iso

AR-3F in AR-LST review

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I have referred earlier to John Crabbes AR-LST review in Aug 1973 issue of Hi-fi News. It is now reprinted in Aug 2017 issue of the Hi-Fi News. There is also some interesting reading about experimental AR-3F ("F" stood from flat) using similar 6-way spectral balance adjustment that is used in LST. This review was supposed to made by Frank Jones, but as he was recruited by AR editor of the mag stepped in...

Kimmo

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Regarding British magazine review of the AR-LST.

First off I don't find it unusual for many posters not to comment on your post here "ISO", because there aren't many who do own LST speakers

and primarily because this review might stir many present day owners of other well-respected speakers.

How many 45 year old speakers get reviewed and how often have such good things been said as have been said in this review in Hi-Fi News about the AR-LST.

I'd like to thank you for bringing this review to this forum.

Here's a little taste, and there's more to read in this review.

P.S. Thank you very much for posting about this review ISO.

FM

Untitled.jpeg

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As iso mentioned, this isn't a new review of the LST, but a re-print of a John Crabbe review from 1973.

Never owned LST's but I found the review enjoyable & noteworthy, even 44 years later - thanks, iso!

lst.JPG

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I just wonder if there would be much of a difference between the balance switch and the pots? Or that the 3a was just too small? Apparently not if it was never taken from the experimental stage. Opinions?

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Thank you for your kind words...

Autotrafo was only practical way to adjust HF to same level than mid and LF. With 6dB slope crossover this was too much for single AR tweeter but Tom may know if steeper 12dB or 18dB slope had been enough to make single AR tweeter to survive with spectral balance transformer. 

BTW Crabbe mentioned sometimes "as I happen to be blind". I do not know how blind he was or when he was blinded but this makes the following remark noteworthy "it is true that ear is tolerant of inaccuracies in presentation of a stereophonic aural picture that would seem absurd to the eye if applied to a stereophonic visual picture". 

Kimmo

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On 7/16/2017 at 10:41 PM, ar_pro said:

As iso mentioned, this isn't a new review of the LST, but a re-print of a John Crabbe review from 1973.

Never owned LST's but I found the review enjoyable & noteworthy, even 44 years later - thanks, iso!

lst.JPG

Anyone have a link to the full article?

thanks 

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Unfortunately, Hi-Fi News does not provide a link to either the original, or the re-published review, which sadly still falls under copyright.

Regarding the "stereophonic aural picture", Crabbe seemed very much concerned over "the disposition of the drive units in the LST", making the case that the resultant stereo image is "vague" if the listener is sitting to one side of the room, ie: off-center.

He also observed anomolous "frequency-dependent shifts", where "overtones don't necessarily move with fundamentals, or high notes with low notes". His test for this involved playing a harp recording in double-mono mode, indicating that it (the harp's image) "hopped around all over the place depending on which notes were being plucked or harmonics excited".

His listening observations also included a diagram that proposed some non-standard side-wall placements for the LST in a listening room. 

He also mentioned a test height of 18" for the LST. I've never owned a pair, but doesn't that seem on the low side?

Crabbe's review is certainly worth referencing, along with the very short Julian Hirsch piece in Stereo Review, the 1972 test from Audio magazine, and the 1971 CBS Labs report.

And based upon his description of the never-to-be-produced AR-3F, that speaker was seen as an answer to the criticism of "European perfectionists" who felt the AR-3a to not be capable of a "non-flat balance" without modification. According to Crabbe, the issue was the inability of the 3a's tweeter in a built-to-be-flat configuration to handle the more powerful American amplifiers without putting AR's famous repair policy into a death-spiral.

But would I be incorrect in suspecting that AR's experimental AR-3F eventually became the very real AR-10pi?

 

 

 

 

 

 

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