Electronics, Lighting, & Gadgets - can you run a horn from light batteries?

5AAs: V_bat_terminals=5.7V I=0.8A
6AAs: V_bat_terminals=6.7V I=1.0A

5.7 x 0.8 = 4.56W
6.7 x 1.0 = 6.7W

Quite a difference in power, was there any difference in volume ?

5.7 x 0.8 = 4.56W
6.7 x 1.0 = 6.7W

Quite a difference in power, was there any difference in volume ?

I thought there was, but you know, it is approximately just logarithmic :). More seriously, there might be some threshold effect there - I thought that there was a bit more difference in the loudness than the log scale would suggest. In my configuration, I will stay with 5 AAs - the advantage of the hub system is that there is a reasonable guarantee that the power for the horn is always there. However, when going with a standalone battery-powered horn system, I'd indeed go with 6 rechargeable AAs.

As a byproduct of this discussion, I have looked around at PC oscilloscope add-ons and realized that they have moved quite a bit up in quality and down in price since the last time I have done it. It may be time to replace my past cheap add-on :thumb:.

I thought that there was a bit more difference in the loudness than the log scale would suggest. In my configuration, I will stay with 5 AAs - the advantage of the hub system is that there is a reasonable guarantee that the power for the horn is always there. However, when going with a standalone battery-powered horn system, I'd indeed go with 6 rechargeable AAs.

4.56W 6.7W - that's a difference of 32% I would expect it to be noticable.

You are misunderstanding why a logarithmic scale is used.

Your hearing is (approximately) logarithmic and so a logarithmic scale is used to compensate - that is to say an perceived audible difference in volume appears similar to the measured difference. This allows a scale to be used and measurements to be taken that are easier to understand and manipulate.

The relationship between power in and SPL of the horn is probably neither linear nor logarithmic, however I would expect it is more efficient at the higher power input.

:)

ps. all volume controls on audio equipment are also logarithmic - otherwise the first few % of the control would be overly sensitive and not fine enough and anything in the upper part would have very little noticable effect (to the human ear).

4.56W 6.7W - that's a difference of 32% I would expect it to be noticable.


1.7dB or 20% change in distance from source, when this has not been really an A/B comparison, since I have been switching cables and have been moving my head around?? I am not sure that such a difference would have been that easily noticeable. Anyway, I thought that the difference in loudness was a bit more significant that the above, because, for the higher power, it was working closer to its intended operating conditions, i.e. for the reason below



however I would expect it is more efficient at the higher power input.

Your hearing is (approximately) logarithmic and so a logarithmic scale is used to compensate - that is to say an perceived audible difference in volume appears similar to the measured difference. This allows a scale to be used and measurements to be taken that are easier to understand and manipulate.

If I may translate for the non-audio crowd...

What seems like a linear change in your brain is more or less a logarithmic change in actual sound pressure levels. Having audio knobs change volume logarithmically is a way of making them match what Just Makes Sense to your brain.