briodo

That is awesome. How did you wire?

And I finished the frame. I do not know the source of the cloth, as I bought it years ago and have enough left to do many speakers. Not sure that was a good idea, but it is what it is. Also the colors in person do not match the photo. The AR91 is original and the two look identical in pattern and color, not sure why my cell came to a different conclusion. All in all I'm happy with outcome. The AR91 and AR58S sound alike, which should not be a surprise. My wife helped me do AB test using speaker out switch on the receiver and we could not tell the difference. Next on the bucket list is make like Frank Marsi and stack them. That should be fun.

Bondo is my friend and what I used for the broken corner. Memories of my youth fixing rear quarter panels on my Plymouth Duster. The challenge after was getting a smooth and consistent base to finish, which is why I ended up using paint. After reading what JKent did on his AR11's, I now realize there is a much better way. Also, I would not use Gel Stain on a speaker again. While they came out OK, the finish is imperfect and does not match the true color of the factory finish as shown next to the AR91. It's not a true stain and will require sanding to remove it, which probably won't happen until the next time I have to repair these 20 years from now. Meaning, yeah, probably good enough for now. Good question on the tweeters, while the mids came from a pair of AR92's, the tweeters are original. No pic of the back of the tweeters to share

This is an excellent thread I only found after I finished the AR58S. Obvious oversight on my part, and can only roll my eyes at this point for not paying better attention. Truly impressed with the overall process as there is so much to be learned from the phased approach you took, materials researched and applied, all the way to finish of the cabinets and grills. Good on you, Kent, fantastic effort and collaborative discussion, Finding out the smartest person is usually a community effort supporting their passion!

Struggled with the little metal inserts for the 1" driver. Most were falling out and tacky glue did not work, so resorted to clear caulk, which provided a solid adhesive connection between the cabinet and metal insert. Drivers are in and the speakers are installed next to a pair of AR91's with original finish. The only thing I believe has been done to the AR91's was 12" refoam and caps replacement. You can compare the difference in color between the factory finish of the AR91's and my redo using coffee colored gel stain. Not sure I would use gel stain on a speaker again, BTW. While it covers a lot of imperfections, it is painful to work with, which is what I went through on the tops. I finally gave up and accepted the dark walnut paint job over stain. And with polyurethane top coat, I can finally have potted plants on these speakers without worrying about the ring :-). Last step is new grill cloth, the original looks pretty lame now the rest of the speakers have been cleaned up. I'm running out of amplifier capacity to drive the 2 pairs of 12" 3 ways, but use the A/B switch on my Luxman to sample. The AR58S sound really very nice.

I used a bead of caulk and 6 small screws for each crossover board. The reason for delay s the original tweeter/mid-range screws had rust which I had to repaint and several threaded screw inserts fell out of the particle board around the 12" drivers. Gluing them all back to avoid having to deal with a loose insert if the drivers ever have to come out again. But I am pretty excited to hear how they sound.

I did add a brace above where the 12" woofer is installed to increase cabinet strength. More pictures as I put things together.

Finally the tweeters are from the original AR58S, and just needed a good cleaning. The mid-ranges were another ebay purchase some time ago from someone parting out an AR92. I had to spray paint to match the original drivers they replaced. I was going to leave the silver, but the brown outer ring from the AR92 was too much, so painting was really the only option. Some scratches on the plastic are evident if you look close while removing the velcro patches that hold the AR92 foam cell cover in place.

I did replace the crossovers with AR91's purchased off ebay. New Dayton caps and connectors. The connectors are really very nice by the way.

Zoom in where the bondo repair was done and my supplies

Now for the painted tops and back

Time for an update. While the project is not yet complete, the majority of work is behind me. The cabinets pass the Wife acceptance factor and now have the opportunity to join the household for musical enjoyment. The cabinet with the broken top was repaired with bondo and both cabinets had their tops and bottoms finished with wood grain filler to achieve a smooth finish, then painted with Dark Walnut spray. I tried 3 different types of stain before giving in to paint with a polyurethane top coat as I just could not get the tops to look correct. I was not able to ever get the tops smooth and the stain just magnified all the surface imperfections. Wood filler, sand paper, paint and polyurethane at least got me to the point where they are acceptable. The rest of the cabinets came out well, using gel stain and sanding to get things smoothed out. I had to keep remembering these were never going to be in a fashion show, so focused on just being good enough. I'm happy with where they are. Some front and side shots...

AR10pi are in a class by themselves when compared to other 3-ways, and represent state of the art speaker design for their era. Absolutely worth refurbing. I would put them on an auction site with lots of pictures, ask a reasonable price for start and see what happens. Someone who has a passion for refurbishing old classics will bite. Would love to pursue myself, but as many others on this site can attest, its not too many speakers, just not enough rooms... Good luck

Agree with Aadams. Difficult to stop natural chemical reaction between metals over time. Encourage you to replace with new, whether they are pots or L-pads. And I have refurbished 3 early AR series pots, all worked perfectly for a year or two. I now just replace.

Excellent write up on a topic that I view as one of the most challenging parts of speaker refurbishment. The AR9LS & LSi grill screens are the deepest I have seen from AR and present a formidable challenge to get a smooth, professional finish. Thanks for taking time to document the steps with clear photos. I need to do both my 9LSi and AR98LS, simply have never attempted due to experience with other grills that came out marginal despite being 1/4 the depth. There is hope!!

I appreciate that feedback, and my comparison was on the upper range of the two speakers. I have not done an A/B with 9 & 9LSi. They are on different floors of my house and my wife drew the line on helping with speaker relocation other than out to the garage... I use the term listening to music VS the speaker with the 9. It simply disappears in ways the 9LSi does not. Both set ups have same amplifier, preamp, and source so I'm left wondering about what else I can tweak. Harry recommended resistor change and fiberglass type insulation for dampening, which I believe would help based on other sources confirming it works better than polyester fill. Then again, the 9 uses that white polyester fill. It may be I have to just start experimenting similar to what others have done. Thanks for letting me vent!

That makes perfect sense, taming the wild beast so to speak. I have not done any scientific measurement of where the issue is from a frequency perspective, but it finally hit home while listening to the AR91's I refurbished next to the AR9LSi's. They sounded remarkably alike (no surprise) until particular female vocal came through at what appears to be around 2K on my graphic equalizer. The adjustments I made are close to what you've found, but the equalizer impacts both pairs of speakers. That's when it hit me about having a similar crossover design built into the AR9LSi, with both -3 and -6db down for all three upper drivers. Schematic review shows all three driver circuits are different enough to indicate this is not just a "get the same resistor network parts" from the AR9 and wire it all up (although I have been known to do that). Leading to my question if anyone has taken the time to do such a design?

Great topic IMO. I own both and have a strong preference for the original 9, but wonder if it has more to do with crossover design than driver and orientation. The ARLSi upper MR is just too hot in current design. I've been messaging with Harry about his resistor change for that driver along with other enhancements and then realized the original AR9 crossover offers flexibility in adjusting drivers to the listener's taste. The AR9LSi requires external electronics to do the same. Has anyone taken to the time to design a AR9-like 3 switch resistor network for the AR9LSi? I can't find anything such an animal in the forum, but may not be searching correctly.

Thanks Glenn, found the replacement parts using your parts list and have them on order. Will spend time figuring out alignment as they do not appear to require shims. Will invest some time learning technique. I did replace the red/black original caps with Dayton NPE last week and found a whole new speaker to listen to. Learning that craigslist purchases still require cracking the case open even thought someone replaced the foam surrounds. Just want to share my appreciation for the details on your rebuild. Provides all key points to restore a pair of AR12's to like new condition. The grill specs alone cover a whole list of systems from that era. Original foams from that era are hard to find, and your replacement design actually looks better than the foam, IMHO. Kudos to you

My compliments to the author on this restoration. Great pictures and excellent details of how to bring back a truly rare classic. I have a pair of 12's I have done minor repairs on since they were purchased 5 years ago, a craigslist score for less than $100. The 10" had been refoamed but the caps were the red and black NPE that I replaced with Dayton NPE. I assumed the midrange was good since it does play but now looking at Glenn's close ups of the foam replacement makes me think mine have been "repaired" at some point with some coating due to the foam disintegration. I have a couple of pics attached and would appreciate feedback for those of you who have seen the correct foam material in place. The midrange drivers do not appear to have been touched, but the glossy surface tells me these are not foam surrounds at this point. See below. I tried to get different views on single driver, but the other looks identical. Do these appear correct?

That is really good to know. I found a post from 2011 started by Carlspeak on capacitor values and will spend more time researching. I don't need to rush this repair and the sunk cost of the Dayton's are not going to force my decision if a better option is out there. It is clear the old ones have to go, just want to be good enough to represent the original design/sound knowing the surrounds will need to be redone in 20 years...

Rethinking this comment, will remeasure tonight using 22 + 2.2 combo. Otherwise I'm deviating from specified parts and that is a slipper slope.

You just need matching risers for your listening chair! ?

Today was spent measuring the caps on all 6 crossover boards, qty 2 AR58S, and qty 4 AR91. I included the replacement Dayton NPE replacement caps in the measurement test as well. No surprises. Collins were way out, Unicom had good and bad, the TI's were 3 for 4 within tolerance. My baseline assumption of 5% tolerance is acceptable. I will be replacing all the caps on the AR91 crossovers due to age. However, my lesson on using Daytons (especially when doing series or parallel to reach target value) is to measure them before use. The 22uf I purchased all measured within tolerance without combining with the 2.2uf to reach the target 24uf goal for what I called C3. results attached for those who appreciate measurements. AR58S and AR91 Cap Value Measurements.pdf

Thanks Stimpy, doing surrounds is my favorite part. I bought the 58S on Craigslist from a young Mom going through a divorce for $45 in 2012 or so. She told me her ex-husband worked in a car stereo store, which is likely source of whatever he used, which appears to be a passive radiator. I actually tore the paper cone trying to remove the hard plastic/rubber/epoxy he used, so Tom was spot on about them being beyond normal repair. I thought I got a heck of a deal, my wife looked at me in disbelief when I brought them home. Glad I'm not in this for the money. Crossovers are out and ready to work replacement caps for both pairs. Took a picture of the AR92 and AR58S crossover boards. BTW, I was pleased to see the 91 board connectors and switches fit the 58S back panel cutout. I will need to figure out how to save the SN label on both AR58S I tried a little heat and careful vacuum approach on the mid-range dome, no joy. It is really stuck. I've done several domes using that technique before, so something is different and appreciate some ideas on alternative methods. I don't mind a couple of dimples, but current dent is too much...