
ATC's low frequency drive units come as a four unit range-9inch, 12inch, 15inch (3inch voice coil) and 15inch (4inch voice coil). Each unit has a short coil operating in a long magnetic field which has the advantage that during normal operation the coil always remains within the linear magnetic field. The 9inch and 15inch units are also offered with a long coil and short magnetic field.
The bass drivers incorporate the latest design principles and are all well known for their very low distortion levels, a quality which complements the outstanding performance of the ATC mid-range dome. Each bass driver has its voice coil formed of edgewise-wound copper ribbon wire, wound on an aluminium or kapton former. New adhesive technology is used, along with small coil-gap clearances to give very high power handling ability, with first class durability. The suspension of each ATC bass driver has been developed so that large excursions yield only very low distortion, and each unit has a diecast chassis and a bolted ceramic magnet structure, with a symmetrical magnetic field, to reduce distortion even further. All of the magnet's metal parts are finished in black to assist heat dissipation from the voice coil, an aid to durability. ATC naturally offers its customers a full technical service, and all products are fully guaranteed. If you require further information, please contact ATC.
ATC SPECIFICATION - GENERAL NOTES.
Measured and calculated parameters in the attached specifications have been made in accordance with the recommendations of the Standards Association of Australia and IEEE Standards of the U.S.A.
References: 1.
Australian Standard Specification No.1127 "Sound System Loudspeakers" Part 5. 2. USA - IEFE Specification Standard No.219-1975
1.POWER RATING
(A) NOMINAL POWER RATING =E2/Z Watts
Test Signal: Frequency weighted white noise.
Test Amplifier: The test amplifier used has a nominal power output capability of at least four times the nominal rated power of the loudspeaker.
Test Voltage: E is a true RMS voltage.
(B) MAXIMUM INPUT POWER = E2/Z Watts
Test Signal Sine wave.
Test Frequency: The Frequency at which minimum impedance occurs above resonance.
Test Voltage: E is the true RMS voltage which may be applied to the loudspeaker continuously without thermal overload of the voice coil.
(C) MAXIMUM PROGRAM POWER
The power amplifier rating defined by nominal power rating test specified in (A).
2. Other standard impedance values are available to special order.
APPLICATION NOTES Each of the loudspeakers specified has a specific range of applications. It is important that the following recommendations be considered when choosing an ATC loudspeaker.