Speaker wiring/impedance issues - experts needed!!!

shredd

calling all tech weenies and other smart expert guy types...
OK. I wired up a bass cab with four 8-ohm speakers, using standard series/parallel wiring, in order to have the cab end up with an 8-ohm load, which the amp that runs it requires.
After finishing, checking my wiring accuracy and quality of the solder joints, I put a normal ohm-meter on it, and it measured 43 ohms!!
At this point I crapped my shorts and panicked...then I went online to look up different wiring sites and so on...all the series/parallel wiring diagrams were the same, but one site (written by an IT guy/systems engineer) wrote of the difference between \"impedance\" and \"resistance\", and that any speaker coil will vary in impedance throughout it's freq'y response, and that a normal ohm-meter can give a widely varying ohm reading.
SOOOO...what I want to know from all youse smart guys is: does this odd ohm-reading mean something is messed up? Will it blow my amp, or run at 4-1/2 watts 'cuz the impedance is too high? Or is this normal???
For once, I have no idea what's up with this thing. Please help!

791979

Hi shredd,

I have no idea what the problem is here. I guess I would start by measuring the speaker terminals alone. See if you get 8 ohms on all of them, if not and they are all \"wrong\" by the same amount I would be thinking you have a problem with the multi-meter.
HTH

shredd

Thanks - sadly, I was moronic enough to NOT check each speakers' impedance before doing the wiring...but they're brand new Celestions, so I'm betting they were checked out before being sold and are probably OK. AND....I checked the cab with TWO different multimeters, and both gave the same reading. :?
So...I'm tyring o find out if there's something actually wrong, if anyone's ever had something like this come up. I need opinions from all you engineering experts.
And all you other guys - take a plain ol' ohm-meter and measure your cabs. Are you getting a nice even 8, or 4, or whatever ohms? Or some other kinda reading/s? Check in, you guys.

thehootman

Make sure your solders are good. Make sure the terminals of the meter are clean. Make sure you have a good contact between the probes and the wire to the speakers. If this contact is bad, is has more resistance and thus raised the impedance value.

My cabs are pretty much spot on +- 0.5 ohm

philflood

I remember an important lesson from back in my auto mechanicing days - A new part is not a known good part. With your readings essentially \"off the scale\" I am of a mind to guess that one of your drivers is bad. I can't come up with a wiring scenario that would get you at 43 ohms with 4 8 ohm speakers. Test the load from the pos to neg of each driver. you shouldn't need to unwire the entire cab to do that. See if they all read close to 8 ohms. Good luck.

guitar3456

no, the IT guy's site is correct. DC coil resistance can vary all over the place among different speakers. You'd need a special LCR metering device to actually measure impedance. If you have the wiring accurate, it should be fine. I'd be more worried if you had a DC resistance of 4 or less. Then, you would have something out of whack or a possible short.

shredd

I knew I could count on all youse smart fellers. And, not surprisingly, you were all right...except 'flood, and only because all four speakers tested OK, although more like 6.something ohms rather than a nice even 8.
Turns out the REAL problem wasn't

my wiring my solder joints either of my multimeters the wiring diagram/layout I used. [/list:u]

DRUM ROLL PLEASE...the problem turned out to be the GARBAGE 1/4\" in/out jacks this cab was built with. (the kind that switch open/closed when a plug is inserted). Once I bypassed them and checked impedance (with both multimeters) directly at the wiring, they came out a moderately close 5.9-6.3 ohms. So I'm going to replace them with some good quality ones...even if I haveta order them online (I doubt Radio Shack - the ONLY electronics supplier in my little town, has anything any better.)
Anyone wanna help me with my laundry? :shock: :shock:
MEANWHILE - on to a new crisis. I've started a new thread for this one. It's an even STUPIDER problem than this one, 'cuz I caused it myself :oops: :oops: ...please check it out, and advise...