I am running 18 separate speakers, that are "passive",
with 3 Amplifiers driving them ALL.
Respect "Ohms Law!" and you can safely run in "series",
several speakers without presenting a low impedance that
is hard on the amplifier.
In addition, I implement 2 Velodyne subwoofers.
An 18" and a 15" one in front, one in the rear.
I implement front speakers, and side speakers, along
with rear center speakers.
Stereo ONLY, simply put, just 2 separate systems working
together to fill the room EVENLY with sound.
I have done speakers in both parallel and series, for over
30 years without ANY incidents at ALL.
PS Audio GCA 500, and a GCA-250 do the lions share,
while a Pro Hafler 300 wpc. @8ohms and 500wpc. @4ohms
for the side speakers.
NO sound processors are used, just PURE 2 channel sound
that is IMHO, the finest "Surround" Sound I have heard
so far.
Every speaker adds +3db. so you can see that this is an
easy way to squash the -10db. that most people have,
from their listening spot.
My idea was simple, 1 speaker must play very Loud to try
and fill a given room.
Placing speakers, in key locations where the hearing, is
able to pick up sound literally "ALL Around".
So I have plenty of "Headroom", and there is NO need to
ever increase the Volume, since the moment the "play"
button is engaged, it is as if a metamorphosis of the
Audio kind takes place.
Never be afraid to think outside the box.
Some of my Best ideas, have spawned out of the box.
Love Your Music!