I always thought a timbre matched , "specialized" center channel was the best speaker for the center channel. HT setups w/identical satellites for (at least) the left/center/right channels always seemed sort of low end.

Lately, I've been reading that, in terms of performance, the satellite set up is probably better, particuarly w/bookshelfs. The argument goes only real advantage to a specialized center is space considerations on top of a TV. You're paying for a convenient orientation that compromises the original speaker's design. In addition, original mixes are intended for identical L,C,& R speakers in theaters and recording studios, at least that was the claim by an Etown home theater guru/independent home installation consultant.

There are some excellent center speakers in certain product series, but they usually cost more than a single bookshelf. Some of the entry series (supers, DM's, Alpha's ...) don't have the greatest center speaker either, at least not as good as the bookshelf.

What do you guys think? Any performance advantage to a specialized center speaker?
Any performance disadvantage to using an identical bookshelf for the center channel?




[This message has been edited by BEC (edited June 09, 2000).]

If you want to insure that your speakers have the correct tonal balance (timbre) across the front, adding a speaker identical to the main speakers will solve this problem. Some speakers are designed as sets that maintain their tonal balance although the enclosure design/dimensions may differ than the mains. In any case, timbre matched speakers are very important in directional (particularly panning) audio. If the tonal balnce between each speaker is different, the perceived sound will sound "off". Try to use a similar speaker from the same manufacturer of your main speakers. An identical model will make it easier to achieve the correct timbre match but also look for center speakers designed to work with your mains. To achieve a matched tonal balance, the center will use similar drivers as those used in your main speakers.

I'm not saying that you can't use different speakers or speakers that aren't timbre matched. Hell you might even like it. All I'm saying is that matched speakers are "ideal" for multichannel systems. Hope I haven't confused you to much.

Summary:
identical speaker: good
timbre matched: good
anything else: no good

I don't think you read the post very well.I am acquainted w/the virtues of a timbre matched speakers. I already have matching LCR speakers from the same series.

The Point: is there any performance advantage to a specialized (yes, obviously timbre matched) center speaker over a identical satellite bookshelf used as a center? Was there ever a need for a specialized center speaker as opposed to getting a third identical bookshelf. What do you gain from the M-T-M configuration - seems like you cut down on horizontal dispersion.



[This message has been edited by BEC (edited June 10, 2000).]

"is there any performance advantage to a specialized center speaker"

Usually not!

However, many speakers are not magnetically shielded and their specialized centers are. This is the only reason I could find.

Sorry 'bout that. I was taking it from the standpoint of a general center channel speaker and not from a matched one. Anyways...

If the center is matched to the other mains, there shouldn't be any major difference besides driver set-up and enclosure design. Timbre matched speakers are designed to sound the same. (as you already know)

Was there ever a need for specialized center speaker? Yes & No.

No, because identical speakers are capable of doing the job.

Yes, because although it wasn't "needed", it offered some advantages over a verticla design. Contrary to your idea about it's possible compromised dispersion, the horizontal orientation provides "better" horizontal dispersion. To expand the soundfield of the center channel they put speakers in the M-T-M arrangement which creates a wider sound source.The vertical orientation of conventional speakers have a narrow sound source. (Just visualize each respective speaker arrangement and it'll make sense)

Summary:
Sound: identical in either case (if timbre matched)
Dispersion: Specialized speaker has improved dipersion.

I hope I addressed your questions correctly this time.

3U36, I have to disagree. I'm sure you have it backwards:

The MTM design used horizontally results in an off-axis suckout due to comb filtering effects. This translates to poor off axis coverage in the horizontal plane (to the left or right of center).

The MTM design used vertically, as in a THX setup, results in limited vertical dispersion which reduces floor and ceiling bounce. The reduction in floor and ceiling bounce provides for more direct and less reflected sound. Less reflected sound allows for more a more controlled listening experience. Because THX is based on reconstructing the sound originally created on a foley stage, with minimal modification by the home listening room, limited vertical dispersion is part of the design parameters.

In fact, it's known my center speaker (a Super Center) has > -10db at 30deg. off-axis, HORIZONTALLY in the midrange, which provides NO performance advantage I can think of.


To recap: the plane w/pole cancellation (the line of MTM) has LESS midrange dispersion, leading to a limited sound field (dipolar instead of monopolar). Good in sweet spot - bad off axis.