1 True Watt

[Puffin]

My mind has been exercised since my thread on bass response by loudness, i.e how many watts does it take to produce 1 true watt.

I suspect that my logic may be a bit skewed as in "well 1 watt is 1 watt isn't it?"

I have an SPL meter. I have not used it in my current system, but did when I had built my Fostex Horns and Pass Labs F2 (5Watt Class A). Pass labs ethos is that the "First Watt" is the most important.

The Fostex are 96dB which I understand to be1 watt @ 2.83 volts. I also understand that measurments should be taken at 1 metre away.

I measured the Fostex and F2 together and when I got to around 96dB I felt I was in danger of damaging my hearing and backed off.

My current set up is 94dB speakers with bridged monoblocks capable of well in excess of 220W. The sound is effortless. However I wondered if I were to repeat the SPL test whether I would get a similar result.

My question is if the meter is reading 94dB, am I only providing 1 Watt?

[Ali Tait]

I'd say that the given sensitivity is probably measured without the speaker in a cabinet, so it will be higher with the driver in the cabinet. By how much I couldn't say.

[DSJR]

There is a proper way of doing it, but usually with the complete speaker system and averaged over different frequencies I think, although some manufacturers claim the sensitivity at the peakiest part of the frequency range.

[Ali Tait]

I think it's usually done on a flat baffle.

[Puffin]

Damn, I live in a house

[NRG]

http://www.hi-fiworld.co.uk/index.ph...nsitivity.html