The loudspeakers sold under the brand name ATL initially came from the ATL Lautsprecher Vertriebsgesellschaft and were exclusively developed by Hans Deutsch. The speakers offered by ATL Elektro Akustik Vertriebsgesellschaft since 1989 came from Klaus Dotter (before Canton), Gerald Gessner (before Symo) or Norbert Schäfer (before Phonogen and Canton), have nothing to do with Hans Deutsch anymore.
HD series (1983-1989)
Developed by Hans Deutsch (HD) and sold from 1982 onwards, the series was later partly continued by Hans Deutsch Lautsprecher GmbH.
The hallmarks were the horn resonator, almost undamped cabinets and extremely simplified crossovers.
- HD 304
- HD 304 S
- HD 306
- HD 306 S
- HD 308 i
- HD 308 S
- HD 309
- HD 310
- HD 310 i
- HD 310 S
- HD 311
- HD 312
- HD 312 S
- HD 313
- HD 314
- HD 314 i
- HD 316
- HD 318
Top models from the Hans Deutsch development for ATL (1983-1989)
Standard series and Pro-Line (1989-1994)
Series developed by Klaus Dotter and sold from 1989 onwards,
- 701 Pro
- 704 Pro
- 705 Pro
- 706 Pro
- 707 Pro
- 707/II Pro
- 708 Pro
- 709 Pro
- 710 Pro
- 711 Pro
- 712 Pro
- 715 Pro
- 719 Pro
Avantgarde series (1990-1994)
Design-oriented series developed by Klaus Dotter and sold from 1990 onwards.
Introduced in 1992, the 911 is a design box penned by Norbert Schäfer that is not associated with any series. The speakers are recognizable by their high-quality, seamless finish, a very narrow baffle and side-mounted woofers. The tweeters and woofers are designed and manufactured by Norbert Schäfer.
- 911 (1992-1994)
The design-oriented Slim-Line complemented the 700 series. The conception still goes back to Klaus Dotter; the development was completed by Gerald Gessner.
Characteristic of the speakers is their narrow front, where only drivers with a diameter of up to 10cm fit, and the laterally mounted bass drivers with paper cone.
The Trans family from the development of Norbert Schäfer goes back to large diaphragm experiments that the physicist had started in 1982 at his company Phonogen.
Still at Phonogen, the Transfer model had appeared at the end of 1987. From summer 1989 it and further models, a little later the Transmaster, should become available at ATL.
All models of the Trans-Line are based on the same loudspeakers, which are only used in different numbers and arrangements. The tweeter magnetostats and the woofers with flat diaphragm were developed and manufactured by Norbert Schäfer; the midrange drivers with flat dome tweeters are versions of the LPM100 by Nokia (formerly SEL or ITT) adapted at ATL.
The drivers used in the ATL speakers are based on the types used in the Phonogen speakers, but they are further developments and cannot be exchanged without modification! From the outside, the ATL can be distinguished from the Phonogen The boxes are distinguishable from the Phonogen speakers by the rectangular shape of the bottom and top panels.
All Trans are closed 3 way cabinets with equalising ports, so called line source direct radiators.
Characteristic of the Trans boxes is the extreme directivity of the tweeters. The Translife and Transfer models can therefore usually only be used by listeners of average height in a sitting position.
Speakers with foil cone are subject to ageing in a special way. This is also the case with the Norbert Schäfer tweeter, which is expressed by an increase in impedance. This causes the drivers to become quieter, the crossover frequency to change and the components of the crossover to be subjected to an increasing load, which can lead to burnout: Discoloration of the traces, melted bonding and cracked load resistors on the crossover boards are visible consequences.
The nominal value of the impedance of a tweeter is 2.6 to 2.8 Ohm.
The Trans-Line did not find a successor until the end of the nineties: Norbert Schäfer, together with engineer Joachim Zürn, founded the Translife Media GmbH in Schöntal, where the Largo, a further development of the Transmaster was built.