AR-91 woofers specs

[Andre]

Hello all,

Just got a pair of AR-91 last weekend in excellent conditions. As usual, woofers will need a re-foam, beside that, they are almost mint.

Before pulling the woofers out, I did tried them, at a very low volume, and all drivers had sound coming from them.

I've two meters, and with one, I read 2.5 ohms on both while with the other one, I read 2.75 ohms, again on both drivers.

Now my question is this, are these woofers, # 200003-1 (square magnet) rated at 4 ohms ( ? ) still in specs, since I was expecting more in the vicinity of 3.1 to around 3.4 ohms , or are these reading well within the expected value.

Thanks for your help

André

[RoyC]

Your dcr readings are where they should be for this woofer. Readings over 3 ohms are typical of those with replacement voice coils.

Roy

[JKent]

Nice find Andre!

I have a pair of these terrific speakers. Here are a couple of threads on the restoration:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6565

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6546

I'd recommend replacing the PVC (black & red) caps. If you have the 100uF can cap it is probably still good but the PVC caps are prone to leakage.

Good luck!

-Kent

[Andre]

Good Morning Roy & Kent, thanks you so much for the reply, and clarification on these woofers reading.

Kent, I've read your threads on refurbishing your 91. Nice job, and I hope you're still happy with those AR. They look very nice.

A bit about me, and how I came to like AR's speakers.

In 1976 I was transferred in Lahr Germany with the Army. The only thing to do for past time, for me anyway, while in Germany, was skiing, hockey, camping, and my favourite, buying audio equipment. When I came back to Canada, beside turntable, amp, tuner, etc... I had three pairs of AR speakers. AR-18 was my first pair acquired in 1977, AR-10pi also in 1977, and finally, AR-91 in 1979. To make a long story short, Over the years my AR-10pi were sort of destroyed by my kids when having their party, and as for the 91, I gave them away in the early 90s, which I regretted not long after. For the past 15 years or so, when I finally got in audio (stereo) again, I've been looking for a pair.

A few info, the 91 was produced from 1979 to 1982, although lots of them where still being sold in the mid 80s. In 1981 when posted back to Gagetown (Army base) in New Brunswick Canada, I saw AR-91 at an audio shop being sold for 1400.00$ CAD, quite a bit more than what I paid in 1979 in Germany.

Anyway, back for a few more questions if you guys don't mind.

The drivers are 12", basket size on the round side, or if you want, 11⅜" measured from the flat side. The measurement for the suspension is 10⅜" with a lip of, 1¼"

Now having said that, you will notice on the photo that there is a ¼" glued cork lip around the metal basket. This is where the suspension attache, is glued.

Kent, I noticed that prior fixing your woofers, the suspension was sort of folded over the cork lip attachment, and glued on the metal rim pass the lip.

How are your new suspensions now attached, are they exactly glued on the cork lip, or folded over the lip, and glued on the basket frame.

I understand by reading lots of threads, that the correct suspension is hard to get at time.

I've contacted Larry at "vintage_ar" and he has just responded. He says he has the proper suspension for these woofers. It will be my first time buying from Larry, although over the years, I've recommended him to a few friends, and other people on AK to get in touch with this person. So far, they all seem to be very satisfied with his product.

I've some pictures showing what I mean exactly about my rambling. Also, what do you think about the cross-over, and which capacitors should I really be concerned.

More questions , Some people will prefer polypropylene while some the electrolytic type capacitors, what do you people suggest.

I've re-foamed some drivers before, notably, four 12" Cerwin Vega type for a friend of mine, with moderately good results. Luckily, I've lots of speakers that need to be re-foamed, so I'll practiced on three or four pair before attempting the 91. I've two pair of PSB 40r that will need new foam, a few Realistics, and if everything turn out good, I'll then do my AR-18.

I can't afford to mess-up on the 91.

Thanks

André

[RoyC]

Andre,

I do some work for Larry. His foam for this woofer is the proper replacement. It fits as it should on the masonite (not cork) mounting ring. Another surround being sold for this woofer has a larger outer lip and will extend past the masonite. Under no circumstances, however, should the foam be glued to the metal basket when the masonite ring is present. Later versions of the woofer had a protruding metal mounting ring stamped into the basket instead of the masonite ring.

Roy

[Andre]

Thanks Roy,

Yes, after scraping the old foam, I realized this is in fact as you mentioned, a masonite ring, not cork.

I was a bit concerned about seeing other drivers on AK, the same as the one on the AR-91, suspensions being glued on the outer metal ring as you pointed out. This is why I mentioned this. Thanks for the clarification.

As I mentioned on the other post, I have sent people to his site, including a few from France members from an audio club that I belong to, and they where very satisfied with his product.

Later on tonight I will strip a woofer from the PSB 40r, and take a few photos of the suspension with some measurements. Larry said he might be able to supply suspensions kits that will fit the same.

Since you are doing work for Larry at time, I like to pick your brain/knowledge, if you don't mind. I intend to use shims when changing the suspension on the AR-91.

My question is, is it better to first glue the suspension to the masonite, and then to the cone, or the other way around, cone first, and then to the outer masonite ring.

Thanks

André

[RoyC]

My question is, is it better to first glue the suspension to the masonite, and then to the cone, or the other way around, cone first, and then to the outer masonite ring.

Thanks

André

Always glue to the cone first. Larry's kit will include instructions and shims.

Roy

[DavidR]

On 1/20/2015 at 1:26 AM, Andre said:

Hello all,

Just got a pair of AR-91 last weekend in excellent conditions. As usual, woofers will need a re-foam, beside that, they are almost mint.

Before pulling the woofers out, I did tried them, at a very low volume, and all drivers had sound coming from them.

I've two meters, and with one, I read 2.5 ohms on both while with the other one, I read 2.75 ohms, again on both drivers.

Now my question is this, are these woofers, # 200003-1 (square magnet) rated at 4 ohms ( ? ) still in specs, since I was expecting more in the vicinity of 3.1 to around 3.4 ohms , or are these reading well within the expected value.

Thanks for your help

André

I have a pair of 91s with the woofers (round magnet) out of the cabinet so I can re-foam  them and I just put my Fluke on them. Both were bouncing between 2.5 and 2.7 ohms. (I was just using touch-probes and not the grabs)

All of the caps were within spec so I'm going to listen to them first with the original caps and then replace them with some Dayton polypropylene caps I bought. All of the new polypro caps are VERY close to their stated values.

Good Luck with your restoration.

[Andre]

Thanks Roy, I'll follow your instruction.

David, I had read that the 91 also came with the round magnet woofers. If I remember correctly, my first pair of AR-91, bought in Germany early 1979, had very low serial number, below 100.

But those were never opened, so I don't know if they had the round or the square magnets.

The one I just got, the serial number are, M 009919, and M 009921 . What are your serial number?

I will do the same, listen to them for a while, and then, update a few caps, and see if it makes any difference, which it should, since these speakers could be as old as 35 years.

Thanks

André

[DavidR]

M002115 and M002125

[Andre]

I guess up to a certain number, AR-91 had the same round magnets as the AR-11, and mid way ( ? ) in the production, they switched to a square magnet.

Any difference, I would not thinks so.

AR had so many types of drivers, even in the same production run.

André

[Andre]

Hi David,

Just noticed you added pics of your 91. They are in excellent condition, very nice.

I noticed some differences between yours and mine. The red dots, I presume, are inspection decals. My wife says that I had the same red dots on the one we first bought in Germany in 1979. She appears to have a better memory than mine.

The woofers cones are not the same colours, also, the suspension appears to be different, what's left of it on both sets.

There is also the cross-over, as you mentioned earlier on, they are different, and the round magnets versus the square one.

As soon as Larry sends me the kits, I'll start the restoration. Still debating if I should re-cap now, or wait a while.

André

[JKent]

Still debating if I should re-cap now, or wait a while

The PVC caps are notoriously leakage-prone. Your xo has 2. At the least, I'd replace those.

Just my 2 cents....

-Kent

[DavidR]

Hi David,

Just noticed you added pics of your 91. They are in excellent condition, very nice.

I noticed some differences between yours and mine. The red dots, I presume, are inspection decals. My wife says that I had the same red dots on the one we first bought in Germany in 1979. She appears to have a better memory than mine.

The woofers cones are not the same colours, also, the suspension appears to be different, what's left of it on both sets.

There is also the cross-over, as you mentioned earlier on, they are different, and the round magnets versus the square one.

As soon as Larry sends me the kits, I'll start the restoration. Still debating if I should re-cap now, or wait a while.

André

Yes, the red dots are inspection decals. Number 5 inspected mine. LOL.

Mine are in good condition. The screen fabric has a few pulls and one has a tiny hole on a corner. I'll make due.

[Andre]

The PVC caps are notoriously leakage-prone. Your xo has 2. At the least, I'd replace those.

Just my 2 cents....

-Kent

Hi Kent,

I decided to follow your advice, and replace, not only the Callins NPE wih black PVC casing, but all of them. Might as well since the whole speaker is apart, do it all now just to make sure.

Thanks for your advice.

André