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Hi guys,
While reading this thread ( https://www.eevblog.com/forum/projects/bullshit-alarm/ ) I remembered a cheap "hi-fi" system a friend had, ofcourse it was labeled with a PMPO power of several kW. The non-bullshit power rating for that size of speakers would be around 8W or so.
So, what would happen, if you actually turned on a, say, 10kW loud speaker inside of a small apartment, on full power and play something nasty?
Aside from severely annoying the neighbors, would there be any noteworthy effect? Smashed windows perhaps? What about the health issues? After a few minutes, could someone get their hearing damaged?
Thanks,
David -
I just love the "wattage" ratings on audio gear.
My singer recently showed up with this "600 watt" (right on the box, big letters) powered monitor. I turn it over...2.5A fuse, 120V...
But getting to your question, I have seen youtube vids of powerful car audio systems where the bass synced with the shutter speed, the deflection of the body panels and glass was astonishing -
Warning: High sound pressure levels can and will destroy hearing in an instant, even a collapsed lung is possible.
Electrical power is less than half the story, it is acoustic energy that we want for that we also need efficient transducers (loudspeakers).
High to mid-range frequency's are fairly easy to reproduce at high SPL's by horn-loaded compression drivers,
they have a efficiency of up to 110dB measured at 1 meter for each Watt put in, so even 0,1 Watt can easily damage your hearing at 100dB.
More fun and a lot harder are (really) low Frequency's, especially in a enclosed space (apartment) speaker placement becomes critical and frequency dependent to produce a good standing wave (normally avoided) with plenty of acoustical
power you can let windows shake and doors rattle. (I even cracked a wall once with about 100 Watts..
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Regular subwoofers aren't very good for this because they usually don't work efficiently below 40 or even 50 Hertz (don't have to for normal music).
For this we are talking sub-sonic: 5-20 Hertz so frequency generator and custom speakers.
Actually with 30Kw of power and efficient speakers that can handle that and a room that supports a low enough standing wave frequency
that happens to match the resonant frequency of the brick walls, you can take down a house, maybe.
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The Soulman is on the money
This gentleman may be of assistance too
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I would appreciate it if someone came up with a demolition company that used loudspeakers to take down houses with terrible songs.
NEVER GONNA GIVE YOU UP
*CRASH* -
Original giant speaker (BTTF)
And someone just had to make a real version.
7kW big enough ? -
Well, your body presents an impedance mismatch to the sound waves, so when they enter your body there must be some standing waves, reflections, etc. It likely matters how much water and fat there is in people. Everything has a resonant frequency.. If in fact it exists and is not an urban myth, I could see some frequencies perhaps causing enough oscillation and loss in heat to perhaps present a risk of.. SHC...
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Immediate issues: Hearing loss..... and expect the Police to kick down your door. You won't hear them knock.
Potential issues include other physiological damage and structural stresses. Get some resonance happening and you never know what will happen.
Speaking of resonance, I seem to remember hearing about some experiments with large structures using a comparatively small device. The device set a relatively small mass oscillating at the resonant frequency of the structure. It did not show any ill effects quickly, but over time, the structure(s) also exhibited oscillation at noticeable and then troubling intensities.
So, as long as the input energy from a resonant source exceeded the losses from the resonant system, you could end up with some pretty dramatic results. -
Here is a system from a guy that used to hang out on our forum. He goes by the alias, "basspig" for obvious reasons:
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Speaking of resonance, I seem to remember hearing about some experiments with large structures using a comparatively small device. The device set a relatively small mass oscillating at the resonant frequency of the structure. It did not show any ill effects quickly, but over time, the structure(s) also exhibited oscillation at noticeable and then troubling intensities.
Reminds me of the collapse of the tacoma bridge near us:
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When we were about 15 my friend and I built a subwoofer in the corner of his room with an old 12" driver in a big tuned box, I think the amplifier was only about 50W but we managed to knock a painting off the wall in the livingroom downstairs. It's all about the frequency, in that case I suspect we hit the resonant frequency of the wall on which the painting hung. I don't think you'd actually do serious damage in most cases, you'd just piss everyone off and possibly damage your hearing depending on the frequency involved. Beyond a point I don't think adding more power makes it any louder, there's only just so much air in a room to move around. 10kW is probably only going to sound modestly louder than 200W.
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Well, if you want to knock things off, there is always this:
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James, you stumbled on the magic formula for bass nirvana..
I have an old corner Klipschorn with a 15 inch woofer and metal horn - multicelled horn, it looks like a microwave antenna..
Between the two it can attain extreme levels of undistorted sound. It goes through you.
Somebody would have to be dead not to want to dance.
Quote from: james_s on Today at 23:03:35When we were about 15 my friend and I built a subwoofer in the corner of his room with an old 12" driver in a big tuned box, I think the amplifier was only about 50W but we managed to knock a painting off the wall in the livingroom downstairs. It's all about the frequency, in that case I suspect we hit the resonant frequency of the wall on which the painting hung. I don't think you'd actually do serious damage in most cases, you'd just piss everyone off and possibly damage your hearing depending on the frequency involved. Beyond a point I don't think adding more power makes it any louder, there's only just so much air in a room to move around. 10kW is probably only going to sound modestly louder than 200W.
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My day job is as a mastering engineer but I work part time setting and tuning up high end studio speaker systems for artists and producers that you would all be familiar with, these systems run anywhere from $20k to $175k.
The largest system I've set up is in the private studio of a well known producer here in L.A. It has somewhere around 11,000 watts of available amplifier power per channel in a room that's somewhere around 600 - 700 sq ft. The effect of listening to that system turned up is profound, a very physiological fight or flight response. I started sweating and the hair literally stands up on your body.
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... and the hair literally stands up on your body.
From your anxiety - or the sound pressure? -
I've only experienced sound levels like that a few times, and for brief periods. The extreme low frequency content seems to trigger a response in my body that is involuntary. I'm the one controlling the level so panic is not the issue!
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The extreme low frequency content seems to trigger a response in my body that is involuntary.
The brown note?
Years ago we had a small set up in a ballroom for a drum 'n bass gig. Not a lot of power. The subs were about 2400W RMS per side (3 tuned 800W cabinets and class AB amps). With the aid of the right music at sound check we took out a couple of windows and destroyed a couple of hundred glasses in the bar (as they vibrated out of their racks).
I used to use good 3M earplugs and then a decent set of ear muffs over those. I've run 1600W RMS in my living room with a small and relatively inefficient driver. Aside from upsetting the neighbours there were no major issues, but I had everything remove/tied down first.
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My day job is as a mastering engineer but I work part time setting and tuning up high end studio speaker systems for artists and producers that you would all be familiar with, these systems run anywhere from $20k to $175k.
The largest system I've set up is in the private studio of a well known producer here in L.A. It has somewhere around 11,000 watts of available amplifier power per channel in a room that's somewhere around 600 - 700 sq ft. The effect of listening to that system turned up is profound, a very physiological fight or flight response. I started sweating and the hair literally stands up on your body.
nice post, I have to ask if you have any experience with the JBL 4350 monitors?
I have often wondered what it would have been like to be present at The Who's mastering sessions. -
My day job is as a mastering engineer but I work part time setting and tuning up high end studio speaker systems for artists and producers that you would all be familiar with, these systems run anywhere from $20k to $175k.
The largest system I've set up is in the private studio of a well known producer here in L.A. It has somewhere around 11,000 watts of available amplifier power per channel in a room that's somewhere around 600 - 700 sq ft. The effect of listening to that system turned up is profound, a very physiological fight or flight response. I started sweating and the hair literally stands up on your body.
nice post, I have to ask if you have any experience with the JBL 4350 monitors?
I have often wondered what it would have been like to be present at The Who's mastering sessions.
I haven't heard the JBL 4350 and have never seen them in a recording or mastering studio, sorry! -
No one needs hearing loss, subtle brain damage,
or p!ssed off neighbours
who may not gas if one day your house is burning down due to a gross electrical/electronic mishap/blunder,
with YOU in it BBQing away...
i.e. "no more loud @sshole next door, and no more cig butts and dog turds thrown over every time we complain"
Big loud sloppy bass frequencies are boring and usually pumped out by amateurs with small peckers
That's what their ex-girlfriends tell me
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I remember Mythbusters did a prgram about this. They tried to reproduce 'the brown note' - fail
They also tried 1KWatt with a 4 foot woofer in a car to try and blow the windows out - do not remember the out come.
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Pro quality Mackie active studio monitors with built in amplifiers are extremely flexible. Look at the extremely rugged and powerful systems pro studio rental companies offer to rent.
They come with tripods to get them up and have active feedback systems too so they can produce a very tight, balanced sound both indoors and out. -
Interesting bit in here about the satellite shake and bake testing that ESA does to the commercial sattelite s they manufacture.
http://omegataupodcast.net/242-satellite-testing-at-estec/
Pics also there of the facility and the equipment, plus some very interesting discussion as well. Yes an hour and a half of audio to listen to, but well worth it in conjunction with the photos from there. -
I vaguely remember seeing that mythbusters. I think they went about it in the wrong way, I have little doubt that it's possible to knock a window out of a vehicle but it's going to depend greatly on the design of the vehicle, the method of attaching the window and the frequency of the sound. I don't think you'd do it by raw power, it's going to take resonance. I've certainly had various parts repeatedly vibrate apart in cars, and I've had a windshield nearly fall out after the bond gradually deteriorated with age, baking in the sun and exacerbated by body flex once the joint started to fail.
I should add that this was all due to normal mechanical vibrations in the car, no crazy audio systems involved.