Floor-standing speaker systems from the oldest German speaker company, Isophon (established in 1929). The production of acoustic systems was established in the city of Stuttgart together with the leaders of the German automobile industry - the companies "Daimbler-Chrysler" and "Porsche".
Roland Gauder, the company's chief designer, spent 8 years developing these speakers. A number of companies (in particular, Thorens, Restec, etc.) use these speakers as a reference for testing their equipment.
The applied proprietary technology "Acoustical Hologram Technology" determines the mutual geometric arrangement and electrical circuit of the filters of the HF emitter and three HF heads, the operating frequency bands of each HF loudspeaker. The unique delay line in the HF emitter circuit is calculated so that the phase radiation errors are minimal, and the entire system as a whole works as a single point source that paints a holographic sound picture in depth. WBT screw terminals allow TRI-WIRING connection.

Characteristics
Nominal power, W: 300
Peak power, W: 560
Nominal input resistance, Ohm: 4
Execution - aluminum MDF coating
Frequency of crossover section: 140/3 400 Hz.
Acoustic design: single vented.
High-frequency speaker silk - 1/25 mm. (1 ").
Medium-frequency speaker thick-layer cellulose - 3/120 mm. (4.7 ").
Low-frequency driver: thick-layer cellulose - 2/225 mm. (9 ").
Height, mm 1220
Width, mm: 250
Depth, mm: 460
Weight: 56 kg
Three pairs of acoustic terminals-Triwiring (WBT terminals) are used.
Two 4" midrange drivers on the front panel and one 4" midrange driver on the side panel implement Acoustic Hologram Technology (AHT)
Two 9" bass speakers inside the speaker implement bass-reflex technology
1 "tweeter works in the range of 12-20kHz, two mid-range speakers - up to 340 Hz, and one - from 340 to 12000 Hz