Comparison of sound - AR3 phenolic mid vs. AR3a mid in AR3

[Chris1this1]

I ask if anyone has compared the sound of the AR3a mid, used in an AR3 application using the last AR3 crossover iteration when the AR3 was sold using the AR3a mid. 

I have a spare pair of AR3a’s, as well as my main pair, both original with ceramic woofers and 3/4” tweeters.

 I have a loose pair of alnico woofers, and phenolic tweeters. I am contemplating converting the spare pair from AR3a to AR3, while still using the AR3a mid. This is merely an experiment since I have most of the parts at my disposal, no complaints on the AR3a sound, just want to do a comparison since I have never owned AR3’s, just worked on them for clients.

 

I mainly would like to get opinions on justifying the effort without having the proper AR3 mid, but having everything else.

 

[GD70]

Hi Chris!

Based on this thread, you would need to mod the crossover since the two didn't share the same parts according to Roy.

Cheers, Glenn

 

[Chris1this1]

Thanks Glenn, that would be the plan should I go forward with this. I am reluctant since although with the crossover mods, I am still locked into using an AR3a mid. Wondering how close it would sound with the mods to an actual AR3 mid. 

[lakecat]

Hi Chris....I actually did this to a pair of 3's as the mids were shot and had an extra pair of 3a mids. I did what Roy said to do. They sounded okay...but seemed not up to par. I eventually found a pair of 3 mids...changed everything back...and got the sound back I liked.

I am certainly no sound expert but just an opinion. Maybe I didn't have something correct?...dunno. I would curious to see what you thought if you do this. No big deal to change it. 

[RoyC]

On 12/3/2019 at 11:40 AM, Chris1this1 said:

I ask if anyone has compared the sound of the AR3a mid, used in an AR3 application using the last AR3 crossover iteration when the AR3 was sold using the AR3a mid. 

I have a spare pair of AR3a’s, as well as my main pair, both original with ceramic woofers and 3/4” tweeters.

 I have a loose pair of alnico woofers, and phenolic tweeters. I am contemplating converting the spare pair from AR3a to AR3, while still using the AR3a mid. This is merely an experiment since I have most of the parts at my disposal, no complaints on the AR3a sound, just want to do a comparison since I have never owned AR3’s, just worked on them for clients.

 

I mainly would like to get opinions on justifying the effort without having the proper AR3 mid, but having everything else.

 

Hey Chris,

I'm not sure it is worth the conversion effort without a properly functioning pair of original type AR-3 mids with which to compare. Using the 3a mid with the appropriate crossover modification (addition of a .4mh parallel coil, and removal of the .06mh series coil found in some iterations of the 3), can result in a significant improvement over a typical pair of AR-3's with degraded original mid drivers, but although the outcome sounds quite satisfactory in terms of being in AR-3 territory, it is not exactly the same as a pair of 3's with properly functioning original mids.

AR adapted the later 3a type mid to the AR-3 in the same way as we have implemented the more modern HiVi tweeter in early AR models; using a parallel coil to bring it into the overall sonic ballpark of the original. As you well know, however, using a rebuilt original tweeter allows the use of the original simple crossover, which results in somewhat different sonic characteristics and system interactions. While both tweeters are quite satisfactory for most people, there are some sonic differences which may be of consequence in a discussion of this nature. I believe it is the same for the AR-3a mid as used in the AR-3.

Roy

[lARrybody]

Today I picked up a pair of AR3 speakers, serial numbers C35565 and C35411. They look pretty much original except the mids are A.13 type from some MkI AR11 or 10pi speakers. I don't know yet if any crossover mods have been done. I have a pair of nice A.11 front wired mids (the type without the center dot)  from some 1969 AR3a speakers. I know Roy does suspension work on AR3 tweeters and midranges, but does anyone work on the AR3a midrange suspensions which have probably degraded by now? 

[RoyC]

13 minutes ago, lARrybody said:

Today I picked up a pair of AR3 speakers, serial numbers C35565 and C35411. They look pretty much original except the mids are A.13 type from some MkI AR11 or 10pi speakers. I don't know yet if any crossover mods have been done. I have a pair of nice A.11 front wired mids (the type without the center dot)  from some 1969 AR3a speakers. I know Roy does suspension work on AR3 tweeters and midranges, but does anyone work on the AR3a midrange suspensions which have probably degraded by now? 

Larry,

The AR-3a/AR-11 mids' cloth dome suspension is a cloth roll, like a modern tweeter, and does not degrade or require maintenance. Other than front vs back-wiring there is not much difference between your mids. They will all work well with the crossover change mentioned above.

Roy

[Dchristie]

Hi Chris,  now that you actually have a working original phenolic 3 dome midrange, it would be great if you could compare it with the 3a midrange dome  for sonic comparisons. I have been very impressed with the cloth 1.5 dome and actually have it in my pair of 3s ( with the crossover mod) since I have not had the luck of finding an original, properly working phenolic mid. Would be great to get your impressions of the 2 different midranges and how they do or do not  affect the final sound of a 3 speaker. If no negative difference is detected , then using a more durable, modified,  3a cloth mid in a 3 speaker might be a good thing in the long run IMO .

Thanks

Dean 

[Chris1this1]

16 hours ago, Dchristie said:

Hi Chris,  now that you actually have a working original phenolic 3 dome midrange, it would be great if you could compare it with the 3a midrange dome  for sonic comparisons. I have been very impressed with the cloth 1.5 dome and actually have it in my pair of 3s ( with the crossover mod) since I have not had the luck of finding an original, properly working phenolic mid. Would be great to get your impressions of the 2 different midranges and how they do or do not  affect the final sound of a 3 speaker. If no negative difference is detected , then using a more durable, modified,  3a cloth mid in a 3 speaker might be a good thing in the long run IMO .

Thanks

Dean 

Dean, 

I never went through with the conversion as I originally inquired about above, so I don’t have the two like speaker systems to compare. I currently have this new to me pair of AR3’s and a minty pair of late production AR3a’s, in the original configuration with rebuilt tweeters.

I sold the second pair of AR3a’s I was planning on converting. Unfortunately I won’t be able to shed any light on the subject of midrange drivers when used in the AR3 application. 

Chris 

[Dchristie]

Thanks Chris. Any chance you would be willing to  just remove one of the mids from your AR 3a  speaker and replace it for one of the phenolic mids in one of the new AR3 speakers ( with the correct xover mod of course) and then you could compare  a single AR3 with the modified cloth dome to your other AR 3 speaker with the original phenolic dome mid. Although you would only be comparing essentially mono AR 3 speakers with different mids, it would most likely give you some idea what the AR3 speaker with the cloth dome sounds like in comparison to the AR 3 speaker with the phenolic dome mid . 

Just an idea.

Dean

[Chris1this1]

4 hours ago, Dchristie said:

Thanks Chris. Any chance you would be willing to  just remove one of the mids from your AR 3a  speaker and replace it for one of the phenolic mids in one of the new AR3 speakers ( with the correct xover mod of course) and then you could compare  a single AR3 with the modified cloth dome to your other AR 3 speaker with the original phenolic dome mid. Although you would only be comparing essentially mono AR 3 speakers with different mids, it would most likely give you some idea what the AR3 speaker with the cloth dome sounds like in comparison to the AR 3 speaker with the phenolic dome mid . 

Just an idea.

Dean

Dean, 

if for some reason in the future I would be required to remove a mid from the AR3’s, I’d conduct this experiment. At this point, I’d rather not disturb them. 

[Cropper]

Hi all,

 

Have a question on the above discussion - could anyone with experience of both explain what the audible difference between using the AR3a mid (with the final crossover from the schematic) is compared to the AR3 mid with one of the earlier crossovers is?

 

Long story short I got hold of a pair of AR3s that had been factory modified to AR3a back in the 70s and due to the state they were in when I got to them I decided it would be best to get them back to AR3 for a number of reasons. The one drawback of doing this (or the main one I guess) is that it's very challenging to get AR3 Mids and the one piece of these speakers that didn't needed replacing was the AR3a mid that they came with.

 

Once someone pointed out that AR themselves actually used AR3a mids in AR3s at the end of production with a different crossover I assumed that they wouldn't have rolled them out and sold them to people if they sounded noticeably different to earlier iterations, particularly if it was worse, so went with this option. Seems dangerous reputationally. But obviously read the above conversation and now am worried that a) they won't sound right once I finish them in a week or two and b) resale value will be much lower.

 

I planned to sell these on one day as just a standard refurbed pair of AR3s (they have alinco woofers, AR3 tweeters and a pair of mids that were used by AR in AR3s, and I've got a decent crossover in there made up of jantzen coils, Mundorf Mcap EVOs and Jantzen Silver Z-caps) that in all honesty in my opinion I was hoping someone would recognize that they should sound better than a lot of stuff that is being sold as 'original' on Epay for $2000-$4000.

 

Now I deliberately built the crossover using two 15uf caps for the 30uf, so I could remove a 15uf and replace with 9uf and remove a coil if a pair of AR3 mids miraculously turn up for a reasonable price (unlikely I think) to get to the original AR3 24uf crossover, but I ask this question partly because in the future, the way I am having to do this may be one of the only ways to re-build a pair of AR3s and I'm still kind of blown away that they may sound inferior or at least not true to the original AR3 sound. Perhaps I misread and AR3 considered the last iteration of the AR3 an improvement and those who are used to the older ones will just notice it's different, but wanted to check.

 

Any thoughts much appreciated, I want to do right by these AR3s!

[Dchristie]

Hi Cropper, as Roy has pointed out in other discussions , a late model AR 3 with the factory approved later cloth midrange and the appropriate crossover mod is still an AR 3 speaker but it may not sound identical the the AR 3 speaker with the phenolic tweeter. However, this is always subjective but it stands to reason that the changes could be audible to some listeners. Personally, my AR 3 speakers with the cloth mid sound very good to me but I have not directly compared them to the earlier model with the phenolic tweeter. But, they are still an AR 3 sold as an AR 3 by AR so I am not as worried about the cloth mid so much. Probably the bigger issue with reselling AR vintage speakers is whether for not they are original as replacing crossovers, refinishing cabinets , and so forth often are issues with buyers who want everything to be original. Once again, I restore my speakers with new crossover components, cabinet restorations and other changes to meet my approval and not necessarily to keep them original. I do not believe that the later cloth mid necessarily made the late production AR 3 inferior to the original as this would once again be subjective  to the listener but certainly AR was not concerned as the evolution of the AR 3 to the AR3a was never considered a step back . My AR 3s do sound different compared to my AR 3a speakers but I enjoy both. I am sure you will also like the sound of your restored AR3s. 

Sometimes we get concerned about issues which seem to be really important to the final sound but in reality, contribute less to the final sound than a lot of things that we have no control over since the adhesives, compliance, and other physical characteristics of these decade old drivers have changed since they were new. However, it is amazing that they still work and also still provide a lot of satisfaction to those of us that like to fool around with them.

I am sure others have their own opinions and may chime in as well, but I try to not take this hobby too seriously and just enjoy the whole vintage audio experience.

Just my 2 cents worth!

[Dchristie]

Just reread my response above and realized that I referred  to the AR 3 with "the phenolic tweeter " a couple of times which is obvious since I think that all of the AR 3 versions may have had the phenolic tweeter in common. What I meant to say was phenolic midrange  since this was the topic of concern. Probably most folks understood the intent but I wanted to clarify just in case.

[Cropper]

Thanks dchristie, that’s very helpful and makes a lot of sense.

When you consider everything else that can vary with these speakers at this point I guess it’s hard to even imagine there being a specific sound, and is of course all subjective either way.

Yeah interesting on the collecting ‘original’ speakers part - I’m assuming they have someone the trust to work on them otherwise they’ve just bought a pair of speakers with worn cabinets and out of spec (or soon to be out of spec) drivers, pots and caps. Either way, these particular speakers had to be worked on extensively and will hopefully sound good for a long time yet afterwards.

I shall continue as I am, thanks again!