In around 1898, a sound increasing device (aka acoustic amplifier) was developed in UK by Horace Short and Charles Parsons of Turbine fame. The amplifier was powered by compressed air and was commercialised on a wind-up gramophone of the era.
This was a dangerous weapon, but armed few citizens because of the significant cost. It was suited to large venues and possibly outdoors events.
The unit can be seen and heard at https://www.youtube.com/watch?v=J7SV65DFNy8
The compressor seems to make a lot of noise - until the amplifier starts. The recording has Automatic Gain Control and this limits the perceptual loudness but the commentator tries to shout over the unit later in the video and this gives you a better idea. It would seem that audio was rescued by electronics. Does anyone have other examples of early or pre-electronics Audio?