AR MST

[Guest]

There is precious little information on the MST loudspeaker. The baby version of the LST/LST2. I have just bought a pair for £15. Sadly the previous owner had blown the bass units. Does anybody please have any information on the Thiele Small Parameters for the 8" units used (or any other information at all?). Looking at the volume of the cabinet they must have been rather special.

[tysontom]

>There is precious little information on the MST loudspeaker.

> The baby version of the LST/LST2. I have just bought a

>pair for £15. Sadly the previous owner had blown the bass

>units. Does anybody please have any information on the

>Thiele Small Parameters for the 8" units used (or any other

>information at all?). Looking at the volume of the cabinet

>they must have been rather special.

The best bet, rather than hunting for woofers out there with similar Thiele parameters would be to replace the woofers with genuine AR-type replacement parts, available from AB Tech Services, (800) 225-9847. Is the woofer actually "blown," or is the surround gone? Do the voice coils rub? It's a pretty rugged woofer, but it's not completely idiot-proof.

The original AR part number for this woofer was #1200001-1, with a rating of 8-ohms and a 27-Hz. free-air resonance. Although AB Tech does not have the NOS AR woofer, they do have exact duplicates from OEM vendors.

--Tom Tyson

[Steve F]

>>There is precious little information on the MST loudspeaker.

>> The baby version of the LST/LST2. I have just bought a

>>pair for £15. Sadly the previous owner had blown the bass

>>units. Does anybody please have any information on the

>>Thiele Small Parameters for the 8" units used (or any other

>>information at all?).

Proffski,

This is from a post of mine on 9-29-02:

"3. "RE: AR MST"

 

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."

Victor Campos, who was involved with the MST's design, said on "Shop Talk" (a Boston-area hi-fi radio talk show in the '70's) that the the MST's woofer design optimized all the theoretical magnetic and mechanical parameters for an 8" woofer in that sized enclosure. He said of the MST, "It could put out bass like nobody's business for an 8" woofer."

Hope that helps.

Steve F.

[kkantor]

Not positive, but pretty sure...

...the MST used the standard 8" that was in the AR-7. This is about it:

http://www.arsenal.net/speakers/ar/documents/part_04.jpg.

The product was not really AR's finest moment... I know, I had a pair. The were a far-fetched attempt to cash in on the LST concept, didn't work, and were dumped quick. Incidentally, they shouldn't be confused with the LST-II, a much more successful smaller sibling.

-ken

[Guest]

Thank you all for the superb response to my query concerning the MST. I realise that the speaker never set the Hi Fi world alight. But I do consider it extremely worthwhile preserving something from such a classic American manufacturer such as AR. Some people collect stamps, I chose to collect speakers... :-)

[dynaco_dan]

Hello Ken

You certainly have a well deserved reputation in the hifi industry.

I tried to read the scanned photo of the MST woofer spec sheet but with my old eyes and hearing going, my god I'm really falling to pieces. lol

Would it be possible for you to re-scan the fact sheet or re-type that valuable information again, please.

Thank you and I hope this request is not too imposing on your privacy.

Thank you.

Vern

>Not positive, but pretty sure...

>

>...the MST used the standard 8" that was in the AR-7. This is

>about it:

>

>http://www.arsenal.net/speakers/ar/documents/part_04.jpg.

>

>

>The product was not really AR's finest moment... I know, I

>had a pair. The were a far-fetched attempt to cash in on the

>LST concept, didn't work, and were dumped quick.

>Incidentally, they shouldn't be confused with the LST-II, a

>much more successful smaller sibling.

>

>-ken

>

[kkantor]

Vern,

It's no imposition at all. I love to help out here when I can.

Unfortunately, I'm in the same position you are... the prints are very faded and the scans are hard to read. I no longer have access to the original document, but Mark might, since I sent him a bunch of old engineering material.

Meanwhile, I will D/L the scan, and see if I can use some software to make the data more visible.

Ken Kantor

www.tymphany.com

www.aural.org

[kkantor]

OK, here's what I can make out, or deduce.

What I can read:

Fs is 27 Hz.

Fc is 56 Hz.

-3 dB on axis should be between 1800 and 2000 Hz.

What I can deduce:

Vas should be roughly double the volume of the box, whatever that is.

Qts should be between 0.40 and 0.45.

Hope this helps!

Ken Kantor

kkantor@gmail.com

www.tymphany.com

www.aural.org

[dynaco_dan]

Hello Ken

Thank you for taking the time, out of your very busy life, to try to answer my request.

It is important for archival information to be kept and handed down to the next generation of hifiers.

Such as our libraries, which contain old manuscripts.

Also for the many present viewers and future viewers of Arsenal as there has been feedback from Europe for something I wrote earlier.

It seems hifi has no language or age barrier.

I will keep this information, thank you very much.

Personaly, I never saw or heard MST's but if I hadn't had a WF (wife factor) back then, I'm sure I would have.

Most of my friends had AR speakers or wished they had.

AR and hifi was new to me in 1965, when I read a Consumers Report article about, "the widest range loudspeaker, they had ever tested", the AR4x.

I went to a local hifi store and the salesman suckered me in with the old switch the speaker and add loudness.

Well, I was young, married and hifi challenged and was now financed up to my eyeballs for a system.

A week later I was downtown listening (oh, oh) in a local Miller's store (biiggg mistake) at a wall of small bookshelf speakers.

The music I heard, had to be coming from a large speaker hidden somewhere from my view, I was sure of that.

It was a pair of AR4x's among the group and I felt sick, they were massive in sound and clear as a bell (great smile factor).

I went back to the store I had bought my yucky system from and I was going to be financed up to, even higher than my eyeballs.

I was going to charged about full list plus returning my week old speakers.

I wasn't married long enough yet and I didn't know how I could get them by the wife, so I suffered with the yuckys for maybe 3 years.

I then sold my yucky's and bought AR4x's and life was good again.

For a while, at least.

Until I got the bug for the AR amp, tuner and turntable.

Keeping the wife pregnant must have distracted her. lol

Then, after a few years, AR3a's which were my then ultimate (here we go again), until the LST's came along (oh no) and I caught the LST bug (yeh).

Wifey wasn't so understanding by this time so the LST's had to wait for another 15 years.

Maybe hifi-itis is a cause of marriage breakups? lol

I was thinking of joining the local chapter of hifi anonymous here. lol

AR was badly demonstrated by almost every dealer here because of it's low markup.

You had to have good friends steer you to AR or teach you the better sound of AR. The stores certainly weren't playing them to sell.

Seeing your comments, Ken, also Steve's, Tom's, Mark's and many, many others comments goes to show what an influence Ed Vilchur and Henry Kloss had on the hifi community at the beginning, for some of us at least.

You will also be in the library of notable figures that had a great influence on hifi.

We will be reading more of your many accomplishments as time goes by I hope.

We also may hear from some young upstart, that you may have influenced, with some positive conversation that may lead to another hifi explorer of a new hifi era just ahead.

Thank you again Ken for your time and feedback.

I rattle on sometimes. Sorry.

Have a great day.

>OK, here's what I can make out, or deduce.

>

>What I can read:

>

>Fs is 27 Hz.

>Fc is 56 Hz.

>

>-3 dB on axis should be between 1800 and 2000 Hz.

>

>

>What I can deduce:

>

>Vas should be roughly double the volume of the box, whatever

>that is.

>

>Qts should be between 0.40 and 0.45.

>

>Hope this helps!

>

>Ken Kantor

>

>kkantor@gmail.com

>

>www.tymphany.com

>

>www.aural.org

[Guest molecules]

C'mon, tell us what the yucky's were !