Acoustic Research AR9

1 9 7 8 1978
1 9 8 2 1982

Last truly visible Acoustic Research from the beginning of the Teledyne ownership and before the subsequent various ownerships and fortunes.
Not that AR had been as successful in the 1970s as it had been throughout the 1960s but at least it had been present.
The 1980s and 1990s turned out to be more of a disappearing act improvised in several steps... even seeing an attempt at an AR3a reissue in Japan.

The AR9 is a very vertical 59kg four-way loudspeaker with five drivers.

The two 30cm drivers are placed on the sides of the enclosure to keep reflected sound-cancelling waves above 200Hz - big room necessary because that makes four 30cm drivers outputting long waves of sound !

The goal of this was to avoid the "wall dip" : where walls' reflections cancel out some of the bass output, making the transition between low mid and top of the bass range difficult and straining the amplifier's output.

The filter was also designed accordingly with two ranges taken into account. Neutral above the resonant frequency, it kicks in actively (so to say) below that frequency to keep damping as efficient as possble while maintaining output.

Nominal impedance is spec'ed at 4 Ohm with a big dip down to 3,2 Ohm.
It is naturally there, with the 'two way' filter, the acoustic suspension and the moderate 87dB efficiency that some amplifiers will scream "I can't do this !" and some won't mind at all.

The other three drivers are placed vertically, all surrounded by a big (and patented) "acoustic blanket" to keep enclosure reflections to a minimum.
The high-mid and high drivers are liquid-cooled and three 3-position switches (resistor networks) allow to fine-tune response of the front drivers. In-house made drivers, of course.

The AR9's stringent engineering made it and still makes it somewhat difficult to drive, a perfect loudspeaker to some and nothing special to others...
We all have different ears. And different amplifiers. And different rooms.

The 1978 AR9 engineering in Tim Holl's own writing here, complete with complete measurements and graphs.

Acoustic Research AR9, image 1 Acoustic Research AR9, image 2 Acoustic Research AR9, image 3
Acoustic Research AR9 specifications
Title Value
System type : floor-standing columnar 4-way system
with five drivers and AR Acoustc Blanket
Bass drivers : 2x 30cm cones
Low midrange : 1x 20cm cone in its own sub-enclosure
High midrange : 1x 3,8cm cone, liquid-cooled with semi horn-loading
Tweeter : 1x 1,9cm dome, liquid-cooled
Frequency range : 18Hz...30Khz
Efficiency : 87dB SPL at 1W and 1m on axis
Power handling : up to 400W continuous per channel
no more than 10% of the time on normal speech
and music source in non-commercial applications
DIN nominal power handling : 175W
DIN maximum power handling : 275W
System low frequency response : -3dB at 28Hz
Effective system Q : 0,5 at resonance
Impedance : 4 Ohm nominal
3,2 Ohm minimum
Controls : three 3-position switches
Crossover frequencies : 200Hz
Crossover network : - Half and quarter section LC networks on lower and
upper midrange drivers.
- Network of upper mid also includes an impedance-
equalizing circuit.
- Full section networks on woofer and highrange drivers.
- Woofer's network also includes a bass extension and Q
optimization circuit.
- Air-core chokes wound with #17 AWG solid conductor
computer-grade bipolar electrolytic caps
- Non-inductive high-power ceramic resistors
Cabinet finish : oiled walnut veneer
Cabinet volume : 120L
Cabinet dimensions : 134 x 38 x 40,2cm
Weight : 59kg.
Acoustic Research AR9 : 1 topic
(last updated topic shows up first)
  • Help with Acoustic research AR9 speakers                             (1)last updated by DJMATTHEW - 02/03/2012, 05H23
page online since : november 2010
page updated : november 2010
page type : LGT / KNB
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