Anyone know much about speakers? Voltages and waveforms, not audio quality.

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lw395 said:
No, if you turn up the input to a an amp rated at "60W into 4ohms", then a "30W 4ohm" speaker will get 60W.
Give or take the fact that speaker impedances are complex and amplifier manufacturers often exaggerate their power.
So, you'd want to keep the volume turned down some. Quote

Quite so higher wattage amp means higher voltage. The speaker will bottom out in its travel so giving distortion not a problem to you although the cone can be distorted and damaged as can the voice coil itself. The next problem is that the voice coil is made of as light a wire as possible to reduce weight so can be melted (fused) so run 60 w into a 30 w speaker at your (speaker's) peril. olewill

Also, most speakers designed for music or PA won't like being used at a high duty cycle, it's a peak rating, not continuous. Probably no issue for normal yacht fog signals.
Click to expand...
 
I've had a similar project on (and off) the bench for about a year. I have a grey horn hailer type speaker and several bits of amplifier from various devices. For the signal, I found a discord of two separate oscillators was the answer - a bit like the horns on good old- fashioned posh cars, waveform doesn't appear to be a big issue. A 4093 chip will provide 4 oscillators - google quad oscillator
As for the technicalities, you can bang in the maximum wattage plus what you'll lose in the mast wiring, and be sure we will hear it across the water!
For those who advocate car horns, = early life failure in these conditions. Even the 'marine' version with SS and good seals is fitted with a metal diaphragm designed to self-destruct after a couple of toots. I made plastic replacement diaphragms which seem OK.
 
lw395 said:
No, if you turn up the input to a an amp rated at "60W into 4ohms", then a "30W 4ohm" speaker will get 60W.
[...]
So, you'd want to keep the volume turned down some.
Click to expand...

Ah, that's a problem then. There is no volume - look again at the board shown above. You put 12v across STDY (for "Steady" tone) and NEG, and connect the speaker to SPEAKER. That's it.

Can it be attenuated with a big resistor, perhaps?

Pete
 
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