Silly and Nuts!

I've seen people doing the wave at sporting events that were slower than 1Hz...  Does that count?

Maybe, If you had a rotary woofer you could have heard it too.

:-)

How can it be really loud if no one can hear it?

The only one who has to know is you and the power company. :-)




One of the listed benefits of this rotary technology is that it uses a fraction of the power that a voice coil type driver requires to get to a useful SPL.

drewfx1

mike_mccue


I'm looking forward to seeing how low I can actually hear.

The problem is you need the signal to be really loud to hear it.

So you have to boost the sub's level to ridiculous levels for frequencies that low to be of any use. May not be of much use for music, but could be fun for making the room shake.

We be talkin' infrasonics, roight?

It's hard to call it infra sonics.

I just got back. We listened to a 4.09Hz test tone. I heard it and felt it. It's hard to call it infrasonic after you have heard it.

The house resonated at 8hz and the root tone was masked by the sound of shaking stuff.

At 4 hertz the house settled down and it was clear and well defined.

We listened to some cool moog synthesization recordings. A field recording of the caldera of an active volcano.

When we got to the markee feature movie sound design it seemed obvious that even the mixes that are notorious for thunderous low content were not prepared to take advantage of this play back technology. The result was a sense of detail and gracefulness with even the loudest deep frequency events.

I am sort of gobsmacked.


Speaking with Mr Thigpen was delightful. I could sort of keep up with his explanations of how the driver and the system works. He seemed very humble and open about the various limitations that must be balanced to make his design work and he had a great enthusiasm for sharing his insights.

It was pretty awesome. :-)


best regards,
mike 

It's interesting as I didn't know it was possible to hear infrasonics, but I find it is! I found these proposed extensions of the equal loudness contours (based on fairly limited research):


But I still question it's practicality for anything other than specialized recordings.

The problem is that, for example, at 10Hz a 40 phon listening level requires ~110dB SPL. But this means that, assuming flat frequency response, the sub is putting out 110dB SPL at 60Hz too. And 110dB SPL at 60Hz is ~100 phon. So the upper end of the sub's frequency range is ridiculously loud to us in order to produce a relatively quiet low frequency.

He cuts off the output of the rotary woofer anywhere between 20 and 40 Hz, and indeed he explains that as he develops the SPL capability for the low notes using higher (but stabilized and consistent) velocities of the fan blades that the character of the upper frequency sound gets harsh.

The corollary is that he uses a traditional cone driver between 30 and 80 Hz and so it is running in a graceful place and isn't trying to go as low as some subs that sound like they are mushy.

The blend seemed really smooth. The lowest notes seemed to be made with ease.

It was the finest stereo or surround system I have ever heard.


I don't personally have an great interest in hearing explosives on film, but I am wildly interested in how "infra"sonics create a sense of mood, atmosphere, and sonic signature of ambient environments.

I am also a slut for crazy low bass and the idea that music can still push the creative envelope in that direction.

Most of the movies barely had any sub 30 content but the few that did were spectacular. Yet, I have heard many real explosions, and what I heard last night was just a far more vivid impression rather than a reenactment of *the real thing*

I always over do the kick drum on my mixes... cause I like it that way. :-) This system would have revealed that my kicks are infra sonic on most systems.

The moog stuff and the pipe organ stuff was very "musical" and suggested that musicians could definitely write for this playback technology.

I can see this slowly becoming a feature at the rave clubs, if that's what they call them these days.


I am also fascinated with the idea that sound is a temporal sculpture of sorts. When you feel and hear the 4 Hz... you know you just bumped into something. So I have an enthusiasm for an increasing awareness that sound is something we actually touch like a sculpture. It's 3d art that we can walk within. A speaker like this will make you aware.


Mosh knows what I mean. :-)


drew, I think you would have really enjoyed speaking with Mr Thigpen and I dare say that you would have been better prepared to consider some of the explanations than I was. I'm still thinking about some of the stuff hoping to have an ah-ha moment.



all the very best,
mike 

finally...those ginormous space battleships can be heard as they traverse the void!..

thanks for the review/writeup mike!

 mike_mccue


He cuts off the output of the rotary woofer anywhere between 20 and 40 Hz, and indeed he explains that as he develops the SPL capability for the low notes using higher (but stabilized and consistent) velocities of the fan blades that the character of the upper frequency sound gets harsh.

The corollary is that he uses a traditional cone driver between 30 and 80 Hz and so it is running in a graceful place and isn't trying to go as low as some subs that sound like they are mushy.

Ah. OK. Forgive me, I didn't read the specifics on the system. This is what you need to do to make it useful for a signal that doesn't only consist of super low stuff - crank up the super low stuff by a huge amount, comparatively. This is like EQing the crap out of it, so it falls more into the "I don't care if it isn't 1000% natural reproduction, but it sounds better to me" camp (full disclosure - I happen to fall into this camp).

I am also a slut for crazy low bass and the idea that music can still push the creative envelope in that direction. 

Most of the movies barely had any sub 30 content but the few that did were spectacular. Yet, I have heard many real explosions, and what I heard last night was just a far more vivid impression rather than a reenactment of *the real thing*

I always over do the kick drum on my mixes... cause I like it that way. :-) This system would have revealed that my kicks are infra sonic on most systems.

The moog stuff and the pipe organ stuff was very "musical" and suggested that musicians could definitely write for this playback technology.

The paper I got those last charts from might be interesting to you:
http://www.noiseandhealth.org/article.asp?issn=1463-1741;year=2004;volume=6;issue=23;spage=37;epage=57;aulast=Moller

But it suggests that infrasonics may not be useful for music:

The perceived character of the sound changes gradually with frequency. For pure tones the tonal character and the sensation of pitch decrease with decreasing frequency, and they both cease around 20 Hz. Below this frequency tones are perceived as discontinuous. From around 10 Hz and lower it is possible to follow and count the single cycles of the tone, and the perception changes into a sensation of pressure at the ears. At levels 20-25 dB above threshold it is possible to feel vibrations in various parts of the body, e.g. the lumbar, buttock, thigh and calf regions. A feeling of pressure may occur in the upper part of the chest and the throat region.

I wonder if your impressions were different than what they describe? 

I can see this slowly becoming a feature at the rave clubs, if that's what they call them these days. 

I am also fascinated with the idea that sound is a temporal sculpture of sorts. When you feel and hear the 4 Hz... you know you just bumped into something. So I have an enthusiasm for an increasing awareness that sound is something we actually touch like a sculpture. It's 3d art that we can walk within. A speaker like this will make you aware. 

I was thinking about things like amusement parks. But I wondered about possible hearing damage with sustained levels of infrasonics that might be over 120dB SPL. Did a quick google, but couldn't find anything that didn't appear to be purely speculative and sometimes completely different conclusions.

drew, I think you would have really enjoyed speaking with Mr Thigpen and I dare say that you would have been better prepared to consider some of the explanations than I was. I'm still thinking about some of the stuff hoping to have an ah-ha moment. 

Well, I might worry that we might offend one another, me being a skeptic and all. But I am in favor of "more bass". And it goes without saying that I would love to play an extended range bass through a system like that!