Subsonic frequency reproduction????

[whyuncertainty]

hello!
I was hoping someone could tell me if there was a way to either buy or build an inexpensive speaker that can handle frequencies below 20hz and/or above 20khz. any info is greatly appreciated. thanks!
-jen

[steveman]

No there isn't.

[loujudson]

Not inexpensively at least. Maybe you want one of the car woofers - the really big ones? I can feel subsonics occasioanlly at stoplights. Closing windows doesn't keep it out!
L

[EricKrk]

I don't think it matters. Usually in the clubs the music is so loud that the sub sonics of the music are loud enough to be heard. At low volumes, they are there, but they can't be felt.

[zmoorhs]

I'd be interested to know why you want to do this, especially in the sub 20Hz range. Some of the frequencies below 20Hz can be really dangerous to fool around with. stike

Anyway, if you can track down a 12 or 15 inch car audio sub that's rated say from 20Hz-2kHz, it's cutoff frequency will probably be 18 or 19Hz rolling off to possibly around 15, so you will indeed get some frequencies below 20Hz. You can buy a subwoofer with that spec brand new on ebay for around 50 bucks.

[zmoorhs]

Originally Posted by loujudson

Not inexpensively at least. Maybe you want one of the car woofers - the really big ones? I can feel subsonics occasioanlly at stoplights. Closing windows doesn't keep it out!
L

Most of what you're feeling is loudness & it's frequencies above 20Hz, probably mainly 20-40Hz. Those pimped car stereos are pushing out a similar volume to what you get in small clubs with their multiple 1-2kw subs booming out those low frequencies.

[space2012]

Originally Posted by whyuncertainty

hello!
I was hoping someone could tell me if there was a way to either buy or build an inexpensive speaker that can handle frequencies below 20hz and/or above 20khz. any info is greatly appreciated. thanks!
-jen

tannoy super tweeter can go over >20khz up to 50khz.
st50, st100, st 200, $3000usd. pair.

some Tannoy studio monitors have a similar supertweeter included and much cheaper. around $1500usd. pair.

if usign passive supertweeters you need also a good analog amplifier.
and good cables. evidence, vovox, etc... lavacable.com

under 20Hz, any 18" jbl 2241h or similar with a well designed vented box can go there watch out the Xmax.
but acording to fletcher munson curves, you need a hell lot more SPL dB to feel it like 1khz.
like 80dB in 20Hz = 20dB in 1khz.
3dB more = double watts or double loudspeakers.

front loaded push-pull isobaric vented box, is nice for shaking the floor.
eminence designer software is nice to design subwoofers.

theres a nice bass shaker for car audio, also.

usspeaker.com
wiki.com fletcher munson curves

[edit machine]

the average person can't hear below 20 hz or above 20 khz, and according to my audiologist an adult living in an industrialized nation can rarely hear above 17 khz so what is the point of having such speakers anyway?

Why do those Tannoys go up to 50 khz? thats just insane isn't it? What can be the benefit of going 30 khz above what a person can hear?

[zmoorhs]

I'm not saying you're wrong about the 'average person', but the limit of human frequency response is actually (ok, 'apparently') 20Hz-23kHz. Also, from what I've read, there's evidence to support the fact the woman are more sensitive to higher frequencies than men, so it may well be that only woman can hear frequencies above 20kHz, although age & damage to our ears is also a major factor.

[whyuncertainty]

thanks for all your help!
and yes, its true that the average person can't hear outside 20hz-20khz, but they are capable of feeling all kinds of frequencies... and its also true that it can be dangerous to fool around with subsonic frequencies, but also relaxing and therapeutic if you do a bit of homework and/or experimentation. personally, i'm intrigued by the idea of writing music that is only sub/super sonic and then experimenting with rooms to play it back in (to study/interact with the reflections) and also see about how well traditional tempered consonant/dissonant harmonic structures stand up in that range.i think i found something quite suitable for what i'm trying to do aside from the servosub and/or rotary sub ideas. Does anyone know anything about these things?

Amazon.com: Buttkicker BK-LFEKit Low Frequency Effect Kit with Amplifier for Home Theater: Electronics

and also about recording subsonic frequencies... i'm a little stumped. i have microphones capable i believe, although i would probably keep it all in the electronic realm rather than try to translate it back and forth from acoustic, but i can't find an interface/daw that i think can really handle it. no protools systm can do below 20hz according to the specs, not even a bajillion dollar HD system. also my partner in crime, a macbook pro stock soundcard is only capable of 20hz-20khz. i was wondering if anyone know of an interface that could do better offhand. thanks! you guys are great!

-jen

[loujudson]

Comment - sub and super refer to slower and faster than sound travels, what you are actually interested in is infra and ultra sonics, though the terms are commonly confused.

Sound Devices recorders go down to 10hz on both mic and line inputs.
You need to look into instrumentation recorders, such as used in seismic research…

Have fun!
L

[golden beers]

you can kill someone using a 7hz signal. if you try hard enough

[loujudson]

Originally Posted by golden beers

you can kill someone using a 7hz signal. if you try hard enough

a. but they'll mess their pants first

b. so will you if you are nearby.

L

[Deeb]

REL make hi-fi subs that go below 20Hz, mine goes down to 16

REL Acoustics : Great Britain's most acclaimed Sub Bass Systems

Read it and weep..... 9Hz!!!!

[monomer]

Originally Posted by zmoorhs

Some of the frequencies below 20Hz can be really dangerous to fool around with. stike

So i keep hearing...
Can you elaborate?
Maybe point to some research done on it?

[monomer]

Originally Posted by golden beers

you can kill someone using a 7hz signal. if you try hard enough

You can fry an egg with a 7Hz signal if you try hard enough.
Or make the mona lisa cry, for that matter...
If it's not working then you are just not trying hard enough...

[golden beers]

Originally Posted by monomer

You can fry an egg with a 7Hz signal if you try hard enough.
Or make the mona lisa cry, for that matter...
If it's not working then you are just not trying hard enough...

. 7hz is the resonating freq of the human body. or as some put it, 'the brown note'

[loujudson]

Originally Posted by golden beers

. 7hz is the resonating freq of the human body. or as some put it, 'the brown note'

as I said above, a mess.

[PeteJames]

Don't forget to budget for plenty of new pairs of boxer shorts.

[Introspective]

I know this is really g33ky, but i watched the episode of Mythbusters where they disproved the 'brown note' myth....it was BUSTED!

Anyway, trouser-flapping bass FTW

[zmoorhs]

Originally Posted by monomer

So i keep hearing...
Can you elaborate?
Maybe point to some research done on it?

Do some reading on infrasound & infrasonics. It's quite common knowledge that infrasonic & ultrasonic weapons are in use now, but it's nothing new. Scientists, especially those working on military projects have been playing around with it for many decades. Tesla did & to a greater extent Gavreau did. http://www.hbci.com/~wenonah/history/gavreau.htm Gavreau created infrasonic weapons so powerful that they couldn't be used without infrasonic armour since they were able to shatter & break matter. Needless to say, he therefor devoted himself to developing infrasonic armour & defense.

Sound weaponary & defense systems have been spotted all over the place in actual use by military forces. Ultrasonic weapons appear to be the prefference for crowd control as certain high frequencies are powerful enough to irritate a crowd so much that it has no choice but to get away from the source of irritation.

[monomer]

Originally Posted by golden beers

. 7hz is the resonating freq of the human body. or as some put it, 'the brown note'

But the Mythbusters proved this to be 'Busted'...

[monomer]

Originally Posted by zmoorhs

Do some reading on infrasound & infrasonics. It's quite common knowledge that infrasonic & ultrasonic weapons are in use now, but it's nothing new. Scientists, especially those working on military projects have been playing around with it for many decades. Tesla did & to a greater extent Gavreau did. http://www.hbci.com/~wenonah/history/gavreau.htm Gavreau created infrasonic weapons so powerful that they couldn't be used without infrasonic armour since they were able to shatter & break matter. Needless to say, he therefor devoted himself to developing infrasonic armour & defense.

Sound weaponary & defense systems have been spotted all over the place in actual use by military forces. Ultrasonic weapons appear to be the prefference for crowd control as certain high frequencies are powerful enough to irritate a crowd so much that it has no choice but to get away from the source of irritation.

I dont think there is realy anything specially weapon like about those ranges.
They are just part of the bigger phenomenon of sound.
All frequencies would have certain behaviour in air.
But saying it's only those ranges are suitable as weapons seems strange.
The high frequencies as a 'crowdpleaser' has to do with frequencies within the hearable range. They have psychoacoustic effects that are realy irritating and confusing.

At the lower end of the spectrum the same theory applies as at other frequencies. If you can find the resonance freq of something you can make it resonate. If you put enough energy into the resonance the object will break.
Nothing special about it realy.

BTW.
I highly doubt the sonic resonance frequency of a human is anything near 7 Hz.

If i take a reasonable person (1.7m being the longest distance inside the body) and assume the human body is mostly water, which has a sound propagation speed of about 1430m/s then i get around 840Hz for the ground resonance of the longest distance inside a human body.
Any harmonic of this distance would yield higher frequencies, so would any shorter distance inside the body.