They look to be in nice shape. Sorry for the rookie question but I've never understood why one would measure DCR 6.5 and one 7-- particularly if they're a "matched set" as seller claims (roughly the same age?) Also, does that difference in DCR mean they will probably not sound identical to each other?
Altec 416 8B 15" Woofer Matched Pair | eBay
Being of "Sound" Mind
No, it's not going to make them sound that much different. They should be fine... I'd go for it if I had the extra money. I want a pair of 416B for my (PA version) A7s. Good luck!
Don't overthink- resistance is not the only factor.
But that said, why worry about it when generally acceptable tolerances are 10%, so even if 6.3 it would not be not off all that badly.
The expensive caps people put into crossovers are likely off more.
Bear in mind eyes and test devices are fiendishly accurate, but your ears compensate/change over a power ratio roughly a trillion to one...does the 7% this is off still seem important?
Your neighbors called. They like your music.
I get a giggle out of the fellas that will buy a dozen caps so they can "hand match" for closest possible value and ESR, then install the whole damn system in an acoustically asymmetrical and untreated room.The expensive caps people put into crossovers are likely off more.
Not all vegetables make good leaders.
The phrase "close enough for rock and roll" comes to mind....though I think it was said earlier about Jazz. And likely every other type of music.
Your neighbors called. They like your music.
Sounds like small differences in resistance, while not the least of my worries, is a minor one at best..... BTW, would 416's with consecutive serial numbers for example be likely to have very similar DCR readings when brand new? If so, is it mainly wear and tear that causes them to drift apart with age? Things like relatively high amounts of wattage being pumped through them, or over excursion possibly due to things like less than ideal cabinet tuning/porting? Being dropped on the floor for example wouldn't effect DCR readings would it?
Being of "Sound" Mind
I would expect new parts from a common production run to be very close in terms of DCR, if not spot on.Originally Posted by voice of the theater
Think about the simplest causes for resistance in a circuit. Number one in my experience has been oxidation or failure/degradation of mechanical connections with soldered connections following close behind.
Woofers in particular have 3 common areas where things start to go awry over time. First on my list is the point where the tinsel leads attach to the woofer input terminals, this is both a soldered and mechanical connection on older Altec woofers. Next is the joint where the tinsel leads are soldered to the voice coil, usually buried in black adhesive at the point where they pass thru the cone. If there's already questionable contact area at that joint, hard use can cause heat cycling in addition to it's naturally high vibration environment.
The same forces can also sometimes act on the voice coil wire itself where it's sharpest bends are made coming from the cone onto the former, and where the coil actually bends. This is a common "burn out" point for the same reasons.
Also, i have seen tinsel leads that have actually become flaky themselves over time.
Sometimes, if you have a large DCR difference between two of the same model, it's worth your time to clamp on the test leads and carefully probe the above mentioned points with a chopstick or toothpick while watching the meter for variations.
Not all vegetables make good leaders.
Posting Permissions
Bookmarks