Re: [Phys-L] Acoustics: Does a speaker create a displacement antinode? (amplifier power)

[brian whatcott <betwys1@sbcglobal.net>]

A power doubling is represented by an increase of 3 dB, an increase of 
X10 by 10 dB.
It follows that the power multiplier to arrive at 110 dB from 100 dB 
would be ten times the output power required for 100dB  at constant 
efficiency and one hundred times the power is needed to increase 100 to 
120 dB.

Brian Whatcott   Altus OK

On 4/9/2014 12:40 PM, Bill Norwood wrote:
> Bernard,
>
> I mean whatever comes out of he speaker that commonly gets measured in
> terms of dB - say a mfr will claim that his speaker will "put out" 120 dB I
> guess right at the front plane of the speaker enclosure.
>
> So, I would need to know for this case what amplifier power would be
> required to drive a speaker at 120 dB vs. at 110 or 100 dB.
>
> Bottom line is that I am trying to add an environmentalism aspect to my
> claim that extremely loud, outdoor, band music not only contributes to
> sound pollution for a neighborhood, but it also wastes a lot more
> electrical energy than one might expect.
>
> Thanks, Bill
>
>
>
> On Tue, Apr 8, 2014 at 4:46 PM, Bernard Cleyet <bernard@cleyet.org> wrote:
>
> > On 2014, Apr 08, , at 12:55, Bill Norwood <bnorwood111@gmail.com> wrote:
> >
> > > Hi Jeff,
> > > Long shot here, but since you are looking a bit into audio:
> > > If one increases by 10 dB the sound level out of a speaker at a specified
> > > distance, by what factor has the amplifier power requirement increased?
> > > Thanks, Bill Norwood, U of MD at College Park
> >
> > You mean sound pressure level????  by sound level OR do you mean sound
> > intensity?
> >
> > I  measured in Watt/m^2
> > p        "         "     Pa
> >
> >
> > I proportional ~ to p^2
> >
> > http://en.wikipedia.org/wiki/Sound_intensity
> >
> >
> > Sound pressure level (SPL) or sound level is a logarithmic measure of the
> > effective sound pressure of a sound relative to a reference value. It is
> > measured in decibels (dB) above a standard reference level. The standard
> > reference sound pressure in air or other gases is 20 µPa, which is usually
> > considered the threshold of human hearing (at 1 kHz).
> >
> > http://en.wikipedia.org/wiki/Sound_pressure
> >
> >
> > from these and knowing the log manipulation rules "you" can find "your"
> > answer.
> >
> >
> > bc lazy
> >
> >
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