Guest ed426 Posted July 19, 2006 Report Share Posted July 19, 2006 can someone tell me if the mid and tweeter drivers are the same in the 3a and the 5. Link to comment Share on other sites More sharing options...
dynaco_dan Posted July 19, 2006 Report Share Posted July 19, 2006 >can someone tell me if the mid and tweeter drivers are the>same in the 3a and the 5.Hi there;A very good question and this is the answer.The AR-3A and AR-LST used a 3/4" 4 ohm tweeter and 1 1/2" 4 ohm mid-range.The later AR-2AX, the AR-5 and AR-LST/II used a 3/4" 8 ohm tweeter.The AR-5 and AR-LST/II used 1 1/2" 8 ohm mid-range drivers.The drivers to the naked eye are identical physically.Unless there is markings, such as part numbers, the only way to accurately identify them is to measure their DCR with a digital VOM.The 4 ohm would measure about 2.75+/- ohms.The 8 ohm would measure about 5.75+/- ohms.If you were to use a 4 ohm driver in an 8 ohm system, the driver would be about 2+/- db louder than an 8 ohm driver.The speaker would be brighter in the highs than normal, this may not be a bad thing, if your high range hearing is declining, as it is with all of us, as we age.If you were to use a 8 ohm driver in a 4 ohm system, the driver would be about 2+/- db lower than a 4 ohm driver.If both AR-3A's are 8 ohms, then the highs would really be missing compared to the correct tweeters.In the LST's, if one or two of the drivers have the wrong 8 ohm drivers, there would still be enough output so that it wouldn't likely be noticed, because of the dual drivers from each radiating surface, unless the same two on one surface is replaced.A pair of LST's I picked up had an 8 ohm tweeter in one place.I could not hear this in general listening.I used a scientific approach.Using a Radio Shack sound level meter, taping a toilet paper roll to it's end and repeating a test tone.I placed the tube over each individual driver and the levels were compared.It also works much better without any toilet paper on the roll. lol In the AR-LST/II's, if a single 4 ohm tweeter or midrange was used, there may be a beaming of output with the more efficient driver or not, because there is fewer drivers on each radiating surface.Good luck. Link to comment Share on other sites More sharing options...
Guest ed426 Posted July 20, 2006 Report Share Posted July 20, 2006 >>can someone tell me if the mid and tweeter drivers are>the>>same in the 3a and the 5.>>Hi there;>>A very good question and this is the answer.>>The AR-3A and AR-LST used a 3/4" 4 ohm tweeter and 1>1/2" 4 ohm mid-range.>>The later AR-2AX, the AR-5 and AR-LST/II used a 3/4" 8>ohm tweeter.>>The AR-5 and AR-LST/II used 1 1/2" 8 ohm mid-range>drivers.>>The drivers to the naked eye are identical physically.>>Unless there is markings, such as part numbers, the only way>to accurately identify them is to measure their DCR with a>digital VOM.>>The 4 ohm would measure about 2.75+/- ohms.>>The 8 ohm would measure about 5.75+/- ohms.>>If you were to use a 4 ohm driver in an 8 ohm system, the>driver would be about 2+/- db louder than an 8 ohm driver.>>The speaker would be brighter in the highs than normal, this>may not be a bad thing, if your high range hearing is>declining, as it is with all of us, as we age.>>If you were to use a 8 ohm driver in a 4 ohm system, the>driver would be about 2+/- db lower than a 4 ohm driver.>>If both AR-3A's are 8 ohms, then the highs would really be>missing compared to the correct tweeters.>>In the LST's, if one or two of the drivers have the wrong 8>ohm drivers, there would still be enough output so that it>wouldn't likely be noticed, because of the dual drivers from>each radiating surface, unless the same two on one surface is>replaced.>>A pair of LST's I picked up had an 8 ohm tweeter in one>place.>>I could not hear this in general listening.>>I used a scientific approach.>>Using a Radio Shack sound level meter, taping a toilet paper>roll to it's end and repeating a test tone.>>I placed the tube over each individual driver and the levels>were compared.>>It also works much better without any toilet paper on the>roll. lol >>In the AR-LST/II's, if a single 4 ohm tweeter or midrange was>used, there may be a beaming of output with the more efficient>driver or not, because there is fewer drivers on each>radiating surface.>>Good luck. Hi Vern,If one were to replace all four mids and all four tweeters in an LST with all 8 ohm drivers, one would be able to compensate for the decrease in output by moving to a higher output tap on the autotransformer for the respective driver bank. It would be a bit trial and error. How about this: with the standard 4 ohm driver, take your level meter with toilet paper roll, I like your scientific approach, and with a set input frequency record the input voltage to the driver. Also record the output sound level with your level meter. Then replace the driver with an 8 ohm driver and adjust the input voltage signal at the same frequency to obtain the same output level as recorded with the level meter for the 4 ohm driver. With the difference in voltage values recorded, we can design the autotransformer with the appropriate taps to give us the new voltage outputs needed. The rest of the LC circuits would remain the same. Am I missing something?What do you think?Ed Link to comment Share on other sites More sharing options...
RoyC Posted July 21, 2006 Report Share Posted July 21, 2006 > Am I missing something?Ed,Using an existing crossover with drivers of a different impedance will change the crossover points, and the sonic character of the system.Roy Link to comment Share on other sites More sharing options...
Guest ed426 Posted July 21, 2006 Report Share Posted July 21, 2006 >> Am I missing something?>>Ed,>>Using an existing crossover with drivers of a different>impedance will change the crossover points, and the sonic>character of the system.>>RoyRoy, Then why does the AR5, which has the same crossover as the 3a, which I am told, have the same break points using different impedence drivers?Ed Link to comment Share on other sites More sharing options...
RoyC Posted July 22, 2006 Report Share Posted July 22, 2006 Ed,The AR-3a and AR-5 crossovers are not the same. They have the same crossover board layout, but have different crossover component values. For example, the tweeter cap in the AR-5 is 4uf, and the 3a's is 6uf. In fact, with the exception of the potentiometers, they do not share a common component.Roy Link to comment Share on other sites More sharing options...
Guest ed426 Posted July 24, 2006 Report Share Posted July 24, 2006 Roy,Right you are, Roy. I found the specs that night of the post; the break points are different. Someone told me the components in the crossover for the 5 are the same as the 3a, apparently not.Thanks again.Ed>Ed,>>The AR-3a and AR-5 crossovers are not the same. They have the>same crossover board layout, but have different crossover>component values. For example, the tweeter cap in the AR-5 is>4uf, and the 3a's is 6uf. In fact, with the exception of the>potentiometers, they do not share a common component.>>Roy Link to comment Share on other sites More sharing options...
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