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Author Topic: Does turning the volume up use more battery power?  (Read 10266 times)

paul.fr

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Well. does it?
Is it different between devices such as an Ipod or a "standard" radio / cassette player?


 

Offline RD

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Does turning the volume up use more battery power?
« Reply #1 on: 21/09/2008 19:20:03 »
More power output (sound) requires more power input (from batteries).

The audio amplifier circuitry in a digital device is no different from an "old fashioned" analogue radio or cassette player.
Digital devices have a Digital to Analogue Converter chip (DAC) whose analogue output is then fed to the audio amplifier.   

 

Offline FuzzyUK

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Does turning the volume up use more battery power?
« Reply #2 on: 21/09/2008 20:05:50 »
Devices specifically for headphone use usually drain less power than audio amplifiers designed to shove lots of noise out of loudspeakers.

Typically headphones may only provide a few milliwatts of output power; loudspeakers in home radios or TV's may be in the order of 3-5 watts; louts in cars and noisy neighbour may be booming away with several tens of watts. Music festival equipment may be pumping out several hundred watts of power. Ironically low power scratchy music from headphones can be most annoying to others on a train. Shoot all offenders regardless of what power they are using
 

Offline Pumblechook

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Does turning the volume up use more battery power?
« Reply #3 on: 21/09/2008 21:00:37 »
Almost all audio output amplifiers are run in what is called Class B and the DC current (and therefore power) increases  with increased audio output.  Usually most of the battery power is used up for the final audio stages so the fluctuation is significant.

The whole point of using Class B is to get the power consumption down.  Class A was the norm in days gone by where the DC power to an amplifier is high and constant irrespective of audio level.   Low level audio stages in radios etc are in class A but the power involved is much less.   

http://www.electronics-tutorials.ws/amplifier/amp_6.html

Class B ampflifiers can be 70% efficient whereas Class A amplifiers are something like 10% efficient.   A class A would use 10 Watts of DC power to produce 1 Watt of audio.   A Class B would only require 1.4 Watts to produce 1 Watt of audio.  And as the audio has peaks and quiet bits then the average DC power is somewhat less with class B so an even greater saving wrt Class A. 

Early car radios used Class A audio output amplifiers and could flatten a battery if left on even with the volume right down. 
« Last Edit: 21/09/2008 21:53:18 by Pumblechook »
 

Offline techmind

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Does turning the volume up use more battery power?
« Reply #4 on: 21/09/2008 21:28:25 »
If you place an ammeter (probably initially on 100mA range for a headphone device) in series with the batteries, you can test this for yourself. In general, though, yes. The higher the volume the faster you'll drain the batteries on your favorite personal electronics.

Of course there'll be a non-zero minimum power even when the volume is at zero as some of the power still has to run the radio-receiver or mp3-decoding part of the electronics too.
 

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Does turning the volume up use more battery power?
« Reply #4 on: 21/09/2008 21:28:25 »

 

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