And YOU thought you had a subwoofer system

[Aaron'z 2.5RS]

HI all,

This is slightly OT (home audio), but lends to the overall picture of what our sub systems do and DON'T do... I found this in the OT forum and thought i must share...
http://www.rotarywoofer.com/

Many of you will rationalize this with Phenix Golds Cyclone http://www.phoenixgold.com/webfaq/cyclone.htm
But that technology doesn't come close to this new technology.

To any of you that actually care to learn about all things audio, it's a must read, as conventional subwoofer technology has been tossed out the window with this one. There is a review that covers everything including physics of WHY it does what it does...
http://www.iar-80.com/

Edit: The link to the actual review "The only Subwoofer" http://www.iar-80.com/page142.html


Again, this is only to further your personal knowledge base, and not ment to open a spiraling vortex/vertex in your universe... so read with caution...

Now, if we could some how retrofit/re-design this into the car enviroment...

Enjoy...
Aaron

* Registered users of the site do not see these ads.

[ScubaruImpreza05]

WTFBBQ! Looks like a radiator fan

[Aaron'z 2.5RS]

Originally Posted by ScubaruImpreza05

WTFBBQ! Looks like a radiator fan

Yes, yes it does, but it is oooohh so much more...

Learn yourself brotha...

[Daishi00]

Looks intriguing. I'll have to give this a read in a bit.

[neg_matnik]

Interesting stuff. However, it seems that it's only useful to reproduce sound below 20Hz and it's probably very bad with transients. You'll still want to keep a conventional subwoofer around.

[hondaftw]

Originally Posted by neg_matnik

Interesting stuff. However, it seems that it's only useful to reproduce sound below 20Hz and it's probably very bad with transients. You'll still want to keep a conventional subwoofer around.

anything to counter with this argument aaron? haha jk

[Okeyd57]

For 23 to 25,000 bucks for total install, I'll be using conventional subs for a long, long time !

[Aaron'z 2.5RS]

Originally Posted by hondaftw

anything to counter with this argument aaron? haha jk

Yup, i do

E. Opposites in Transient Response and Accuracy

As mentioned above, all conventional subwoofers have reactances which make it inherently impossible for them to achieve correct bass transient response, and thereby also make it inherently impossible for them to reproduce bass accurately. Furthermore, these reactances also make their bass energy occur in the wrong phase and at the wrong time. This means that the sonic contribution from all conventional subwoofers inherently cannot possibly add correctly to the sonic signal put out by the main loudspeakers. And this in turn means that the composite sonic signal will necessarily be inaccurate. It also means that the bass energy from conventional subwoofers inherently cannot possibly form the correct pedestal foundation for any and every musical transient and sound effects transient, so these transients (from your system as a whole) cannot possibly achieve the correct dynamic impact, correct peak energy and shape, nor correct sonic quality.
The TRW subwoofer is just the opposite. Rather than it being inherently impossible to achieve correct transient response, the TRW instead is completely the opposite in that it inherently has perfect bass transient response, so it does achieve virtually perfect bass transient response, and does so with ease. This means that the TRW inherently produces virtually perfect bass accuracy. It also means that the sonic contribution from the TRW subwoofer inherently occurs in the correct phase and time, to add correctly to the sonic signal put out by the main loudspeakers. And this in turn means that the bass energy from the TRW inherently does form the correct pedestal foundation for any and every musical transient and sound effects transient, so all these transients (as put out by your system as a whole) can and do easily achieve the correct dynamic impact, correct peak energy and shape, and correct sonic quality.
A crucial factor, in being able to achieve accurate bass transient response, is having frequency response all the way down to DC. A subwoofer like the TRW, which does inherently have frequency response down to DC, can correctly reproduce a step waveform, which is the basic test waveform for evaluating bass transient performance. Any subwoofer like conventional subwoofers, which inherently cannot achieve response down to DC and fail to do so by many octaves (indeed an infinity of octaves), cannot correctly reproduce a step waveform (again, the test waveform for evaluating bass transient response), and therefore cannot correctly reproduce any bass transient from program material.
Furthermore, conventional subwoofers, in the portion of their low frequency response that rolls off and fails to extend down to DC, happen to roll off at a steep rate of 12 dB per octave or worse, and any subwoofer that exceeds a 6dB per octave rolloff steepness will commit even further errors in its bass transient response, which are seen in the step test waveform as overshoot below the zero axis, and possibly also ringing thereafter. The TRW does not have these steep rolloffs, so its transient response does not have overshoot and ringing that make the transient response of conventional subwoofers inaccurate in these further ways.
As we'll discuss later, accurate bass transient response is audibly crucial, for all kinds of music and sound effects. Every kind of music and sound effect is continually changing, so every sound we care about is a transient, not a steady state tone. This means that the transient response of a loudspeaker, including a subwoofer, crucially affects the correctness, accuracy, naturalness, and reality of every sound we hear from our systems.
In all these aspects of transient response, it is the TRW that is right, and conventional subwoofers that are wrong. So, which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

[Aaron'z 2.5RS]

Originally Posted by Okeyd57

For 23 to 25,000 bucks for total install, I'll be using conventional subs for a long, long time !

But at the same time it is high end home audio, so it goes with the territory, i've sat in front of $80-100K systems and i guarentee there are plenty out there having houses built just for it...

[industrial]

Man thats expensive but such an interesting read. Thanks for posting that up. Hopefully in 5-10 years we'll have $500 versions.

[fireball_jones]

5hz is like what whales communicate at, isn't it?

Neat idea, I guess.

[ekw]

part of me keeps looking at the "fan",
reading "$12,900 transducer"
and thinking: April Fools joke.
but, then I remember for high end HT, nothing is unreasonable.

[couchflambeau]

Originally Posted by fireball_jones

5hz is like what whales communicate at, isn't it?

Neat idea, I guess.

Not sure about whales... but isn't that what the Navy uses to communicate with submarines? Yeay! Your own personal ELF array!!

http://en.wikipedia.org/wiki/Extremely_low_frequency

Pretty cool... but for the $$$ I don't need faithful reproduction of a UH-60 that bad. I'll stick to silly cones for now.

[Aaron'z 2.5RS]

It will actually do 1hz at the same level as 5hz. From how it reads, it will do all frequencies at the same level, no roll off at all.

The fan spins at a constant rate, the fans motor has enough torque to keep it from slowing down, then the blades are of variable pitch and it's the pitch (and the subsequent swing of the blades) that creates the various frequencies (positive and negative waveforms)

They say it outputs the same throughout it's range....

Honestly, i could see a much smaller version in a car, it would have to be in sort of an infinite baffle set-up (that is how it's used in the home, to separate the front waveforms from the rear waveforms)
A DC motor structure and the transducer it used to change the pitch of the fan blades it powered from a "normal" amp..... I could see it being "doable"

[DuckStu]

I would think the DC motor would be powered by wall socket,...and the blade pitch would be powered by your amp.

Amps do not output a continuous dc current.

[Daishi00]

Originally Posted by ekw

part of me keeps looking at the "fan",
reading "$12,900 transducer"
and thinking: April Fools joke.
but, then I remember for high end HT, nothing is unreasonable.

Ha that's exactly what I thought at first. I mean, to people that drop $5k on a 0.5 meter cable $5k for a sub is NOTHING).

[Aaron'z 2.5RS]

Originally Posted by DuckStu

I would think the DC motor would be powered by wall socket,...and the blade pitch would be powered by your amp.

Amps do not output a continuous dc current.

Which part of this post did you read, sir??

If you read this:

A DC motor structure and the transducer it used to change the pitch of the fan blades it powered from a "normal" amp..... I could see it being "doable"
Today 08:16 AM

I was speculating on HOW WE could retrofit something like this into our CARS... and a DC motor would be the only way to go, and the AC from the amp would be used to control the blade pitch on the fan (just like the actual model, but that has an AC motor and a transducer to control the blades)

Please read.

[Aaron'z 2.5RS]

bump, to try and keep people reading...

[V6TurboTA]

Looks like a total sham to me.

The combination of ultra cheesy website, extrapolated results, THD ratings you wouldnt even see on radio shack equipment... puhhhleeease.



~v6

the price isnt scary... I was reading a review in Home entertainment on a new projector a few hours ago... I read the whole review before looking at the price... then I see the unit is $29,999!!!
That was almost as rediculous as the review on the home theatre in some guys house in FL... grand total aproximately $290,000.

[Aaron'z 2.5RS]

I donno man, did you read any of the review http://www.iar-80.com/page142.html

The only extrapolated results, i saw were of the cone woofer below 20Hz... I'm sure the THD rateing were set so high to account for the cone woofer and it's THD at such low freq.

The following distortion test were measured on the rotary woofer. The microphone was three meters from the woofer. The system was calibrated with a Bruel and Kjaer 4145 microphone, pistonphone and 2204 sound level meter. The spectrum analyzer was calibrated to be flat to below 1 Hz using a signal generator and voltmeter. In this test configuration the rotary woofer was able to maintain greater than 110dB sound levels down to 1Hz. Typical maximum sound levels in the 2800 cubic foot test room are around 115-119dB with 350 watts total input power (motor plus audio amplifier power) between 1 and 30Hz.

For comparison most conventional subwoofers will not achieve 110dB output at any frequency 20Hz or lower with 10***37; distortion or less.

Because these distortion measurements include the room they are likely higher than actual anechoic readings. The room walls experienced resonance modes between 10 and 15 Hz. Below 5Hz there is significant volume velocity at 110dB such that a door will swing back and forth. At 1Hz you don't hear anything other than the rattling of doors, walls and the air moving through the transducer and the room. The THD number includes all harmonics and room noise up to 2Khz.

1 Hz measurement, 110dB 7.24%THD

Read the review.... at least some of it...lemme know if it changed your mind any...

[V6TurboTA]

I read the specs

Specifications: Amplifier Requirement: 200 watts @ 8 ohms Impedance: 8 ohms 0Hz - 40Hz Frequency Response: 1Hz - 30Hz +/- 4dB Suggested Crossover: 20Hz @ 18dB/octave Sensitivity 94dB 1 watt 1 meter @10Hz Maximum Acoustic Output: >115dB between 1 and 20Hz. Distortion: Typically 3***37; or less between 1 and 30Hz @90dB Warranty - 3 years parts and labor Patent Pending

They are terrible at best. 3% thd is unacceptable imho.
As unacceptable as a $25,000 SUB-subwoofer that will RARELY do anything as very few sources use 20hz and down (from what i gather it suggests you cross it over at 20hz and down). In fact a decent amount of quality subwoofers use subsonic filters to entirely remove those frequencys for a few main reasons. First and foremost because you cant hear them, secondly because they use extremely high amount of power to produce (which rob power from tones that are actually audible), and thirdly because most of them simply cant reproduce sounds that low

I read some of the review. I dont know anything about the source (website) and I dont trust any source I dont know about.
It seems like one giant sales pitch to me, but what do I know...

When a product is new, innovative, and actually works, EVERYONE talks about it. Not just one website that looks like it was made in a few hours. They would have a booth as CES, etc etc... ESPECIALLY for such a high ticket item.

At least thats my always skeptical view.

~v6

[Aaron'z 2.5RS]

I see what your saying man, but i spent an hour reading throught the review, and all of the reasioning is gone through about Why subs tipicaly have sub-sonic filters, and why a sub cannot couple to the air properly at such low frequencies, why normal subs require such power to even touch sub-sonic freq. and you may not be able to hear them, but tactle feeling is as much a part of hearing low freq AS hearing it... I mean how often can you hear a helocopter or jet before you see it.... you "feel" it first...

It may certinly be a sales pitch.... i'm not saying either way, just passing on info...

[02BlueSuperRoo]

Can humans even hear this thing?

[V6TurboTA]

I totally agree with you on the feeling it part. If that was not true bass shakers would be useless

This is an interesting piece. I'll say that. I am eager to see how this pans out in the grand scheme of the audio world.

~v6

[earshot]

Originally Posted by Aaron'z 2.5RS

Honestly, i could see a much smaller version in a car, it would have to be in sort of an infinite baffle set-up (that is how it's used in the home, to separate the front waveforms from the rear waveforms)
A DC motor structure and the transducer it used to change the pitch of the fan blades it powered from a "normal" amp..... I could see it being "doable"

It would require a huge enclosure, even a scaled down model. In an IB setup in a car you are asking for trouble. I don't see how it is much different than the cyclone, you still use the air pressure from outside the cabin to change the air pressure inside the cabin, yeah the blades don't spin back and forth, they use a variable pitch system, more expensive, more moving parts. Is this thing noisy like the cyclone was?

I'd pay $1,500 for one.