Right now, my center is an identical speaker as my Left and Right. Seems to be the best way to have a seamless sound field across the front. However, I am relocating due to a job transfer and re-evaluating everything in my home theater and which stuff will survive the move. I am considering moving to fixed screen so that I can use Carada's new masking system which would mean a traditional horizontal center channel speaker. The problem is that the ones that I have had at home despite manufacturer's claims, have been significantly inferior to the floor standing models. Has this changed? B&W appears to have a substantial center that blends with the 800 series. What other high-end speaker companies do?

There are some great center out there. You do have to be careful about off-axis listening with an MTM array, but there are some large centers with a vertically oriented tweeter and midrange flanked by woofers. I am still of the opinion that as far as off-axis listening goes that a vertically oriented center is best, however I think the most major combing problems with off-axis listening are ameliorated with a vertically oriented Tweet Midrange array, that's my .02

The paradigm signature centers come to mind, but there are many others as well.

Another trick to get things really REALLY coherent, is Audyssey. Even with imperfectly matched speakers, occassionally grossly imperfectly matched speakers, Audyssey does wonders at making them blend together. It's one of the most impressive parts of Dynamic EQ, IMO, and the biggest change to my system, and I do not have my surrounds matched to my fronts, now it's amazingly cohesive. Just an aside thought. OBviously starting with matched speakers is best, but...

I can't speak for all, but the Revel Salon makes a wonderful, natural sounding center. It is excellent for center vocals, and since it is quite large can also handle the load that is given to the center channel.

Joey

I can't speak for all, but the Revel Salon makes a wonderful, natural sounding center. It is excellent for center vocals, and since it is quite large can also handle the load that is given to the center channel.

Joey

??? the salon isn't a horizontally oriented speaker. Not relevant.

I think he meant the Voice center. And I'm guessing it's one of the better dedicated centers.

Right now, my center is an identical speaker as my Left and Right.


I've tried something similar myself, running a single (inexpensive) PSB Alpha B1 (2 way monitor) as my center speaker.

Seems to be the best way to have a seamless sound field across the front. However, I am relocating due to a job transfer and re-evaluating everything in my home theater and which stuff will survive the move. I am considering moving to fixed screen so that I can use Carada's new masking system which would mean a traditional horizontal center channel speaker. The problem is that the ones that I have had at home despite manufacturer's claims, have been significantly inferior to the floor standing models. Has this changed? B&W appears to have a substantial center that blends with the 800 series. What other high-end speaker companies do?


FWIW I'm currently running a Revel performa C52 as my center and wouldn't have any issue with running a C32. But I have the extra room in my TV rack for the C52 immediately below my 37" LCD TV.

I do NOT have room (in my rack) for a Revel Ultima Voice (1 or 2) center speaker, and suspect that it does not have that much more to offer over the Performa C52 that I already have, let alone that it costs 2-to-7x (used) what I paid for my used C52.

FWIW while I enjoy movies with 5.1 surround sound, they are at most 20% of my music/HT system usage. Music (both 2 channel and MC) is where it's at for me 80% of the time.

Cheers

Don't forget my Aerial CC5 center speaker which integrates so well with my Aerial 9s.

Wouldn't using an AT screen be less of a compromise than moving to a horizontal centre channel in your case?

There are some great center out there. You do have to be careful about off-axis listening with an MTM array, but there are some large centers with a vertically oriented tweeter and midrange flanked by woofers. I am still of the opinion that as far as off-axis listening goes that a vertically oriented center is best, however I think the most major combing problems with off-axis listening are ameliorated with a vertically oriented Tweet Midrange array, that's my .02.

Hi Chris,

Can you please elaborate on how a vertically oriented tweeter midrange array ameliorates off-axis combing problems? Does this have to do with the fact that in most cases the audience's ears are close to equidistant from the drivers regardless of how far off-axis they are seated?

Thanks.

Larry

Hi Chris,

Can you please elaborate on how a vertically oriented tweeter midrange array ameliorates off-axis combing problems? Does this have to do with the fact that in most cases the audience's ears are close to equidistant from the drivers regardless of how far off-axis they are seated?

Thanks.

LarryNo. It is because you do not change your vertical position very much but you do move your head horizontally all the time.

You can do 3 identical center channels as LCR under the screen with excellent results.

IE Three Revel Voice 2's as LCR, all three positioned under the solid/nonAT screen.

Revel even recommends this as a perfectly acceptable option. Just don't put them on the floor. Use their stands.

Bulldogger asked if high-end centre channels have gotten better. I don't know what the "old" ones were like but there are certainly acceptable centre channels now. I've got an ATC C6 active centre-channel which is a very good match for my ATC Anniversary 100 mains. Almost the same in terms of overall size, frequency response, and output. In my opinion you don't have to have IDENTICAL speakers up front (although it would be nice for a number of reasons) to get optimum results. It just depends on what your speaker manufacturer has to offer. The ATC speakers from the 50 up are designed to be mixed and matched so it isn't surprising that they work well together...

There are some great center out there. You do have to be careful about off-axis listening with an MTM array, but there are some large centers with a vertically oriented tweeter and midrange flanked by woofers. I am still of the opinion that as far as off-axis listening goes that a vertically oriented center is best, however I think the most major combing problems with off-axis listening are ameliorated with a vertically oriented Tweet Midrange array, that's my .02

Hi Chris,

Can you please elaborate on how a vertically oriented tweeter midrange array ameliorates off-axis combing problems? Does this have to do with the fact that in most cases the audience's ears are close to equidistant from the drivers regardless of how far off-axis they are seated?

Thanks.

Larry

No. It is because you do not change your vertical position very much but you do move your head horizontally all the time.

Hi Chris and Kal,

Please excuse this crude drawing attached. I am attempting to show that if your ears are centered on two vertically oriented drivers on-axis, and you move off-axis, but your ears are still at the same height, the distance to each driver to the ear will remain the same even though both distances have increased from the on-axis distance. If you have equal distances you can't have comb filtering.

For horizontally oriented drivers if the ear is equi-distant to both drivers on-axis, and the listener moves off-axis at the same height, the distances between each driver and the ear becoming progressively different lengths. With different lengths you have a potential for comb filtering.

Larry

If you have speakers designed from the ground up for wide dispersion (vertical and horizontal), you won't have any problems.

Most folks with dedicated HT's and reclining seats will move their heads up and down at least one foot during a movie. So, you have both horizontal and vertical head movement that is significant. It can only be accomidated with speakers that have wide dispersion patterns.

Hi Chris and Kal,

Please excuse this crude drawing attached. I am attempting to show that if your ears are centered on two vertically oriented drivers on-axis, and you move off-axis, but your ears are still at the same height, the distance to each driver to the ear will remain the same even though both distances have increased from the on-axis distance. If you have equal distances you can't have comb filtering.

For horizontally oriented drivers if the ear is equi-distant to both drivers on-axis, and the listener moves off-axis at the same height, the distances between each driver and the ear becoming progressively different lengths. With different lengths you have a potential for comb filtering.

Larry

Exactly.

With a vertically oriented MTM array, you still have combing if you move off-axis vertically, but you can arrange the speaker so the tweeter is level and at ear height, which avoids the combing. People who aren't sitting in the sweetspot still have their head at the same height, so still no combing even if they're off-axis.

With a horizontally oriented MTM array, you won't have combing in the sweetspot, but anyone sitting off axis will.

MTM arrays horizontally have this weakness, but doesn't mean that they are always a terrible choice. I use a horizontally oriented MTM center channel for instance, but I don't hold any fantasies that combing isn't an issue for off-axis listening, it certainly remains an issue. That's why I sit in the sweetspot, and relegate my guests to the inferior seats! :p

Wouldn't using an AT screen be less of a compromise than moving to a horizontal centre channel in your case?

I have an AT screen. I plan to use a fixed AT screen if I switch.Right now I have a retractable screen.

For horizontally oriented drivers if the ear is equi-distant to both drivers on-axis, and the listener moves off-axis at the same height, the distances between each driver and the ear becoming progressively different lengths. With different lengths you have a potential for comb filtering.

Larry

What do you think of this approach. I like Mcintosh speakers and find that you get very wide dispersion with their approach. It's almost like an electrostat sound but with better imaging.

What do you think of this approach. I like Mcintosh speakers and find that you get very wide dispersion with their approach. It's almost like an electrostat sound but with better imaging.

Hi,

I certainly will defer to the more knowledgeable forum members on this design, but with two woofers, 32 mid-range drivers, and 20 tweeters and rated at 1200 watts per channel, it certainly should have no problems with reaching reference levels given adequate amplifier power. ;)

What I obviously don't understand is with so many drivers spaced over 3' horizontally apart in some instances, how can serious comb filtering be avoided? At least in our simplistic example an on-axis listener could be positioned to be equidistant from a pair of horizontally spaced drivers. How can even an on-axis listener be positioned equidistant from 20 tweeters and 32 mid-range drivers? :confused: I'm assuming that all tweeter are playing the same sounds and likewise with all mid-range drivers.

Larry

What I obviously don't understand is with so many drivers spaced over 3' horizontally apart in some instances, how can serious comb filtering be avoided? At least in our simplistic example an on-axis listener could be positioned to be equidistant from a pair of horizontally spaced drivers. How can even an on-axis listener be positioned equidistant from 20 tweeters and 32 mid-range drivers? :confused: I'm assuming that all tweeter are playing the same sounds and likewise with all mid-range drivers.

Larry

I am not sure. With the speakers that I have, which have a 5 tweeter array that is a Bessel array http://www.aes.org/e-lib/browse.cfm?elib=6012, I do not hear comb filtering.

Hi,

I certainly will defer to the more knowledgeable forum members on this design, but with two woofers, 32 mid-range drivers, and 20 tweeters and rated at 1200 watts per channel, it certainly should have no problems with reaching reference levels given adequate amplifier power. ;)

What I obviously don't understand is with so many drivers spaced over 3' horizontally apart in some instances, how can serious comb filtering be avoided? At least in our simplistic example an on-axis listener could be positioned to be equidistant from a pair of horizontally spaced drivers. How can even an on-axis listener be positioned equidistant from 20 tweeters and 32 mid-range drivers? :confused: I'm assuming that all tweeter are playing the same sounds and likewise with all mid-range drivers.

Larry

I suspect that the multiplicity of the drivers increases the complexity of the interference such that its spatial distribution is more fine-grained and approach randomness. Of course, this also requires that you are listening far from the array with regard to the wavelengths involved, something that is likely when one see the small size of the drivers.

I am not sure. With the speakers that I have, which have a 5 tweeter array that is a Bessel array http://www.aes.org/e-lib/browse.cfm?elib=6012, I do not hear comb filtering.

Hi,

Unless it went over my head entirely, the quoted abstract made no mention of Bessel arrays being immune or resistant to comb filtering.

However, I have a theory that subtle comb filtering is so much a part of our daily lives that we have been acclimated to its sound and it simply is not obvious to us, and therefore in many cases, not objectionable. For example, it's virtually impossible to be in any normal acoustic environment without the ground or a floor, to varying degrees, presenting our ears with a "ground bounce" reflection which will interfere with the direct sound to cause comb filtering. We've been constantly exposed to this comb filtering from birth, and now it's probably a normal background noise that in all likelihood is psycho-acoustically filtered out by our brain.

Kal alludes to another good example of why we may not hear comb filtering, and that is the fact our hearing has a finite resolution. Put comb filtering nulls and peaks too close together for a particular frequency and we simply will not be able to hear it even though our RTA clearing shows it. This limitation in human hearing doesn't require an array of small drivers, just the right combination of signal frequency and a reflected timing delay from the direct signal to produce filtering that is beyond human hearing.

I'm not saying that we can't create audible comb filtering, either deliberately for special effects, or inadvertently. My point is that, in many cases, even if we measure its presence, it may be either beyond our ability to resolve the peaks and nulls, the level may be below our threshold of hearing, the frequency may be outside our audible range of hearing, or it may simply be filtered out by our brain as noise so we don't notice it.

Just my two cents. :o

Larry

when drivers are in an array where they are positioned approx 1/4 of the average wavelength apart, you have a line array. in these cases, they combine to act like a single point source with very advantageous characteristics. like extreme directionality, and very fast fall off when you go off axis.

when drivers are in an array where they are positioned approx 1/4 of the average wavelength apart, you have a line array. in these cases, they combine to act like a single point source with very advantageous characteristics. like extreme directionality, and very fast fall off when you go off axis.

As a single source or signal line source, yes. But as a "point" source?

when drivers are in an array where they are positioned approx 1/4 of the average wavelength apart, you have a line array. in these cases, they combine to act like a single point source with very advantageous characteristics. like extreme directionality, and very fast fall off when you go off axis.

The older model the XRT28 behaved that way for sure. The newer XR200 does not. Well I can't hear it and I do notice that sort of thing. I do not know how that was accomplished but that has been greatly improved. With the XRT28, if you moved to the sides it was clearly audible. With the new speakers it is almost like what you would hear from something like Martin Logan but not exactly. Not sure about the center channels. I have never moved off axis while listening.

Hi,

We've been constantly exposed to this comb filtering from birth, and now it's probably a normal background noise that in all likelihood is psycho-acoustically filtered out by our brain.


I'm not saying that we can't create audible comb filtering, either deliberately for special effects, or inadvertently. My point is that, in many cases, even if we measure its presence, it may be either beyond our ability to resolve the peaks and nulls, the level may be below our threshold of hearing, the frequency may be outside our audible range of hearing, or it may simply be filtered out by our brain as noise so we don't notice it.

Just my two cents. :o

Larry

I know exactly how comb filtering sounds from my experimentation with AT screens. Perhaps it is possible to measure it, but I can not hear it. Comb filtering if very annoying once you become aware of it. I am interested in some speaker brand with great center channels that are the equals of the front left and right.

Right now, my center is an identical speaker as my Left and Right. Seems to be the best way to have a seamless sound field across the front. However, I am relocating due to a job transfer and re-evaluating everything in my home theater and which stuff will survive the move. I am considering moving to fixed screen so that I can use Carada's new masking system which would mean a traditional horizontal center channel speaker. The problem is that the ones that I have had at home despite manufacturer's claims, have been significantly inferior to the floor standing models. Has this changed? B&W appears to have a substantial center that blends with the 800 series. What other high-end speaker companies do?

You might want to check out Cinepro's AFM center channel speaker. I heard it at last years CEDIA and was very impressed. It was quite large... ~12" H x 36" w. I also heard their smaller mighty cc speaker at Sim2's room and it also sounded really nice but the larger cc array speaker was extremely impressive.

Can you please elaborate on how a vertically oriented tweeter midrange array ameliorates off-axis combing problems? Does this have to do with the fact that in most cases the audience's ears are close to equidistant from the drivers regardless of how far off-axis they are seated?

Larry,

Equidistance of the right and left ear to the driver is one factor, but an even more glaring problem is lobing cancellation due to interaction between the drivers themselves. Lobing will occur regardless of ear equidistance, and is inherent in any speaker with multiple drivers, because whenever you have sound radiating from more than one point source, the radiation patterns will create a cancellation axis with a noticeable change. (Speakers with coincident driver designs like Thiel try to solve this by placing the tweeter inside the woofer, but this poses other technical challenges, there are no free lunches).

Where the horizontal vs. vertical driver arrangement comes into play is in directing the inevitable cancellation axis. The attached image shows the difference. The left side view shows how a vertical driver array directs the lobing cancellation axis above and below the heads of all seated listeners, regardless of where they are positioned horizontally. The right side shows how a horizontal driver array will direct the cancellation effects at certain listening positions, making for an uneven experience across the seats.

This is why vertically oriented driver arrays make for a more consistent soundfield across the various seating positions. However, horizontal arrays are more form factor-friendly for a center speaker positioned above or below the display, which is why the majority of manufacturers favor this design. A good compromise as Chris pointed out is to vertically stack the tweeter and midrange drivers, flanked by the less localizable woofers, which adds less thickness to the speaker dimensions than a traditional left or right vertically oriented speaker.

There will still be comb filtering effects between the speakers, but at least you're controlling the lobing effects for each speaker with a vertical driver design.

Hope this helps,
Philip

This article may prove useful in understanding the issues:

http://www.audioholics.com/education/loudspeaker-basics/vertical-vs-horizontal-speaker-designs

Larry,

Equidistance of the right and left ear to the driver is one factor, but an even more glaring problem is lobing cancellation due to interaction between the drivers themselves. Lobing will occur regardless of ear equidistance, and is inherent in any speaker with multiple drivers, because whenever you have sound radiating from more than one point source, the radiation patterns will create a cancellation axis with a noticeable change. (Speakers with coincident driver designs like Thiel try to solve this by placing the tweeter inside the woofer, but this poses other technical challenges, there are no free lunches).

Where the horizontal vs. vertical driver arrangement comes into play is in directing the inevitable cancellation axis. The attached image shows the difference. The left side view shows how a vertical driver array directs the lobing cancellation axis above and below the heads of all seated listeners, regardless of where they are positioned horizontally. The right side shows how a horizontal driver array will direct the cancellation effects at certain listening positions, making for an uneven experience across the seats.

This is why vertically oriented driver arrays make for a more consistent soundfield across the various seating positions. However, horizontal arrays are more form factor-friendly for a center speaker positioned above or below the display, which is why the majority of manufacturers favor this design. A good compromise as Chris pointed out is to vertically stack the tweeter and midrange drivers, flanked by the less localizable woofers, which adds less thickness to the speaker dimensions than a traditional left or right vertically oriented speaker.

There will still be comb filtering effects between the speakers, but at least you're controlling the lobing effects for each speaker with a vertical driver design.

Hope this helps,
Philip

Hi Philip,

Thanks, the visualizations were extremely helpful.

I'm wondering whether two individual center channel speakers stacked below and above a display might produce a similar mitigating lobing effect to the Vertical Speaker Driver Array?

Thanks.

Larry

I know exactly how comb filtering sounds from my experimentation with AT screens. Perhaps it is possible to measure it, but I can not hear it. Comb filtering if very annoying once you become aware of it. I am interested in some speaker brand with great center channels that are the equals of the front left and right.
Have a look at Mark Seaton's Catalyst speakers. Very capable design, coaxial driver (meaning: no combing or other anomalies, in any direction), lots of positive feedback, pictures and info on this forum.. :)

I do not know whether it is of any interest to you but based on my set up I am very satisfied with the performance of my center speaker.

I am using B&W 800Ds as my L&R and the big HTM1D at the center and I have to say integration is excellent. The specific center speaker is a full range speaker and an excellent match to the 800Ds since it has exactly the same mid and tweeter as well as three of the bass drivers of the 802D (8") to compensate for the 2x10" that each of the 800Ds have.

The only thing that it needs and I am building it right now is a base to lift it up a bit (it is floor based) so that you have the tweeters and mid as close with regards to height as possible.

I do not know whether it is of any interest to you but based on my set up I am very satisfied with the performance of my center speaker.

I am using B&W 800Ds as my L&R and the big HTM1D at the center and I have to say integration is excellent. The specific center speaker is a full range speaker and an excellent match to the 800Ds since it has exactly the same mid and tweeter as well as three of the bass drivers of the 802D (8") to compensate for the 2x10" that each of the 800Ds have.

The only thing that it needs and I am building it right now is a base to lift it up a bit (it is floor based) so that you have the tweeters and mid as close with regards to height as possible.

If you are raising it up why didn't you just get 3 800D's? Or will the HTM1D still be lower than the 800D's even with the base to accomodate a lower video display?

I do not know whether it is of any interest to you but based on my set up I am very satisfied with the performance of my center speaker.

I am using B&W 800Ds as my L&R and the big HTM1D at the center and I have to say integration is excellent. The specific center speaker is a full range speaker and an excellent match to the 800Ds since it has exactly the same mid and tweeter as well as three of the bass drivers of the 802D (8") to compensate for the 2x10" that each of the 800Ds have.This is a perfect example of a rare properly-done horizontal-appearing center channel speaker. The 3 bass drivers are closer to each other than 1/2wavelength in their passband and less than 1/4wavelength from the midrange driver at crossover. In addition, the midrange and tweeter are vertically arrayed. In other words, it will not suffer from the interference and lobing of the majority of horizontal center speakers.

I do not know whether it is of any interest to you but based on my set up I am very satisfied with the performance of my center speaker.

I am using B&W 800Ds as my L&R and the big HTM1D at the center and I have to say integration is excellent. The specific center speaker is a full range speaker and an excellent match to the 800Ds since it has exactly the same mid and tweeter as well as three of the bass drivers of the 802D (8") to compensate for the 2x10" that each of the 800Ds have.

The only thing that it needs and I am building it right now is a base to lift it up a bit (it is floor based) so that you have the tweeters and mid as close with regards to height as possible.I agree. That is an excellent center that blends extremely well.

I agree. That is an excellent center that blends extremely well.Sure but it usually suffers from not being at the same height as the L/R speakers. Of course, if one could accomplish that (and not with the B&W stand), one could also just use three identical speakers for L/C/R, as I do. :D

What I meant by raising it is to bring it as high as I can till the Marlan head reaches the bottom of my screen which is 90cm from the floor. It will not be at the same level as the 800Ds head but much better and closer that leaving it on the floor.

Right now I use the included spikes and have it tilted up and it still sounds great. I believe that when I finish with the custom stand there will be a great reduction in height difference between the tweeters of the mains and I will only use a very slight tilt. In other words it will be the closest I can get to having 3 of the same speakers without using an AT screen (which was my choice).

Sure but it usually suffers from not being at the same height as the L/R speakers. Of course, if one could accomplish that (and not with the B&W stand), one could also just use three identical speakers for L/C/R, as I do. :D

That's what I do now as well. I just have another identical floor standing speaker behind an AT screen. It was a vast improvement over the "matching" center channel, even on a stand at the proper height.

Well you have to decide between compromising video with an AT screen (my view) or sound with a matching center. Fortunately, the HTM1D fits the bill for me albeit raised and with a slight tilt.

Well you have to decide between compromising video with an AT screen (my view) or sound with a matching center. Fortunately, the HTM1D fits the bill for me albeit raised and with a slight tilt.

That's exactly the decision. Last time I made it, I decided that being more of an audiophile, the AT screen was the lesser of two evils and according to a Stewart white paper sound is more important. Screen Excellence has a new AT screen however,that is an extremely smooth micro-fiber. BAD ASS screen but kind of expensive, and lower gain. That's as close as I have seen as having your cake and eating it too. http://www.screenexcellence.com/fabrics/enlightor-4k.html

I don't doubt that there are excellent At screens that none of my guests would even notice any difference, but in my case and space right now this was not an option. And for people that have to have a screen with no space at all behind the wall (thus no space for a big speaker), I am saying that there are good solutions such as the HTM1D if you are into B&W. Yet, I went for a Stewart 2.40 140" curved screen which I hope can be turned to an AT screen at less than buying a new one should I chose so in the future.