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Vintage speaker repair questions

post #1 of 4
12/2/09 at 4:10pm
Thread Starter 
Yesterday I got hold of Realistic Nova-4 speakers in my local goodwill for a glorious 10$. The cabinets seem to be in good shape, I dont see any major issues other than fading color on the wood and the odd scratch here and there. Opened it up only to find the foam surrounds completely missing on one of the speakers, and torn up pretty badly on the other.

I did a very brief test to see if the drivers were still functioning by connecting it to my amp and they seem to be working fine. Infact the one with the torn foam produced surprisingly deep and clear bass. The tweeters seem to be in good shape, except a minor tiny dent on one of them, but this doesnt seem to affect sound.

I removed the woofers from the housing and connected the speakers to test the tweeters and ran some frequency sweeps and the tweeters and crossover seem to be working fine.

The woofers other than the missing foams, seem to be in good shape, the cones look good, no dents or tears, dont look like they are deteriorating, and the spider looks ok as well and doesnt seem to be sagging or anything. So I have used some dust blower to clear dust off the surface and I've set it aside.

Here comes the dilemma. Should I even bother refoaming these woofers or should I just get new 8 inch drivers? I have never done refoaming before, but it doesnt look that hard and I dont think I'll have much to lose other than some time and 20 odd dollars. But is it even worth it is the question.

OTOH, new drivers bring so many other questions. How do I select drivers? Is there some science behind this or should I just go ahead and pick any 8 inch woofer from Parts Express? Can anyone give me some recommendations?

I would love to find more info on the Realistic Nova 4's as well, all I can find now are some pages on AudioKarma about refoaming and such but not much detailed info on the models.

I also need some nice wood polish and repair kit to restore the wood. Pledge can only do so much, while it definitely looks better now than when I brought them in, I am sure theres some stronger stuff out there which can restore this

Then I want advice on bracing, and filling. Should I consider dynamat on the inside surfaces? Is there anything else I can do that might be worth doing? Is the Mountain Mist Fiberloft fill a good choice for filling the cabinet?

Amazon.com: Mountain Mist Fiberloft Premium Polyfill Pillow Stuffing, 12-Ounce: Home & Garden


Thanks in advance
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post #2 of 4
12/2/09 at 5:33pm
I'd try the refoam. It's inexpensive and should be pretty easy. You've taken the time to test that everything else is good, and why do that if you were just going to throw the drivers out?

As far as the other changes... I'd wait and see if there's problems you're really trying to address with the sound of these speakers before you mod them. There's a chance that the engineers who made them actually knew what they were doing and they'll sound good without any changes... and you can always make these changes later if you decide these speakers are lacking.
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post #3 of 4
12/3/09 at 4:05am
Try a refoam kit. They're inexpensive and more labor than skill. You can handle it.

Buying replacement drivers opens a can of worms. They might not work well with your cabinet dimensions and crossover. Crossovers are designed to work best with the stock woofer. If you're willing to redesign the crossovers or have Madisound do it (they will for a fee), then you could probably get another woofer to work. Still, for the lowest amount of pain and expense, refoam the woofers you have.

Extra cabinet bracing can change the internal volume of the speaker, which will change the sound. Though using Dynamat and fresh stuffing won't hurtand will likely help.

If you're handy with a soldering iron, you might want to put some new caps and resistors into the crossover. That can help a good deal if you have old components inside.

As for the finish, strip off the old one. You can use various chemical strippers and steel wool to get it off. Then use denatured alcohol or mineral spirits to neutralize the stripper and get the wood nice and clean. You will probably want to lightly sand the cabinets with 0000 steel wool or 220 or higher grit sandpaper. When you're done with that, use a stain of your choice to get the color you want. After the stain dries, try a wipe on tun oil or polyurethane finish. Those can be wiped on with a clean rag and are self-levelling. That's important because other finishes have to be applied evenly for a good finish. Something that's self levelling is much easier to handle and gives you a good finish without a lot of effort. After the finish dries, rub out the cabinets with something like Briwax or another paste style furniture wax. Give it a good buffing with a soft rag, and you should be very pleased with the finish you get.
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post #4 of 4
12/7/09 at 8:32pm
Thread Starter 
Wow, thanks Uncle Erik, I was looking into doing some work on the cabinets. Very informative and descriptive, I was totally lost at Lowe's looking for a one step solution. I'm gonna give that a shot. I'm dropped the filling and dynamat ideas for now, will try refoaming and see how they sound first before I decide to work on bracing and stuffing.
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