stoni Posted March 9, 2010 Report Share Posted March 9, 2010 I found a local well known A/V business that says they can run several tests on my AR-1 Speaker...(S/N 07374...in same home since original purchase).It's $75/hr with estimate of 1 to 1 1/2 hrs. He doesn't have an anechoic chamber, but said the tests would include:1) An impedance sweep.2) Areal time analyzer to give a frequency response plot, which he said should be valid in most of the frequency range covered by the Altec 755A.Do these sound ok or do you think I need them &/or other tests done?I want to be sure I get the right tests regarding my own listening pleasure, but I I think it sounds great already.I would also like any future buyer to feel more secure re my test results.Thanks in advance for any advice you can share with me.Toni Link to comment Share on other sites More sharing options...
speaker dave Posted March 10, 2010 Report Share Posted March 10, 2010 If you are concerned about the condition of the units, then the best test is a sinewave sweep at a couple of volts input (perhaps up to 10 volts for low freqeuncies only!) This will tell you about its general health. Listen for rattle and buzzes that could be detached voice coil or surround, rubbing voice coil, stuff int the gap, rattling grille etc.The real time analyzer test is useful and will give you a view of the frequency response of the unit, health of the full range (midrange/tweeter), etc. It will also show how the speaker interacts with the room and its boundaries (bass frequencies). You might try different room positions and see where the smoothest and most extended bass is.You will, of course, get a printout of the curves and post them to this forum, as most of us haven't much direct experience with the AR1!!Because this is a very early design, don't expect much in terms of upper range extension and response smoothness. Hey its a 57 Chevy, high on cool factor and low on modern conveniences.I don't see a great benefit to you from the Impedance curve, other than for general curiosity sake.Regards,David Link to comment Share on other sites More sharing options...
soundminded Posted March 10, 2010 Report Share Posted March 10, 2010 I found a local well known A/V business that says they can run several tests on my AR-1 Speaker...(S/N 07374...in same home since original purchase).It's $75/hr with estimate of 1 to 1 1/2 hrs. He doesn't have an anechoic chamber, but said the tests would include:1) An impedance sweep.2) Areal time analyzer to give a frequency response plot, which he said should be valid in most of the frequency range covered by the Altec 755A.Do these sound ok or do you think I need them &/or other tests done?I want to be sure I get the right tests regarding my own listening pleasure, but I I think it sounds great already.I would also like any future buyer to feel more secure re my test results.Thanks in advance for any advice you can share with me.ToniTest one speaker at a time if you have two. Connect it to one channel of a high quality 200 watt per channel or more amplifer such as an Adcom. Place the speaker on the floor in the corner of a room with the woofer closest to the floor. Get a CD with a 30 hz test tone. Start with the volume at zero and slowly increase it. As the sound gets louder, if the windows start to rattle, loose objects vibrate and fall off of shelves and tables, plaster falls out of the ceiling, pictures fall off the walls, and fillings in your teeth fall out before the speaker rattles, the speaker is functioning perfectly and as the manufacturer intended. As for the tweeter, if it works and doesn't rattle, buzz, or produce any other unpleasant sound that's probably as good as it is going to get. It's a relic of a bygone era Villchur et al used early on in their first effort probably because it was rugged enough for theaters and available. If the capacitors have not been replaced in the last 20 or 30 years, then replace them. BTW, before attempting the test, get the phone number of your homeowner's insurance company's claims rep. You may need to give him a call shortly afterwards Link to comment Share on other sites More sharing options...
genek Posted March 10, 2010 Report Share Posted March 10, 2010 As for the tweeter, if it works and doesn't rattle, buzz, or produce any other unpleasant sound that's probably as good as it is going to get. It's a relic of a bygone era Villchur et al used early on in their first effort probably because it was rugged enough for theaters and available. If the capacitors have not been replaced in the last 20 or 30 years, then replace them.Considering the driver used and the period in which it was designed, should we really think of the AR-1 as a woofer-tweeter system, or is it really more like a full-range speaker with a subwoofer? Link to comment Share on other sites More sharing options...
soundminded Posted March 10, 2010 Report Share Posted March 10, 2010 Considering the driver used and the period in which it was designed, should we really think of the AR-1 as a woofer-tweeter system, or is it really more like a full-range speaker with a subwoofer?The first time I ever encounered the concept of a "subwoofer" as I recall was with the Infinity Servostatic I and later the IA. The idea was that the crossover frequency was so low that bass frequencies fed to it were non directional, that is their source could not be determined by aural cues and therefore only one was required even for stereo. (This also has the advantage of cancelling out vertical tracking rumble in from turntables since the signal fed to it is mono.) Subwoofers were later used in the mini 3 piece systems from the likes of Cambridge Soundworks and Bose and also from from Infinity with their Reference Standard system. I'm not sure of the AR1 crossover frequency but I doubt it was that low. The same AR 12 inch woofers used in AR9 as other AR systems are subwoofers in that system because of their 200 hz crossover frequency. In other systems they are just woofers. Link to comment Share on other sites More sharing options...
Zilch Posted March 10, 2010 Report Share Posted March 10, 2010 755A is may have been considered "fullrange" at the time, but it's down 10 dB at 10 kHz.It was a common distributed PA speaker; think announcements in homeroom coming from that little box up next to the clock.Mass-produced and cheap at the time, they can go for as much as $1000 a pair, now:http://www.audiokarma.org/forums/showthread.php?t=113689 Link to comment Share on other sites More sharing options...
soundminded Posted March 10, 2010 Report Share Posted March 10, 2010 755A is may have been considered "fullrange" at the time, but it's down 10 dB at 10 kHz.It was a common distributed PA speaker; think announcements in homeroom coming from that little box up next to the clock.Mass-produced and cheap at the time, they can go for as much as $1000 a pair, now:http://www.audiokarma.org/forums/showthread.php?t=113689According to the Lansing Heritage site, up until around 1958 they had never encountered program material with energy above 12 khz. There was no reason at the time to build drivers capable of more. The design of the K2 which claims response to 40 khz strikes me as one more example of current high end lunacy. It looks suspiciously like just an updated version of the JBL Hartsfield. Link to comment Share on other sites More sharing options...
speaker dave Posted March 11, 2010 Report Share Posted March 11, 2010 755A is may have been considered "fullrange" at the time, but it's down 10 dB at 10 kHz.It was a common distributed PA speaker; think announcements in homeroom coming from that little box up next to the clock.Mass-produced and cheap at the time, they can go for as much as $1000 a pair, now:Plus or minus 4 to 7kHz...thats better than I would have guessed. I'd pay $1000 for a pair!Davidp.s. Whats our wager on how many posts to get this into the kitchen? Link to comment Share on other sites More sharing options...
Zilch Posted March 11, 2010 Report Share Posted March 11, 2010 It looks suspiciously like just an updated version of the JBL Hartsfield.All JBL flagship speakers are 2-ways, and thus merely variants of the same 60+ year-old theme. p.s. Whats our wager on how many posts to get this into the kitchen?My money's on RSN.... Link to comment Share on other sites More sharing options...
stoni Posted March 11, 2010 Author Report Share Posted March 11, 2010 So happy to hear all of your comments! Thank you!I will set an appointment with my A/V expert. A pair of AR-1's just sold for $2000 aprx on eBay bout a week ago!A single & a 755a each sold on eBay 7/09 and another one 2/10....$1200-$1300.I saved those sales details as a Word Doc.I need to shine a light into the speaker in a dark room to confirm it REALLY has a 755a.I don't have the original Manual, but I do have the following. Let me know if they are something you want me to put on the AR forum. OK?I will remember to share graphs and any info with you all. BROCHURE: 1 8 1/2" x 11" Page folded in half. Page 1: Photo of Bookcase model (like mine) with books on both sides & the 755a & woofer in front of the speaker.the AR-1 SPEAKER SYSTEMA REVOLUTION IN ENGINEERING ACOUSTICSACOUSTIC RESEARCH, INC.24 Thorndike St., Cambridge 41, Mass.Page 2: Title: The Acoustic Suspension* PrincipleThis page is copyrighted.Page 3: Title: TECHNICAL DATAIncludes 2 graphsPage 4:Press Comments.and a PRICE LIST! AR-1 AR-1U AR-1W AR-1WU The prices are from $132 - $185!!! The 2nd Document is ONE 8 1/2" x 11" sheet titled INSTRUCTIONS FOR THE USE OF THE AR-1 ACOUSTIC SUSPENSION LOUDSPEAKER SYSTEM.Maybe this is the Manual??? Only the front has any info on it. Link to comment Share on other sites More sharing options...
Carlspeak Posted March 11, 2010 Report Share Posted March 11, 2010 If you can, scan those docs in at high resolution and contact via PM geneK, our webmaster.It doesn't look any of those are in our library.Thanks for the offer! Link to comment Share on other sites More sharing options...
stoni Posted March 11, 2010 Author Report Share Posted March 11, 2010 I'll do that. I think my neighbor will help me make sure it's 'high resolution' etc.I found an online 1954 brouchure almost like mine. It's also four pages and same size. . It's pages 1 & 4 are different. Page 1: The cloth cover on the AR-1 looks dark with a marble pattern.The company address is different.Page 4:The prices are the same, but the testamonials layout is different.Can I post the web address here?-- Link to comment Share on other sites More sharing options...
stoni Posted March 11, 2010 Author Report Share Posted March 11, 2010 I just noticed a LINK in a post so I'll go ahead & put it here.http://www.technicalaudio.com/pdf/Gordon_C...ricing_1954.pdf Link to comment Share on other sites More sharing options...
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