tazada wrote on Wed, 30 March 2005 06:40 |
I was never good at DB, but as he said above, 3DB raise in SPL requires 2x the power. If you make a chart like this:
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You could just do the math... 10*log(p1/p2) + Sensitivity or the opposite calculation 10^((SPL - sens)/10)
p1/p2 can be reduced to p1 if p2 is 1 watt. BTW 10^() means ten rased to whatever power in the parens.
If you are doing these on a calculator....
To find how loud a speaker can get (not taking into account power compression and other weirdness) use the first equation. With your example of a 715 96 dB + 10*log(3200) = 131.05 dB max
3200
log x 10 + 96
To find the power required to get your particular speaker to a certain volume, use the second equation. Say you want to hit 124 dB. 10^((124-96)/10) = 630.96 Watts.
124 - 96 / 10 then hit the 10x key (the x should be superscript) which is usually found above the log key if you calculator has it.
Most of this stuff can be found in the Study Hall on here.
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Now to put this in perspective, a 3db change is about what it takes for the human ear to say "aha! that got louder!"
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I think this is very subjective... Kind of saying what is "twice as loud." Very hard to qualify.
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Could someone explain what the diff sensatvities mean, i have heard that with SPL every 3 SPL db's means the perceived sound is doubbled, is this true?
Also with theese speakers do i want to run them closer to the continus rated level? what exactly is the program level? Also i was told the reason theese need so much power is because they have a lighter new magnet and dissapte most of the power as heat, not sound.
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Generally, the more senstive a speaker, the better. It means your power requirements will be less. That's a good thing. Generally speaking, a higher sensitivity, indicates that the speaker is more efficient allowing it to turn more electricity in to actual sound.
As far as where to run them... Continuous power is (correct me if I'm wrong guys) more a measure of the speakers capacity when dealing with content with a high average to peak power ratio. Like a sine wave. Signals that are not very dynamic (heavily compressed material) will max out at a speakers continuous level. The Program rating is more of a real world rating as far as musical content goes. Since, music is usually very dynamic, the average power is pretty low. There are huge peaks however. There's where your peak rating comes in. Basically, if you run either of those speakers at their continuous rating (800 and 1200) you'll have about 6 db of dynamic headroom in your system. Which is acceptable. It will also mean your speakers are averaging a SPL in the mid to upper 120s. That's pretty friggin loud.