Electronics > Projects, Designs, and Technical Stuff
Audiophile Related - Understanding power, peak, contious and dBs
TimFox:
I already explained this:
3 dB SPL (note the suffix) is the sound level associated with dropping a pin.
3 dB (no suffix) is a power ratio.
bson:
--- Quote from: DW1961 on August 01, 2020, 08:42:54 pm ---"Increasing an amplifier from 25 watts to 50 watts (double the power) increases the acoustic power by 3dB."
https://geoffthegreygeek.com/amplifier-power/
--- End quote ---
That's complete nonsense. Acoustic power and electric power are linearly related by the loudspeaker's efficiency. Pa = eff * Pin. "3dB" is just a red herring since 25W to 50W is also 3dB.
TimFox:
--- Quote from: bson on August 02, 2020, 08:42:53 pm ---
--- Quote from: DW1961 on August 01, 2020, 08:42:54 pm ---"Increasing an amplifier from 25 watts to 50 watts (double the power) increases the acoustic power by 3dB."
https://geoffthegreygeek.com/amplifier-power/
--- End quote ---
That's complete nonsense. Acoustic power and electric power are linearly related by the loudspeaker's efficiency. Pa = eff * Pin. "3dB" is just a red herring since 25W to 50W is also 3dB.
--- End quote ---
Misleading: Since the acoustic power is proportional to the electric power for a linear loudspeaker, increasing the input (electrical power) by a factor of two (3 dB) will increase the output (acoustic power) by a factor of two (3 dB). DW1961 may be confusing amplifier power rating with amplifier power output.
DW1961:
--- Quote from: TimFox on August 02, 2020, 08:48:18 pm ---
--- Quote from: bson on August 02, 2020, 08:42:53 pm ---
--- Quote from: DW1961 on August 01, 2020, 08:42:54 pm ---"Increasing an amplifier from 25 watts to 50 watts (double the power) increases the acoustic power by 3dB."
https://geoffthegreygeek.com/amplifier-power/
--- End quote ---
That's complete nonsense. Acoustic power and electric power are linearly related by the loudspeaker's efficiency. Pa = eff * Pin. "3dB" is just a red herring since 25W to 50W is also 3dB.
--- End quote ---
Misleading: Since the acoustic power is proportional to the electric power for a linear loudspeaker, increasing the input (electrical power) by a factor of two (3 dB) will increase the output (acoustic power) by a factor of two (3 dB). DW1961 may be confusing amplifier power rating with amplifier power output.
--- End quote ---
OK, so the way I am understanding it now is like this:
-Double the amp power, you get a 3dB increase in acoustic power.
-Acoustic power causes sound pressure, which can be measured objectively.
-Acoustic power does now equal loudness.
Adding x2 the power adds +3dB of acoustic power, but only increases volume by 23%.
Note to self:
Just thought of something else I want to bring up and going to make a note of it here:
PLEASE DISREGARD REPLYING TO THIS FOR NOW: Ohms and average power for any 4-8 ohms rating and any 4-8 ohms speaker. An amp rated at 100 watts at 4 ohms may give an 8 ohms speaker nearly the same power calculated at 4 ohms depending on frequency?
TimFox:
The physical statements are correct. (You should be more careful about the use of common terms such as "adding" and "multiplying"; "adding twice the power" means "tripling the power" in plain English, since 1 + 2 = 3. Doubling the power does add 3dB to the result).
The final statement about the volume is not a physical statement, but the result of psychoacoustic experiments with the perception by human listeners, and is related to the Weber-Fechner law.
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