How To Fine Tune Center Channel Speakers
Location, location, location for your center
channel speakers. It's the mantra
of real estate agents, and it could just as easily apply to your Center Channel.
Why? Because moving a speaker, any speaker, but especially a center channel, up, down, left or right, may significantly alter its sound. It's very
dependent on your particular setup, the room itself, the TV and the
center channel location relative to the TV, the distance from the wall behind,
and any shelving in close proximity.
The tonal changes that occur are generally insignificant but in some unique
cases they can be quite audible. A large number of enthusiasts don't recognize
this, and tend to blame the center channel speakers for any tonal differences that in fact may
result from the interaction of the speaker with the room, the face of the TV
picture tube or screen, or nearby surfaces.
Several interesting emails from
owners got me experimenting with this
phenomenon. Knowing that the tonal balance between either an
Axiom VP100 or
Axiom
VP150 is excellent with our front-channel bookshelf and floor-standing
models, I decided to put the matter to a test and try to find an undesirable
location for the center channel. The good news is that a bit of fiddling with
your center channel speakers placement can restore the tonal balance if you should detect any
imbalance between your VP100 or VP150 and your Axiom main speakers.
To document how center channel speakers tonal balance changes with different locations, I
set up an experiment using an A/B comparator and my trusty sound-level meter,
doing listening comparisons with the
Axiom VP100 and
Axiom VP150. I was also
interested in discovering whether certain center channel speakers positions sounded more
natural or “better” than other positions.
The results are fascinating: Changing your center channel speakers location will certainly
determine how neutral or transparent your center channel loudspeaker will sound,
and how well it will tonally blend with your main left and right speakers.
During this discussion, you should keep the following in mind: Moving any
speaker will alter its perceived tonal balance relative to where you are
sitting. This has been scientifically documented and supported by data gathered
in tests conducted over many years at the National Research Council (NRC) in
Ottawa, Canada, the facility where Axiom continues to measure and audition
initial speaker prototypes. There, every speaker is auditioned in four different
locations, and each listener rotates listening chairs, so by day's end, all
listeners have heard each speaker in four different positions and from at least
four different seating locations.
In my first test, I connected the
Axiom VP100 and
Axiom VP150
center channels and placed them on a 16-inch
stand well out from my TV monitor, one center beneath the other. All the tests
were done with both M80ti's and M22ti's as the main left and right speakers.
With the loudness levels perfectly equalized, I switched between them using pink
noise, movie dialog (male and female) and a variety of different music, with an
emphasis on vocals. I also switched to pure stereo to compare the tonal quality
of the vocals in stereo against the same signals through the VP100 and VP150.
The similarity between the two was astonishing. I could barely distinguish them
except for a slightly fuller sound from the VP150.
I put the VP150 on top of my TV monitor and left the VP100 on the stand in front
of the TV. Now the two centers sounded quite different from each other, and the
tonal differences remained when I exchanged the positions of the two speakers.
Was it just the location that produced these different tonal balances—and the
different location relative to my ears?
It was indeed, because when I moved the VP100 from its stand and placed it on
top of the VP150, the two center channel speakers again matched extremely well and blended
seamlessly with the M22ti's or the M80ti's. I reversed the positions again, with
the VP150 on top of the VP100. The tonal match was excellent. I also tried the
two center channel speakers beside each other on top of the TV. The two center speakers sounded
somewhat different again, with more noticeable timbral differences between the
center channel speakers and the main speakers.
The lesson in all this is that if you detect noticeable tonal differences
between your
VP100 or
VP150 center channel speakers and the main left and right speakers, and you find
those differences audible or distracting, then it's time to experiment with
placement. Try different locations, even sliding the speaker slightly to the
left or right on top of the TV monitor, even if it isn't exactly symmetrical.
Some Axiom speaker owners have found great success putting their center
channel speakers almost on the floor
or on a short stand with the center angled up towards the listening area.
For improved coverage or use with a large screen and a front projector, try two
center channel speakers, one above and one below the screen. That way, for most
viewers, the two center channel speakers running in parallel will image the dialog in the center
of the screen, rather than too far above or below the screen. This dual
center channel speaker formation will also reduce the effect of the location on the
tonal balance.
Click here to read more about
these
center channel speakers.

by Alan Lofft
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