Changing the Standard for
Identifying 7.1 Surround Wires
I ran into a common problem on an install
the other day. It was a great system: cool
room, nice gear. The installation team
had wrapped up and was headed out
the door to another job; it was my turn
to configure, debug, tune, and calibrate
everything I could think of. I flipped on
the surround processor’s internal speaker
test noise to get a rough idea of what I was
in for. The left channel came on. Center
channel, check. Right channel...was
coming from behind me. Oh. Oops. Hey,
wait! Installation team! Don’t leave yet…
|Anthony Grimani (firstname.lastname@example.org) is|
president of Performance Media Industries, with offices in Novato and San Anselmo, CA.
After a few minutes of pecking around,
we found the problem. The wire for the
back-left speaker was connected to the
right speaker output of the amplifier.
How could this happen? When labeling
the wires, the technician had used the
terminology “LR” for the left-rear speaker. However, the “L” and “R”
were on separate labels, and the “L” had come off. Now there were two
wires–the other being the right speaker–with a single “R” on them. You
see how things went off the rails from there. In the end, it took three of us
about 30 minutes to solve the whole thing (the integrator spent the entire
time apologizing to me). That’s 30 minutes I could have been calibrating,
30 minutes the technician could have been on another job, and 30 minutes
the integrator could have been selling another system. One-and-half manhours
wasted because of a silly little label.
There’s a Better Solution
We seriously need a simple new standardized convention for labeling each
one of our 7.1 channels. Labels may seem like a small and insignificant
thing on the surface, but my recent experience demonstrates how
important they can become. So, here is what I’m proposing.
First, let’s call them “front,” “side,” and “back” channels. Fronts go
in front of you, sides go to your side, and backs go to your back. Simple. I
know it’s popular to call them surrounds and rears, but all the speakers that
aren’t fronts are technically surrounds, and my example above shows why
it’s a bad idea to use an “R” for rear. I’ll also give “height” an honorable
mention, because I’m starting to see that pop up in a few places.
Next, how do we differentiate
left and right for the fronts, sides,
and backs? Use upper case for the
fronts and lower case extensions
for the sides and backs. This looks
like Sl, and Sr for the side-left and
side-right channel respectively.
In fact, I’d argue that you don’t
even need a “front” designation;
they’re just the L, C, and R. That way you know a wire with an upper “L” is the
left, not a side left or back left speaker–even if a label gets torn.
What About Subwoofers?
|Figure 1: This new 7.1 home theater wire labeling convention is easy for installers and technicians to remember. It’s robust in the event labels get damaged. It’s also short and easy for manufacturers to print on the back of amplifiers and receivers|
We should not start their labels with “S” for fear of mistaking them for
sides. So let’s use “W” for “subWoofer.” Also, by now you should know
that you should be using at least four subs these days. It’s been pretty well
demonstrated that four at the wall midpoints, or more typically corners,
(vastly more ergonomic with only slightly lower performance) is the way
to go. That means you will have at least four wires coming in labeled
“W.” It may not matter for some systems where the subs are fed the same
signals. However, I like to split the feeds up to trim levels and
delays separately during calibration and eek every last bit
of performance out of the room. (This is not recommended
unless you have experience doing this sort of thing and a lot
of sophisticated test gear to back you up.) I say we start with
“W1” in the front-left corner, and then go clockwise around
the room with “W2,” “W3,” and “W4.” See Figure 1 for a
graphical form of what I’m talking about.
This convention is easy for installers and technicians to
remember. It’s robust in the event labels get damaged. It’s
also short and easy for manufacturers to print on the back of
amplifiers and receivers. This convention applies to speaker
connections, as well as any line level interconnects between
the surround processor and amplifiers or perhaps an old disc
player with analog outputs.
The point here is to use a simple convention to save time
and money. I don’t have to track down problems, technicians
don’t have to undo beautiful wiring, and so on. Let’s all agree
to a convention, stick to it, and be happy!
Chase Walton contributed to this column.