S-7-WAA, Wire colors on Speakerlab 7WA crossover

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James2010-10-01 15:11

I have a 1979 crossover from a Speakerlab 7WA and I have figured out component specifications for all but one inductor, but I have a good idea what it should be. My problem is the wiring. There are white wires and blue wires for the 10" and 12" speakers but I'm not sure which wires go to which speakers.

It would be great if anyone could help with this. With a little help, I should be able to draw up a reasonable schematic.

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James2010-10-06 15:05

Via an e-mail exchange with Speakerlab, I've learned that the crossover for the Speakerlab 7WA generally had green wires for the 12" driver and blue wires for the 10" driver. They had no idea why that particular crossover set would have white wires unless maybe it was a supply problem. In any case, Speakerlab recommended that I connect the white wires to the 12" driver and the blue wires to the 10" driver.

Rob2010-10-16 01:57

I'm not 100% sure about the advice you received and possibly it doesn't matter as long as you keep the drivers all in phase.

I had the 1979 6WA and still own the 1979 7WA's. The 6WA's was a three way minus the 10 inch (W1008R) woofer used as the fourth driver in the 7WA's. I built both as kits and the kit manuals show the 12 inch driver (W1208R) in each being connected to the blue leads. Blue on the red dot (positive) and blue/black on the other lug (negative). I agree there in no white and my manual shows the greens going to the 10 inch with the green on the red dot (positive)and green/black on the other lug. Reds go to the Mid and yellows to the Tweeter.

Now why I think it might not matter. Both the 6's and the 7's crossover at 1kHz and 5 kHz. The 6's were rated 8 ohms and the 7's 4 ohms which leads me to believe that the 12 and 10 inch drivers in the 7 are wired in parallel off the same crossover. If this is the case then the blue or white could be hooked up to either the 10 or 12 and vice versa.

Nice speaker by the way.

James2010-10-16 05:23

Thank you for the reply. It's interesting that you have the instructions and they show blue to the 12" and green to the 10". I have come up with a copy of some 7WA instructions (uncertain of year) that show green to the 12" and blue to the 10". I'm not overly concerned but it will make at least some difference because there is an extra inductor on the Blue circuit which makes it a 3rd order path with an additional 90 degrees of phase shift. I'll have to think on it.

Rob2010-10-16 06:24

That does muddy the water. Is the third order meant to better phase align the smaller 10 inch driver with the sealed acoustic push/pull of the 12 inch driver or is it meant to roll off the 12 from the mids quicker? If in doubt, let your ears be the judge.

You might find the following thread interesting. It has schematics for the older 7's on page 1 and driver specs on the bottom of page 2.

I'd be interested in the crossover values you came up with as I started this search tonight looking to rebuild my own crossovers. I can tell you the zener diodes fried about 15 years ago (my Dad decided to relive a disco party. No kidding.), which lowered the tweeter volume until I replaced them. I've seen others complain about the speakers sounding dull, so I'd start there if yours are overly dull.

Rob2010-10-16 06:25

James,

Forgot the link.

http://audiokarma.net/forums/showthread.php?t=278246&page=2

James2010-10-18 04:07

The phase shift is sort of the mystery. In the end, you are likely correct in that I will have to finish both speakers and try both wiring options to find the better one. That's assuming I can hear the difference with the songs I pick. At this point I have the drivers and crossovers but haven't built the cabinets yet. Unfornately, it might be several months before I get to working on them. There are other home projects that need to be done first. (Intersting thread on AudioKarma, thanks.)

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