Anyone ever hear (or feel) the thigpen rotatry woofer?

[RichP714 3,163]

 

http://www.rotarywoofer.com/index.htm

[TNRabbit 371]

Yep; I've heard of them but never HEARD one...

[elgrau 89]

"Evergreen Aviation uses a rotary woofer in its Titan Missile Exhibit"

 

So this implies to be that such a sub-woofer (and sub-woofers in general?) are great for "movie sound" needs, but I may be wrong (not be a "student" of music), but is not the lowest "valid" musical note around 22 Hz? Which is (coinsidently?) the low end of my EPI 1000's? i.e., sub-woofers (like this) only "needed" for HT; not 2-channel music! Or am I wrong?

[RichP714 3,163]

I guess it all depends on what you listen to; PDR posted this chart awhile back:

 

http://www.independentrecording.net/irn/resources/freqchart/main_display.htm

 

looks like pipe organ fundamentals go to 20Hz, so I'm guessing the subharmonics go even lower (whether they're audible I haven't a clue, my Cornwall II's go to 40 Hz and they're plenty deep; my subwoofer project will go 15-45 Hz (yes, mostly aimed at HT, but I want it to be accurate enough for 2 channel too).

 

Subwoofers in general are supposed to 'augment' and take over from the main speakers; most of the time, that means they are set for 'I paid for this, I'm going to hear it' levels; that and the group delay/phase alignment between the sub and mains give them a bad name, but properly utilized they're supposed to add realism (yes, even to 2 channel) in that some of the acoustic cues the brain interprets as 'hall size' are at or near the threshold of hearing.

 

So, in a way, it's not about the boom, it's about the soundstage depth........

[BillD 239]

I found this online, which would indicate that instruments do indeed make those low notes.

 

 

The fundamental tone of 16.4 Hz represents a 32-foot organ pipe, which is found, except in the very largest organs, only in the pedal section of large instruments. Although the 32 foot pitch is found frequently on large instruments (like cathedral organs) it is not the deepest note of an organ as stated in the question. Some organs, such as the Atlantic City Auditorium organ, USA and Liverpool Cathedral Organ in the UK have 64-foot ranks giving the lowest note as 8.2 Hz. On most organs offering 64-foot ranks, the sound is either produced by a stopped 32-foot pipe, or acoustically, where two shorter pipes are tuned so that the beats between them produce a 64-foot tone. Many huge organs do have a 64' rank (usually called gravissima), but nearly all of them are produced by either a stopped 32' or acoustically. There are not more then 5 organs that has a true (not acoustic, stopped, nor digital), (only counting the rank(S) that accually goes down to the sub-sub-contra C) 64 foot rank, three of them are the organ at the Atlantic City Convention Hall Main Auditorium, the organ at Sydney City Hall, and the one at Worcester Cathedral, in UK. The shortest lengh that will produce 16.4Hz (CCCC) is 16 ft, although this note is the C of the sub-contra octave, this 16ft pipe is stopped on the top, so it produces the note that corresponds to twice that lengh(32ft) .

Also should be mentioned, the lowest (true) note on an acual organ is CCCCC which is 8 Hz, that single note cannot be heard alone. THE lowest note is produced by either stopping the 64' or combining the 64' and the fifth(42 2/3) to produce a 128' CCCCCC which is 4 Hz.

[elgrau 89]

But 90% of folks are lucky to hear 30 Hz tone! Use your 'Virtual Test Bench' tone generator (or real one!) and be amazed as you watch your speaker cones "wabble" away at below 30 Hz (for most!) and hear NOTHING!

That being said, I don't "trust" sub-woofers to be giving me a true, natural sound that the musician(s) ever intended to be there (4 sigma organ pieces excepted, but again, 90% can't hear it anyway!) and I also think that they "mess up" the bass stereo effect. But whatever; different strokes...I'd never have one and I'm happy with the 22 Hz response of my 1000's (at least 8 Hz below what I can hear).

 

Also, that "Elements of Radio" book from 1943 I have states (in several places) that the "audible human range" of hearing is 30 to 15k Hz! Guess they were more "realistic" back then BEFORE the "audiophile" salesmen of today started conning us into thinking we needed a system good to 20 to 20k Hz!

[snow 240]

 

 

 

Also, that "Elements of Radio" book from 1943 I have states (in several places) that the "audible human range" of hearing is 30 to 15k Hz! Guess they were more "realistic" back then BEFORE the "audiophile" salesman of today started conning us into thinking we needed a system good to 20 to 20k Hz!

Huh? 30khz to 15kz is both higher and lower than 20kzh to 20k Hz.

 

 

 

REGARDS SNOW

[BillD 239]

Well, back in the day, I could hear the 19kHz pilot tone on FM if it wasn't notched out. No more. Kids are using ringtones up there so teachers can't hear when their phones go off to tell them they have a message.

[elgrau 89]

"Huh? 30khz to 15kz is both higher and lower than 20kzh to 20k Hz."

 

Read it again Snow. 30 to 15k = 30 Hz to 15000 Hz .....OBVIOUSLY. Since when does 30 = 30k?? And exactly as they wrote it in the book: 30 to 15k Hz

 

 

Not to mention: 15kz?? or 20kzh?? what the f units ARE that?? :dd

[RichP714 3,163]

 

 

.....you watch your speaker cones "wabble" away at below 30 Hz (for most!) and hear NOTHING!.....

 

That depends on the tuning of the driver very much; when the woofer loses it's groip on the air it'll move and do basically nothing; that doesn't mean you wouldn't hear it if it was tuned to a lower Fs.

 

My Cornwall II's are rated 42 (or something) to 20K, and they'd beat the piss out of Polk SDA-1's (rated to 20 Hz), yet their phenolic diaphragm tweeter was lucky to be flat out to about 15Khz.

 

I don't know about hearing 15Hz, but I know I can feel it (I've been in an earthquake; weird)