515B Matched Pair

[josh]

I have seen 515B's and other pairs of drivers listed as "matched pairs" on eBay and other places. What is the significance of a matched pair and how is this accomplished? Can I have a pair reconed to be a matched pair? How does this work?

Thanks
Josh

[Gary L]

Hi Josh. I think, and this is only my opinion, a matched pair would be nothing more then close in manufacturing date. Possibly two woofers taken from a pair of speakers that have always been together.

In answer to your question, "Can they be reconed to match?". I am quite certain if you sent two identicle baskets to GPA and had them reconed and remagnetized that Bill would see to it they were as close to one another as possible.

I am not all that familiar with the 515B but with 416 woofers they came in various finishes, a few different impedences and a couple of colors. Then there are a number of different styles between 416-A and B and Z and differences within some of those.
I think matched would signify two woofers of the exact same style but not much more as each could have some differences in magnet strength or DC readings and even different materials used in the cones or spiders.

Best bet is to have them rebuilt if you are seeking close performance specs.

Other opinions here could be interesting.

Gary

[josh]

Gary,
Thanks for you opinion. You have some very good points.
I guess am trying to figure out if Altec sold speakers in "Matched Pairs." How else would someone claim they are matched unless they did lab tests or something along those lines. There is more to a speaker than just reading measurements across the voice coil.

Josh

[Zilch]

The matching that MATTERS, of course, is rarely done.

However, the likelihood of achieving that is better with devices of identical manufacture.

[Mr. Widget]

I guess am trying to figure out if Altec sold speakers in "Matched Pairs." Nope... they made tons of these things and there was no one at the factory measuring each unit and matching them. (They may have done special testing for some military contracts or other special applications, but the likelihood of running into a set of those would be pretty unlikely.) There are other companies that do measure most or all of their production and grade them. Grado and other cartridge manufacturers do that... the units that measure better cost more and are labeled differently than the ones that simply pass. Meyer Sound measures each of their drivers and they become gold, silver, or reject. Before they built their own drivers they used JBL 2441s... they would measure every one... label them gold, silver, or ship them back to JBL for someone else to buy.



How else would someone claim they are matched unless they did lab tests or something along those lines.How do they claim that a tweeter with the dome mashed in is in mint condition? There are all types out there.



There is more to a speaker than just reading measurements across the voice coil.Yep.

As for the importance of matched drivers or consecutive serial numbers... there is a certainly validity to that. I have measured frequency response and impedance curves on many identical models from a variety of manufacturers and typically close serial numbers do perform more similarly than models from different production runs. That said, consecutive serial numbers is no guarantee of matched performance... but it is a good starting point and as you point out identical DCR is certainly no guarantee of matched performance.


Widget