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previous: Doc Those SPL/efficiency ratings @1watt... -- 4/20/2000 8:55 PM

Re: SPL [sound pressure level] question

4/21/2000 6:47 PM
Doc	Re: SPL [sound pressure level] question Gentlemen, I apologize for the sloppy math in my previous post. I was trying to pull it from long term memory. I guess I kind of jumped into the water head first and hit a big rock just below the surface. What I do believe is true is that 6db increase in speaker efficiency means double the loudness. So a speaker with an efficiency of 100db would be perceived as twice as loud as a speaker with 94db efficiency, using the same electrical input signal. Also, a 2-driver array will be 1.4x as loud (+3db SPL) as a single speaker, and 4-driver array will be 2x as loud (+6db SPL) as a single driver . So a 4x12 cabinet should generally sound twice as loud as a single-12 cabinet when driven from the same amplifier, assuming proper load matching. (Driver/baffle interaction and phase cancellation chip away at this theoretical relationship.) I'll have to check my speaker building books for the proper handling of the logarithmic/ decibel equations to get the math to come out right.

4/21/2000 6:47 PM

Doc

Re: SPL [sound pressure level] question

Gentlemen, I apologize for the sloppy math in my previous post. I was trying to pull it from long term memory. I guess I kind of jumped into the water head first and hit a big rock just below the surface.

What I do believe is true is that 6db increase in speaker efficiency means double the loudness. So a speaker with an efficiency of 100db would be perceived as twice as loud as a speaker with 94db efficiency, using the same electrical input signal.

Also, a 2-driver array will be 1.4x as loud (+3db SPL) as a single speaker, and 4-driver array will be 2x as loud (+6db SPL) as a single driver . So a 4x12 cabinet should generally sound twice as loud as a single-12 cabinet when driven from the same amplifier, assuming proper load matching. (Driver/baffle interaction and phase cancellation chip away at this theoretical relationship.)

I'll have to check my speaker building books for the proper handling of the logarithmic/ decibel equations to get the math to come out right.