AR-2ax repair

Given that this thread is 7 pages long I figured I would summarize the general steps I took to restore my speakers. This does not include any of the cabinet restoration. This is not intended to be a recommendation for anyone venturing into the restoration of a pair of Acoustic Research speakers, it is simply one man’s ADHD rabbit trail to reach the point of having a fully functional, nice sounding pair of AR-2ax speakers.

In the beginning I saw a pair of AR-2ax speakers, and they were good.

I saw that the foam surrounds on the woofers were bad so I knew that when I tested for audio I would need to do so at a very low volume to avoid damaging them. I heard sound from woofers but nothing from the mids or tweeters. Turned the pots to see if I could get sound from them. Pots were very stiff and I still could not get sound from mids or tweets.

I carefully removed the woofers. After lifting the first one up I decided to take them outside to continue because the rock wool inside the cabinet was very broken down and small particles of it were floating around my living room at this point. I really didn’t think about what would be inside them. I have only taken apart newer speakers up to this point and they all have had poly-fill.

After removing the rock wool I took my air nozzle at a low pressure setting, got behind the speaker, put a cloth over my head and face, and blew out the cabinets (I am not recommending doing this, just reporting what I did). I found them so much more enjoyable to work on them with the insides cleared of that dust.

I then applied a very low volume signal to each tweeter and mid at the output of the pots. They all worked. They also ohm’ed out good.

I took pictures of the wiring and components inside since I knew I would have to remove and replace things. I then removed the tweeters and mids because with my 6’5” frame and large hands there was no way I was going to work inside the cabinets without doing so. I then clipped the wiring, I used a pencil to mark the location of the boards, then carefully removed them. I have a tack removal tool that works great for removing staples.

I removed the pots and opened them up. There was more blueish green corrosion than metal inside. I soaked them in a solution of salt and vinegar then took a soft tooth brush to clean them up. The discs were very pitted and chipped. Decided I would need L-Pads.

The particular speakers I had were originally manufactured with cloth surround woofers. I was informed that the original cloth surround woofers and the ones with foam surrounds used different inductors. When the woofers in my speakers had been changed out, the inductors had not been changed so I had the wrong coils for the existing woofers. I had two choices, re-foam the existing woofers ($26) and purchase the correct coils ($25) or purchase a pair of cloth surround woofers ($$$). I decided to purchase cloth surround woofers.

I purchased a pair of 6 ufd caps and a pair of 3.9ufd caps to replace the existing ones. I purchased 4 L-Pads and 2 25ohm 10w. resistors to replace the pots.

I wired up the L-Pads, capacitors, and resistors. I made up a schematic to make sure that I had the wiring right.

I had some weather stripping in the garage to use for sealing the drivers. 3/4" wide x 1/2" thick. After scraping all that nasty black stuff off the drivers and the cabinet and putting in the weather stripping, I installed the tweets and mids and wired them up.

I purchased 4 bags of the pink home insulation, from Lowe’s. Home Depot sells a similar insulation in yellow that can also be used. I stuffed 2 bags into each cabinet leaving the woofer wires hanging out of the cabinet.

I then wired up the woofers and installed them, sealing them with the weather stripping. I had a few issues that I found with the woofers which were easy fixes using epoxy and glue, and which I will not cover in this summary.

I then hooked up my receiver to my speakers. I gradually turned up the volume, listening for any issues. I got them up to a volume beyond normal listening levels and they still sounded great.

SUCCESS

Well worth the effort.

I leave you with this quote:

“Always remember the last words of my grandfather, who said ‘… a truck’” Emo Phillips
 
I purchased 4 bags of the pink home insulation, from Lowe’s. Home Depot sells a similar insulation in yellow that can also be used. I stuffed 2 bags into each cabinet leaving the woofer wires hanging out of the cabinet.
For what it's worth... on several acoustic suspension speakers I worked on there was a piece of cheesecloth placed on top of the insulation covering the woofer hole area. I assume it was intended to keep glass fiber dust either out of the woofer motor assembly, out of the repair person's nose or both. I'm sure it has nothing to do with acoustical performance. Just an observation.
John
 
For what it's worth... on several acoustic suspension speakers I worked on there was a piece of cheesecloth placed on top of the insulation covering the woofer hole area. I assume it was intended to keep glass fiber dust either out of the woofer motor assembly, out of the repair person's nose or both. I'm sure it has nothing to do with acoustical performance. Just an observation.
John
Agree, cheese cloth in AR's, and a piece of fabric in KLH's.
 
Yes. Kent made me aware of this in a PM. thanks for the observation tho. He suggested cintraline (sp.). Either way, I will be putting something in there. Thanks
 
Ok, we will see how this works. I'll going to post a video of a song played on my Onkyo's and then on my Ar's.
my phone's microphone isnt great but you can still hear differences in the 2 speakers

First one is Onkyo's.


 
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Hi Michael,
AR 2ax sound seems to be warmer and sweeter than Onkyo's. Is it also real on a live listenig? In other words what are the differences in the speakers in your opinion?
Thank you
 
Hard to tell from my laptop speakers. What really matters is what you think.

I know they enjoy and benefit being feed power. Looks like another pair of AR's going to a good home.

Barney
 
AR 2ax sound seems to be warmer and sweeter than Onkyo's. Is it also real on a live listenig?

Not exactly what warmer or sweeter means. I hear these terms and some I understand, others I'm not sure.
Given that the recording is not great, the differences are more distinct in person.
I thought at first that the ARs had better separation but I actually think the Onkyo's do. This may be attributed to the fact that they each have 2 tweeters out of phase with each other. Of course this is a more artificial separation. In any case, my living area messes with any stereo sound.
My wife prefers the ARs, my opinion is they each have strengths and weaknesses. I think for the music I typically listen to, I prefer the onkyos. Once I get a dedicated, more acoustically favorable room, a TT and maybe a vintage receiver and play more subtle music, I would prefer the ARs.
Either way, I welcome any thoughts and opinions. I realize we all have different tastes and ears.
 
If you're used to a more modern speaker that are designed for more modern music listeners and equipment, it will take some getting used to a speaker like the 2ax. You might eventually enjoy it for what it has to offer, ie, a much more laid back presentation, something to listen to all kinds of music without it slapping you in the face with it. I'm not saying that's what your Onkyo speakers are doing, but they are brighter, more detailed, which also has it's benefits to a lot of people. I prefer the darker, laid back "East Coast" sound of AR's myself.

The bottom line is that it's why a lot of us enjoy having multiple sets of speakers(and amps, and turntables...) to rotate in and out, depending on moods, etc. One doesn't have to live with only vanilla for the rest of one's life.
 
That makes perfect sense. Actually, up until recently I never really listened to the Onkyo's alone. I've always used either 5.1 surround for movies or 7 channel stereo for music. So I've had rears, a 12" sub and a nice center channel in the mix. I didn't realize how good they actually sounded on their own.

I hope to someday have a variety of components to choose from. But until then, I'm sure I will enjoy what I have.
 
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