[AR11 VS AR3a]

On 6/5/2021 at 2:15 PM, AR55 said:

I doubt that you will find a cream colored AR tweeter.  I have never seen a working one come up for sale.  You may have some luck finding the black, second generation tweeter found in the second generation AR-10B/11B.  It doesn’t show up every day on eBay, but I wouldn’t be surprised to see one for sale in the next few months.  I recently restored a pair of first generation AR-11A’s that had blown tweeters, and was able to replace the tweeters with a pair of eBay sourced 11B tweeters. 

 

I don’t think that you will find an audible difference in the sound of the first & second generation tweeters.  Other than cosmetics (black dome verses cream dome), it appears that the addition of Ferrofluid to the 10B’s/11B’s tweeter’s voice coil was the only change that AR made.  This gave it more power handling ability.

 

If you can’t find an 11B tweeter, you may want to consider replacing one or both tweeters with aftermarket tweeters.  I purchased a pair from Midwest Speaker Repair (Midwest Speaker Repair MT-4121 .75-inch dome tweeter) to use as backups, since I am now running 2 pairs of AR-11’s in my system, and didn’t want to risk not having a replacement if a tweeter blows.  I compared the AR 11B tweeter to the MT-4121 tweeter, and felt that the MT-4121 may be a little bit brighter, but otherwise I could hear no difference.    

I am kicking myself as apparently there was a listing on ebay for the cream tweeters at some point, and I missed it...which has been annoying me! 

I'm in the UK and AR3as are rare enough over here, so when I found this pair of AR10s I did end up paying over the odds for them as I'd never seen any over here before in all my years of looking. I got a pair of AR3a improveds, but I never liked them and I couldn't figure out why, when comparing to a pair of AR3as I restored for a friend they sounded terrible. Ended up getting a minty pair of AR5s which I really like, and then a month later these AR10s come along.

They are in storage at the moment as I don't have enough spare cash to get the parts required for restoration, and I have been cogitating what to do about the tweeters for a long while now. The reason I was hoping to get a cream tweeter is that the later ones had ferrofluid, and by now is probably all gummed up and not performing as originally designed. Having one with old fluid and one without made me think they wouldn't sound the same. As far as I can remember the AR3a style tweeter did work, but it was dented quite badly. I was thinking about using it with my AR5s as one has an aftermarket tweeter, but the AR5s tweeters are a different impedance I think? 

I had thought about aftermarket, which would make more sense I suppose as then I could get a pair of aftermarkets and keep the cream for spares, but I'm still undecided.

I have some HiVi Q1R from the AR5/AR3as which I could use, but I know they're not meant to be a good replacement for the later AR9/10/11 models. 

On 6/5/2021 at 10:27 PM, DavidR said:

I bought a pair of 2nd generation 10Pi a few years back. One tweeter was the original p/n 200011-1 and the other was the AR replacement p/n 1200084-0. The original tweeter went OL on the voice coil so I bought a pair of the Midwest replacements. I have the 1200084-0 sitting on the shelf in a box. I might be convinced to part with it. However, it came with 2 small dings in the dome. PM me if interested and I can post a picture of it. Keep in mind these can not be rebuild (at this time) and it has ferro-fluid.

That could be ideal! I would be interested to see a few photos if possible. How does the 1200084-0 differ from the original tweeters? There were some documents linked on other forum posts about these tweeters but I think with the new website the file has been lost and the link no longer works

[AR11 VS AR3a]

Recently I picked up a pair of AR10 Pi for restoration, but unfortunately one had the wrong tweeter. One came with the original cream tweeter, but the other one was an AR3A tweeter. I'm now searching for a replacement original cream tweeter, which is proving quite difficult. I don't suppose anyone has one for sale? I'm not sure what my choices are other than finding an original replacement 

[AR3a Improved not right]

Coming back to this topic a year later, I've tried a few things to get the 3a Improved's to sound better. I got hold of some HiVi replacement tweeters, but still, even with them, I wasn't happy. I moved house, and put them in a different room in a different layout, that didn't help. I swapped the amp, and bluetooth receiver, even plugged direct in, but nothing was working. 

Eventually my partner gave me the all clear to replace them because even she was fed up with them not being up to snuff, but we didn't want to use her AR7s as the house is still a building site so we didn't want to get them dirty. So I started scouring online trying to find something that would work. Finally a pair of AR5s came online, a nerve wracking ebay auction later and they were mine. 

I finally have the AR sound back that I've been wanting for so long!! They sound amazing, even with the smaller woofer, everything I want is there. They are in mint condition, I've never seen a speaker look so tidy, let alone ones that are 50 years old. I think they're too good for the house, so might have to put them in the boxes occasionally when things get messy. They even came in their original boxes, with original paperwork! I was worried that if it wasn't a 3a then it would be a waste of time, but I don't think they are missing anything the 3a provides. Maybe the lowest of low end but compared to the 3as I have, they are just miles ahead. 

I think it is something to do with the bass driver now. I thought it was the midrange but actually I believe its the woofer of the 3a Improved's, messing with how I'm hearing the crossover into the mid driver. The woofers in the 5s had previously been refoamed by the seller, but with the correct foam supplied from vintage AR on ebay. Comparing how both woofers act, the 3a Improves move much slower back to resting after performing the push test, so I think maybe the surrounds on the 12inch woofers from the 3as are not compliant enough. The surrounds definitely feel different, the 5s feeling a bit tougher and stiffer. Either that, or there is not as much stuffing as there should be. The bass on the 5s is smooth, deep. natural and everything I wanted from an AR speaker. The 3a is just not there. I haven't had them side by side to directly a/b them but having listened to the 5s for a night, I know its definitely the woofer thats not right. 

I think my next step when I can find time, is to get them next to each on the same amp, and take FR curves in the room, and see exactly where they differ. Also I could borrow a DATS speaker measurement system off a friend, so can measure the 12 and 10 inch woofers and see how their T/S specs look. Then maybe trying to refoam them if the tests showed thats the problem, however I had justified the great expense of these 5s to my partner by suggesting I sell the 3as...but I really want to see if I can get them performing again.

[AR3a Improved not right]

Thanks for the quick replies everyone! This forum is great, much more useful than other vintage hifi forums I'm on. Thanks for all the photos, very interesting to see all the different types of mid driver. I'm pleased that my mid drivers are made in the USA, even if they are more suited towards the AR11. Is there any crossover mod I could do to them to bring them more in line with the original driver? or are the differences so minute that they're not worth the effort? Also a good thing that the foam on the woofers seems legit. That black mark is just paint, there is no hole.

23 hours ago, Aadams said:

Have you performed the woofer push test?  Have you downloaded and read the AR3 restoration guide?   You really need to read the woofer seal section of the restoration guide. These speakers are supposed to have level switches not pots.  Are you sure the level switches or pots are working properly?

I thought I had written this in the previous post but it must have deleted...I have read the guides thoroughly, during my last 3a restoration and through working with the improveds. First thing I checked was the acoustic seal with the push test. I checked all over the cabs looking for leaks at any point. They both test fine, I even removed a bolt to see the difference and feel the air getting pushed out the hole, they're definitely sealed. The switches are both working fine. 

14 hours ago, RoyC said:

You won't be able to compare them to the AR-7 or any other model in any meaningful way until you correct the tweeter situation. The level controls cannot compensate for the new crossover point and frequency response changes caused by these tweeters. I assisted another 3a Improved owner regarding replacement tweeter options, and after much experimentation he settled on AR-11 type replacement tweeters (https://www.midwestspeakerrepair.com/shop/home-audio/tweeters/dome/mw-audio-mt-4121-75-inch-dome-tweeter/), and retained the original .1mh coil in the crossover. He did not prefer the HiVi tweeter...and I don't know anyone else who has tried the HiVi in this model. (Of course the best option would be rebuilt original tweeters.) To use any other inductor coil you will need to remove the existing .1mh parallel tweeter coil or place another coil in parallel to achieve a desired value (ie you would place another .1mh coil in parallel for a resulting .05mh value). Just keep in mind any additional coil will interact with the existing one.

Damn thats a blow...those tweeters cost nearly 4 times as much as the HiVis...and nearing what I paid for the speakers in the first place. It also comes close to what a pair of 2axs would cost me. I'm thinking that perhaps it would make more economic sense to pick up another pair of AR speakers that have the original tweeter still working, and then to swap out those with some HiVis. I would then have another pair of ARs for the same price as those midwest tweeters.

14 hours ago, RoyC said:

The 3a Improved is different than the 3a. It was a short-lived transitional model, apparently marketed primarily outside the US about the time the AR-11 was introduced here in the States (note the European AR-3a and the 3a Improved cabinets are the same.) The mid and tweeter crossover circuits are actually significantly different than the original 3a, and the switches do not provide the flexibility of the variable controls of the original 3a. Like the AR-11 it has a more forward midrange character, so you can expect a different outcome compared to your earlier 3a project...regardless of the tweeters you use.

Your replacement mids, woofers, and woofer surrounds all look very good, and will work just fine. If that really is a hole in the woofer surround mounting ring it must be repaired, and can be filled with epoxy putty. It is not, however, likely to be the primary cause of the differences you are hearing compared to the AR-7 or your earlier 3a project. Btw, it is much more likely you are becoming somewhat accustomed to the sound of your beasts rather than "caps breaking in". They are breaking you in. 

Roy

That would perfectly explain why I feel like its lacking low end. I was confusing lack of low end with a more prominent midrange, perhaps a subtle use of the bass tone control would suffice. Since it has an 11 midrange then its more of an 11 than a 3a? The Improved crossover looks like halfway between the 3a and 11 anyway so its a bit of a hybrid? 

I had these for about 6 months as is before I swapped the caps, they definitely sound better! The sound stage has improved dramatically. The also feel more sensitive somehow...records seem a lot louder and more dynamic than before.

On 11/27/2019 at 10:25 PM, JKent said:

I don't know how awful the Marantz tweeter is. Apparently it was selected because it fit in the hole. But relatively little sound comes from the tweets and if you turn down the Hi levels the speakers "should" sound OK--maybe lacking sparkle and air, but not bad. . i find it difficult to describe the sound of speakers but if you could give more of a description than "bad" it might help.

Its hard to describe, they just don't sound as I remember the previous AR3as to sound, but as we have discovered that they aren't really like the 3as so that may be where I'm getting bad from. Theres a lot less deep bass definition that I remembered. Its not like the real low end is lacking, when I play a brand new electronic record that goes down really low and loud, it definitely there and it feels like its rattling the room. But when playing something from their era, disco, funk, soul, 70s 80s pop etc it feels like theres something missing that I remember from the 3as. I have played these records on other sound systems and hifi's so I know its there somewhere. I definitely still prefer the 7s at this moment in time, but that may be due to the tweeters. I agree that I can't make any proper judgment on these until the tweeters are sorted, it seems that they're just throwing everything off balance.

[AR3a Improved not right]

Thanks for the quick responses! Heres some pics of the drivers. Further investigation shows that the mids are the tonegen replacements, which is a bit annoying. They look the part and they sound okay, but I would imagine drivers not made in the US in the 90s couldn't rival the original 70s US made drivers. 

I haven't had time to take them down and check all the impedances of all the drivers, will be able to get round to that during the weekend. When I first got them they sounded very phasey so checked and one cab was completely out of phase with the other, so thats no longer a problem now. When recapping the crossovers nothing looked out of place, the original caps measured in spec too. I left them in there so I could switch back if I want, but the new caps definitely do sound better.

As for placement, one of the reasons my boss raves about them is because he calls them a bookshelf speaker, they need to be placed by walls. I have placed them by walls, but unfortunately the ones behind them aren't real walls, more like a wooden board that hides the eaves of the attic roof. I had wondered about that, but currently theres nowhere else for them to go. I am due to move house soon so can get them in the corner of some real solid brick walls. They are also high up, about 2 feet. Would they benefit from being lower down perhaps? 

Since they were treated badly, then set up out of phase, it makes me wonder if the previous owner had used the correct foam when refoaming the woofer. Is it possible he used a foam that was too stiff or not stiff enough? A good original refurbed pair of AR3as has shown up so I may get them if the price is right, I can then used this dodgy pair in the workshop...I'm just not convinced I will get the original vintage sound I'm looking for with them.

[AR3a Improved not right]

My first experience of Acoustic Research was a few years ago when I started a new job, and my new boss asked me to sort out a pair of AR3a's he picked up for cheap years back. I refoamed the drivers, replaced the lpads and caps, plus new HiVi tweeters. They sounded incredible! So I then set on the task to find myself a pair. I found a pair of AR3a Improveds on ebay and got a hold of them. The drivers had already been refoamed but the tweeters had been replaced with some nasty marantz ones. I wasn't happy with their sound, but figured new caps and new tweeters would solve them sounding flat and dead.

Meanwhile my girlfriend was in need of a new hifi so for her birthday I got her some AR7s and an A&R A60 amp. She absolutely loved them, and so do I. The moment I turned them on I knew that was the AR sound I was after, but also noticed the sounded miles and miles better than my AR3as...which concerned me, but I forgot about it. Then every time I went to her house and listened to a record I was just blown away by how great they sounded, and I knew that my AR3as should sound even better, as when I fixed my bosses pair both her and I were blown away by them. They sound so bad comparatively that I've been starting to look at finding another pair of AR3as...

But I know before I start spending more cash I need to figure out whats wrong with these guys. I had initially wanted to wait until I got hold of some tweeters before I recapped them. My boss was going to the US for christmas so was going to hang on until he could get some cheap from parts express, as over in the UK to find those tweeters was nearly 3 times the price of getting them in the US. But this weekend I had enough and decided to recap them. 

Straight away they did sound better, I sat my girlfriend in front of them and the moment I played a record she turned to ask me what had I changed. The more we play them the better they sound, must be the caps breaking in, but we are both in agreement that they still aren't as good as her AR7s. I can't see how that attributes to the tweeters. I know the high end will be improved once the correct tweeter is in there but surely the mids and bass should sound like proper AR3as? The seller said the mid domes were replaced about 15 years ago, correct from AR, and I checked the part number and appearance and they are the same as the originals in all aspects. Also I'm thinking that perhaps the foam he used wasn't correct, I can't put my finger on it but they definitely do not sound right. 

I know mine are the improved, and so they have a different crossover. But surely that cant amount that much to how much worse than the AR7s they are. I want to get the Hivi tweeter in there, but since the improved crossover is different, how would that affect what I have to change for the tweeter? I know for standard AR3as the recommended changes are changing the capacitance to 3uf and adding a 0.07mh inductor, but would they be the correct measures to take for the Improved considering the crossover is different? Should I just remove the 0.1mh inductor thats in there? When I recapped it I ordered 2x3uf instead of 1x6uf so I've only put 1x3uf cap in there waiting for the new tweeters.

 

I really don't want to have to get another pair, but right now I'm looking at anything AR...AR2AX are easy to find here, a lot cheaper than what AR3as go for too, but I feel like I really need to get these right first.