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Old 4th July 2007, 04:48 PM   #1
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Default Sensitivity dB Calculations

Hello everyone, drawing a blank here.....

I am looking at the WR125ST, which is 85.6 dB w/ 1 watt. Since it is a 16-ohm nominal speaker, that is 4 Volts input.

How do I determine the dB with 2.83 Volts (0.5 Watts) input? I know there is an equation out there, just can't seem to find it.
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Old 4th July 2007, 05:22 PM   #2
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Just did a little experiment in Unibox. With 0.5 Watt, the output is at 82 dB, ~3 dB less. What is the equation the relates cutting the wattage in half, reduces dB by 3?
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Old 4th July 2007, 06:55 PM   #3
sreten is offline sreten  United Kingdom
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Hi,

Sensitivity should be stated as dB/2.83V independent of impedance.

The standard version is 85.6 dB (? 86dB) 8ohm, expect 83dB for 16ohm.

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Old 4th July 2007, 09:45 PM   #4
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Quote:
Originally posted by 69stingray
What is the equation the relates cutting the wattage in half, reduces dB by 3?
Hi Zach,

The equation is 10X the power = 10 more dB.

2X power and 3 dB is close enough for approximating.
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Old 5th July 2007, 01:25 AM   #5
Svante is offline Svante  Sweden
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Quote:
Originally posted by 69stingray What is the equation the relates cutting the wattage in half, reduces dB by 3? [/B]
10 * log10 (P/Pref)

So if P/Pref=0.5, 10*log10(0.5)=10*0.301=3.01 dB.
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