MINe 109 wrote:

In article ,
Howard Ferstler wrote:

The other comments by the assorted nitwits who occupy this
group are being ignored.

Like this? Shouldn't you just ignore them? I mean, if you say you're
ignoring something, you aren't really ignoring it, are you?

I have a center channel question. My tv system has Linn Kabers with an
active crossover and tri-amped (take that Cantatas!), but I'd like to
add a center speaker someday, if only to hear those three channel
classical reissues. The new Linn speakers are too expensive and aren't
really a perfect match unless I add to the cost by spending for a
tweeter upgrade with no local dealer. I suppose I could find some used
Kabers; the biggest problems there would be that they aren't shielded so
placement would be trickier. How dissimilar can a center channel be and
give acceptable results?

Stephen

While you can get away with a bit when it comes to adding
surround-channel speakers and a surround processor to a
stereo-speaker package, things are usually not quite so easy
with a center speaker.

I think that the center should be pretty close to the
quality of the left and right mains, particularly when it
comes to whether the mains are two- or three-way models.
Even if the L, C, and R basic designs are in the same
categories (all three being two way or all three being three
way), it is a good idea for the crossover designs to also be
similar. If the systems (drivers and crossovers) are not all
that compatible, there will be issues involving the phantom
images forming up between the L, C, and R speakers, and this
will be the case even if all three systems are close in
terms of power-response smoothness. With a lot of music this
will be no big deal (and no deal at all, I suppose, if one
is not a tight-imaging freak), but with some music it might
be important.

One reason I replaced my old center, good as it was, and
built the new one was that all the drivers in the new one
were similar to those in the left and right mains and the
crossover points and crossover designs were similar. The
crossover situation was not a hundred percent identical,
however, since the woofer/mid crossover points were a bit
different (350 and 450 Hz) and the new center has
second-order filtration in all sections, whereas the
left-right mains have a first-order high pass network for
the midrange, with the rest being second order.
Consequently, there would be phase-related artifacts that
could impact phantom imaging between the three systems.

On the other hand, the earlier center was a two-way job,
with completely different midrange drivers and an utterly
different crossover design. As a result, there was no way to
get tight focus in-between the center and each main-channel
system, even though all three measured nearly identical in
terms of their power-response related room curves.

So what does the new speaker deliver in the way of an
improvement? Well, the driver layout allows for a bit more
clarity in the dialog, for sure. The old design simply was
too limited when it comes to a clean first-arrival signal.
The problem was inherent in the left-right orientation of
all of those drivers (a factor with systems of that kind
that would have the drivers actually facing the listener at
equal distances to each driver panel) and the system was
also located in front of a heavy drape, which compromised
the off-axis output and demanded that tweeter levels be
jacked up a bit to compensate. As John Stone noted in past
debates with me, the Allison tweeter is not happy when
driven down to the low crossover point used with two-way
Allison crossovers, and so goosing them to offset drapery
absorption is not a cool idea. These limitations were a
compromise that was not acceptable in my main system, with
its potent left and right speakers. In addition, the phantom
images between the center and the left and right mains are a
bit tighter with the new speaker, but not enough to allow
the speaker to jump well ahead of the earlier versions. Yes,
I am not a tight imaging freak.

For me the main issue is that the newer system simply has
better midrange drivers (the same as those in the L/R mains)
and less of a push on the tweeters, and I think they deliver
a bit more clarity for that reason.

Anyway, the closer a center speaker is in terms of quality
to the left and right mains (driver accommodations and
crossover design) the better. In some cases, this might mean
that the center speaker would have the same tweeter and
midrange (or pair of midranges), but not have a woofer. This
would allow it to at least be smaller than the left and
right mains. The processor would then route the bass to the
L/R mains or to a subwoofer. The result should be pretty
good.

Let me say that a few years back Waveform sent me some
egg-shaped MC satellites to review and as part of the
project I set them up in combination with an NHT VS1.2
center speaker in my main room. I oriented the VS1.2
vertically (it is an MTM design that can be set up
vertically or horizontally, with the former obviously being
a much better idea) and the result was a terrific soundstage
in spite of the radically different designs. I should point
out that the VS1.2 is really an outstanding loudspeaker,
even if its list price was but a fraction of each of the
Waveform MC jobs.

The conclusion: you can sometimes get away with installing a
different brand and cheaper center speaker in combination
with some upscale L and R jobs and get good, or even
excellent results. In a way, that makes such things into a
crap shoot.

Howard Ferstler