AR-MST: dimensions, weight?

[ra.ra]

I am trying to find some specific information on the forgotten step-child, the AR-MST, and have been unable to locate it on this site or other audio sites. Even though I am not the most facile user when researching the depths of CSP, I have looked in the Library, conducted searches of the discussion forums, and reviewed product literature and corporate timelines. Still, I have not been able to locate any original corporate product literature nor have I found any reviews which might list such data.

I would love to see some AR literature on this latest model of the "classic" era, but most specifically, I am interested to learn the dimensions and weight (in lbs.) for one AR-MST speaker. I understand there were a few variations of this speaker (four tweeter, three tweeter, MST-1, etc.) but I'm sure any of these are close enough as I suspect they all used the same general cabinet.

Any specific knowledge or documents would be appreciated.

[ironlake]

go craigs list for minneapolis and electronics and type in ar speakers and there are two armst pairs of speakers along with new 8 inch woofers and he wants 100 bucks for all of it.

[Steve F]

From a post of mine, probably back in '04 or '05:

"The MST (formal model number was AR-MST/1) 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 (the European version used 4 tweeters, but the US version had three), 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."

7/30/12:

Add'l specs:

Dimensions 14 3/16 x 21 x 7 3/4" HWD

Weight 25 lb ea.

System Q 1.0

Woofer FAR 25 Hz

System Resonance 55 Hz

Great trivia : The AR-MST was the very last AR speaker to use the white linen grille cloth.

Steve F.

[ra.ra]

Thank you, Steve, for the excellent feedback. As I was reading your notes, I thought I had seen most of this response before, and then I realized that you added the dated addendum which very well satisfies my specific questions, and then some.

I find it interesting to learn that the tweets x-o at different frequencies, and I suppose that is the intended magic of this particular design. I am not familiar enough with the crossovers of the LST or LST-II to know if this practice is typical of the tri-face, multiple driver speakers of similar shape.

Am now curious to see a schematic for this speaker, but I am also perplexed by the paucity of company or industry printed literature (catalog, brochure, advertisement, cut sheet, critical review) for this product available on this site or the internet in general. This leads me to believe that AR execs may have felt the MST was DOA when it hit the market. Even this attached chart, which I refer to frequently, fails to acknowledge the MST in the timeline - - - no mention of a new speaker debuting in 1975.

[michiganpat]

go craigs list for minneapolis and electronics and type in ar speakers and there are two armst pairs of speakers along with new 8 inch woofers and he wants 100 bucks for all of it.

hmm...my sis is in anoka, and we're going there to visit in a few weeks....but my wife would kill me if I bought any more speakers...

[dynaco_dan]

Hi there

You only live once.

A divorce isn't all that expensive.

AR-MST's only come along once in a while.

Tough choices, heh?

[Kev_Rat]

By a weird coincidence I'm currently in the chase for a pair of these. Never heard of them before today. I wonder how they will compare with the 17s

[dynaco_dan]

Hi there

I've never seen or heard MST's.

From what I do remember in other members write-ups is that there was a 4 tweeter and then later a 3 tweeter version.

There was a disadvantage to the fourth tweeter and was dropped later on.

I don't know if the price was adjusted downward on the conversion.

A bit less work manufacturing them and less materials.

For those with an AR appetite, Tom Tyson for one, stacking a pair of them on top of AR-LST/2's and them on top of AR-LST's would look kinda nice.

[KlausDK]

Here is some information on the MST from an AR catalogue from 1974, curtesy of Mike Tarelli. It looks like it co-existed with the LST, LST-2 and the other AR speakers from the classical era. I don't know if the weight for the MST is listed correct, it is certainly not for the LST.

BRgds Klaus

[Steve F]

The 4-tweeter European MST was apparently a contemporary of the LST and LST/2, but the 3-tweeter US MST/1 was introduced in 1975, with the 10 Pi and 11 as an ADD family speaker.

There were a lot of interference problems with the 4-tweeter version, so bad that AR's internal communications showed the AR-7 to be a superior speaker. After much re-engineering, the 3-tweeter configuration was settled on for the US, but the MST/1 was a mere blip on the radar screen of AR's history.

I did hear it, however, and it sounded quite nice. Victor Campos (previously from KLH) who did the LvR 10 Pi/Neil Grover tests was quite enthusiastic about the MST's capabilities, especially its bass response for an 8" speaker.

Steve F.

[ra.ra]

Thank you, Steve, for your additional comments, and Klaus, for your input and catalog via Mike Tarelli. This may, in fact, be the only company product literature I have ever seen for the MST.

Based on the 4-tweeter configuration and the Royal Opera House shown, along with the 1974 date noted, I have to suspect this catalog page was for European distribution. It is difficult to discern from the 'nude' photo, but it appears that the tweets are rear-wired, which also seems consistent with Euro versions of AR-6's and AR-7's which used the same (or very similar) tweeter.

It is also interesting to see that the x-o frequency was adjusted when the 3-tweet version became the MST-1 for U.S. distribution. Also, getting back to my original question (dimensions, weight?), this information shows that the U.S. version became 1-1/2" deeper and 5 lbs. heavier. despite having one less driver (albeit a small one).