His records were of poor quality since about half of his 66 sides were recorded with an acoustic horn, not a microphone.

They are sometimes called acoustic cleaners or acoustic horns.

By the late 1800's, the acoustic horn became available.

To make them, people talked or sang into acoustic horns, and there was nary a noise filter in sight.

These typically consisted of large acoustic horns attached to stethoscope-type earphones worn by monitors.

The method of transfer involves the use of thorn needles and a giant acoustic horn on a carefully restored gramophone.

Performers were typically grouped around a large acoustic horn (an enlarged version of the familiar phonograph horn).

It was one of the first electrical recordings of a song, using an electrical microphone instead an acoustic horn.

It is attached to an acoustic horn, a widening duct which serves to radiate the sound efficiently into the air.

The overall length of acoustic cleaner horns range from 430 mm to over 3 metres long.