Using a pair of speakers as center (instead of only one)

[psg]

Hi,

As many of you know, I'm on a quest to find a good center for my La Scala's.

In the "KG4 as center for La Scala?" thread, Frzninvt suggested a sideways La Scala (a setup he uses). I posted a picture of what it would look like over my TV in that thread. I tried lying one of my mains on its side and listenned to a 5.1 movie. The sound was great when seated in the middle, but not so hot when seated on the side: less high frequency, and a feeling that sound was coming from a loudspeaker instead of being transparent. I'm guessing my seating is closer to the front speakers than Frzninvt's and the angle gets bigger.

The ideal would be a single vertical Cornwall, mounted horizontally. I'm not likely to find that anytime soon!

I think a good compromise is to use a pair of black Heresy's. The 97 dB efficiency goes up to 100 or 103 when you double them (depends on whether it's just a doubling of power or if the doubled area goes into it as well) so it is easily matched to 104 dB. The impedence in parallel is 4 ohms, which is still okay. I've read that someone on this forum uses a pair of speakers and likes it, and another saying that it muddies the sound because of the phase interference of two closely spaced point sources. I'm sorry, but I never kept those threads and can't find them again.

Any others with opinions on this? Would a pair of Heresy's work? Or should I just buy one (perhaps brand new for close to the same price?)

Thanks!

[D-MAN]

A single would work just fine.

DM

[psg]

A single would work just fine.

So you think one is enough? Or that two leads to trouble?

There's a 7 dB difference... It's manageable, but it's on the edge.

[Q-Man]

You want a center speaker to localize the sound with the picture. It should draw your attention to the screen. Two center speakers defeats this. If you do use two, place them above or below the tv on their sides with the tweeters next to each other.

One speaker will work ok for now. When you get potivated enought to find a way to fit in a LaScala then you can use the Heresys for an extra pair of surrounds or front effect speakers.

[j-malotky]

Peter

I also must advise against using two centers.

A 7 db drop should be manageable. Most processors that I have seen have a 20 db range per channel. It really depends on your room and distance between your and your speakers.

What I did in my HT was build my own center to use in between my Khorn mains. I put a single K400 and K77 over my screen and a pair of K22 (Heresy) woofers under the screen. The pair of K22's makes the woofer section 100db vs the 97 db.

Here is a thread with Pics. http://forums.klipsch.com/idealbb/view.asp?topicID=50440

Do not lay a LAS on its side, unless you remove the K400 and mount it Horizontally. The K400 squawker on its side is way too narrow of a spread and will only sound OK if you are straight in front of it. Way too limiting IMO.

You are on the way to having a killer Heritage HT. Enjoy.

JM

[psg]

Q-Man,

The two speakers would be upright and side-by-side, over the TV (no room under it since it has an integrated stand).

JM,

I really like your center design. I guess I need something like that. The top part would be perfect over my TV. Did you use a standard La Scala crossover to do it? I can see the cost getting prohibitive rather quickly unless you started with an old La Scala to get the parts...

So the La Scala on its side isn't okay (which I agree to), but all your sideways Heresys are okay?

Does the Heresy have wider up/down dispersion, translating to wider horizontal dispersion when on their side?

Also, a friend of mine sent me this link which also discourages using two speakers:

http://www.audioholics.com/techtips/roomacoustics/loudspeakerplacement.php

Lastly, is to determine when 2 center channels are warranted. Many people

like the idea of 2 center channels because there is a lot of sound coming

from the center channel, and 2 channels can handle that better than one. It

is estimated that the average movie soundtrack has 60% or more of the sound

directed at the center channel. Also, many people with projections screen

TVs do not like the notion of sound coming from above or below the screen,

and therefore try a speaker above and below. All of this may seem well and

good, but in most cases 2 center channels are more problematic than they

are worth. Typically you wind up with interfering wave patterns between the

two speakers that cause areas where certain frequencies are cancelled out

and other areas where they are doubled. If this seems difficult to

understand imagine dropping a pebble in a pool of still water. The ripples

radiate from where the pebble entered the water. Now drop a second pebble

in the water in a different location, and you can see how the two ripple

effects interfere with each other. This is similar to what happens with two

center channels. It is not a problem with stereo channels, because their

signals are different and designed to function in a stereo mode. But with

two center channels the signal is the same and thus the interference

pattern. In general we recommend avoiding 2 channels, and rather than buy 2

center channels, and the necessary amplifiers, buy one better center

channel.

Thanks guy! Get it going! Anyone on the pro side?

[Q-Man]

It's like the problem that you can have when you stack two idenical speakers. One speaker should be upside down on the other

to keep the tweeters as close as possible. Other wise they will cancel each other out at certain frequencies. You could remove the tweeters from the cabinets and put them together.

[Jim E]

Peter,

I would advise using an additional LaScala for the center channel. The overall heigth would require removing and modding the top section for placement above the screen but you would still benefit a greater return. It is generally agreed that use of the same speakers for all the front channels is your best bet. There are tonal changes between other the other models that would worry me more than just the reduced spl levels. The addition of a sub would be helpful as well.

Good luck,

Jim

[psg]

I would advise using an additional LaScala for the center channel. The overall heigth would require removing and modding the top section for placement above the screen but you would still benefit a greater return. It is generally agreed that use of the same speakers for all the front channels is your best bet. There are tonal changes between other the other models that would worry me more than just the reduced spl levels. The addition of a sub would be helpful as well.

Sounds like I need a vertical Cornwall!

BTW, I have a sub (Hsu STF-3). Helps a lot with the La Scala.

[Griffinator]

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On 11/12/2004 8:35:43 PM psg wrote:

A single would work just fine.

So you think one is enough? Or that two leads to trouble?

There's a 7 dB difference... It's manageable, but it's on the edge.

----------------

Despite the fact that most amps are perfectly stable at 4 Ohms, the characteristic of the sound output changes dramatically when they run that low. Speakers that were once well-balanced become bass-heavy and rather throaty-sounding when run in parallel.

I've made this argument before, and been shouted down by people who use two-speaker center installations. It's cool, I'm getting used to being shouted down by other forum members...

I blame Fox News for this phenomenon - people watch Sean Hannity and The O'Reilly Factor and think that's the proper decorum for debating with an opposing viewpoint...

[psg]

On 11/13/2004 1:54:25 PM Griffinator wrote:

A single would work just fine.

So you think one is enough? Or that two leads to trouble?

There's a 7 dB difference... It's manageable, but it's on the edge.

Despite the fact that most amps are perfectly stable at 4 Ohms, the characteristic of the sound output changes dramatically when they run that low. Speakers that were once well-balanced become bass-heavy and rather throaty-sounding when run in parallel.

Thanks for your input. I t really sounds like a single reconstructed La Scala would be ideal, followed by a vertical Cornwall. The problem is finding these speakers anywhere near locally to avoid shipping them. There also that RC-7 on ebay (with the likely scratched side!), but that would be a huge mismatch; I think a single Heresy is better (except for the lower WAF).

I've been in contact with the seller of a black pair of Heresy's in the Eastern US, but even that involves considerable overhead of shipping into Canada, 15% in taxes and possibly huge brokerage fees. So that is limiting my enthousiasm.

Anyone want to split a pair of black Heresy's? I'm sure the seller wouldn't mind shipping the two boxes at separate places...

[Frzninvt]

Two centers will work well together! I have decisive proof! The Academy is on top of the TV and the La Scala is on its side below. These speakers operate as one and you cannot distinguish one from the other whether you are watching TV or listening to music.

As to the La Scala only sounding OK on its side I say BULLSH*T, mine is on its side and while the dispersion is not huge it still sounds better than just GOOD! I can still hear it well even though I sit off axis from it, but that is why I have the Academy since I realize having it on its side is somewhat of a compromise. I have DeanG's Jensen PIO AA in it so the level of detail in the center is more than a standard La Scala will reproduce.

My centers receive 4X the power that the mains and rears do, this adds to an increase in presence, detail and dynamics. Both are powered by separate amplifiers as well. I realize that this may not work for everyone but it works for me!

A split La Scala may work better for you PSG, I have never tried one of my verticals for center since they serve as my rear effects speakers. I cannot imagine it being better than a La Scala since the front stage is all horn loaded drivers.

The Heresy/Heresy's should work fine, try a single and see how well it works for you. Add the other one if you feel that the single is not fitting the bill.

Someday when I get a different TV I may be able to place my La Scala upright, it will stay on its side for now though.

[psg]

On 11/14/2004 7:40:20 AM Frzninvt wrote:

Two centers will work well together! I have decisive proof! The Academy is on top of the TV and the La Scala is on its side below. These speakers operate as one and you cannot distinguish one from the other whether you are watching TV or listening to music.

Good to know! Thanks!

As to the La Scala only sounding OK on its side I say BULLSH*T, mine is on its side and while the dispersion is not huge it still sounds better than just GOOD! I can still hear it well even though I sit off axis from it, but that is why I have the Academy since I realize having it on its side is somewhat of a compromise. I have DeanG's Jensen PIO AA in it so the level of detail in the center is more than a standard La Scala will reproduce.

No disrespect intended! Mine sounded great when on-axis, but sounded wrong seated on the corner of my couch. If you've seen the picture of my setup, you'll see it's a small place and my angle is likely greater than yours.

My centers receive 4X the power that the mains and rears do, this adds to an increase in presence, detail and dynamics. Both are powered by separate amplifiers as well. I realize that this may not work for everyone but it works for me!

A split La Scala may work better for you PSG, I have never tried one of my verticals for center since they serve as my rear effects speakers. I cannot imagine it being better than a La Scala since the front stage is all horn loaded drivers.

If it's easy, you could try it and report back!

The Heresy/Heresy's should work fine, try a single and see how well it works for you. Add the other one if you feel that the single is not fitting the bill.

Someday when I get a different TV I may be able to place my La Scala upright, it will stay on its side for now though.

Thanks for the good advice!

[jtkinney]

I too am using 2 center speakers with good results. I have a pair of Heresy's on either side of a 50" RPTV. I know it should have comb effects, but except for pure tones, I can't find a peak or a null anywhere. I think with the frequency changing so rapidly for most media, without a realtime analyzer with a bunch of microphones your going to miss it.

Just my thoughts.

[Frzninvt]

My brother in law Gilbert uses two vertical Cornwalls for his center in his Krell HT and believe me it makes a difference! His damn TV supports the weight of both of those monsters! WoW!

For me the La Scala/Academy combo is downright scary for realism. They are powered by independent amplifiers though with 400W available on demand but rarely see more than a couple to five watts of Class A power.

[Griffinator]

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On 11/15/2004 1:35:29 PM Frzninvt wrote:

My brother in law Gilbert uses two vertical Cornwalls for his center in his Krell HT and believe me it makes a difference! His damn TV supports the weight of both of those monsters! WoW!

For me the La Scala/Academy combo is downright scary for realism. They are powered by independent amplifiers though with 400W available on demand but rarely see more than a couple to five watts of Class A power.

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This is a major difference.

All I was arguing was that running them in parallel off one amp channel is going to produce a drastically different sound characteristic than running one off that same amp channel...