Darrell Peart Posted July 28, 2011 Report Share Posted July 28, 2011 A few questions on the AR-LST please… I have always assumed it is sort of an upgrade from the 3a? -- better handles the mids and highs?Does the AR-LST2 relate to the AR-LST sort of like the AR-5 relates to the AR-3a? What does LST stand for?If I were looking to buy a pair of LST’s is there anything I should know/ look for?thanks Quote Link to comment Share on other sites More sharing options...
dynaco_dan Posted July 28, 2011 Report Share Posted July 28, 2011 A few questions on the AR-LST please… I have always assumed it is sort of an upgrade from the 3a? -- better handles the mids and highs?Does the AR-LST2 relate to the AR-LST sort of like the AR-5 relates to the AR-3a? What does LST stand for?If I were looking to buy a pair of LST’s is there anything I should know/ look for?thanksHi thereThe AR-LST or laboratory standard transducer, is much more than just an upgrade from the AR-3A speaker system.The similarities are they use the same drivers, as in the later AR-3A production, just 3 more mids and tweeters.The cabinets internal volume is the same.The power handling capabilities is likely quadrupled for the mids and highs.They used a ceramic magnet for the woofer and foam surrounds.A switched autotransformer was used to alter their output, as per owners manual posted in the library.I posted an original scanned AR blueprint into the library que section, un-labled, sorry.The copy is poor but does also show the bypass resistor.There is not much documented here, as yet, in what variations were serial numbered and dated.There is the earliest crossover board, rear mounted, and the later mounted through the woofer opening and internally mounted.A large capacitance change, resistor bypass, and switch source changes are not documented nor do we, at present at least, have no serial number or time period when each was performed.The added power output and angling the drivers off of axis gave the speakers a wow factor when used with good equipment.Outstanding reproduction by most standards, not everyone will agree with this comment.Needed healthy amounts of clean amplifier wattage to show their stuff.A pair in mint condition may fetch $2,000.00 or more depending on condition, supply and demand.I've only given a general idea of their worth to us owners.The AR-LST 2 is basicly a parallel system but using less drivers same as the AR-5's.Tom Tyson will likely write a more thorough and romantic description of one or both speaker systems.The differences between the 2 systems is quite audible but both can be very satisfying to their owner.Some may never miss the lesser LST 2's sound characteristics same as an AR-5 and AR-3A comparison.The drivers have not been available new for well over 25 years now.Current new production goods are different in construction and sound characteristics if they are needed to be replaced.Packing and shipping them requires special packaging techniques as they are about 100+ pounds packaged for shipping. Quote Link to comment Share on other sites More sharing options...
Darrell Peart Posted July 28, 2011 Author Report Share Posted July 28, 2011 Thanks Vern,Does the extra mids and tweeters of the LST make for a better balance with the woofer than with the 3a? Quote Link to comment Share on other sites More sharing options...
dynaco_dan Posted July 29, 2011 Report Share Posted July 29, 2011 Thanks Vern,Does the extra mids and tweeters of the LST make for a better balance with the woofer than with the 3a?Hi DarrelIf you look at the five different graphs in the AR-LST manual, you will be able to read and see the repeatable outputs.There is at least one that is the same as the AR-3A speaker system.There is also one output, 2, that is about as flat as can be done by dynamic drivers.I've written previously about my in home demo against my AR-3A's.I felt that the LST's were worth twice the price of AR-3A's, they were and so was their powerful presentation.That was using my AR amplifier only, my other toy's came much further down the road.The AR-LST's were returned.The LST's like all speakers are not without their faults but also they have more than most speakers of what hifi is all about.You do need a stable, as in 4 ohm capable and even 2 ohms to be safe, medium clean power amplifier.There likely is no limit to the amplifier output size that can be used with them.They were not designed to be disco speakers but will handle 500 watt clean peaks or more.They are fused, it should be derated.A minimum of at least 30 watts per channel 20 - 20,000 hz.AR said 25 watts but that is really for only the better quality amplifier outputs.I am certain that many an amplifier of poor quality died a painful death due to the speakers variable demands. In addition, the AR-3A's were outstanding with my AR amplifier.Later a loaner Crown DC-300 and IC-150 was tested with the AR-3A's.It took less than 30 seconds to feel the powerful gut massaging bass that may have been there before but to a much lesser degree.I think I still smile thinking of that one time experience.Due to poor WAF and potential for divorce, the Crown equipment was sadly returned, also. Quote Link to comment Share on other sites More sharing options...
Darrell Peart Posted July 30, 2011 Author Report Share Posted July 30, 2011 I've written previously about my in home demo against my AR-3A's.I felt that the LST's were worth twice the price of AR-3A's, they were and so was their powerful presentation.They were not designed to be disco speakers but will handle 500 watt clean peaks or more.They are fused, it should be derated.Later a loaner Crown DC-300 and IC-150 was tested with the AR-3A's.It took less than 30 seconds to feel the powerful gut massaging bass that may have been there before but to a much lesser degree.I think I still smile thinking of that one time experience.I recently hooked up a Phase Linear 400 series two (running through the preamp of my Marantz 2285b) to my AR-10pi's and then to my AR-3a's - I instantly could hear a big difference.I would love to hear a pair of AR-LST's. I might have to save my pennies,sell off some other stuff, and buy a pair. Their shape is very interesting - I could make a really neat pair of speaker stands for them. Quote Link to comment Share on other sites More sharing options...
dynaco_dan Posted July 30, 2011 Report Share Posted July 30, 2011 I recently hooked up a Phase Linear 400 series two (running through the preamp of my Marantz 2285b) to my AR-10pi's and then to my AR-3a's - I instantly could hear a big difference.I would love to hear a pair of AR-LST's. I might have to save my pennies,sell off some other stuff, and buy a pair. Their shape is very interesting - I could make a really neat pair of speaker stands for them.Hi DarrellThere is a great demand for LST'S in 100% mint original shape, which keeps the prices high.If 10 out of 10 they could still be not in 100% working condition.My ebuy experience is, sellers tend to lie or stretch the truth a bit.There could be one or more drivers dead and also their shipping, packaging and handling is very critical. Quote Link to comment Share on other sites More sharing options...
LST2 Posted February 11, 2020 Report Share Posted February 11, 2020 Hello, does anybody know precisely the difference between AR-LST and AR-LST 2? Thanks a lot for your answer. Yours, J. Neidlinger from Germany Quote Link to comment Share on other sites More sharing options...
xmas111 Posted February 11, 2020 Report Share Posted February 11, 2020 The LST has 4 tweeters, 4 mids and a 12" woofer and is a 4 ohm speaaker. The LST-2 has 3 tweeters, 3 mids and a 10" woofer and is a 8 ohm speaker. Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 11, 2020 Report Share Posted February 11, 2020 On 2/11/2020 at 3:40 PM, LST2 said: Hello, does anybody know precisely the difference between AR-LST and AR-LST 2? Welcome J. Are you asking about difference in sound or difference in appearance? I see xmas111 has just posted the difference in configuration and impedance. The library section has LST Brochures. Use this link http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_brochures/ @Aadams Adams Quote Link to comment Share on other sites More sharing options...
Ajax4 Posted October 31, 2022 Report Share Posted October 31, 2022 17 minutes ago, Ajax4 said: Power limits unknown -- using Phase Linear DRS900/450rms3dbpeak. And Bryston 4 or 7B. Like all ARs they sound increasingly better as clean power increases. My AR amp clipped at 90+watts and woofer bottomed distorted. Damping factor very important I suspect. Obtained a pair used at disco - 2 midrange blown also 3 tweeters. At the time could replace all oem . Autocorrelator rocks. Quote Link to comment Share on other sites More sharing options...
newandold Posted November 2, 2022 Report Share Posted November 2, 2022 On 10/31/2022 at 8:26 AM, Ajax4 said: LST’s at a disco?! (Small wonder the drivers were toasted…..) The industrial version of the Bose 901 was well suited to that task back in the day but not AR…(anything) Quote Link to comment Share on other sites More sharing options...
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