Acoustic Research AR 9 upper midrange and tweeter replace or rebuild

[69AMX390]

I purchased a pair of AR 9 that need upper midrange and tweeters.  Would love to get them up and running.  Does anyone repair upper midrange and tweeters.  I would like to keep original and avoid putting chinese replacements in.  Or used is an option.  Did any other models use the same drivers.  Any help would be appreciated.     

[ar_pro]

For  replacements in the AR-9, you can use vintage upper-mid and tweeter drivers from the concurrent AR-90, AR-91, and AR-92 systems.

These are not to be confused with new "replacement" drivers available in several locations, as they're not the same.

I haven't looked recently, but good-condition individual mids & tweets were selling for about $100/each for a long time on eBay.

 

[DavidR]

The one guy who had any success with rebuilding the 200029 tweeter has gone silent right after his success.

member name: seventy1

[AR surround]

11 hours ago, ar_pro said:

For  replacements in the AR-9, you can use vintage upper-mid and tweeter drivers from the concurrent AR-90, AR-91, and AR-92 systems.

These are not to be confused with new "replacement" drivers available in several locations, as they're not the same.

I haven't looked recently, but good-condition individual mids & tweets were selling for about $100/each for a long time on eBay.

 

I thought that the UMR on the AR-90 was the same as that on the AR-9, but the one in the AR-91 and AR-92 is somewhat different even though it looks it the same.   Is it that one can use the UMR from the AR-91 and AR92 in the AR-9/AR-90, but not the other way around?

[Aadams]

53 minutes ago, AR surround said:

Is it that one can use the UMR from the AR-91 and AR92 in the AR-9/AR-90, but not the other way around?

There is a fairly recent thread that discusses this.  The quick version is the statement above is correct. IIRC, the 91/92 mid has less ferro fluid in order to enable its use at the lower crossover of 700hz.  The 90/9 mid has more ferro fluid in the expectation of higher acoustic output but still suitable for a 1200hz crossover point..............used in a 91 or 92 it would not comfortably extend to 700hz.

 

[ar_pro]

Right - the AR-91 & AR-92 mids had a lower crossover frequency, and were somehow enabled to do so - I don't know if it was the amount of ferrofluid - but AR worked some mojo on them.

The drivers from the AR-9 wouldn't be suitable for the AR-90 or AR-91, but the reverse usage would be OK.

[69AMX390]

Is it common to rebuild dome midranges and tweeters in other brands?  I guess used would be fine.  Just so I get the correct ones to replace my bad ones.  

[Aadams]

1 hour ago, 69AMX390 said:

Is it common to rebuild dome midranges and tweeters in other brands?

Some AR3 mids can be repaired.  No one offers a service to rebuild later AR dome mids and there are no new drop in replacements. Tweeters from classic era ARs are repairable by experts using proprietary methods.    New replacement tweeters for ADD series through Verticals (AR9 series) are available from Midwest Speaker. 

[69AMX390]

Are the tweeters from Midwest speaker the same quality as the originals?  I had read they are made in China.  Would hate to put Chinese parts in my "made in America speakers"    

Since any original would be over 40 years old, is an original's quality compromised?  I am just looking to do what is best.  

[Stimpy]

The 9s and 90s both use the same tweeters and dome mids.  The same LMR drivers too.  Nothing different.  The 91 and 92 also use the same tweeters, but as noted, slightly different mids.  However, the 91 and 92 dome mids will work fine for the 9s or 90s.  Though, not vice versa.  I wouldn't use a 9 or 90 dome midrange in a 91 or 92.  Regardless, that gives the OP four different models to source parts drivers from, for the restore.

[lARrybody]

I found this explanation of the upper midrange differences on the web.

 

AnonymousMarch 10, 2014 at 2:26 PM

One area Teledyne-era AR90/AR-90 owners (& AR9/AR-9 owners, too, for that matter) need to exercise caution in, IMO, has to do w/replacement speakers for the AR90/AR-90.

Specifically, there has been a increasing tendency for those parting out an AR91/AR92 to claim that the AR91/AR92 midrange driver (OEM PN=200032) is 100% the same as the AR90 upper-midrange driver (OEM PN=200028), as if the factory routinely shipped AR90/AR9's w/PN=200032's installed. Since the factory specs and wiring diagrams for the AR90/AR9 specify only the PN=200028 then this was not the case.
Differences : The PN=200028 has a larger volume of Ferro-Fluid (for cooling) than the (OEM PN=200032), which also reduces the PN=200028 air cavity below the dome (via that extra Ferro-Fluid) which also raises it's resonant freq, hence it's dedication to the upper-mid range, while the converse is true for PN=200032. But since PN=200032 has a better low freq response, how does that play out when coupled to a AR9/90 crossover? And what loss of sustained power handling is encountered wrt the lower volume of Ferro-Fluid ?

In short, if the Teledyne-era factory felt that anechoic chamber response testing & power-applied-vs-driver-temp testing allowed for one driver to be used in both applications there very likely would never have been a 200032.

 

[Stimpy]

13 minutes ago, lARrybody said:

I found this explanation of the upper midrange differences on the web.

 

AnonymousMarch 10, 2014 at 2:26 PM

One area Teledyne-era AR90/AR-90 owners (& AR9/AR-9 owners, too, for that matter) need to exercise caution in, IMO, has to do w/replacement speakers for the AR90/AR-90.

Specifically, there has been a increasing tendency for those parting out an AR91/AR92 to claim that the AR91/AR92 midrange driver (OEM PN=200032) is 100% the same as the AR90 upper-midrange driver (OEM PN=200028), as if the factory routinely shipped AR90/AR9's w/PN=200032's installed. Since the factory specs and wiring diagrams for the AR90/AR9 specify only the PN=200028 then this was not the case.
Differences : The PN=200028 has a larger volume of Ferro-Fluid (for cooling) than the (OEM PN=200032), which also reduces the PN=200028 air cavity below the dome (via that extra Ferro-Fluid) which also raises it's resonant freq, hence it's dedication to the upper-mid range, while the converse is true for PN=200032. But since PN=200032 has a better low freq response, how does that play out when coupled to a AR9/90 crossover? And what loss of sustained power handling is encountered wrt the lower volume of Ferro-Fluid ?

In short, if the Teledyne-era factory felt that anechoic chamber response testing & power-applied-vs-driver-temp testing allowed for one driver to be used in both applications there very likely would never have been a 200032.

 

I agree 100%.  But, if the OP can find 200032 domes, to get his 9s up and running, there's no reason not to.  The resonance frequency of the 91/92 domes, shouldn't matter, as they'll roll off much higher, in an AR9 circuit.

[Stimpy]

Oh, years ago, I came home to the smell of burnt electronics, in my listening room...?  After an inspection of all my gear, everything seemed OK.  So, I pulled the grills on my 90s, and found a deformed, distended dome midrange.  It was hanging out like a detached eyeball...!  Well, it didn't take too many guesses to realized that my younger brother must have blown up my speakers.  Though, he never confessed to the deed, I knew it had to have been him.  

Well, I pulled the dome, and off to the local AR dealer I went.  My dealer replaced the dome, no questions asked.  I took it home, installed it, and all was good.  Fast forward to a recent recap, and after pulling the drivers, I discovered the replacement dome was a 200032 and not a 200028.  I never heard a problem from using the incorrect dome.  I doubt the OP would either.  Still, look for 200028 domes.  But, don't be afraid of the 200032 domes either.

[lARrybody]

I went back and reread the post from seventy1 that DavidR referred to. 

What a interesting thread. I wonder if the addition of ferro fluid to a AR 91,92 midrange would make it have the characteristics of the AR 9,90 midrange.  

[Stimpy]

What gets me is the 200028 domes had ferrofluild on the outer and inner sides of the voice coil.  The 200032 domes only had ferrofluid on one side, which I assume was the outside?  It just boggles my mind, that ferrofluid stays in place, and does not migrate into the inside of the coil.  While I know it's magnetic, it is still a fluid, and as such would exhibit the tendencies of a fluid.  But, it doesn't.  Cool.  And weird.

[DavidR]

21 minutes ago, Stimpy said:

What gets me is the 200028 domes had ferrofluild on the outer and inner sides of the voice coil.  The 200032 domes only had ferrofluid on one side, which I assume was the outside?  It just boggles my mind, that ferrofluid stays in place, and does not migrate into the inside of the coil.  While I know it's magnetic, it is still a fluid, and as such would exhibit the tendencies of a fluid.  But, it doesn't. 

This is what I remember Carl telling us. The AR9 and 90 #200028 mid has half the resonance of the #200032. One has to wonder how they even got the fluid on one side, and one side only,  in the 200032 driver. Then to get it to stay in place.

[DavidR]

Soon after Seventy1 posted that thread I PM'd him here and on AudioKarma to let him know I have 2 donor tweeters but he has not even opened the PMs

The tweeters still work but have diminished output in the extend frequency range. Good thing I had spares for my AR91s

[69AMX390]

Does anyone have an opinion on whether the new replacement tweeters are of good quality compared to the originals.  I realize the originals are old and the ferrofluid could be compromised (dryed up).  I guess my questions is what has everyone else chosen to get the best performance.  New or used?

[DavidR]

Midwest speaker sells a drop-in replacement. You will not be able to tell the difference. I put one in one of my 10Pi and an original. I could not hear a difference.

They come in 4 and 8 ohm versions so make sure you buy the correct one if you decide to go that route.

 

https://www.midwestspeakerrepair.com/shop/home-audio/tweeters/dome/mw-audio-mt-4121-75-inch-dome-tweeter/

[DeSelbyofDalkey]

I installed the Midwest Speakers tweeters in my AR90s. They are very, very good—at least as good as the original AR tweeters: Wider, smoother response than the originals from my pair. They do not use the AR tweeter plastic bezel, so dispersion is wider than original. I contacted Midwest Speaker and they said that using the original tweeter plate on top of their tweeter is fine as long as it is not screwed in too tightly. I tried it and the AR plate does see to focus the treble a bit more, but until I get a second bezel I cannot know about the effect on two.

The Midwest Speakers tweeter is slightly more efficient (more sound per watt) than the original. It somewhat upset the balance of the entire speaker. Not terribly, but noticeably so. The -3db switch reduced output slightly more than I wanted, so I will probably try installing a 1 ohm 22w resistor to see if it helps match the tweeter to the rest of the speaker better. I can live without it, but I want to try.

For the price, the Midwest Speaker are still excellent options. They are very well made and are straight drop-in replacements.

[kkc]

On 12/9/2020 at 11:53 PM, DeSelbyofDalkey said:

I installed the Midwest Speakers tweeters in my AR90s. They are very, very good—at least as good as the original AR tweeters: Wider, smoother response than the originals from my pair. They do not use the AR tweeter plastic bezel, so dispersion is wider than original. I contacted Midwest Speaker and they said that using the original tweeter plate on top of their tweeter is fine as long as it is not screwed in too tightly. I tried it and the AR plate does see to focus the treble a bit more, but until I get a second bezel I cannot know about the effect on two.

The Midwest Speakers tweeter is slightly more efficient (more sound per watt) than the original. It somewhat upset the balance of the entire speaker. Not terribly, but noticeably so. The -3db switch reduced output slightly more than I wanted, so I will probably try installing a 1 ohm 22w resistor to see if it helps match the tweeter to the rest of the speaker better. I can live without it, but I want to try.

For the price, the Midwest Speaker are still excellent options. They are very well made and are straight drop-in replacements.

Thanks for the feedback on performance.  I was wondering if I should experiment or use drop-ins with my blown tweets and aging UMRs...!  Still ummin...and aaaahin...!