to either add more sealed subs in the HT room or Im going to build two massive Horn designs and use my TC2000 15" woofers that I will not be using any more.

My ultimate is still getting a Rotary sub but I do not like spending $14K on audio.

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post #29 of 282 Old 12-28-2010, 05:06 PM
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IB array (4x18) in my family room and twin ported subs in my HT room? Just added two LMS5400s to the HT room.

thats a lot to keep up with lol
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post #30 of 282 Old 12-28-2010, 05:07 PM
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Quote:
Originally Posted by rwaaudio View Post

Having response to below 1 hz is the key to transient response and this is the reason the rotary woofer is so accurate at producing bass below 25 hz with real authority.

Surprised no one questioned this statement.

Noah
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