AR MST

[Guest]

Hi

Can any member tell me more about the AR MST? Were these a development of the LST or an alternative (read cheaper!) model?

The LST was available in Denmark where it was one of the dearest speakers available, but I have never seen a spec or price for the MST.

Many thanks

Robert Hartnett

Denmark

Proud AR 3ax owner

[Guest OpusX]

You are right...there is a real paucity of information on the MSTs and I am almost embarrassed to say that I can't add much to the body of knowledge and I even own a pair of them. Would love to get a system assembly drawing with a parts list and a schematic of the wiring.

Bought them in late 1976 when I was stationed in Germany. The LSTs were out of my range of affordability and I didn't have enough amp for a set of 3As. Figured I would eventually trade up on both accounts and eventually added a set of 11s. (Still have both sets and have recently acquired a set of AR90s.)

The MSTs were a two-way system (as opposed to the three-way config of the LSTs) with an 8 inch woofer and 3 of the .75" tweeters. For their size they had plenty of the characteristic clean AR sound and have provided me with years of faithful, maintenance-free service and hours of nice listening.

[Guest]

Dear Peter

Many thanks for your helpful reply. I won a pair on an auction and will collect them from the UK next month. Purchased sight unseen, and qualities unknown is a little risky, but I figured that they were related to the LST which is a speaker I have long wished to acquire but have never seen.

My AR3ax's are driven by a Luxman M120 and they provide an excellent sound, although I must have the bass unit surrounds done one day.

Best wishes

Robert

[Steve F]

Dear Robert,

I hate to pick nits, but there was no such thing as an AR-3ax, unless it was a special model marketed only in Denmark that wasn't available or advertised in the U.S. The models here were AR-3, 3a, 3a Improved (in the UK), 2, 2a, and 2ax, but NO "3ax."

Regarding the AR-MST:

The MST was introduced in March 1975 along with the 11 and 10Pi as part of AR's new ADD (Advanced Development Division). The cabinet was shaped like a smaller version of the LST, with three radiating cabinet panels--one forward facing, and two angled away to the left and right of the front panel.

It used an 8" woofer and three 1 1/4" cone tweeters (similar to the tweeter in the AR-6 and -7), not the 3/4" dome. The speakers were mirror-imaged, with two of the tweeters side by side above the woofer on the front panel, and the third tweeter on the side panel. One side panel was blank. AR's instructions were to orient the speakers with the tweeters on the inner panels for a more tighly-focused stereo image, and to place the speakers with the tweeters facing out for a more diffuse, spacious effect.

The forward-facing tweeters crossed over from the woofer at 1600Hz; the outer tweeter handled frequencies above 5000Hz.

There apparently were some response irregularities in early-production MST's due to measurement inconsistencies between AR's different testing facillities, but this was straightened out in due course.

It was actually quite a nice sounding speaker, but the relatively high price ($159 ea. in 1976) for a speaker with a 3dB down point no better than an AR-6 and the difficult-to-place LST-type cabinet limited its commercial success.