Sound system

[Megatech1966]

Is 5 to 24 volts ac normal for a line input on a sound system?

[Circlotron]

1 volts RMS is more like it.

[coromonadalix]

it depends if it as an high voltage input,   i did saw in the past some commercial stuff having high voltage signal input

BUT

your description is to vague

model, brand, what is driving the unit etc ...   photos

[themadhippy]

could be 100mV or it could be 10V,theres  no official standard as far as i aware

[CaptDon]

There is one specific case where this could be normal although it is very dated. Sunn in particular made 'booster amplifiers' where the speaker output voltage (28.5vrms @ 100w) from an instrument amplifier (guitar etc.) was daisy chained to the booster amp input which drove a speaker stack and this could continue to be multiplied down the line. The booster amp output voltage was the same as the input voltage although the current was boosted to drive the speaker stack. Other manufacturers copied this idea and there was also a similar amplifier offered by Seeburg for daisy chaining jukebox speakers in large clubs. The Sunn booster amps did have a gain control so you could go from 0 (no sound) to a slight gain over the input signal although 'unity gain' would be the normal setting. Almost as obsolete is the '25 volt line' which was largely replaced by the 70.7 volt distribution system.

[donlisms]

Your question does not provide enough information to be able to answer it very well.  Are you trying to find out if an existing system is working normally? Or if something will work if you try it?  What devices are you trying to connect?

When you say "line input", if you mean it in the technical sense, for example what would be in the specifications, then it will typically have a maximum of... perhaps +12 dBu (3 volts) to +20 dBu (7.75 volts).

24 volts would be about +30dBu, which would definitely be way above normal, and no normal line input could handle it.

Speaker outputs are commonly put through a properly-configured direct box, which will pad the signal down appropriately (often through a very simple resistive divider).