OT - any audio speaker experts here?

I have a set of maybe 25 year old Fisher speakers that I was thinking would be nice for the shop. Not been used in a long time and have been in a dry basement. Hooked them up and the sound is muffled. Decided to look inside. Speakers look fine. There are a couple electrical components wired in-line between the three speakers in each box. I took pictures. I believe the greenish ones are capacitors. Not sure about the small rectangular ones. Was wondering if anyone knew what might have gone wrong with these? Can bad caps cause muffled or muted sound? What are the rectangular things? I recapped the selection receiver on a 1953 Seeburg many years ago (a kit with great instructions) so I know enough to be dangerous.

The rectangular things are resistors, looks like 2.2 ohm, from your photo. The green things are indeed capacitors.
Are there three powered drivers? (Woofer, midrange and tweeter?) The tweeter is the thing in your top photo.
If you can find a model number, I bet you can find a wiring diagram, specs for replacement capacitors and resistors, etc.
A few years ago, I rebuilt the crossovers in a set of Polk Audio speakers that I have owned since 1982. There is a very active community of vintage Polk owners, and I'm sure there are boards for Fisher speakers, too.

And Dave, I forgot to mention one thing: you can disappear down the rabbit hole on rebuilding old speakers, just like you can with old tractors, so: Beware! :wink:

The square device is a resistor and the round device is a capacitor. I would guess the woofers are both open or the voice coils are both seized which is the normal failure mode of most low tier speaker systems. You can check all the components except for the capacitor for continuity with the resistance scale on a VOM and learn a lot. Looks like the resistor is 2.2 ohms and the raw speakers themselves should probably check somewhere in the 4-6 ohm range. You should also hear a "pop" thru each speaker when you check for resistance. PartsExpress.com is a good place to buy replacement parts.

Yes, has woofer, mid range and tweeter. I found the model number, ST-888. Haven't found a schematic yet but still looking.

Those Polk speakers were THE thing to have at one time. The resistors should
make no difference but the caps are what allow different frequency to pass. I
don't see a cross over network so these are all that control the sound. First
thing would to unplug each speaker and hook a little sound to it and see what
you get. A transistor radio is enough. Might be jammed voice coils. If that be
it then new speakers time.

What typically fails in these speakers is the foam surrounds that suspend the speaker cones turn to dust and the cone no longer moves as much air when it moves in and out. Look at the front of the individual speakers and confirm that the foam rings are intact at the edges. If they are gone, and I suspect they are, the only solution is to replace the drivers or have them reconed. There is a place in Fort Wayne, IN called Speaker Workshop that I have had recone speakers for me in the past, they do good work.

Brian

Have the units been exposed to high humidity? If so, look for corrosion on contacts resulting from the humidity. Also, check the cones for warpage and/or age induced deterioration. You may wish to simply replace the electrolytic capacitors rather than trying to determine if they need replacement.

A couple of years ago, I gave a killer stereo system to my nephew for complete restoration. The SX-1980 Pioneer receiver was in almost perfect condition, not even needing to be recapped, but both the AR 3a and Dyne Audio speakers needed lots of work due to humidity even though all had been professionally resuspended about five years previously.

He and my brother, both Purdue EEs, spent many hours working on the system restoring it. Most of the time was spent on the speakers. They were able to find all needed information on the net.

Dean

This is the company that resuspended the AR-3a and Dyne Audio speakers that I gave to my nephew. One of the Dyne Audio tweeters had a burnt out voice coil which they also replaced.

They are in Michigan and I would recommend them to anyone.

Dean
Meniscusaudio

Forgive if someone else has said this (am actually busy today ), but sounds to me like the problem isn't with the components, but with the speaker material. There's a thin fabric in speakers. It's the part you see when you look at the front of a raw (non-enclosed) speaker. Over time, that material will dry out and become brittle. Heat, UV light, even ozone can destroy that fabric over time.

If I may make a suggestion, I just recently bought a couple of new speakers. They were quite inexpensive, they're waterproof, small, bluetooth compatible, or can connect a 1/8" jack. I bought two. You can pair them together via bluetooth, then one plays left sound and the other plays right sound. I also have an mp3 player that has 2 wired outlets. I can run a wire to each speaker, then each speaker plays both right and left sound.

Been a long time since I've had a stereo system set up. So to me, these sound absolutely incredible!!
https://www.amazon.com/gp/product/B07VV2B4JD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Here's the mp3 player. It's only 8GB. There is a more expensive model, but both of them accept up to 128GB micro SD card, so I went with the smaller unit. All metal, very strong and durable. Music sounds great!
https://www.amazon.com/gp/product/B07QCX7V7R/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

I am pretty convinced of what I need to do here. If it were for sure just a matter of replacing a few caps...I would give it a try. But since they have been in the basement for most of 30 years and there may be damage to the actual speakers and I probably paid about $300 for the set brand new...

I think these need to go.

Burnt a small set of early 80?s fishers in a bonfire a few years back. Woofer cones fell apart. Can get cheap speakers on Craigslist / kijiji, hard to get excited about repairing old ones.

As others are getting at, the caps and resistors are just for filtering to cut highs from the woofer and powerful low frequency from the tweeters.

If they have foam surround they are probably dead. Once the foam and or the "spider" (centering the small end of the cone) distort then it's game over and they start buzzing or rubbing.

Have you tried them on any other sound source to make sure it's not an amp problem? You can also electrically separate and test each component (low volume or leave the cap on for the tweeter!) and see if any of the individual drivers are good.

Check out PartsExpress.com for replacement components; good to deal with. Eminence manufactures and also sells drivers. Mostly pro stuff but many suitable options for home equipment.

I personally just use speakers with cloth or paper surround as it will outlast foam.

(quoted from post at 15:27:07 01/22/20) Burnt a small set of early 80?s fishers in a bonfire a few years back. Woofer cones fell apart. Can get cheap speakers on Craigslist / kijiji, hard to get excited about repairing old ones.

Click to expand...

Yeah, I bought a pair of very nice wood-cabinet speakers while in USAF, in the mid-80's. Hooked them to a Sony receiver and dual cassette deck. Haven't used any of it in 20 years. Not even sure where the cassette deck is, as the wife used the original box for something else.

Can't help but wonder what condition my prized speakers will be in if I can ever find them again. On the other hand, they weren't waterproof OR portable. My new ones can be used in the shop, outdoors, in the truck, with the computer, or with any TV. ...And of course, with the mp3 player. Not sure this old body could lift the old speakers nowdays anyhow. :?

The caps drying out is what kills the old Heathkit stereos.