MANUFACTURERS SPECIFICATIONS
System Type: Two way, totally enclosed.
System Components: 8 inch bass, 1 1/2 inch cone tweeter.
Crossover Frequency: 2000 Hz.
Frequency Response: 40 to 20 kHz
Recommended Amplifier Power: 15 watts (min.) Nominal Impedance: 8 ohms.
Dimensions: 9 by 15 by 6 1/4 inches deep.
Weight: 11 lbs.
Price: $ 60.
Latest addition to the AR range, and the smallest, is the AR-7. Measuring only 15 by 9 by 6 1/4 it turns the scale at only 11 lbs.--compared with the big LST at 90 lbs.! Nevertheless, it can give a very good account of itself as we shall see. The tweeter is a 1 1/2 inch type very similar to the one used on the AR-6 but the crossover frequency is 2000 Hz instead of 1500 Hz. A two-position level control is fitted and, like all AR systems, the AR-7 is guaranteed for 5 years. And like the other systems, it is an acoustic suspension type with a sealed enclosure. System resonance is just under 60 Hz-truly remarkable in such a small box.
Measurements
Figure 1 shows the response measured with one-third octave pink noise. A was taken on-axis with both positions of the level switch, B at 45 degrees off-axis and C is an average of 5 positions. Response is very smooth, particularly in the important region from 200 to 2 kHz and it will be seen that dispersion is good. Low-frequency distortion and some SPL measurements are shown in figure 2. The system would handle 41 watts (continuous, sine wave) at 41 Hz and 62 watts at 100 Hz without audible doubling or other signs of distress. Figure 3 shows the tone-burst responses at 100, 500 and 5000 Hz and the impedance curve is given in figure 4. Average was 8 ohms with the lowest point at 5 ohms.
Fig. 1--Response with one-third octave pink noise. A was taken on axis, B
at 45 degrees off-axis and C is an average at 5 positions.
Fig 2--Low-frequency distortion and SPL.
Fig 3--Tone burst responses: A is 100 Hz, B 500 Hz and C: 5000 Hz.
Fig 4--Impedance characteristics.
Listening Tests
Sensitivity was about average for this kind of system-which means that a power level of some 20 to 25 watts is needed.
AR put the minimum power requirements at 15 watts which seems reasonable. Because of their small size (and price) four AR-7's would be ideal for a quadraphonic system in a small or medium size room and a total power of 50 watts would be adequate. The overall sound quality is typical AR low coloration, a smooth treble, and a clean bass with low distortion. We predict that the AR-7 will become the standard for other speakers in the under $100 class and supplanting some speakers of even greater cost.
-T.A., G.W.T.
(Audio magazine, Feb. 1973)
Also see:
Acoustic Research AR-6 Loudspeaker System (Jan. 1972)
AR (Acoustic Research) AR-7 loudspeaker (ad, Feb. 1973)
AR M1 Speaker (Equip. Profile, Jan. 1992)
Acoustic Research AR98LS Speaker (Jan. 1985)
AR (Acoustic Research) MGC-1 loudspeaker (ad, Nov. 1986)
Acoustic Research LST Speaker System (Dec. 1972)
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