soundminded Posted January 24, 2022 Report Share Posted January 24, 2022 I need a replacement upper midrange for AR9 part 20028. Anyone know of a source or know of one for sale. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 24, 2022 Report Share Posted January 24, 2022 You can sometimes find them on eBay or the 200032 which will work. I tried one of these and found it to be a very good replacement. https://www.midwestspeakerrepair.com/shop/home-audio/midranges/others/mw-audio-mm-2044-acoustic-research-copy-midrange/ Quote Link to comment Share on other sites More sharing options...
soundminded Posted January 24, 2022 Author Report Share Posted January 24, 2022 Thanks David. I'm looking for an exact replacement. There are other AR midrange domes of the same size and similar type available but they aren't quite right. They are close though. Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 25, 2022 Report Share Posted January 25, 2022 17 hours ago, DavidR said: You can sometimes find them on eBay or the 200032 which will work. I tried one of these and found it to be a very good replacement. https://www.midwestspeakerrepair.com/shop/home-audio/midranges/others/mw-audio-mm-2044-acoustic-research-copy-midrange/ Soundminded has a point about the P/N of the AR domes. I uploaded Tim Holls description of the AR91 /92. He points out the difference between the dome drivers used in the AR9 and those that were used in the 91/92. He points out that with the mid units used in the AR9 / 90 the full VC gap (both sides of the VC) have ferro fluid, raising the fs of the driver in the AR9. So likely the (stock) crossover in the AR9 would have to be altered to maintain the original response of the design if the 200032 is installed (which could also lead to other issues). I wondered what the differences were and found the Tim Holl paper in my files. Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 25, 2022 Report Share Posted January 25, 2022 Since I had the drivers out I thought I would check them on DATS. I was surprised as how close these drivers were test wise, considering these units are likely 40+ years old. A unnamed EBAY vendor is offering what is stated to be OEM replacements for a range of vintage AR (3 way) systems. I would really like to see performance data before I would consider dropping 120 dollars per unit. THese will function obviously but will the system perform as it did originally. If that is the goal I would guess crossover alteration would be required. -T Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 25, 2022 Report Share Posted January 25, 2022 @tenofossil Its my understanding that the 032 can be used to replace a 028 but not the other way around. Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 25, 2022 Report Share Posted January 25, 2022 17 hours ago, soundminded said: Thanks David. I'm looking for an exact replacement. There are other AR midrange domes of the same size and similar type available but they aren't quite right. They are close though. You're in luck! Animal37 just posted a pair on eBay. Item # 334304399850 Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 25, 2022 Report Share Posted January 25, 2022 2 hours ago, DavidR said: @tenofossil Its my understanding that the 032 can be used to replace a 028 but not the other way around. I guess that would require measurements after installation in the AR9 to determine whether or not it would be ok. If the higher freq rolloff of the 200028 was taken into account in the crossover design it is possible using the 200032 might result in a response rise in the lower mid to upper mid region. But, listening or even better response measurement would be the final word. -T Quote Link to comment Share on other sites More sharing options...
soundminded Posted January 25, 2022 Author Report Share Posted January 25, 2022 David Thanks. Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 25, 2022 Report Share Posted January 25, 2022 47 minutes ago, teknofossil said: I guess that would require measurements after installation in the AR9 to determine whether or not it would be ok. If the higher freq rolloff of the 200028 was taken into account in the crossover design it is possible using the 200032 might result in a response rise in the lower mid to upper mid region. But, listening or even better response measurement would be the final word. -T I believe it was RoyC who broached this subject and tried an 032 in an AR9 and could hear no difference. Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 25, 2022 Report Share Posted January 25, 2022 At some point we may will be forced to accept a swap or one of the replacements I linked above. It's inevitable. Quote Link to comment Share on other sites More sharing options...
soundminded Posted January 25, 2022 Author Report Share Posted January 25, 2022 I want to thank everyone for all of the help they've given me. I haven't posted here for a long time but I knew whenever I needed help I could always count on you guys. Thanks again. BTW, it wasn't really urgent. On some recordings when they are played very loud and there's a lot of content near the low end of its range there is a moment of harmonic distortion. It's been that way for a long time and it's not really a serious problem. It's not the amplifier or the source. I recapped the crossover network except for the cans on advice I got here with inexpensive electrolytics so that the sound would be the same as original. I had the woofers and lower midranges refoamed at the same time so the drivers were out anyway. That was 14 years ago. I just decided it might be nice to replace that one driver. Quote Link to comment Share on other sites More sharing options...
Stimpy Posted January 25, 2022 Report Share Posted January 25, 2022 Years ago, my brother blew a 200028 dome mid, in my 90's. So, off I went to the local AR dealer, and no questions asked, they swapped the dead driver for a new one. Well, I was very surprised, when years later, I pulled the speakers apart, for a recap, and I found the replacement mid was a 200032! I never heard any differences between the two. Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 25, 2022 Report Share Posted January 25, 2022 Well, that settles that. If it isn't audible... Quote Link to comment Share on other sites More sharing options...
ar_pro Posted January 25, 2022 Report Share Posted January 25, 2022 Yes, I recall that the general rule was that the AR-9 & AR-90 dome mid could be replaced with one from the AR-91/92 (and AR-58), but not the other way 'round. To this day - knock wood - I have never encountered a bad driver of this type, which is a little amazing. Even the tweeters appear to be more resilient, compared against Classic-era tweets. But DavidR is right, the clock has to be ticking on these old speakers. Quote Link to comment Share on other sites More sharing options...
Pete B Posted January 26, 2022 Report Share Posted January 26, 2022 Which ones did you measure Tom? Very curious, my AR-9 s only have one working upper mid. Quote Link to comment Share on other sites More sharing options...
Stimpy Posted January 26, 2022 Report Share Posted January 26, 2022 5 hours ago, teknofossil said: Well, that settles that. If it isn't audible... Just trying to relay my direct experience and help out... Not preaching gospel... Same driver, just different amounts of ferrofluid. Plus the UMR in the 9 & 90 is high passed at a higher frequency, so it does cut off the low end response of the dome, which should help mitigate the differing resonance frequencies between the 200028 and 200032 domes. Maybe that's why they sound the same, to me...! But, you're welcome to listen and draw your own conclusions. Fine with me... Quote Link to comment Share on other sites More sharing options...
DavidR Posted January 26, 2022 Report Share Posted January 26, 2022 Stimpy, doesn't the 032 only have ferrofluid on one side of the VC ? I want to know how they keep it on one side ........ Quote Link to comment Share on other sites More sharing options...
Stimpy Posted January 26, 2022 Report Share Posted January 26, 2022 11 minutes ago, DavidR said: Stimpy, doesn't the 032 only have ferrofluid on one side of the VC ? I want to know how they keep it on one side ........ Yes, the 032 has ferrofluid on one side of the voice coil, where the 028 has fluid on the inside and outside of the coil. Magnetics keeps it in place, but how you get it into one side is beyond me...! Quote Link to comment Share on other sites More sharing options...
lARrybody Posted January 26, 2022 Report Share Posted January 26, 2022 I am assuming that the 044 midrange found in the AR58S is more in line with the 032 dome midrange. The difference being the black waveguide. My only problem I have encountered with any of these three midranges is pushed in domes. My appreciation for these 3 and 4 way speakers never yielding, because we tend to live our life’s in the midrange. Quote Link to comment Share on other sites More sharing options...
JKent Posted January 26, 2022 Report Share Posted January 26, 2022 22 hours ago, DavidR said: You're in luck! Animal37 just posted a pair on eBay. Item # 334304399850 I see that same seller has the 200044 listed also. Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 26, 2022 Report Share Posted January 26, 2022 14 hours ago, Pete B said: Which ones did you measure Tom? Very curious, my AR-9 s only have one working upper mid. Hey there Pete! Those were the 200032 mids. These are the ones intended for the AR91 that used a 700hz LF to mid crossover point. Quote Link to comment Share on other sites More sharing options...
teknofossil Posted January 26, 2022 Report Share Posted January 26, 2022 2 hours ago, lARrybody said: I am assuming that the 044 midrange found in the AR58S is more in line with the 032 dome midrange. The difference being the black waveguide. My only problem I have encountered with any of these three midranges is pushed in domes. My appreciation for these 3 and 4 way speakers never yielding, because we tend to live our life’s in the midrange. IMOP, people that push in driver domes should be locked in stocks on the town common and vegetables lobbed at their heads.... -T Quote Link to comment Share on other sites More sharing options...
soundminded Posted January 26, 2022 Author Report Share Posted January 26, 2022 Stimpy, I used to tease Ken Kantor. He'd play his LSTs at a volume more suitable for Cerwin Vega or Klipsch than AR in his dorm at MIT. He'd constantly blow the tweeters out, take them down to AR and they'd replace them for free every time. I told him they'd keep them on a shelf under the counter so they'd be ready every time he came back for more replacements. I also told him the reason they hired him was that it was the only way they could recoup the losses they took on all of the free tweeters they gave him. Companies like AR and KLH had incredible service policies. They also had very tight quality control. From what I understand Edgar Villchur was a wonderful boss to his employees as well. And of course his products were a great value for consumers. Quote Link to comment Share on other sites More sharing options...
Stimpy Posted January 26, 2022 Report Share Posted January 26, 2022 24 minutes ago, soundminded said: Stimpy, I used to tease Ken Kantor. He'd play his LSTs at a volume more suitable for Cerwin Vega or Klipsch than AR in his dorm at MIT. He'd constantly blow the tweeters out, take them down to AR and they'd replace them for free every time. I told him they'd keep them on a shelf under the counter so they'd be ready every time he came back for more replacements. I also told him the reason they hired him was that it was the only way they could recoup the losses they took on all of the free tweeters they gave him. Companies like AR and KLH had incredible service policies. They also had very tight quality control. From what I understand Edgar Villchur was a wonderful boss to his employees as well. And of course his products were a great value for consumers. Too funny! While I'd love to own a pair of LSTs, they do scare me. Whether accurate or not, I guess I feel the drivers from my Vertical Series ARs are more robust than the earlier 3/3a iterations. So, in my mind, I feel those drivers (tweeters/mids) are more fragile. While I don't crank, I'd always worry that I'd blow something. Even now, I use a preamp with dual RCA outs. One set of outputs drives my AR amp, and the other drives my Martin Logan amp. Depending on music and mood, determines which amp gets turned on. It's like having 2 cars, the mileage gets split between speakers, to help them last longer! Quote Link to comment Share on other sites More sharing options...
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