From a simple acustical transducer in the early 1920, the modern loudspeaker enclosure system is a precise piece of electro acustical engineering as well as a superb cabinet making. The pictorial sequence illustrates its most representative models

The high efficiency accoustical enclosure type Hartsfield made by JBL in the USA in the mid fifities. It was originally developed for sound reinforcement comprising a 15 inch woofer and a high frequency horn.

In 1954 the american engineer Edgar M. Villchur developed a new type of loudspeaker enclosure system operating by the acustic suspension principle. Originally the first model AR-1 used only a 12 inch woofer. A separated electrostatic transducer was used for the reproduction of the high frequency range.

The assembled experimental acustic suspension developed by E. Villchur in 1954.

The loudspeaker enclosure made in several versions. Commoly known as the voice of theatre was made by Altec in the USA. It used a 15 inch woofer and a sectorial horn respectively for reproducing the low and high frequency ranges.