refurbish mainstream bookshelves

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hello to all


I am in the process of figuring out what speakers to but next.My last set were klipsch lascalas.I have a cyrus 2 psx amp, an older arcam alpha cd player that is getting a new clock and I am using cat 5 braided for speakers.Does this combo scream for a certain type of speaker?

Meantime I picked up a pair of polk rb-15's. I hate them. Can I use these enclosures to make something I can listen to? they are 6.5" x 6.5" x 10.5" and have a small bass port


thanx to all who use their big brains for good
 
I have been refurbishing some commercial speakers for some time now, and I have concluded that there is no point. It is much easier to build from scratch, where you have the choice of units, box, crossover etc. You will have to choose units suitable for the box, cut a new port, work out why the tuning is different to the intended frequency, work out why there is a crossover suckout...all I had to do was replace the bass unit, and it's turned into a major project. The one I designed from scratch is much better behaved, yet I've neglected it due to this refurbishing project, which I do want to complete, but..

Don't let me put you off, though, if you want to do it. :)
Be prepared for more work than you intended.:D
 
Hate to do this, but I can't seem to post a new topic?

http://forum.ghostnote.net/showthread.php?p=140131#post140131

Guys, I need help picking the woofers that go in here.

I took the old woofers out (the rubber gaskets in both had completely corroded) to measue about what I should look for. Dad had an old voltage meter and I used it to test both old speakers, they both come to be at about 3.6-3.8 ohms, so I'm assuming they're 4ohm speakers.
The hole in the cabinet is 9some inches, and the distance across mounting screws in the old speakers is 10", so i'm assuming I need 10" speakers.

Other than that, I don't really know what I need?
 
is there an actual crossover in the speakers? I have seen some cheaper speakers that will connect the woofer directly to the input terminals, and then use a non-polarized electrolytic in series with the tweeter and midrange. This generally works OK, but a "real" crossover sounds better, but must be tailored for the speakers in question.

How I would proceed would depend upon my budget.

1. one solution would be to get a new set of surrounds and try to fix the woofers. too messy and unpredictable for me!

2. The cheap solution would be to simply replace the woofer with an inexpensive one from some place such as parts express. I'd recommend their Dayton 10" "classic" woofer. It's a good quality, inexpensive, 10 inch woofer, but it's 8 ohms. I don't think using an 8 instead of a 4 (are you SURE it's 4 ohms, cheap/old analog multimeters might be inacurate on the low ohmage setting. the impedance of the woofer will generally set the impedance of the entire speaker, does it say 4 or 6 or 8 ohms on the back?) would be too huge of a deal, especially considering that you are installing a whole new woofer. You might also have luck with a 4 ohm pro-audio woofer. Just stay away from a subwoofer, these might not play high enough to hit the midrange crossover

3. replace woofer and get a new crossover. I'd build my own crossover, but you can get 3 way premade XO boards from rat shack, PE, etc.

4. replace all the drivers and make a crossover. I would highly recommend building the "Lyra" design (speakerbuilder.net) into this box. be sure to plug that port pipe. You can also find other designs online, or get a generic crossover and some drivers and make your own (in which case getting some L-pads for the tweeters and midrange might not be a bad idea).

the boxes you have are a ported design. ported cabinets have to be tuned for the specific woofer they are using. I would either use the Thiel-small parameters and the box volume and port diameter to calculate the port length for your replacement woofer, or just plug it up (PVC pipe cap or a sock). If you plan to use the speaker's original crossover, I would replace any bipolar electrolytics in it, as these dry up after 20 years or so (cheap parts, easy to replace)

Personally, I'd go with options 2 or 4.
 
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