This page
provides links to downloadable wiring diagrams for the various Sound City
speaker cabinets you might own. These are admittedly crude examples (I'm
no artist), but they are accurate. Also, these diagrams can be used with
any cabs that have two or four of any size speaker (10s, 12s, 15s, etc.).
 Here
is a link to a page that describes speaker wiring generically and mathematically
(with equations).
 Here is a link to a Sound City site page that discusses measuring what's called
DC resistance (Re), from which you can determine and extrapolate the nominal
impedance of a speaker or speaker cabinet, and
 Here is a link to an impedance calculator that works very well (courtesy of Sadowsky Audio and Sadowsky Guitars, Ltd.).
Please note
that all the following linked files are in PDF format, which requires
Adobe Acrobat Reader be installed on your computer. (Click here
to download a free copy of Adobe Acrobat Reader if you need it.) 
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Please Note: The L610 wiring diagram above shows six 16ohm speakers, but at least one L610 cab I've seen has had six 8ohm speakers; therefore, the same equation shown in the wiring diagram can be used, but the combined DC resistance (Re) would yield a measured 5.333 ohms; therefore, the cab's nominal impedance would be 8 ohms. 
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Please
Note: As you view the following two wiring diagrams, please realize
there is much discussion about what seriesparallel wiring looks like versus
what parallelseries wiring looks like. I believe this is a semantics issue
more than anything because electrically, these two methods are the same.
Also, many people feel they can hear differences between the two; I'm not
one of these people. So, if my parallelseries wiring diagram looks like
someone else's seriesparallel diagram, so be it. I think it's just semantics. But I've been wrong before! 
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 Wiring
Two Cabs in Series
This wiring scheme can be used for any two cabs as
long as A) they each have the same nominal impedance (2, 4, or 8
ohms each) and B) their combined nominal impedance isn't greater than
16 ohms when connected in series.


What's "ParallelSeriesParallel" you ask?
I know this is a Sound City site, but some bass players might be using
their SC heads with these very popular 8x10 Ampeg cabs, which have two
sets of four 10inch speakers in them. If you use one of these cabs,
here's a way to rewire each set of four 32ohm 10s in parallelseries
so that when you use the two sets of four 10s together (in mono, i.e.,
in parallel) your SC amp sees an optimum 16ohm load.
Hence, my use of the term ParallelSeriesParallel. For what
this might be worth... 