Just wanted to post some pictures and details of todays project before I bolted it up. The subject was a Wharfedale Pacific Center. For awhile I've noticed it has some cabinet resonances and a bit of sibilance on vocals. Here's what I did, and from initial impressions it seems to have helped considerable.
- Added 4 vertical and one horizontal brace internally made from 1" square dowel rod. Braces are very very snug inside, and glued down with liquid nails.
- Put about 3 thick coats of water putty inside, especially on the back of the front panel - followed by one coat of a water based sound damping liquid.
- .22uf Cornell Dubilier foil/film caps added as bypass for the two series capacitors, used modelers clay instead of hot glue to hold them down and reduce vibrations
- All crossover solder joints re-done with 4% silver solder
- Cut off all the cheap (and corroded) push on connections internally and soldered wires directly to drivers and binding posts. Also cleaned everything with Caig de-oxit and treated binding posts with Caig pro-gold.
- Tweeter de-coupled from box with a 3 layer sound mat akin to whispermat.
- Driver gaskets were horribly thin, so used gasketing putty instead.
All of this stuff is simple and cheap, and the same ideas can be applied to any manufacturers speaker.
After enough experience with cabinets, it's pretty easy to tell where one needs help with a simple knuckle knock-knock. This particular cabinet had some resonance, especially on the front panel ... after the mods it feels much more solid, and the sonic performance reflects that as well.
Every cabinet made has resonances, even $5000 speakers. If you're building a cabinet from scratch there are much better ways than what I've done here to minimize the resonances, but for a pre-made cabinet adding bracing is the best method. The bracing/strengthening raises the resonance frequency, hopefully above (or near) the crossover point. If you can get it above that point, it'll never come into play because the tweeter simply doesn't produce enough energy to excite the cabinet. The result is a much smoother response curve and good-bye to the colorations.
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!