Aadams

I meant, you did a good job, getting them to match. Paul Desmond sounds good.

Good job getting them to match.

This might work. Try the link below. Maybe the only 8inch for sealed enclosures still being manufactured. https://www.humanspeakers.com/e/parts/001.htm

I do not have 8 inch ARs from that period but all the replacements I have seen say " Service Replacement" on a very similar the sticker. I thought yours might be service replacements when I first saw your photo. Yours are probably original, but bearing a service mark from the company that refoamed them. Assuming all your voice coils are good, you will spend several hundred Euros to have better speakers than if you merely refoamed those originals. Otherwise they are marketable as is in Italy, which had a large AR following.

If all have this tag (below) they are unlikely to be anything other than AR.

It looks like they might have been bridged for Bi amping. That is a guess. The good news is they are not Cello nor are they AR original and therefore have no provenance of value. They are worth the price of their working parts but could become a very good deal if they can be easily restored to proper working state with existing circuitry . I would bridge all three terminals for use with an equalizer and a single MODERN power amp. Edit: I reread the first post and see they are not currently for sale.

I remember reading this thread about tri amping LSTs a few years ago. I finally found it. It might be helpful. Among many images it contains the following:

If you are trying to post directly from a phone you could have a problem. It always works when you resize on a computer. At least for me.

No. The information in the chart was first presented in 2015, as far as I know. To my eye, it appears that the AR curves are closest to Toole's "Trained Listeners Only." Yes. You are correct All of the listener curves are considered valid and acceptable. The chart is saying the only way to satisfy the preferences of most home listeners is to design high quality loudspeakers that can produce steady state "sound power" throughout a home listening space as represented by the heavy dashed line. I added the red lines to highlight range of effect due to reflectivity in normal listening spaces. The heavy dashed line is not an on axis line. It is the Harman version of this The paper is freely available at the link above. In addition to target curves for loudspeaker design, there are Harman target curves for Cinema and Studio spaces. All of which are aimed at satisfying the tastes of listeners in those spaces; Akin to Roy Allison creating speakers to meet the expectations of a listener whose ear is attuned to the acoustics of Boston Symphony Hall.

Turns out there is a graph that answers your question from Lansing Heritage The bold dashed line is close to the published target of Revel and some JBL Compare to these below

Update: The above is still true but Harman International now, in 2023, explicitly states that speaker brands Revel, JBL Synthesis and JBL Professional are intentionally designed and built to achieve in room performance that conforms to the "Harman Curve" for loudspeakers, which looks and reads an awful lot like the AR philosophy for loudspeakers from Roy Allison days. Entry pricing for 2 way six inch is about $600 each. JBL L100 Synthesis, @ $5k/pair, which looks like an L100 Century is in this group.

$175 - $150 for tweeter rebuilds + $80 USD 4 hole woofer and 2 mids ------------------ $105 or less for everything. The tweeters are so degraded they must be rebuilt or replaced even if they seem to work.

It is possible that both speakers contain their original drivers. The factory would have installed an adapter for the 4 hole woofer. Inside the box, AR would have accounted for the different woofers by changing the crossovers and the speakers would sound perceptibly identical when new. The problem for me is the 6 hole woofer is wrong. It could be the original frame with a new cone and voice coil or it could be the wrong part altogether. So.......................Assuming the speakers have not been modified internally and the only alterations are what we can see in photos: If you are critical listener they will not sound identical in their current form. If you are a casual listener they may sound good enough. You haven't mentioned the price. To me, in their current state, they are worth the combined value of their seperate, working, genuine AR parts on ebay. Maximum.

It looks to me like both cabinets were cut for the earlier and larger diameter 6 hole frame woofer. One woofer is a 6 hole and the other woofer with the flat dust cover is the later 2ax woofer with 4 holes. Both woofers may be AR but I can't recall ever seeing an early 6 hole 10 inch woofer with a smooth paper cone. The 4 hole frame is too small for the woofer opening and would need an adapter to correctly seal the cabinet. I can't see an adapter ring in these photos The only way to really know is to extract the 6 hole woofer and look at the magnet for date and model info. I would consider this pair as compromised and be looking for matching woofers which could be difficult in Denmark. They are not worthless but they are not at an ideal starting place for restoration if you want a matching stereo pair. Others may have more to say. Good luck. Otherwise the speakers look good in the photos.

So the board ,3a 2ax etc, received specific notches for the pots somewhere after it was cut and printed but before it was populated and wired. Is that correct?

Did you skip the step where you compare the 2nd, untouched, tweeter to the restored tweeter? I can't find your analysis of that comparison. Apparently pots had enough unit to unit variation in performance that they had to be measured and preset before being installed in a specific position to make it simple for the user to set up a stereo pair. Most of us found out about the notches after the fact. If you are going to keep appearance and parts as original, installing the pots as original is very simple compared to your tweeter work, which practically none of us can do. I still think original is always preferred but in the case of pots, unless they were spotless, would replace the original pots with LPads and resistors or modern pots. The pot tab notches become superflous. If you keep the speakers you will revisit those pots. The AR2ax incorporates the super tweeter in a way that makes the unmeasured performance of your repair easier to accommodate if it is extending too far into the midrange. The tweeter was originally designed for the AR3 which had very specific performance requirements to blend with the dome mid at 7500hz. If its natural rollof is not correct it would be noticeable in an AR3 application. All that matters is your tweeters sound like a matched pair. All Classic ARs sound very similar, If you want your speakers to sound like an AR, this is the target for an AR2ax EDIT with the controls set to full increase. They will sound unbearable in a normal room to most listeners. I think you are within range.

I installed 3 sets of Dayton Lpads several years ago. I noticed the behavior to which you refer and thought it was the "full on" feature. Rebuilt tweeters don't need that level of signal but it might help those that have not been rebuilt.

Your result is probably close enough because your pot settings are in the range of the most common settings for AR Classic 3 way or 2.5 systems. The appearance is also correct. I can count on two fingers the number of other people who are known to do this specific mechanical repair. The most important goal is for you to create a matched pair. It would be a bonus to be able to match the performance curve of the original spec for the AR3 which was aimed at linear power response rather than high on axis output. According to history on this site, reject rate for the four blob tweeters was high with a large percentage being sent back for rebuild.

From an AR3 Brochure in Early 60s. That supertweeter was designed to crossover at 7500hz and smoothly rolloff to 18db down at around 4k hz. Don't know what influence the crossover network played in this chart. I just happened to find a clear one to enlarge.

I think you have plenty of monitors. I, for one, am waiting for the second tweeter results. One question: Considering this is a stereo pair, if you rebuild the second tweeter in a different fashion how do you insure they will have near identical performance? Also, if you omit the 4 dots on the second tweeter does it count as mod or restoration? Assuming it works correctly. The CSP community has never been much of one for watching videos of AR speakers playing on computer speakers.

From a 2021 post above.

Nice. How does it sound compared to the tweeter in the other box?

While we are on the topic of AR 91, I will say this sight does have a block feature. I have never used it.

More Evidence that Roy Allison was way ahead in his thinking about home audio reproduction. Image on the left came from the Harman Luxury Brands web site.

The domed tweeters were added to prop up the power response of the mid/tweeter 2 series. The domed tweeters were never intended to be on-axis spl demons. The graphs below may help. The tweeter is the later 3/4 inch but the effect is very similar with the 1 inch tweeter. The graph shows he mid tweeter of the 2ax responding above 10k on axis. AR6 on the right hand side.