Rotary Woofer facts - Page 2 - Home Theater Forum and Systems -

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post #11 of 19 Old 02-24-11, 08:01 AM Thread Starter
Join Date: Feb 2011
Location: new berlin ,wisconsin
Posts: 51
Re: DIY Rotary Woofer

Thanks, the rotary subwoofer is the most exciting and realistic sounding audio product
I have ever owned. I have been an audiophile for 50 years and this rotary subwoofer
excels in reproducing very low bass. The added excitement that one gets with this
sub is exhilarating. Listening to the Mormon Tabernacle choir with that immense pipe
organ is awesome with this rotary subwoofer. It is so solid and clean sounding with
out a hint of strain. In the past I used infinite baffle subwoofers (two 24" Hartley
subwoofers) built into the floor of my room. They worked well, but couldn't come close
to the performance of the rotary subwoofer. We are talking about frequencies down
to 16 hz with the pipe organ, and that is we are just loafing around. Going down from
there it gets better and better. There is lot of movies with content below 10 hz and
some that go much lower. I also have several cd's that have very low bass, that without
the rotary subwoofer, one would not hear and feel the tremendous power and
extension. Some of these recordings would destroy conventional subwoofers (Apollo 13
rocket taking off with bass content below 5 hz) is one example. As good as the rotary
subwoofer is with bass that is low and continuous, transients are its forte. A great
example is the very low thunder clap (Telarc CD-80447 Surround Sounds, track 9), with bass
that is frightening and sounds very realistic. I only use around half its total output and because
of this there is even lower distortion and headroom to spare!!!!!!!
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post #12 of 19 Old 02-24-11, 08:08 AM Thread Starter
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Re: DIY Rotary Woofer

These are pictures of the 24" Hartley subwoofers that I used to use.
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post #13 of 19 Old 02-24-11, 08:20 PM
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Re: DIY Rotary Woofer

$11,000 for a manifold? That doesn't sound right.
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post #14 of 19 Old 02-24-11, 09:15 PM Thread Starter
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Location: new berlin ,wisconsin
Posts: 51
Re: DIY Rotary Woofer

The price of the manifold varies with the type of installation. I talked to Bruce
Thigpen about the requirements of the manifold, location and size of the opening
and made a detailed drawing and sent the drawing back to Bruce for approval. After
receiving approval, I constructed the manifold and took pictures and sent the photos
back to Bruce for his comments. The manifold that I constructed was approved by
Bruce and I then ordered the rotary woofer, motor controller and rotary woofer controller.
The next step, after I received these items, was installation of the rotary subwoofer
and testing. Bruce Thigpen's assistant, Winston Wright, flew out from florida to do the
final installation of rotary woofer and motor controller. Because I constructed the manifold and did the design the cost was considerably less. If Bruce did all the design,
construction, installation and testing the cost would have been 20k. Every installation
is different depending the location of rotary subwoofer and opening into one's room.
One of his customers had a lot of reconstruction of the room to allow for the rotary to
operate properly and the cost was far more.
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post #15 of 19 Old 02-24-11, 09:25 PM Thread Starter
Join Date: Feb 2011
Location: new berlin ,wisconsin
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Re: DIY Rotary Woofer

Some pictures of another rotary install.
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post #16 of 19 Old 02-24-11, 09:35 PM
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Join Date: Dec 2010
Location: Halifax, NS
Posts: 165
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Re: DIY Rotary Woofer

Mmmmmm. Gear Pr0n. I hate this thread for making me really want one of these.... effortless low end down below 1hz and not having to worry about it the way you would a traditional speaker. No worries of over exerting the driver for the low frequencies and not worrying about overpowering it. My main problem with audio equipment is worry. I worry about abusing the equipment and also worry about disturbing others with it. That's why I got an 18" driver that can easily do 800 watts max and am only giving it 500 max. I would very much like to see some video of this thing in action .
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post #17 of 19 Old 02-25-11, 08:11 AM Thread Starter
Join Date: Feb 2011
Location: new berlin ,wisconsin
Posts: 51
Re: DIY Rotary Woofer

There are videos of the rotary woofer operating on youtube. Yes, you are correct
about overdriving conventional subwoofers. In the past I used two 24" Hartely
subs and was always concerned about exceeding the excursion limits, as well as,
overheating. The way I handled that problem was to use subsonic filtering and
limiting protection. I used a Velodyne Digital Drive SMS-1 subwoofer management system
which had adjustable (15hz - 35hz subsonic filter (12db/octave to 48db/octave.
Before I used this device I occasionally bottomed out the woofers and thought I destroyed
them. Now with the rotary subwoofer that is not a concern (I am not even close
to the full output. The rotary is built very well and requires no maintenance. I also
have a few close up pictures of the rotary subwoofer and this might be of some help
for trying to build one (diy). It is unfortunate that this rotary subwoofer is so
expensive, but being a custom product and the fact that not many are being sold,
its understandable. When I purchased the rotary subwoofer,only 28 of these units
had been sold. Feel free to ask any other questions about the rotary sub.
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post #18 of 19 Old 02-25-11, 04:30 PM
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Does the technology appear scalable. It would be pretty amazing to see one in the normal passband for reduced cost
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post #19 of 19 Old 02-25-11, 04:48 PM Thread Starter
Join Date: Feb 2011
Location: new berlin ,wisconsin
Posts: 51
Re: Rotary Woofer facts

The rotary woofer could not compete with conventional woofers when producing
frequencies above 30 hz. The fan speed would have to be much faster and the
mechanical linkage would have problems pitching the fan blades faster, causing high
distortion. The increased fan speed would also cause way too much noise and
turbulence. This design is for very low bass only.
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