Vertical vs Horizontal Center Speaker Designs

[chriscmore]

As an alternative, I may end up going with a projection system and an acoustically transparent screen. I have a pair of floor standing towers, powered at 250 watts each, as my front left and right. I can pick up a matching bookshelf speaker from the series, a 3 way powered at 150 watts, and place it directly behind the screen. Thoughts?

Acoustically ideal. Presuming the bookshelf sounds similar to the towers, you'd benefit from having the sound come directly behind the image, having vertically aligned drivers without horizontal wave interference, and getting rid of any large object in the center of your soundfield that could defract and diffuse your imaging.

The amp differences are a very minor contributor compared to speakers and acoustics.

Regarding the screen, feel free to contact me if you have any questions.

Cheers,
Chris
Seymour AV

 

[chriscmore]

I gather that it would be better to set my center up vertically than leave it horizontal. Because my center is designed as being horizonatal will it not benifit me to set it up on its side?

Polk CSi5 on top of a Hitachi.

Well, it's a free tweak to try out.

On the "come on, do it..." peer-pressure side, you would get rid of the wave interference from that speaker's 2 6.5" midrange drivers by rotating it vertically. That should allow the speaker to sound tighter and image more precisely across the room. The section on the $600 MTM speaker would be very similar to what you face, as you have a MTM speaker with a dome tweeter.

On the "what were you thinking..." side, you may find the aesthetics of a tall speaker sitting on top of your TV too much. Also, it's image would shift a couple inches higher, further away from your image.

Again - it's free to try it, but I'd bet if you could live with it like that it will sound better.

Cheers,
Chris
Seymour AV

 

[morkys]

I am wondering the same thing. I have PSB image speakers and my center speaker is a large beast with good specs, but, it is the traditional MTM design. My Image T65 towers have 3 woofers each. I have a few options to consider. I could try another T65, or an ever so slightly smaller T55 or a B25 bookshelf for a center speaker. Putting my C60 center speaker vertically would push the tweeter too far down. Unfortunately, my large subwoofer is rather in the way, so if I chose a tower center speaker, I'd have to move my subwoofer to a corner or the side of the room. Not ideal, but possible.

Any thoughts? What about if I somehow managed to realign the drivers on my center channel so that the tweeter was at the top?

 

[itschris]

What are the comprismises of having the center behind the perfed screen. I would have to assume you're gonna lose some sound quality and some picture quality. Maybe it's won't be noticable, but I can believe you're not giving something up by doing that.

 

[j_garcia]

They make acoustically "transparent" screens that filter out very little.

 

[jostenmeat]

Yeah, as far as audio, the effect is negligible. OTOH, some believe that AT can't be quite as good without some optical coating, or something.

IMO, it's a no brainer for the very large cumulative benefits in audio.

I don't use one, but that's partially because I have an enormous screen coupled with a projector with "average" lumen output, and so I went the way of high gain.

If you can achieve enough brightness, and actually have the money for AT, I think its very well worth it. The gains in audio are just too much to ignore.

 

[TLS Guy]

Hi Fernando -

You're spot on. You'd achieve the number one goal of having an identical model serve as your center channel. Rotating it 90 degrees would be for the most part fine because as you mention there aren't redundant drivers. And lastly, the only compromise is as you said within the crossover region. The steeper the crossovers, the narrower and less audible this compromise would be.

Another lastly (I rarely settle with just one), is that if your TM speaker's drivers are widely spaced they may not image as well as a rotated center. A few "main" speakers space out their drivers to make the soundstage taller, although I don't like this practice as it tends to undermine the driver integration and overall imaging. I love big soundstages, but not by gimmickry.

All in all, it should be nearly perfect and a fine compromise for the benefits you'd get.

Cheers,
Chris

Chris,
i enjoyed your presentation at SOTA and talking with you there. If a TM speaker is going to be placed on its side, then you need to make sure it has even order crossovers. Odd order crossover will result in a tilt to the lobing error of 15 degrees. Not a good thing for a center channel speaker.

As I said at SOTA, the center channel speaker is the toughest of all, and far more often than not really lets the side down. In order to have speech intelligibility many users are forced to run the center too loud, which destroys any chance of having a realistic acoustic perspective.

The speech discrimination band is 1000KHz to 2500KHz primarily. This is just the region that crossovers and driver displacements cause maximum impairment of speech quality. Ideally a full range driver would be optimal here. However I know of no full ranger that would have acceptable spl and bass performance in an enclosure small enough to be a center channel speaker.

I think at present the optimal solution is a coaxial center driver. That is my solution. It is to use the SEAS Prestige T18RE/XFCTV9(H1333) coaxial driver. I use two of them in a TL. The second driver, the top one on the picture, does not have the tweeter connected. It is the fill driver fed from a separate amp via active crossover.
The TL being non resonant adds to the excellent speech clarity. This unit is also an fine music reproducer with an F3 at 45 Hz 12db per octave roll off. It is a joy to listen to vintage mono recordings through it.

Now this SEAS unit is available in an excellent kit speaker, the LOKI kit.

I have recommended this unit previously and will again here. It is an accurate very neutral speaker. If your mains are good neutral speakers it will match fine. It makes no difference if this speaker is on its side or vertical.

I have now found a driver that closely matches the Thiel/Small parameters of the bass/mid speaker, and you could use a couple either side to increase power handling below 500 Hz and correct the step response.

I'm convinced that at this time coaxial speakers work best for the center channel, especially as regards speech clarity.

At SOTA the only rig I considered that had excellent speech clarity were the Pioneer speakers, and they used coaxial drivers.

I will hopefully have time to write my report on the sound quality on offer at SOTA over the weekend.

 

[the grunt]

It's possible that no center channel (using just L/R in a phantom center configuration) would sound better than using duplicate centers. Experiment and see, but don't spend non-returnable money on this approach.

That was my experience when I experimented a while back. A few drawbacks I found to running a phantom center was soundstage collapsing to the side you’re sitting closest to. Not being able turn up the volume on the center channel separately. And not getting any center channel info coming from the mains when using analogue inputs.

I gather that it would be better to set my center up vertically than leave it horizontal. Because my center is designed as being horizonatal will it not benifit me to set it up on its side?

If you have room for a horizontal center turned vertically you might have room for another main above the TV. After experimenting with almost every center channel configuration I could think of I realized I could fit another main upside down above my TV and found center channel nirvana. (eventually I’ll get a projector and screen but the apartment is a bit small for that).

Trying a MTM center vertically above the TV did pull the soundstage up like chriscmore mentioned, however this didn’t happen with the main up there probably because the tweeters were still just above the TV where a normal center would sit. The only difference I notice in the sound field having the center tower above the TV than in front of it and level with the mains is a much more expansive front soundstage. The sounds emanate from the TV but expand and produce a wall of sound up front. Very neat.

Also as chriscmore says, aesthetically it was a bit much at first. After having it there for a while it still looks just wrong, but it sounds just right so who cares how it looks.

 

[gixxerific]

Good read yet again, all the articles I Have found here are very informative.

I hear yet again about 3 identical speaks for the front. Problem is that gets expensive. Most of the manufactures that sell speakers by the singles are in the upper price range already. So economically that is not an option for us beer budget audioholics with champagne taste.

Dono

 

[morkys]

Interesting approach with the tower speaker upside down set above the plasma. Totally impossible with a projector unless you use an acoustically transparent screen, and then there is no need to have the speaker up so high.

 

[TLS Guy]

Good read yet again, all the articles I Have found here are very informative.

I hear yet again about 3 identical speaks for the front. Problem is that gets expensive. Most of the manufactures that sell speakers by the singles are in the upper price range already. So economically that is not an option for us beer budget audioholics with champagne taste.

Dono

Your best solution is to build your own from scratch. If that is a stretch for you and you have good neutral mains the LOKI will be an excellent solution, for just about any situation. There is MINIMAL skill required to put it together.

That unit is one of the best coaxial units, if not the best around. In my view it sounds much better then the KEFs.

You really are short changing yourselves with horizontal MTM lay outs.

If you build your own box you really get the cost down. I know no way of getting such a good center for the money.

 

[the grunt]

I hear yet again about 3 identical speaks for the front. Problem is that gets expensive. Most of the manufactures that sell speakers by the singles are in the upper price range already. So economically that is not an option for us beer budget audioholics with champagne taste

Don’t discount being able to get a single speaker. Both Axiom and a local Focal dealer had no problem selling me singles. If you can’t fit or afford another tower up front then try a matching bookshelf speaker as suggested above by needaglock. Experimenting, I felt this was second best only to having another tower as a center and the bookshelf speaker sounded way better than a horizontal center.

Interesting approach with the tower speaker upside down set above the plasma. Totally impossible with a projector unless you use an acoustically transparent screen, and then there is no need to have the speaker up so high.

Agreed. I bought the tower center originally in anticipation of getting a projector and acoustically transparent screen when I buy a house. I decided there was no use using a traditional horizontal center when I figured out I could fit a tower up there. To my surprise I found out it sounds excellent. The tweeters are only separated 8 inches vertically so pans across the front are smooth. At the same time the vertical separation of the other drivers creates a wall of sound which helps open up the front soundstage, something I find nice since I have to sit so close to the screen/speakers.

 

[jostenmeat]

I hear yet again about 3 identical speaks for the front. Problem is that gets expensive. Most of the manufactures that sell speakers by the singles are in the upper price range already. So economically that is not an option for us beer budget audioholics with champagne taste.

Dono

In addition to grunt's post, I think the most affordable line of speakers that can sell individually are KRK studio monitors. They have a good reputation. And are really quite affordable.

In addition, most ID brands will sell individually. Add Ascend to that list.

I think there are a few mid-priced brands that do so, but perhaps too expensive for you. cheers

 

[morkys]

I wish there was a way I could use the same drivers and make a vertical standing bookshelf-ish mini-tower with a coax top tweeter/midrange/woofer and a midrange/woofer below... made out of the same PSB drivers as in my current center speaker.

 

[chriscmore]

Good read yet again, all the articles I Have found here are very informative.

I hear yet again about 3 identical speaks for the front. Problem is that gets expensive. Most of the manufactures that sell speakers by the singles are in the upper price range already. So economically that is not an option for us beer budget audioholics with champagne taste.

Dono

You usually save money by going for three bookshelfs across the front instead of a pair of towers and an overpriced "center" channel. Why pay for bass extension in the towers, as there are several articles on the advantages of using a single crossover for all channels (e.g. 80Hz) to the sub? Why pay extra for horizontal-ness when most companies bookshelf main is just as capable and can be made to match? And finally in cases where their MTM does sound better because doubling up on the midranges gives it better dynamics, soundstaging, etc, then at least do them justice by vertically orienting the identical three across the fronts.

Aperion sells singles. So does Totem - my personal favorite that's not that expensive. Sometimes you have to ask them specifically if they sell singles or "1.5 pair." B&W doesn't, even though they advertise three identical 800Ds across the front at Abbey Road Studios and at Skywalker Ranch. Some bookshelfs are less expensive for the pair than the "matching" center, so you're sometimes still saving money even with a spare.

Cheers,
Chris

 

[TLS Guy]

I wish there was a way I could use the same drivers and make a vertical standing bookshelf-ish mini-tower with a coax top tweeter/midrange/woofer and a midrange/woofer below... made out of the same PSB drivers as in my current center speaker.

It's much easier to start from scratch.

 

[chriscmore]

I am wondering the same thing. I have PSB image speakers and my center speaker is a large beast with good specs, but, it is the traditional MTM design. My Image T65 towers have 3 woofers each. I have a few options to consider. I could try another T65, or an ever so slightly smaller T55 or a B25 bookshelf for a center speaker. Putting my C60 center speaker vertically would push the tweeter too far down. Unfortunately, my large subwoofer is rather in the way, so if I chose a tower center speaker, I'd have to move my subwoofer to a corner or the side of the room. Not ideal, but possible.

Any thoughts? What about if I somehow managed to realign the drivers on my center channel so that the tweeter was at the top?

As TLS Guy correctly pointed out, if you can concentrate on the 1kHz-2.5kHz zone, you'll improve intelligibility since your C60 has horizontal redundancy in below 2.5kHz. The T55 has the same tweeter, midrange, and crossover as the T65, so yes, it would be great for a center and save a few inches of bulk. Likely if you're crossing over to a sub, you wouldn't notice the handful of Hz lower bass extension anyway. Possibly consider their B25 monitor. It has the same tweeter, midrange and crossover and would match and image almost identically to your T65 for frequencies >80Hz.

Sometimes you can find a loner on eBay, but a pair of B25 are still very reasonable: http://tinyurl.com/5v4tp5

Reconfiguring your C60 to make it as much like a T65 is possible. I'd try to use the same cabinet to keep resonant frequencies similar and just focus on rearranging the drivers.

My general argument is that three B25 across the front would image and timbre match better and for less money than your T65/C60 combo. Or, if one can go AT for the screen, three T65/55s across the front would be impressive indeed.

Cheers,
Chris

 

[chriscmore]

What are the comprismises of having the center behind the perfed screen. I would have to assume you're gonna lose some sound quality and some picture quality. Maybe it's won't be noticable, but I can believe you're not giving something up by doing that.

A woven AT screen will attenuate 0.5-1.5dB, but is smooth, predictable, correctable if needed, and in the top octave beyond where auditory imaging and intelligibility reside. Most processors measure a level match difference of 0.5dB.

Lobing and comb filtering in the more critical frequencies <10kHz are not correctable, predictable, and greatly influence imaging and intelligibility.

One point I brought up at my talk with TLS Guy at the SOTU show that I believe he agreed with (correct me if I'm wrong), was that most home theaters suffer from a center channel intelligibility problem. Evidence of that was Audyssey's new dynamic compression scheme, which worked fine, but is a good cure for the wrong problem. They fix the problem that at the volume where folks turn up their system to understand the dialogue, they then find when the robots start exploding, that it's disturbingly loud. If they had good acoustics in the room, and a vertically-oriented center channel that matched their L/R, they should be able to have the overall volume much lower.

Compensating for clarity by volume is always the wrong fix.

Cheers,
Chris

 

[chriscmore]

Just don't call me perfed...

What are the comprismises of having the center behind the perfed screen. I would have to assume you're gonna lose some sound quality and some picture quality. Maybe it's won't be noticable, but I can believe you're not giving something up by doing that.

Another point is that "perfed" vinyl screens, which look like swiss cheese, are actually very poor acoustically speaking. The "microperf" THX one that you can spend a fortune on will audibly comb filter below the top octave, and requires an in-line EQ, which will compensate tonally but not for the comb filtering. It's fine for huge screens, with the speakers spaced way back.

The regular "perfed" stuff is much much worse and I'd argue not really AT for residential sizes. Here's some stats:

Perfed vinyl "AT" screens: ~49 holes / sq. in.
Microperfed vinyl AT screen: ~200 holes / sq. in.
Woven AT screen (e.g. our Center Stage screen): ~500 holes / sq. in.

Our new weave that we're releasing in December, "Center Stage XD", has triple that hole density at 1,500 holes / sq. in.

A higher hole density shifts artifacts higher in frequency and narrower in bandwidth, further reducing audibility.

Cheers,
Chris

 

[chriscmore]

Trying a MTM center vertically above the TV did pull the soundstage up like chriscmore mentioned, however this didn’t happen with the main up there probably because the tweeters were still just above the TV where a normal center would sit. The only difference I notice in the sound field having the center tower above the TV than in front of it and level with the mains is a much more expansive front soundstage. The sounds emanate from the TV but expand and produce a wall of sound up front. Very neat.

Also as chriscmore says, aesthetically it was a bit much at first. After having it there for a while it still looks just wrong, but it sounds just right so who cares how it looks.

Grunt - Try placing your L/R up on study little platforms. Often speakers sound better raised a few inches off the floor, as it decouples them mechanically and you reduce the bass wave reflection from the floor. It might make them too lean if it's too high, but trying that may even out your front soundstage without having to resort to lowering your TV. If they're crossed over to a sub, you may not notice any change other than image location. I think it might reduce the "mudbass" and clear up any chestiness sound in the 80-250Hz range.

Free to try...

Cheers,
Chris