[Trevor Wilson]

"eponymous cowherd" wrote in message
...

I am thinking about buying a new amp and would like to know how much
power I need. My current amp is rated at 25 watts and I never put the
volume knob past the 1/3 point and I never have problems playing music
LOUD enough. Is the power usage proportional to the volume knob
position,

**No.

am I always using less than 12 watts?

**Impossible to know. I use the following (incomplete) analogy:

Think of an accelerator pedal in an automobile. Push it halfway down and you
might be travelling (assuming a long, straight, flat road) at 150kph. If you
push it all the way down, you are not likely to be travelling at 300kph, as
there are many factors which come into play. Wind resistance, gearing, max
RPM, max torque, road conditions, the amount of fuel/air which can enter the
engine, etc. Similar deal with audio systems. Different levels recorded on
CDs, different gains and the fact that volume pots are logarithmic in nature
(to account for the way humans hear sound).

It we assume all things are perfect and that the system delivers 25 Watts at
max volume (with a sine wave input), then it is reasonable to assume that at
half volume the level will be approximately 2.5 Watts. At 1/4 volume, the
level will be 0.25 Watts and so on.


--
Trevor Wilson
www.rageaudio.com.au




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