Yes, it is for real. I was following a thread over at the cult on that. I believe it is $15,000 for one presently

 

Well, when I think IB/DIY, I don't think $15k! It is a really cool concept though; I've been working through the math on it today in the patent for it.

 

You got farther than I did That stuff is over my head, I heard the price would be substantially less if it ever went to market but I have a feeling the demand wouldn't be that high so the price would probably remain well above "reasonable". I'd LOVE to hear one though.

 

Do some googling- there are some videos of it at work (a helicopter sound was cool)- though they can't do it justice for the low frequencies unless you're there in person, I suspect.

 

Sounds good but can you use it as a fan as well? :laugh:

 

I believe that they are "marketing" them now, as I think I saw an ad in the latest Stereophile (don't think it mentioned a price).
JP

 

Kingjamez at CotIB says he's building a DIY rotary sub!

Yea, Bruce Thigpen is the reason I need the amp. I'm trying to build a DIY rotary sub and have got all the parts on order. I just needed an amp that can actually drive it. I'll use Speaker Workshop to test the amp (and my sound card) and see if it will actually produce subsonic frequencies.

 

If one realy wants to be buffered by lots of moving air ,stick your head out of a car window while moving. A very unpleasant feeling unless one happen to be a bikie...........It is a lot cheeper than buying a glorified fan Kind regards alan

 

not even close to the rotary woofer. There is no net displacement of air, unless, truly, there is a DC signal or offset. You also won't feel ill or nauseous at all... the SPLs to get there are achievable, I suspect, by the TRW, but my room would be destroyed far before I got there.

 

Tzuzz I agree,My eardrums would be wrecked before the room was. I know of a bloke that ignored a "do not enter this area " warning on the top parts of a cruise ship ,This area was reserved for the ship FOG HORN.So it happened that day was foggy , the results,he is now permantly deaf as a lamppost.Kind regards Tzuzz,alan.

 

WOW how loud do you think the fog horns were to cause him to go instantly deaf?

 

I removed the remainder of this post since a moderator or admin deleted sections of it and failed to post to that effect

 

I think (from memory) that at 150Db your eardrums will burst

 

Hey guys... let's try to keep this on topic... thanks!

 

alan

You don't need to stick your head out of the window.

Very high levels of VLF (flutter) are possible when driving reasonably quickly with one window partly open. Presumably the car becomes a Helmholtz resonator excited by the turbulent airflow across the open window. Like blowing over the top of a very large bottle.

I haven't tried adjusting window height to see if the frequency changes noticeably as it might with variations of reflex port area. I prefer to concentrate on my driving.

I think you are much too dismissive of a clever technology with this fan subwoofer. Who knows where further development might lead? The first example of every successful invention is rarely the final evolution. I wonder what Alexander Graham Bell would think of a G4 mobile phone?

The question is not whether the fan subwoofer works but whether the world needs or wants it it. Is the average HT nut willing to buy it in sufficient quantities to warrant manufacture on a much larger scale? And if he did, would civilisation survive high level infrasonics in every home that could afford it?

 

Sorry to revive a one year old thread, but is there any new news?

Bob

 

The last I heard, a bunch of people were making some version of the rotary fan woofer to varying degrees.

Personally, after sREWing around a bunch and setting up my dual 18 IB, I don't think the ultra-low frequencies are necessary anyway.

What I mean is that, I can't hear or feel these very-low effects under 25 Hz or so. Maybe it was the series of Van Halen (I'm talking pre-sammy, pre-1984, *real* rock) concerts.

In any case, I'm thinking if I want true LFE, it'll have to be with buttkickers, or somesuch. Doing it through the air is just too inefficient.

Since the old comparison I used to do with theaters was "is my sound better that what I'd get at a theater", I passed the "absolutely, yes" mark a while ago. I don't think any theater has such a contraption, so I'm wondering who is using this stuff anyway?

 

I can only suggest that you are rolling off too early due to a rumble filter somewhere or you haven't enough displacement. Even my humble PCI can play infrasonic fireworks completely silently. My 4 x 15" IB can produce much more of the same. If you get 100dB @ 10Hz (uncorrected SPL meter) from your IB doesn't your hair shake if you go close enough? At around 15Hz doesn't the air in the room seem to go thick? Slightly lower again doesn't it feel as if your head is pumped up with air? Mine does all of this with hardly a sign of cone movement. Are your speakers in phase? Perhaps you need a house curve?

 

umm ok. It might be great in a hot room. I wonder if it will work with my centeral air conditioner. All kidding aside, the real question is why. Is that price for real?

 

Yeah, when it is in the low 20s, I can 'feel' a vibration in the air- and in certain movies, it really adds to it.

The new IB is new, and I really haven't put it through the paces yet. I have power and xmax to spare, so I can really turn it up, but yes, I do have a housecurve, and could make it a scary one, but not sure how high I need to go...

 

Perhaps your IB simply needs to be a little bit hotter compared with your speakers?
SPLs are vital for maximum effect at such low frequencies.

The fan sub story seems to have gone quiet again.
There were rumours of a much more affordable model in the pipeline.
The Fan Sub website is still claiming that cone subs cannot compete.
That may be true below 5Hz but a few good 18" cones in an IB would go a very long way down without costing the earth.
Place them in a manifold under the floor and you need never know they existed.
Until, that is, the monster is called forth from its dark lair. :hide:

 

Thanks for the reply toecheese. I was hoping to find some fellow that's DIY'd one of these. I think they could be a viable piece of equipment, but not at current prices.

Chrisbee, you wouldn't happen to have a link to the fan club guys would you? When Google searching, all I find is Thigpens unit.

Thanks guys!
Bob

 

Sorry, Bob. I'm not sure what you mean by "fan club guys"?

I only know of the Thigpen as a successful project.

There was some input from Bruce Thigpen on the Cult of the Infinite Baffle forum under general topics on Page3. The thread is called "One amazing subwoofer".

There are lots of links on this page: http://www.rotarywoofer.com/

(Scroll down to further links on the right for another page of links)

The owner of the first installed pair had a construction blog and posted on a number of forums I think. Very patient chap. He answered a lot of questions.

 

Sorry, Bob. I'm not sure what you mean by "fan club guys"?

:sarcastic: Sorry about that dude, my fault. I meant fan sub. You had mention the "Fan Sub" website and capitalized the letters which gave a certain amount of signifigance, I had the impression there was s specific place you were talking about. (is it the rotarywoofer.com site, or is there another?)

I'll check out the cult, thank you for that, sounds like it might be a good thread.

Bob

 

I think diyAudio forum had a fan sub thread with a couple of people threatening to build alternatives. Somebody was making a cylindrical centrifugal fan sub. Rather sophisticated too judging from the images.

I am still at a loss to explain the TRW fan sitting in a hard edged box in the videos and images online. Some sort of radius or fairing would surely have reduced the noise they experienced? This seems such an obvious point that I wonder why they haven't done anything about it. The airflow must be highly turbulent at the rotor tips where the velocity is highest. What am I missing? :scratchhead:

 

I agree, on all counts Chrisbee. They've got some problems from what I've read on the net. I've recently made a financial commitment to going down this same path and am nowhere near their prototype, so I won't speak of "how easy it is". But some of their issues SEEM like they'd have obvious solutions. I've bumped numerous threads on numerous forums gathering information, including a Cult thread you were posting in a while back. I've received lots of links (like yours, and thank you for that), but no real solid DIYers out there. I suppose it's due to one of two things; #1 Nobody really WANTS to DIY one of these, or....#2 Nobody wants to TELL what they're doing??????

Bob

 

I would imagine transient response is the major difficulty with fan subs.
Even at UVLF there is still a need to start and stop a note or effect abruptly.
The chuff of a great organ pipe is quite different from the way some pipes slowly breathe themselves into life.
Albeit an octave higher that the fan sub can manage.
Even underpinning an LFE explosion must still require a leading edge, sustain and decay.

 

I'll be going the way of the VC to pitch the blades. It seems logical since that's what drives a cone in a typical driver. This "should" take care of attack, sustain and decay. I've been saying, "should", "I think", and "maybe" a lot on this project. My system will end up being quad ampped by the time this is all said and done. The fan will only go up to 30'ish'. IB above that, and so on....
I've got the 'real complicated parts' on order. Should be a week of so before the sparks fly. :yes:

Bob

 

Bob

A voicecoil is working against a lightweight cone with limited inertia and limited air mass working against it.

A fan has much heavier blades and is shifting relatively massive quantities of air.

The blades have centrifugal force acting against the support bearings producing friction and possible backlash.

Electro-pneumatics would seem to offer the sort of power required.