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Old 9th August 2002, 07:44 PM   #1
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Default 176 dBA SPL ?

See this for some unintended humour.
The article mentions the Rolling Stones attaining 176 dBA - Is this possible ?.

Eric.
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Old 9th August 2002, 09:13 PM   #2
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All I can say to this article stands below - the other I don`t know
(but likely nobody ever has heard a 176dB sound wave actually, at least not longer than for a fraction of a second - otherwise I guess he/she would be completely deaf forever or maybe even dead).
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Old 9th August 2002, 09:36 PM   #3
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Hi Eric,

Let look at this from the aspect of acoustic power and the electrical power required to produce 176db SPL?s. If you have an output of 1 acoustic Watt (1aW) into an average reverberant living room, you create about 115db of SPL at a listener 3 meters from the source (this is a rough approximation, but realistic). If we give Mick the benefit of the doubt and say he has found very efficient speakers with an efficiency of 10%, it would take a 10 Watt amp to reach 115db SPL at our listener or 1aW output.

Now Mick was said to produced 176db - 115db = 61db more SPL than we did in our hypothetical living room. That is doubling our SPL 21 times = to doubling our output acoustic power 21 times. Therefore, for Mick to have produced 176db in our living room, he needed to produce 2.1MaW. The 10% efficient speakers he found would have required 21 Mega Watt of amplification, if the concert were performed in our living room!

I would say this is a bit of a stretch to make the point of the article.

Rodd Yamas***a
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Old 9th August 2002, 11:25 PM   #4
JBL is offline JBL  Canada
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It is possible to measure 176 db from a speaker.

Spl vary inversly to the square of the distance(I think)

So iy you get very near to a horn loaded thweeter it's very easy to measure very high spl.

Beign infinitly near a speaker would mean an infinite spl
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Old 10th August 2002, 12:34 AM   #5
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According to this website, Someone got to a MAX SPL of 174.9 dB ! :P

Could it be true?

What system could do so much noise?

how many ppl were killed on that day?




Simon
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Old 10th August 2002, 12:57 AM   #6
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Quote:
The 10% efficient speakers he found would have required 21 Mega Watt of amplification
Hi Rodd, I don`t want appear to be hypercorrectly but according the following actual formular for half space radition, there are a couple of megawatts missing in Your calculation :

SPL(db) = 112,2 + 10log(no*Pel) - 20log(r)

where is:

no = efficiency (10% = 0,1)
Pel = electrical Power (Watts)
(no*Pel) = Pac (acoustical Power)
r = distance (meter)
SPL(dB) = 176

according to this, for 176db SPL @ 3m distance in Your living room and 10% speaker efficiency, Mick would has to upgrade his amps somewhat to 210 megawatts (of course that`s frequency dependend also and due to low frequency room boost he could save a couple of megawatts)
Anyway, You might consider bracing Your room walls and to improve the line power distribution a little bit before he plays.
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Old 10th August 2002, 01:23 AM   #7
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Default Loonies Unleashed

It was meant as a tongue in cheek question.
When I saw the article I did some quick mental calculations, translated these to outdoor or stadium venue and decided that this evangelist fanatic is rolling in it.
Did anybody read the rest of the article - this fanaticism concerns me somewhat.
I do remember reading of the US underwater soanar project that is generating something like 150 dBA spl (?) - hence the concern for the welfare of marine speces.

Eric.
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Old 10th August 2002, 02:20 AM   #8
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Hey Christoph,

Yeah, your probably right. I seen the thread when I was at work and tried to get one in from memory. You know, when you start to get old, the first thing to go is the memory. I can't remember the second thing to go?

Anyway, I thought I seen one of those 200MWpc pro-amplifiers go on eBay the other day for less than $200. I also heard that Deep Purple used 100GWpc amplifiers,... BRIDGED!! Although, they did loose some of their damping factor by running in bridged mode. That's why their bass was always so "boomy" in-concert.

Hi Eric,

I did glance over the article. These guys are out there! Be afraid, Be Very Afraid.

SEX&DRUGS&,... ?? Oh,... Sorry. Someone's already got that one.
Rodd Yamas***a
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Old 7th October 2002, 02:03 AM   #9
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Quote:
Originally posted by NU_NRG
According to this website, Someone got to a MAX SPL of 174.9 dB ! :P

Could it be true?

What system could do so much noise?

how many ppl were killed on that day?




Simon
Tis very true
Remember a car cabin is a lot smaller than a concert hall or your living room and trhese guys don't go after quality by any means, and their cars are heavily modified with 1inch plexiglass and interiors made from MDF to increase stiffness and thus not lose pressure. They have multiple arrays of speakers with multiple arrays of Class D amplifiers with multiple arrays of batteries and 1F capacitors etc etc.
I have seen one car in my local area pull off 151dB with 2 15inch subs in a 6cubic foot enclosure. Admittably it sounded horrible but you could feel it shake your body
If you read the rules and stuff for the db Drag racing you will see the microphone is located in the same position for every persons run, I can't remember the exact location, but however, it allows the use of bass loading etc to focus the SPL in one point of the car's cabin. Most people also run just one sine wave of the peak-volume frequency of their system to get even more SPL.
My friends sisters has a $2000 AUD system which can run 137dB consistently, so it proves it isn't very hard. As for sounding good though, they are @$#%... but good fun
The mate mentioned above had a Cerwin Vega Stroke 18inch with a Rockford Fosgate 1100a2 amplifier. It was bridged and ran into the cerwin vega double voice coils which were paralelled.
I sat in the back seat while testing a bass track I made with Cooledit and I had a sine wave sweep from 150Hz -> 0Hz over 1 minute.
On certain frequncies I could barely breath because the bass was shaking my isnides so hard. It was awesome yet freaky.

-Mike
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Old 7th October 2002, 08:46 AM   #10
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A couple sealed 15" Brahmas can reach 145's in an SQ setup.
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