• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Acoustic Research AR-4x Restoration

adgreen

adgreen

New Member
Hi all,

I just picked up a set of Acoustic Research AR-4x's for $75. Plugged them in and they're sounding pretty muffled. I don't have any experience restoring speakers but have found a fair bit of info on this forum and want to make sure I'm understanding everything correctly before I purchase parts to fix these up. From my understanding, these will need the crossover capacitors replaced, which I've found a kit for on ebay in VINTAGE AR's shop:

https://www.ebay.com/itm/194443155630?hash=item2d45b718ae:g:aZQAAOxyBLxRG-IB

As far as the rheostat wiper, I'm reading it may not be worth the trouble to restore it and rather just bypass it completely. Is there any downside to this? By bypassing it, it will operate at full output, correct? For sealing the surrounds I've found a kit on VINTAGE AR's page which seems to be well regarded. And it seems like fiberglass is favored for packing the cabinets, which I can grab at Home Depot. Is there anything else I'm missing here or does that about sum up what needs to be done to these?

Lastly, dumb question, how can I tell if the woofers/tweeters are original? Thank you for any help, really looking forward to bringing new life to these!
 

Attachments

  • front_on.jpg
    front_on.jpg
    147.1 KB · Views: 84
  • front_off.jpg
    front_off.jpg
    116.2 KB · Views: 95
  • back_left.jpg
    back_left.jpg
    184 KB · Views: 84
  • back_right.jpg
    back_right.jpg
    159 KB · Views: 79
Last edited:
Register to hide this ad
They are all original. The AR4 series used three different woofers over time. The light colored cone is second, the grey cone is the last (most recent) one. Perhaps one was replaced in your pair, or, if serial numbers are spread widely, one got an older woofer and one got the newer woofer.

I believe that bypassing the wiper the tweeter will get a bit more power than it would with the pot turned all the way "up". The pot must stay in the circuit.

Personally, I would first try to "restore" the pot. Usually you can get good results...if not, then bypass, or replace with new.
 
Last edited:
I was able to restore the pots in the pair of 4x I had years ago, even though they were pretty corroded.

The surround dope is available from RoyC, a member here. Cheaper than Vintage AR, he may have the capacitors, too.

Nice speakers, those.
 
There’s modern pots on fleabay to replace original corroded pots if necessary.
I would not spend extra for the caps from vintage air, but get them from parts express, much cheaper.

These look to be in very nice condition. No rust on the tweeters around the cone edges where glued to the baskets, which is somewhat common. These should be an easy restore, just a couple hours.
 
Opened these up today and attempted replacing the tweeter control pots as well as the capacitors. One of the speakers is working fine, pot control is responsive and everything is sounding good although slightly muffled (wondering if applying the surround dope will help with that). The other speaker's tweeter doesn't seem to be working. I've attached pictures of how I've wired it- identically to how I wired the other speaker so I'm confused as to why it's not working. I also removed the tweeter and attached a picture of it, maybe something isn't right there. Thank you for any help.
 

Attachments

  • IMG_2503.JPG
    IMG_2503.JPG
    132.4 KB · Views: 63
  • IMG_2504.JPG
    IMG_2504.JPG
    92 KB · Views: 63
Are you sure it was working before? Muffled sound is often indicative of poor or non-existent tweeter output.
 
One of the speakers is working fully, both tweeter and woofer. It sounds slightly muffled, specifically on drum kicks/thumps. On the other speaker, the woofer is working but the tweeter is not- those are the pictures I attached. Going to get a multimeter and measure the DC resistance on everything.
 
Seems like that right tweeter is indeed shot. Got the multimeter in today and here are the readings:

left woofer - 6.2
left tweeter - 4.6
right woofer - 6.2
right tweeter - 0

I found an OEM AR4x tweeter on eBay, listed for almost as much as I paid for the speakers all together. I'm imagining shelling out a bit extra for OEM may be worth it vs going for a Parts Express alternative- especially since I have one OEM working tweeter in good condition already. Are there any other options I am missing?
 
I believe someone here on AK is able to repair some AR tweeters. Do a search here and maybe someone will be able to chime in, too. I'm guessing there's a broken tinsel wire in there. Or a fried VC (hopefully not).
 
@RoyC here and at ClassicSpeakerPages.net, along with Chris1This1 there. I had Chris do mine and was pleased. I did not want to go the HiVi route!
 
kryten79 said:
@RoyC here and at ClassicSpeakerPages.net, along with Chris1This1 there. I had Chris do mine and was pleased. I did not want to go the HiVi route!
Click to expand...

I don't think the HiVi tweeter solution would be a good one for the 4x. I don't believe it will line up correctly, and I don't think it goes as low as the original tweeter.

Chris and/or Roy certainly do great work on the dome tweeters used in the AR3, AR3a, AR2a, etc. I did not realize that either of them worked on the cone tweeters as found in the 4 series...but if they do, I'm sure their quality of work is excellent. I think OP would want to consider having both tweeters restored to get balanced output from them.
 
adgreen said:
Thanks for the info everyone!
Click to expand...

Resistance looks good on the other drivers, but your comments about even the good speaker sounding muffled are concerning. It could be that the tweeter's output has declined with age/stiffness, or it could be the pot (altho you said that it showed a normal range of resistance). Another possible cause is high resistance in the crossover capacitor. A leaky cabinet or overly-permeable surrounds will reduce low frequency output and extension, but I wouldn't think that would manifest as "muffled".

As I mentioned above, if Roy or Chris offer repair/rebuild service for your tweeters, and if you go that route for the bad one, you might want to consider sending them both to get balanced (and best possible) output.
 
I used the HiVi tweeters in a set I had a while back. I wasn’t concerned about an original restore. I just wanted good sound. The HiVi tweeters fit perfectly in my speakers. Sounded good also. Ultimately sold them.
They were an amazing speaker for their size. IMHO
 
There's no doubt the HiVi tweeters are a legitimate option. I certainly didn't mean to imply they sounded bad or were garbage - lots of people like them for price, sound, availability and maybe looks? The pair of 2ax I restored were a Salvation Army find in amazing condition. Even the factory grill cloth appealed to wifey more than the new replacement material. The consensus is the tweeters get "tired" for lack of a better word and can be restored and I wanted them to stay original (other than the caps and pots).
 
kryten79 said:
There's no doubt the HiVi tweeters are a legitimate option. I certainly didn't mean to imply they sounded bad or were garbage - lots of people like them for price, sound, availability and maybe looks? The pair of 2ax I restored were a Salvation Army find in amazing condition. Even the factory grill cloth appealed to wifey more than the new replacement material. The consensus is the tweeters get "tired" for lack of a better word and can be restored and I wanted them to stay original (other than the caps and pots).
Click to expand...

HiVi in 2ax makes sense, with crossover modification.

Not so much for 4x if wanting them to sound close to original. But if this is not a goal, that's a different matter.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom