What would you suggest for the rear center channel?

Here is a diagram, I hope it helps.
-------------
FR...C....FL
SW


RR...?.?...RL
-------------

THX,
Don

This message was edited by dkupper on 10/10/01 17:03.04.

SB
















Just kidding, I have a pair of monopoles for my surround back channel.

This message was edited by Arthur Legardo on 10/10/01 19:12.18.

Don,
Is your question whether to use one, or what kind of speaker to use? I'm sure you're asking the latter.

I can't imagine why a speaker similar to your front-center wouldn't work well, especially if your front L & R and rear sides are similar.

Next-best recommendation would be a third speaker same as your rears.

Larry

Idealy a THX Setup is:


LF LFE CH RF

LR LRB RRB RR

Even thought THX-EX uses a Matrixed "Back" channel they
still recommend using 2 seperate speaker arrays with
the only exception being if you use a DiPole and wire
LR and LRB and RRB and RR into the Di's. You can use a
Center channel that is voice matched to the front CH
if you don't want to wire up another set of surrounds
or if your Receiver only drives one Back Surround and
your not interested in buying a seperate 2ch amp.

I am not sure what I want to do with my setup as of yet
I was thinking about running 4 bookshelfs for all of
the surround channels but I would like to use a DiPole
the problem is AR doesn't make a DiPole and I don't
want to use any other speaker brand in the mix...

Brett, with four (or more) surround speakers, the requirement for diffuse sources is met by the sheer number of speakers.

In other words, the sole reason that bi- or di-polar speakers are recommended for home theater is to emulate the several speakers used for each channel in commercial theaters, along with the increased distance between these speakers and the audience in such theatres.

For instance, when I saw Star Wars, 1st Episode, I counted (who you callin' anal?!) four speakers on each side wall, and another four accross the rear. Talk about diffuse!

I, too, use two rears, fed mono, but separately powered, to supply the bass the sides aren't capable of. I use two partly because my seating arrangement is side-to-side, along one plane, meaning only one seating row.

Read my post in page #5 of Gregorius' "Who are you?" thread for my setup info. I use a DPL decoder to extract rear signal, using 'small' setting for sides, and 'large' for center to steer bass to the BP-20s.

Larry

Larry,

I was asking if I should use One or two speakers. I believe that you recommended not using any speaker except what I already have. So I was just trying to decide between one center rear or two rears. An LRB & RRB setup or just a center channel in the rear.

Also, what is the LFE?

THX,
Don

Dkupper,

LFE is "Low Frequency Effects"

When you hear things like 5.1 6.1 and 7.1 this refers
to the number of musical channels be they stereoscopic
or matrixed (monural)

5.1 = LF,LFE,RF,C,SUR (Monural)
6.1 = LF,LFE,RF,C,SURL,SURR (Stereoscopic Surround)
7.1 = LF,LFE,RF,C,SURL,SURR,SURB (Monural Surround Back)

In 6.1 the Surround is Stereo in 7.1 the Surround Back
is Monural. You can run one or 2 speakers for Surround
Back, but either way it's still Mono Matrixed so the
choice becomes how much "Difusion" do you need in your
application? One Center Channel matched to the front
Center Channel can work very well for Surround Back or
alternately you can use whatever speaker pair you use
for your L/R Surround for Back Surround *you need to
buy another pair of course*

OK, another way of saying "Sub" Thanks.. I am always learning!

dkupper: Does your receiver/amp support a single rear-centre, or Left and Right rear-centres? If single only, then just use one rear-centre (as Larry and Brett say above, a speaker that matches the timbre (sound type and quality) of your existing speakers is best, but any type will do).

If you want to drive two speakers and you have only one output, you will have to hook up a second amp to a preamp-out on your receiver to drive the second speaker (or to drive both rear-centres).

There are those in the business who insist that you need two rear-centres, even when the source sound is mono, to properly spread the sound in your room. Like Larry has pointed out, theatres use loads and loads of speakers, and there are no soundtracks optimized for that many, so you can see they are just spreading the sound around. I've never tried it with a single one in the rear-centre.

Larry: I'm guessing your mono-fed bass-playing rears are not little satellites. -HH-

This message was edited by Harmony Honey on 10/11/01 11:56.29.

dkupper: Note, though, that an LFE track is recorded specifically for low-frequency effects, and is not the "bass" track, per se. The bass in a sound track is quite different. The confusion arises because you can send your bass to the subwoofer along with the LFE. However, most receivers can adjust DD5.1 and DTS LFE tracks individually, quite apart from the bass levels. ... Mike

Hi, Harmony.
You are correct, my rears are about 4' tall, bi-polar, which means the front-and rear-firing drivers are connected in-phase, as opposed to di-polar, which are driven out-of-phase.

The BP-20's have two 6 1/2" woofers and one tweeter on each face. They are identical to my mains, the BP-2000's, except that they don't contain the 15" powered subs. Still, since they're sold as stand-alone speakers, they don't lack in the bass department.


Don,
To answer the question of one vs two rears, that depends on the room size, your wallet, the spare amps you have, the position of your sides (with rears, the sides should be placed directly to the sides, not rearward at all), and the type of speakers all around. In other words, there is no definite answer. If you have the means to experiment, do so. Generally, the more, the better.

The '.1' designation for the LFE channel refers to the limited frequency range covered, considered to be 1/10th of a normal 20-20K Hz range, or 20-80 Hz. (A Hertz is equal to a 'cycle-per-second').

Frequency doubles with each octave; for example, the 'A' above 'middle C' on a piano is 440 Hz. The 'A' an octave higher is 880 Hz, and the 'A' an octave lower is 220 Hz. So, the 'bottom' octave is 20-40 Hz, the next is 40-80 Hz, etc.

To be exact, if you start at 20 Hz, ten octaves actually is 20,480 Hz. To work the other way, starting at 20K Hz takes you down to 19.53125 Hz, but who wants that number on their equalizer panel? :-)

Also, Mike R. is correct: the signal on the LFE channel is as discrete as any other; it may or may not contain the same low-frequency sound as the bass in the normal channels, which can also go down to 20 Hz or lower. Your processor and bass management settings determine how bass sounds are distributed.

Remember the movies with "SenSurround"? It was a separate sound that was only made up of low bass rumbling. No information of the movie soundtracks was contained at all.

Larry


This message was edited by Larry Fine on 10/11/01 12:45.38.

WOW,

Thanks guys, I believe that I will play around a little first then decide. I have been looking for a new set of speakers anyway, this may be the opportunity to get some. My Amp (Denon 3801) does support both configs, one or two rear center channels. Part of my problem is that I would like to mount it in the wall and can not match the front or surrounds at that point.

THX,
Don

Larry,

You never cease to amaze me.. I swear that you are the
honest to god, died in the wool Cliff Clavin of the
Remote Central Forums! :)