Unfortunately, the three models AR-4, 4x and 4xa are frequently used synonymously when searching for one of these speakers on auction websites. If you wonder what the difference between the AR-4, AR-4x and AR-4xa is, here is a short simple answer: It´s all about the tweeter!
The AR-4 is the oldest of the three and by now a sought after collectable made in 1964. The AR-4x is its successor and from late 1965 and 1966. The AR-4x has 2 1/2″ cone tweeters, whereas the AR-4 has 3 1/2″ tweeters. The AR-4x received outstanding reviews and is until today famous for its sound quality. Finally, in 1973, the then AR-4xa speaker had been introduced. The tweeters were switched to the 1 1/4″ tweeters used in the AR-6 and AR-7.
This review targets the AR-4x and AR-4xa, but the differences to the older AR-4 are minor. The 4x and 4xa are 2-way acoustic suspension speakers in beautiful walnut veneer with the typical white Acoustic Research cloth grills. The speaker was also available in unfinished birch and pine.Most likely you will find the older AR-4x, as the newer 4xa had not been sold in high numbers. At the time of its release, Acoustic Research sold both, the 4x and 4xa, with the new 4xa being priced slightly above the older model. However, as the innovations of the new 4xa were minor, its higher price caused many customers to choose the older 4x. Also, by 1973, AR had its AR-6 and AR-7 placed in a similar market segment. It is therefor sometimes claimed, that the introduction of the AR-4xa was unnecessary, making the speaker redundant.
How much should I pay for the AR-4x or 4-xa?
If you can find a pair of these speakers with the original speakers you should pay around 150$, which is a great price for the sound quality you will get. You should be aware that a pair of these vintage speakers is likely to have issues with the speaker foam, if they haven´t been replaced yet. Investing in a new foam kit is definetily worth the effort! A nicely restored pair of these speakers can sometimes be found on ebay for around $350.
Also, AR-6 speakers are nearly identical to the AR-4xa (click here for a review of the AR-6
) with two exceptions. The woofer resonance of the AR-4xa is 65Hz in enclosure, vs. the 56 Hz of the AR-6. The second difference is the cabinet form. The AR-6 is slightly higher and wider, but 2 inches less deep. Auction prices for the AR-6 and AR-4xa are similar.
Refoaming the AR-4xa
|Acoustic Research AR-4xa
The AR-4xa is definetily worth it being refoamed. Many of them have rotted foam surrounds which can easily be replaced. A refoaming kit can usually be bought for around $30, replacing the old foams will take around 1 to 2 hours and is not difficult at all! It does not require any particular skill, just a calm hand and a little patience. We tried out several available foams and recommend to use an 8 inch Surround Kit from Parts Express.
CAREFUL: The AR-4 and AR-4x have mostly cloth surrounds, not foam surrounds. Only the AR-4xa has foam surrounds. Choose the surround kit on the right, if you are planning to refoam the AR-4xa, but not for the others!
Drive units: 8 inch acoustic suspension woofer, 1 ¼ inch high-frequency cone
Crossover: 1600 Hz
Impedance: 8 ohms nominal
Controls: High-frequency level adjustment
Amplifier: Up to 100 watts per channel:
Size: 10 x 19 x 9 inches
Weight: 18.5 lbs
Woofer resonance: Free air 30 Hz, in enclosure 65 Hz
Volume of enclosure: 18.5 litres (0.65 cu ft)
Some noteworthy information is quoted below:
“The Ar-4xa is the improved version of the world´s most widely used high fidelity speaker system, the AR-4x. The AR-4xa uses the same acoustic suspension woofer as its predecessor, but incorporates a new tweeter and a modified crossover network. The 32 mm tweeter is the same as that used in the highly acclaimed AR-6 speaker system, giving the AR-4xa improved treble response and dispersion characteristics.” This quote is from my 1969 Acoustic Research magazine.
The Records and Recording Magazine writes “Excellent performance… a steady frequency response which many more expensive systems would find it difficult to equal… this unit, measured objectively, confirmed fully what I expected to find after listening to it with a wide range of programme material. The AR-4x is a loudspeaker of very high quality, made and designed to high technical standards. It is not very often that one finds such a completely successful enterprise as this.”
AR-4xa Price: $130-200(Depending on overall condition)
AR-4x Price: $140-200(Depending on overall condition)
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