Non picaxe question - audio voltage divider

Captain Haddock

Senior Member
Sorry not picaxe but I'm sure plenty on here can answer this for me, I'm wanting to make a fixed fader for 2x speakers powered by a car audio, can I do this with a simple voltage divider and what sort of range resistors would I need?
I know the audio unit has all this built in but this is on one side of the fader that needs the speakers setting to a different level and old fashioned fader switches seem to be rare and overpriced on ebay when I have a stash of resistors from playing with picaxe.
The scenarion is on a boat, full R fader is in the saloon, full F fader is in the cabin and berth, berth speakers are right beside ears so berth speakers need dropping while cabi n speakers stay louder.
Thanks for any suggestions.


Senior Member
Sometimes it's worth having small amplifiers at point of use and just distribute the audio on telephone wire... Lpads work and are energy inefficient.... We don't have any idea of what power level you are running... or the needed quality of the signal to be heard...


Senior Member
Be careful. Most, if not all, car audios use bridge amplification. None of the speaker outputs have a common ground. Accidentally connecting any output to another, or to a common ground can immediately destroy the output stage. Connecting the 'high' level speaker outputs into an amplifier that isn't designed for it can again have the same destructive results.

I would, as Premelec suggests, use further amplification, preferably from an line level out on the head unit. If that isn't possible, an amplifier designed for 'high' level car audio work.


Well-known member
A man's got to know his limitations. --- Harry in Magnum Force movie
Audio is much different from the days where the output was a transformer.

Find a spec sheet on that "car audio" to figure out what outputs are available to distribute audio to the various points on the boat.