Question from a novice about a pair of AR18b

[Epic2112]

Edit: now on ebay, see post #7 for details...

Hi all, I'm not an expert, so please forgive me if my questions are basic ones.

I just pulled a pair of AR18b speakers out of an old storage space. When I plug them in the highs sound great, but the lows are basically completely missing. If I put my ear up to them, the drivers are definitely producing sound, it's just missing all the lows. Both of the speakers sound the same. I'd love to keep these for myself if they can be repaired relatively inexpensively and easily. The cabinets are a bit rough. Not trashed, but they have their fair share of nicks and scrapes. The grills (or whatever you would call the fabric that covers the front of the speakers) has a snag here and there, but if I pull them off the speaker cones and foam and everything look basically brand new.

Am I correct that short of the foam disintegrating there isn't much to go wrong in these speakers other than the capacitors inside them? Does this symptom sound like it might be caused by bad capacitors? If that's the problem, is it as simple to fix as replacing the caps? Can I use something like these or like these? I'm competent with a soldering iron.

If the fix is more complicated or more expensive, are these worth anything to anyone? I'm the type of person that would rather see something get some use than just put it on the curb and forget about it.

Thanks for the help everyone!

[michiganpat]

lack of bass won't be due to bad caps--in these speakers, the woofer runs full range, and the tweeter has a 1st order high pass filter (single cap). Lack of bass would be due to lack of a sealed cabinet, most likely (if they are the original surrounds) due to compromised foam surrounds.

you could use those caps, I guess...don't seem like the best value for what they are. the older S and non letter 18's had a 6uf cap, with essentially the same drivers, so either would work. I wouldn't put 32 year old caps in anything but the garbage (the 5 pcs you linked to). look at the pic, even though they were never used, they're toast--the ends are puffed out.

I've had good luck with erse NP electrolytics, Solens, and Erse PulseX film caps. I'd go with a nice film cap, they're not too expensive.

I've had good service from Meniscus Audio, they're local to me. film caps have a near infinite service life, unlike electrolytic.

http://meniscusaudio.com/capacitors-erse-electrolytic-c-101_105.html

http://meniscusaudio.com/capacitors-pulsex-polypropylene-c-101_104.html

http://meniscusaudio.com/capacitors-solen-polypropylene-c-101_102.html?page=2&sort=3a

may want to pick up some gasket tape to ensure a good seal between the tweet and cabinet, and the woofer and cabinet

http://meniscusaudio.com/gasket-tape-100ft-p-844.html

(they also sell it by the foot for 12cents/ft)

the surrounds to get are the Boston Acoustics "Filled Fillet" surrounds, they're large roll, and very compliant, what these speakers need to not lose bass response.

might want to call them and see if they have or can get the specific surrounds I mentioned. I know they can get a lot more than what they have listed on their website, I've bought specific (and odd sized surrounds) for some realistic mach1 model 4029 and Smaller Advent surrounds from them....otherwise, tell them you need the most compliant angle attatch surround they have. use aileen's tacky glue and a 30hz test tone to refoam.

this may be their best option if they can't get it

http://meniscusaudio.com/8-foam-p-1236.html

these are a pretty high Q design (the box is undersized for the woofer), and you may be able to improve low bass response somewhat by replacing the polyfill in them with a heavy stuffing of fiberglass insulation. I'm thinking unfaced, 16" wide R13 (for 2x4 walls), a piece about 16-18" long and folded over should do it.

it's something I want to try with my non-letter 18's sometime.

[Epic2112]

Thanks for the response. Is there a chance that the speaker foam is the culprit even if it looks and feels good and pliable? The only speakers I've seen where the foam is deteriorating have been ones where the foam is so bad that it will fall apart if you look at it funny. I poked the foam on these a bit and it's still soft, and there's no evidence I can see of crumbling. I also took a look at the existing gaskets under the woofers, tweeters, and the place where the wires attach. All look and feel good. So, is there somewhere else that might need to be sealed? Or is it possible that the foam on the woofers is bad even though it looks and feels good?

Here's a pic of one of the speakers, just in case something jumps out at you that I've missed:

Thanks again!

[Robert_S]

just in case something jumps out at you that I've missed:

What leaps out is that the woofer does not look like the correct part. The lack of tinsel leads on the front, and the general appearance of the cone, serve as clues to this notion.

See, for example, the following topic:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=870

Further related/informative discussion:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=4332&st=0

These images show what would typically be expected in an AR-18B, woofer wise (pre-refoam!):

Robert_S

[Epic2112]

And right you are. I just pulled out one of the woofers and it's some crap radio shack speaker. However, I'm not sure that explains the complete lack of bass, since they seem to look like they are in fine shape. The label says that they are 50W (max 100W) 8Ω speakers. While I would expect the cheapos not to sound anything like the original AR18B woofers, what would explain the lack of bass? Before I start to look for replacement woofers (or before I decide to sell these), I'd like to know if everything else is in order with them. Is there any way to test?

[michiganpat]

And right you are. I just pulled out one of the woofers and it's some crap radio shack speaker. However, I'm not sure that explains the complete lack of bass, since they seem to look like they are in fine shape. The label says that they are 50W (max 100W) 8Ω speakers. While I would expect the cheapos not to sound anything like the original AR18B woofers, what would explain the lack of bass? Before I start to look for replacement woofers (or before I decide to sell these), I'd like to know if everything else is in order with them. Is there any way to test?

with the woofers installed, if you push on the cone and hold for a 5 count, then let go, they should return slowly if there is a good seal in the box. if they spring back instantly, there are are leaks, which will affect bass

and AR 8" woofers have a very low resonant frequency (somewhere around 30hz), and IIRC somewhat moderate Q & lowish Vas. replacing the woofers with a driver that has a much higher Fs and higher Q and different Vas could cause the bottom octave+ to be missing, or a big hump in the midbass and nothing below. the original AR8" woofers are also very well behaved with a nice natural roll-off, eliminating the need for any electrical filters. I highly doubt the replacement woofer is that good.

I'd look for some original AR 8" woofers. you can usually find them reasonably priced on fleabay....

[Epic2112]

Thanks for all the help everyone. As much as I was hoping to keep these, I dug them up in an effort to clean out my storage space, and I think that still needs to take priority. I've decided to list these on ebay (without the crap woofers), so that someone with the time and the parts can restore them to their proper condition. If anyone is interested, the auction can be found here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110776442188

Thanks again for all the help!

[michiganpat]

Thanks for all the help everyone. As much as I was hoping to keep these, I dug them up in an effort to clean out my storage space, and I think that still needs to take priority. I've decided to list these on ebay (without the crap woofers), so that someone with the time and the parts can restore them to their proper condition. If anyone is interested, the auction can be found here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110776442188

Thanks again for all the help!

if it were me, I'd pick up these woofers and throw in there

http://www.ebay.com/itm/Acoustic-Research-AR-TSW-8-ohm-woofers-NOS-Qty-2-/280615180459?pt=Speakers_Subwoofers&hash=item4155f7d8ab

the 210TSW these came from list a 5khz crossover point, and this had a .31mh iron core inductor in series with the woof...I'd probably toss a .6-.7mh iron core inductor in series with this woofer in the 18B's

[Epic2112]

I thought long and hard about it, actually. In the end, I need to clear out some storage space and maybe make a few bucks in the process. Hopefully the stuff I put on ebay will go to someone who will restore them and enjoy them.