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Tom Schlangen
 
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Hi Fred,

You Will hear a substanial difference if you feed each
amp into their own speakers.


Again, however, the increase is only 3 dB.


No it ain't :-) and the explanation for us tech oriented
types is quite simple and has nothing to do with the electrical
power, but with speaker efficiency: When you stack speakers
(notably woofers) close enough together, fed with the same
signal, power, and in-phase, they act (because of overlapping
wave compression effects) as a single cone with a somewhat larger
cone area and efficiency than two cones separated far enough.
The drawback is higher directivity, but this might even add
to the audible effect when you are in the "beam".

You can ask any old fashioned PA systems guy why in those olde
days of under-kilowatt-PAs the speaker cabinets were stacked
like that the cones in the cabinets are located as near as
possible to each other.

Or, try to find some info about how "Schallzeilen" work;
many comparatively little diameter speakers positioned nearly
together in a vertical line - used e.g in churches, parliament
halls, and so on.

And D'Appolito design speakers get added efficiency this way,
although the primary intention was another goal (single point
wave source).

You can't get sumthin' fer nuthin'.


That's right. In the case under discussion the resulting
higher speaker efficiency is gained by more distortion and
more directivity.

But the priciple works just fine for geetah and bass-ment
stacks, and for stacking PA cabinets, and for "Schallzeilen".

Back to the topic of this thread, I wholeheartily agree
that two amps with two cabinets (or one multispeaker cabinet,
if you can split the speakers in it to be fed by
two amps of the same type) are _the_ way to go.

An added plus is that no modding whatsoever of the gear itself
is required.

If you still don't believe, just take a classic geetah
stack (consisting of bottom cabinet, upper cabinet and
piggy-back amp) separate the cabinets at least 1 metre
horizontally apart, plug in your favourite axe and
compare the result to the verticaly oriented setup
with cabinets stacked vertically. If you don't believe
your ears, just use a sound preasure meter. You won't
be disappointed about the added dBs of sound pressure :-)

Tom

--
Anyone who considers protocol unimportant has
never dealt with a cat. - R. Heinlein