Super-low organ frequencies...

[Corno Dolce]

Alright you low-frequency fanatics(myself included), here's a thread from another forum that dives into low-frequency(Bass notes)production. Keep an open mind - you might learn something:

http://www.avsforum.com/avs-vb/showt...php?p=14094899

Cheerio,

CD

[Krummhorn]

Goodness gracious ... even the average human ear cannot decipher sounds below ~20Hz, this low freq vibration would be something to experience and feel. Talk about getting all your hemorrhoids massaged ... hoo boy.

These rotary subs ... wonder if there are any pics of those?

[Corno Dolce]

Aloha Master Krummhorn,

The link below shows the heart of the Super-low subwoofer. The pitch of the blades is varied by the incoming signal but the rotational speed of the blades remains constant at 800 rpm:

http://home.comcast.net/~thomasw_2/RMAF2005.html

Cheerio,

CD

[Soubasse]

This has become a personal area of interest to me over the past few years as I've been researching the phenomenon of Brainwave entrainment and the effect that particular frequencies - audible and inaudible - can have on mental/psychological functions. It's quite possible (indeed likely) that these sub frequencies in a live situation would enhance the emotional response of the listeners. I'm sure I'm not the only one who has been to some loud rock concerts and felt like something is physically pushing you in the chest when certain bass notes are played. This is also related to the "brown note" concept that Krummhorn alluded to - that has been proven (but I wouldn't like to have been involved in that test!)

The 800rpm confuses me somewhat though, as wouldn't that produce a frequency in itself? Unless the whole idea of the moveable position of the blades produces a resultant. I'll obvioulsy have find out more behind the physics of the thing and re-read that av thread (which is a bit too much at firts glance - I never liked physics at school but now I'm wishing I paid more attention )

Fascinating topic, thanks for posting CD.

[Contratrombone64]

pretty useless unless your audience happens to be whales ...

[Corno Dolce]

Aloha Soubasse,

Good to see you again - Yes, the phenomenon of infrasonics and psycho acoustics(brain entrainment) do fascinate and compel to greater research. During my Air Force days many were the times I could witness the test-run of a turbo-ramjet engine that could produce 1.5 million horsepower - the soundwaves produced would make one feel as if one's chest cavity was being pushed in and one's innards vibrate. I never got the *runs*(diarrhea) because of it - maybe because I thought it was the coolest thing to experience.

CT64 seems to be dismissive of the phenomenon - ah well, can't please everyone. What is so fascinating is that the changing of fanblade pitch, probably at many times a second i.e. 16 times/sec for 32' pitch, 8 times/sec for 64' pitch and 4 times/sec for 128' pitch projected into a baffle will give frequencies that put a *solid* bottom to all upper frequencies.

Now the 128' has become quite famous as a phenomenon in the organ of Middle Collegiate Church:

http://www.nycago.org/Organs/NYC/htm...ollegiate.html

Seismically rattling the rafters, benches and people's innards has never been easier than this and at a minuscule fraction of the cost of building a full-length 128' reed as a Bombarde or compound reed as in a Diaphone.

Cheerio,

CD

[dll927]

All of which may explain why they say that 32's are as much felt as heard.

128'?? Next it will be 256', and it will be like computers - each advance means somebody will try for the next one. But wouldn't they soon reach the point of no vibration at all?

[acc]

128'?? Next it will be 256'

The Encyclopedia of Organ Stops is already a step ahead of you: look here!

[Corno Dolce]

A 128' at 4Hz at least *generates* some psychoacoustic and physical excitement ergo, tingling the auditory nerve by the sound wave's *rhythmical massaging* of the ear drum and palpitation of one's whole body. I would surmise that at 256' you're only *feeling two thwacks* a second - how boring!

Cheerio,

CD

[dll927]

Maybe you've heard this before:

I've seen a story, which I'm sure is imaginary, of some super-rich guy in NYC building a huge cathedral, then tearing it down and starting over, etc. When it came to the organ, it was all over the place with storage rooms down in the basement, ductwork that occupied long distances in the walls, pipes up in the dome, and all sorts of other stuff. In other words, he was never satisfied and kept wanting more and more before even the current work was finished.

If I recall, the guy had made his fortune in trash collecting. (!!!) It must have been before the Mafia got ahold of it. But as I said, I assume the story is a bit far-fetched. I still say there must be limits somewhere on how far down sound can go.

[Corno Dolce]

Aloha dll927,

Tbh, with all the positions of pipework in that *Cathedral* my thoughts land on this:

http://www.albany.edu/piporg-l/hcknback.html

Cheerio,

CD

[acc]

I've seen a story, which I'm sure is imaginary, of some super-rich guy in NYC building a huge cathedral, then tearing it down and starting over, etc. When it came to the organ, it was all over the place with storage rooms down in the basement, ductwork that occupied long distances in the walls, pipes up in the dome, and all sorts of other stuff. In other words, he was never satisfied and kept wanting more and more before even the current work was finished.

Almost sounds like the story of Albert Baron de l'Espée, which is definitely not imaginary.

[Corno Dolce]

Yes, Baron de L'Espee is quite the interesting character.

[dll927]

Corno Dolce -- That's it!! Poor guy must have had his problems.

[Corno Dolce]

Aloha dll927,

Which *little guy*? The Baron??? Nawww, he was a very wealthy chap. He had a big organ in his house in Paris.

Cheerio,

CD