harry398 Posted December 9, 2017 Report Share Posted December 9, 2017 I want to know if these are Identical I know people sell the ar11 replacements as the same as AR3a , but are they really the same? visually, they do look a little different, and they sound different. thanks Link to comment Share on other sites More sharing options...
JKent Posted December 9, 2017 Report Share Posted December 9, 2017 They're the same. The 11 has a thicker mounting plate and the screen is silver color, but it's the same driver. I have a pair in my AR-3a's. Kent Link to comment Share on other sites More sharing options...
RoyC Posted December 9, 2017 Report Share Posted December 9, 2017 The last AR-3a's and the earlier AR-11's and 10pi's were equipped with the same back-wired mid driver. The later 11's and 10pi's had the back-wired mid with the silver grill and pink fiberglass pad. I've used them all interchangeably for many years without issue, or any noticeable differences. If there are differences between any of the back-wired versions I'm not aware of them. DCR and magnet size are the same. There are some slight variations between the back-wired and front-wired versions, but they still work satisfactorily together. No crossover changes were ever made for different versions of the mid, and the back-wired version was the factory replacement for the front-wired version for many years. Nothing to be concerned about here at all. Roy Link to comment Share on other sites More sharing options...
harry398 Posted December 10, 2017 Author Report Share Posted December 10, 2017 Thanks Roy The ar11 produces such a different sound from the ar3a in the midrange, I just wanted to make sure its not the driver. Its all in the crossover design. I prefer the ar3a mid sound, so much that I have tried to mod the ar11 crossover to mimic it. No luck Yet. seems the ar11 is wired on the negative side to the coils, and the ar3a from the positive side. does this have any effect? or is the difference in the resistor set up on the 11 vs potentiometer set up that creats the difference? The ar11 mid produces are very pronounced open sound.......whereas the ar3a is more tighter and pleasing to me. I have been trying to find a spare 3a crossover to conduct this test, no luck yet. My brother is attempting to wire this into a ar11 crossover, some progress.........not there yet. seems there is alot of electrical wizardry that i dont understand...lol.......but the potentiometer changes things.......with the electric coils are the same, caps values slightly different......but the 3a is just far for pleasing to me. any ideas? pic is my Brothers latest thrashing to mimic the 3a in the 11.... Link to comment Share on other sites More sharing options...
cARver Posted December 10, 2017 Report Share Posted December 10, 2017 So I will attempt to describe what I did to my 11 speakers to address a over open sound as compared to all my other 3 way ARs. These speakers were pushed in the corner for months disappointing with the overall sound. This 11 has a reduction circuit that was very different from the 91/90/9 speakers. I was perplexed until fedeleluigi provided an accurate diagram, thanks Fedele! I studied an understood some of how it reduced the output but never liked the thinness of the overall sound. I don't profess to be an expert and always learning, but for example in -6 db position is the 10 parallel resistor reducing the 15 ohm parallel resistor to an overall 12.5 ohm? Does this alter the tone? I don't know but the driver was still unbalanced (loud) and unmusical to my ear. (My opinion) After tinkering for some time with the 3a setup and noticing a strong similarity to the 11 min range circuit I decided to dive in. With all mid resistors removed, I installed a 15 ohm parallel resistor assembly (duplicated with an assorted series of resistors ) (X,Y,Z) sum equaling 15 ohms like original. The midrange positive wire installed in between the 1.5 and 2.5 for a total of 3.5 similar to AR3a b-1 pot spec. See diagram. After some experimenting I have been very satisfied with the speaker balance now. It still doesn't exactly sound like a 3a but it's closer and ultimately enjoyable. I plan on using some sort of potentiometer in the near future to replace this resistor assembly and offer fine adjustment. Having said that................ All the chatter about the “improved 3a” models 11/91/58s has me offering my opinion of my collection of 3 way ARs. The 3a tweeter was dim needing treble gain to satisfy my taste, mids smooth/clear and woofer strong and deep. 58 tweeter installed now and it's a well balanced speaker. The 11 has a stronger tweeter but poor sound quality compared to 9/90/91 style tweeter, the mid is over bearing and thin and woofer is potent but not as deep as the 3a with more punch. Better now with modded midrange crossover. The 58s has the best tweeter of the bunch, mid needed attenuation (cheaper bookshelf- no switches compared to 91) and woofer needed slight poly fill removed to better perform. 91 is similar to the 58 however I believe the cabinet has some mild resonance during thick mid bass passages. Please feel free to comment or ask any questions as this was a multi-day project while tending to a broken heater and being a father LOL. Link to comment Share on other sites More sharing options...
RoyC Posted December 10, 2017 Report Share Posted December 10, 2017 7 hours ago, harry398 said: Thanks Roy seems the ar11 is wired on the negative side to the coils, and the ar3a from the positive side. does this have any effect? coils are the same, caps values slightly different......but the 3a is just far for pleasing to me. any ideas? Harry, The 3a caps are also wired on the negative side. It is not an issue. Differences in tweeters, capacitor values, attenuation circuits, and type of cabinet damping material all have an effect on the overall sound, and account for differences between the AR-11 and 3a. Roy Link to comment Share on other sites More sharing options...
harry398 Posted December 10, 2017 Author Report Share Posted December 10, 2017 Roy, Why does the ar11 have a pronounced open sounding midrange, with the same driver and nearly same cap size and same coils as the Ar3a? Completely different sound in mid circuits. Why and How? That's what I'm trying to figure. Link to comment Share on other sites More sharing options...
RoyC Posted December 11, 2017 Report Share Posted December 11, 2017 On 12/10/2017 at 5:02 PM, harry398 said: Roy, Why does the ar11 have a pronounced open sounding midrange, with the same driver and nearly same cap size and same coils as the Ar3a? Completely different sound in mid circuits. Why and How? That's what I'm trying to figure. Harry, I don't intend to get into the technical aspect of how crossovers work. The smaller parallel AR-11 woofer cap and stronger AR-11 tweeter both contribute more to the overall midrange response, and the switch/resistor arrangement attenuates the mids less than the pots do in the 3a. The only way you are going to make an AR-11 sound like an AR-3a is to use a 3a crossover, and a 3a tweeter or equivalent. If you wish to know more, much information is available regarding crossover and speaker design. Identical drivers can be made to sound quite different when used in different combinations and with different filters (crossovers and attenuation circuits). Roy Link to comment Share on other sites More sharing options...
tysontom Posted December 12, 2017 Report Share Posted December 12, 2017 On 12/10/2017 at 5:02 PM, harry398 said: Roy, Why does the ar11 have a pronounced open sounding midrange, with the same driver and nearly same cap size and same coils as the Ar3a? Completely different sound in mid circuits. Why and How? That's what I'm trying to figure. As Roy stated, there aren't any significant differences between any of the 1½-inch AR-3a/AR-11screened- midrange drivers, hard-wired or back-wired. After AR moved over to Norwood in 1973, the AR-3as were assembled with identical back-wired midrange drivers that were used in the AR-10/AR-11 series. These AR-3a versions were noticeable by the addition of the Velcro-attached grills and the small, blue Norwood label on the back panel. There is a definite spectral-balance difference between the AR-11 and the AR-3a because of the different tweeter and crossover and, therefore, the balance of the midrange output in the AR-11 would seems slightly different from the AR-3a. AR worked on the crossover to clean up the on-axis output for flatter output. Also, by changing the crossover, I don't believe that Acoustic Research reversed the polarity of the midrange/tweeter in the AR-10/AR-11 in relation to the woofer as was done by Roy Allison in the earlier 3-way "classic" AR speakers to reduce lobing around the crossover frequency. —Tom Link to comment Share on other sites More sharing options...
cARver Posted December 12, 2017 Report Share Posted December 12, 2017 4 hours ago, tysontom said: Also, by changing the crossover, I don't believe that Acoustic Research reversed the polarity of the midrange/tweeter in the AR-10/AR-11 in relation to the woofer as was done by Roy Allison in the earlier 3-way "classic" AR speakers to reduce lobing around the crossover frequency. —Tom According to my speakers and Feldele's diagram the tweeter polarity is reversed. Link to comment Share on other sites More sharing options...
RoyC Posted December 13, 2017 Report Share Posted December 13, 2017 4 hours ago, cARver said: According to my speakers and Feldele's diagram the tweeter polarity is reversed. cARver, It is, but the AR-11 tweeter has a much stronger midrange output than the 3a tweeter, so it is used with a steeper, 12db/octave vs the 3a's 6db/octave filter. Reversing polarity is used to mitigate response aberrations or peaks in the crossover region. In many cases this can be determined as a matter of preference and/or interaction with the listening space. It is not the primary reason for the midrange difference's Harry is noting. Your change to the switch/resistor arrangement actually sets the switches to a few of the most useful AR-3a pot settings, which is an excellent way to make the 11's "more forward" mid response similar to that of the more reticent 3a. Roy Link to comment Share on other sites More sharing options...
cARver Posted December 13, 2017 Report Share Posted December 13, 2017 Thanks, that was the goal! Much more musical for my tastes.To me the AR11 has a bit of a congestion presentation from 8-10 feet away where as the 3a/58 are very pleasing. Two different crossover designs/frequencies but sound great! The AR11 tweeter 12db circuit, can you explain? Some further explanation of crossover layout/design in these threads would be beneficial to others on this forum. I really find in fascination and educational. The AR11 tweeter to me is sub par in comparison to the 3a tweeter regardless of output. I always noted the tweeter had excess low tweeter high midrange sound character. "s" sounds were "ch" like. The 3a was smooth but potentially fragile and low output compared to the other drivers in the cabinet. The 58s/9/90/91 tweeter is way better in my opinion. Link to comment Share on other sites More sharing options...
RoyC Posted December 13, 2017 Report Share Posted December 13, 2017 Actually the AR-11/10pi and 58/9/90/91 tweeters are pretty much the same with the exception of the faceplate. The latter have a recessed dome. A 12db octave crossover represents a steeper cut off than the more gradual 6db octave crossover...and it becomes much more complicated beyond that. (Google is your friend. ) The introduction of the parallel component (.1mh coil) in the AR-11's tweeter circuit produces a steeper 12db/octave crossover slope. Along with modifying the tweeter's response it also provides more protection from lower frequencies. Roy Link to comment Share on other sites More sharing options...
cARver Posted December 13, 2017 Report Share Posted December 13, 2017 I see so the inductor is responsible for the additional 6db slope. I haven’t swapped in the 58s tweeters yet because of the wire terminals interference. Once I do I’ll post my results. I posted a question on the slope of the AR9ls per driver like recorded on the 9 owners manual. Maybe you could respond to that post? Link to comment Share on other sites More sharing options...
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