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Cinema
Placing the
Centre Speaker
If you’re using a front projection
screen, or even a plasma TV, placing
the centre speaker is a piece of
cake. With any other kind of television
set, it gets difficult. In most installations
the speaker is positioned in front
of the TV. At best that’s too low, and it
is almost certainly too far forward. Still,
that was initially where we had placed
the centre speaker of our Kappa system.
There didn’t appear to be a choice.
If the speaker’s not too large you could
put it on top of the TV set, of course, but
there are three obvious problems.
First, even a shielded speaker, if it’s
placed right on a TV with a direct-view
cathode ray tube, will cause the image
to go psychedelic. Second, because
they stopped making flat-topped TVs
decades ago, the speaker will fall off
if you so much as breathe on it. And
third, putting a potent vibration source
like a loudspeaker atop 75 kg of plastic
is…well, inadvisable.
You can, of course, order up a piece
of custom furniture, with a space for the
TV to tuck into, and an upper shelf for
the central speaker. Expensive. And a
closed shelf is not the ideal place for any
speaker. And… don’t ever change your
TV set.
The better solution is UHF’s speaker
platform. We actually considered developing
it as a commercial product, until
we thought about the fact that there
would have to be a different version
for every model of TV on the market.
That would give a new sense to the
Putting a centre
speaker right atop a
TV set? Sure…if you
know how.
term “multiple inventory.” Fortunately,
the platform isn’t difficult to build by
anyone who owns a power drill, and
perhaps a protractor.
Here’s the assignment we gave ourselves.
The platform had to accept the
six very different centre speakers we had
rounded up for our very first test series.
It had to be unconditionally stable even
if someone brushed up against it (or if
the cat…but we don’t want to go there).
And — this is the tough part — it had
to be decoupled mechanically from the
TV so that the speaker wouldn’t make
anything rattle.
It was easier than it looked.
We began with a standard prefinished
shelf, 46 cm wide (enough to
handle most centre speakers) and 25 cm
deep. We were fortunate enough to find
one with a shaped front edge, which
made it look more like a commercial
product. Placing the shelf on top of our
Hitachi rear projection TV, we could see
that it fit comfortably, with about half its
depth sticking out at the rear. It was not,
of course, stable enough by itself. If we
let go it would slide right off.
Now came the customization. The
front bezel of the TV is narrow, just
12 cm deep. There is then a 2.5 cm drop
to a deeper (16.5 cm) sloping hood (see
the diagram on the next page). Dimensions
will vary with the TV model, but
the layout is quite consistent. Clearly, it
would be necessary to make a support
that could press against that sloping
surface, to stabilize the platform.
At the same time, we couldn’t allow
vibrations from the speaker to shake up
the plastic casing of the TV. We needed
to decouple the speaker acoustically
from the TV itself, but how. Some sort
of cushion? We rejected that solution out
of hand, because a speaker needs to be
held rigidly in place if it is to project its
full dynamic range. Spikes? Sure, if we
accepted major cosmetic damage to the
TV, or even — with the heaviest of our
test speakers — its total destruction.
The perfect solution was right in our
own Audiophile Store. It is the Soundcare
Superspike.
The Superspike, which is a cone and
a protective “dish” in a single sealed unit,
is unique. The picture on this page shows
one assembled and dismantled. The spike
Not to be missed
The world’s greatest harpist, plus an
exceptional flutist. Original recording
by Keith Johnson, masterfully brought
to CD by Bruce Leek.
ULTRA HIGH FIDELITY Magazine 55