7 x RE Audio XXX 18" subs, Infinite Baffle Sub, Ultimate IB build - Page 14

too funny, my wife complains all the time too from my f20s- everyone else thinks its awesome.

Follow up to my post in your thread on the Cult" forum

http://www.lowertheboom.org/trice/infrasound.htm

Pardon my bluntness, but that reeks of an urban legend / myth. Commercial theaters don't have the audio setup to produce high output subsonic frequencies, especially not ones decades ago.

Awesome. This lunacy has spilled over into the DIY subforum now.

Yeah that stuff is crap. Everyone leaves my room smiling.

Just make sure everything is secure in your home Dave, I have knocked picture frames off the wall and that doesn't go over well at all. There was one room in a house I had awhile ago that really shook violently from the bass, it was an experience to be sure

This was no ordinary theater it was the one being used to create the 9 channel mix for the original version of Fantasia.

Nonbelievers should spend a little time with Bruce Thigpen's rotary sub. When he tested it at the RMAF, people were exiting the room with C/O's nausea/vertigo, I was present at that demo and watched people leave with the complaints

This is my favorite:

1 - 10 Cycles Per Second (Hz) - "Lethal infrasonic pitch lies in the 7 cycle range. Small amplitude increases affect human behavior in this range. Intellectual activity is first inhibited, blocked, and then destroyed. As the amplitude is increased, several disconcerting responses have been noted. These responses begin a complete neurological interference. The action of the medulla is physiologically blocked, its autonomic functions cease." (source; the Sonic Weapon of Vladimir Gavreau, by Gerry Vassilatos)

I knew there was a possibility I could go deaf but not dead

We all have to go sometime

So, what subwoofers existed in 1940 that could fill a large theater with high output subsonic bass?

None. The best speaker available in 1940 was the Shearer horn, which only went to 40Hz.. Pure myth. No speakers existed then capable of any output, let alone high output, at 12Hz. And there was no such thing as tape editing in 1940. Tape was not used for sound editing until the late 40s.

Sure did. My vestibular system isn't particularly sensitive to very low frequencies so no problems.

Larry Borden of Stereo Times was in the room with me. Poor Larry turned green and bolted for the door when Bruce started playing below 10Hz tones.

I'd guess that like many things, any negative effects would be governed by both level of ULF, and perhaps more importantly, ... exposure time.

I'm also guessing that if the excitation freq coincided with resonant freq, whatever effect would likely be magnified.

I remember reading a paper published by B&K back in the 70s that described naturally occurring spaces (cavities??) within the human body that when exposed to a high enough SPL would resonate and cause discomfort. Some of those frequencies as I remember were low but not infra-sonic.
____________
Best Regards,
Carl Huff

Brown notes have been achieved by taco-corp and vuvuzelas. Just sayin' If you will it dude, it is no dream.

How does the sound compare pre and post Dirac ?

Yes, this happened in my room also. People kept telling me, (modeling programs also) that my
IB subs would get torn apart at reference with the power I was feeding them. Nothing could be
further from the truth. With the massive room gain, there are no issues.

On that note:

I love the overkill. But let's be real, if anyone think's this has practical application, they are wrong.
This has so much unused overhead, it's mind-boggling.

I have 4 18" Ficar IB3's set up as dual in-floor Infinite Baffle manifolds in a 1600 cubic foot room.

I can play *anything* at 5dB above reference, flat down to 5hz without breaking a sweat.
My system laughs at War of The Worlds and THX Amazing Life demo mushrooms.
My distortion levels are unmeasurable compared with any box subwoofer. Any additions
to my subwoofer system would add nothing.

Once again, I love this, and there is nothing wrong with it. But for those wanting to
build an IB system, something like my $1500 IB will perform just as well as the one
in this thread at reference levels.

The biggest issue is not output, it's placing the sub(s) correctly to minimize nulls and peaks, which
I was able to do with my dual manifolds.

Once again, not downing this system, it's awesome. Just don't want any newbs wandering
into this thread thinking this is what's needed for a decent Infinite Baffle system.
Edited by S_rangeBrew - 12/31/12 at 9:34am

Well since it was mentioned exactly how much distortion are we talking? At what spl and frequency? I wish my mic did not rolloff below 5hz or I would be flat lower. I have box sealed subs and I can play any movie over reference with a Low shelf boost as well.

Right on Dave! I was just wondering what was going on with that. Good luck and keep us posted.

I'm curious Dave. Why did you switch from Seaton Cat12's to the Quest audio stuff? I remember a long time ago you being very excited and happy with the Cats. Did an amp break and you never got a replacement or something?

"The amps on the Cats were just in idle, but after about 30mins working in theater I had unbearable pain in my ears and I started to think I was going crazy and that the room was to blame. That was until I realized that I had the speakers switched on. So I started to do some tests to eliminate what was causing the problems and finally I found that I could not be in the same room with high powered amps. I tested this with other high powered amps and came to the same conclusion."

that is interesting and the first time that i have ever heard of that.