Vertical vs Horizontal Center Speaker Designs

[the grunt]

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.

Thanks for the advice Chris. I didn’t mean to imply I had any issues with my front soundstage right now, just that having the tower upside down above the TV sort of expands it out vertically without drawing attention up above the screen. Actually I already have my L/R mains up on cinder blocks. While experimenting with different center configurations I had placed a couple bookshelf speakers on top of my mains and was surprised how much more expansive and surrounding the bookshelves sounded than the mains. So I put the mains on cinderblocks and suddenly they sounded even better. And your right it did take care of some issues I was having in the 80-250Hz range.

Thanks,
Dean

 

[morkys]

All the PSB Image speakers use the same tweeter. The speakers with 6.5" woofers all have the same 2500 hz crossover, with the exception that the T55 and T65 towers also have a 500 hz crossover for the bottom woofer(s). The T45 and other speakers with the 5 1/4" woofer have 2200 hz crossovers except for the S50 bipolar surround which have a 2500 hz crossover.

The B25 is the least efficient and handles the least power among the C60, T55 and T65. I think a T55 tower would be really good as a centre. It is more efficient than the C60 and 6 ohms rather than 8 ohms means a bit more power coaxed from the receiver while also having higher power handling than the 2B. With the bottom woofer handling only the 500 hz and below, the T55 actually has less power handling than the C60 in some respects. Fine line there. Of course, the T65 would be a monster center speaker.

Either way, I will try vertical. I think if I can find a used C60 or get a C60 enclosure, I could try to pull it apart and align the tweeter at the top. It will be different from the T55 and T65 because both woofers will be playing everything from 2500 hz on down.

I don't like using bookshelf speakers in my system for the Left and Right because I listen to music full range with this system. I've fiddled with crossovers forever, and while I can get a good sound, it always sounds cleaner with the large towers full range. It's great for stereo and awesome for SACD and DVD-Audio too.

Acoustically transparent screen is only an option if I can remove the screen for listening to audio. SMX and others make very good screens I know, but I'm not convinced that they are what I want to listen to my music through.

 

[irish]

AV/HT newbie. Due to space constraints & WAF factor I'm looking at the Def Tech Mythos 2/3 and 6/7. Speakers would reside on an entertainment system/TV stand. I believe these speakers qualify as MTM but wanted to verify with the pros. Would they suffer the same losses? Thanks for helping out a true beginner!

My plasma is on the stand and bookshelf speakers laid horizontally would block the screen due to size otherwise I'd go with the 3 matching speakers.

 

[TLS Guy]

AV/HT newbie. Due to space constraints & WAF factor I'm looking at the Def Tech Mythos 2/3 and 6/7. Speakers would reside on an entertainment system/TV stand. I believe these speakers qualify as MTM but wanted to verify with the pros. Would they suffer the same losses? Thanks for helping out a true beginner!

My plasma is on the stand and bookshelf speakers laid horizontally would block the screen due to size otherwise I'd go with the 3 matching speakers.

Yes they would. To make a good horizontal center, you need either a coaxial driver, or a three way with at least the tweeter above the mid, and preferably the mid band/pass crossover point spread 350 Hz to at least 4 kHz, like the B & W.

 

[irish]

Yes they would. To make a good horizontal center, you need either a coaxial driver, or a three way with at least the tweeter above the mid, and preferably the mid band/pass crossover point spread 350 Hz to at least 4 kHz, like the B & W.

Thanks for your response! I was pretty sure that was the case but I may have no choice due to my set up. It's a living room/HT set up and acoustically won't be great but it's what we have. I'm still learning and have no idea what the bolded words mean. If I understand correctly when a center is horizontal the tweeter needs to be raised vertically so that it's not in line with the mids...
The stand I have is like this one http://www.avsforum.com/avs-vb/showpost.php?p=15604297&postcount=105 so there isn't room a for a center due to the units being pushed together. I'm also size limited due to using a plasma on it's stand with a 7" clearance from base to screen so bookshelf speakers won't fit.
The best fit from quality mfgs that I've found would be the Def Techs or Paradigm CC-190 which does have vertically aligned tweeters http://paradigm.com/en/paradigm/speaker_only-specification-6-1-3-4.paradigm. Would that be a better option that the Mythos?
Thanks a bunch for helping me out!

These might work too but they're aligned as well http://paradigm.com/en/reference/speaker_only-specification-65-1-3-20.paradigm

 

[TLS Guy]

Thanks for your response! I was pretty sure that was the case but I may have no choice due to my set up. It's a living room/HT set up and acoustically won't be great but it's what we have. I'm still learning and have no idea what the bolded words mean. If I understand correctly when a center is horizontal the tweeter needs to be raised vertically so that it's not in line with the mids...
The stand I have is like this one http://www.avsforum.com/avs-vb/showpost.php?p=15604297&postcount=105 so there isn't room a for a center due to the units being pushed together. I'm also size limited due to using a plasma on it's stand with a 7" clearance from base to screen so bookshelf speakers won't fit.
The best fit from quality mfgs that I've found would be the Def Techs or Paradigm CC-190 which does have vertically aligned tweeters http://paradigm.com/en/paradigm/speaker_only-specification-6-1-3-4.paradigm. Would that be a better option that the Mythos?
Thanks a bunch for helping me out!

These might work too but they're aligned as well http://paradigm.com/en/reference/speaker_only-specification-65-1-3-20.paradigm

The paradigm C190 is on the right lines, but I think you would have to go with an all Paradigm system, as they have a definite voicing about them, that I did not care for when I auditioned them, at least the Studio 100s

 

[lsiberian]

Thanks for your response! I was pretty sure that was the case but I may have no choice due to my set up. It's a living room/HT set up and acoustically won't be great but it's what we have. I'm still learning and have no idea what the bolded words mean. If I understand correctly when a center is horizontal the tweeter needs to be raised vertically so that it's not in line with the mids...
The stand I have is like this one http://www.avsforum.com/avs-vb/showpost.php?p=15604297&postcount=105 so there isn't room a for a center due to the units being pushed together. I'm also size limited due to using a plasma on it's stand with a 7" clearance from base to screen so bookshelf speakers won't fit.
The best fit from quality mfgs that I've found would be the Def Techs or Paradigm CC-190 which does have vertically aligned tweeters http://paradigm.com/en/paradigm/speaker_only-specification-6-1-3-4.paradigm. Would that be a better option that the Mythos?
Thanks a bunch for helping me out!

These might work too but they're aligned as well http://paradigm.com/en/reference/speaker_only-specification-65-1-3-20.paradigm

For If you are interested in a coaxial accessories4less sells KEF speakers for a pretty cheap clip. Still you'd have to like their other offering. I think the best horizontal center I've heard in the budget range is the Beta 360 treated with rockwool and peel-n-seal

 

[irish]

For If you are interested in a coaxial accessories4less sells KEF speakers for a pretty cheap clip. Still you'd have to like their other offering. I think the best horizontal center I've heard in the budget range is the Beta 360 treated with rockwool and peel-n-seal

Thanks for the recommendations. The Beta 360 would be too large for my application although it does look nice. The KEF Q series, iQ60c, looks like it might work pretty well as it's less than 7" tall. The speaker cabinet design is a bit different but that isn't a breaking point. How do co-axials differ from in sound or performance from a more "traditional" design where the speakers are seperate?

 

[TLS Guy]

Thanks for the recommendations. The Beta 360 would be too large for my application although it does look nice. The KEF Q series, iQ60c, looks like it might work pretty well as it's less than 7" tall. The speaker cabinet design is a bit different but that isn't a breaking point. How do co-axials differ from in sound or performance from a more "traditional" design where the speakers are seperate?

If more speakers had a wider bandwidth, then there would be no crossovers and multiple speakers. Multiple speakers are a workaround for a problem, not an inherent advantage.

The point of a coaxial speaker is to keep the sound coherent. What would be ideal is to have a bass/mid cone that crossed over to the tweeter, 4 kHz, then you would avoid a crossover in the speech discrimination band. However no such animal exists at present and crossover to the tweeter in current units is in the neighborhood of 3 kHz.

In a coaxial, the cone of the woofer acts as a wave guide to the tweeter. Things a re designed such that there is usually time coherence. However because a first order crossover is just about never possible, there are phase anomalies at crossover, just like any other speaker. There is symmetrical lobing and therefore the vertical and horizontal axis response is identical. The coverage is therefore conical.

As far as drivers to choose from the most well known are KEF and Tannoy. Thiel also has a coaxial center. Pioneer also have one in their range.

However, after having auditioned KEF recently the SEAS driver is in my view far superior.

You can buy a LOKI kit that is very good value.

I use these drivers in my center speaker. The tweeter is used only in the lower driver, the upper one is an active fill driver and the tweeter not connected.

In this TL, I could not be more happy with it.

 

[User5910]

Perfect8 has an unusual MTM arrangement--the mids are mounted behind the tweeter on the sides of the cabinet, opposed to each other. They claim this is to eliminate cabinet resonance and give a cardioid radiation pattern. Would this give the same kind of comb filtering issues as a regular horizontal MTM or would the opposed drivers create a sort of a virtual centerpoint behind the tweeter?

References

• Perfect8 Cube - MTM speaker in glass enclosure
• Enclosure Baffle Studies - Paper on force cancelling and low resonance of glass enclosure

P.S. I listened to a new Perfect8 tower, about chest high, at AXPONA 2024 that's not on the website yet. It sounded good, but you can't hear the fine details at an audio show.

 

[everettT]

Perfect8 has an unusual MTM arrangement--the mids are mounted behind the tweeter on the sides of the cabinet, opposed to each other. They claim this is to eliminate cabinet resonance and give a cardioid radiation pattern. Would this give the same kind of comb filtering issues as a regular horizontal MTM or would the opposed drivers create a sort of a virtual centerpoint behind the tweeter?

References

• Perfect8 Cube - MTM speaker in glass enclosure
• Enclosure Baffle Studies - Paper on force cancelling and low resonance of glass enclosure

P.S. I listened to a new Perfect8 tower, about chest high, at AXPONA 2024 that's not on the website yet. It sounded good, but you can't hear the fine details at an audio show.

They're not MTM speakers (D Appolito) and I can't imagine directivity being all that good with no forward facing woofer below the crossover and being passive I'm not sure how much cardioid effect it will display. Id like to see measurements of them.

 

[TLS Guy]

Perfect8 has an unusual MTM arrangement--the mids are mounted behind the tweeter on the sides of the cabinet, opposed to each other. They claim this is to eliminate cabinet resonance and give a cardioid radiation pattern. Would this give the same kind of comb filtering issues as a regular horizontal MTM or would the opposed drivers create a sort of a virtual centerpoint behind the tweeter?

References

• Perfect8 Cube - MTM speaker in glass enclosure
• Enclosure Baffle Studies - Paper on force cancelling and low resonance of glass enclosure

P.S. I listened to a new Perfect8 tower, about chest high, at AXPONA 2024 that's not on the website yet. It sounded good, but you can't hear the fine details at an audio show.

That is an absolutely stupid idea, and will NOT solve the problem of a horizontal MTM. In addition all the midrange will be off axis. For those drivers crossover will need to be no higher than 2.5 KHz. So most of the speech discrimination band, actually just about all of it, will be off axis.

There has never been a shortage of people bringing lunatic speaker designs to market, and this one is high up the lunatic scale.

They are correct that the design has the potential for resonance cancelling, but creates more and worse problems than it solves.

I don't know the volume of the enclosure, but having worked with those SEAS Excel drivers, I have a very strong hunch the enclosure volume is too small, and I would expect a nasty honky response.

I would imagine its speech intelligibility is way below par. One of the most important functions of a center speakers is to provide clear AND natural speech.

I know how to deliver that, but I have grave doubts those designers do.

 

[shadyJ]

Perfect8 has an unusual MTM arrangement--the mids are mounted behind the tweeter on the sides of the cabinet, opposed to each other. They claim this is to eliminate cabinet resonance and give a cardioid radiation pattern. Would this give the same kind of comb filtering issues as a regular horizontal MTM or would the opposed drivers create a sort of a virtual centerpoint behind the tweeter?

References

• Perfect8 Cube - MTM speaker in glass enclosure
• Enclosure Baffle Studies - Paper on force cancelling and low resonance of glass enclosure

P.S. I listened to a new Perfect8 tower, about chest high, at AXPONA 2024 that's not on the website yet. It sounded good, but you can't hear the fine details at an audio show.

I saw the Perfect8 tower at AXPONA and was considering giving them some coverage if only to point out that problematic design element, but I only have time and space for a handful of exhibits, and I am trying to only pick a couple of fights at a time. But yes, this design should lead to comb-filtering, among other problems. It would not give a cardioid radiation pattern if the drivers are wired in phase and share the same bandwidth. The on-axis response would probably be pretty bad. I will give the speakers this: they had impressive bass, but it's not hard to get a lot of bass in those small hotel rooms. Here is a pic that I took:

 

[TLS Guy]

I saw the Perfect8 tower at AXPONA and was considering giving them some coverage if only to point out that problematic design element, but I only have time and space for a handful of exhibits, and I am trying to only pick a couple of fights at a time. But yes, this design should lead to comb-filtering, among other problems. It would not give a cardioid radiation pattern if the drivers are wired in phase and share the same bandwidth. The on-axis response would probably be pretty bad. I will give the speakers this: they had impressive bass, but it's not hard to get a lot of bass in those small hotel rooms. Here is a pic that I took:
View attachment 67182

That is a form of exhibitionism bordering on obscenity.

 

[shadyJ]

That is a form of exhibitionism bordering on obscenity.

If that borders on obscenity, here is one that crossover way over the border: this sucker was purported to cost north of 4 million dollars. I trust I won't have to highlight all of the acoustic problems a mess like this would have.

 

[TLS Guy]

If that borders on obscenity, here is one that crossover way over the border: this sucker was purported to cost north of 4 million dollars. I trust I won't have to highlight all of the acoustic problems a mess like this would have.
View attachment 67183

That looks like something from a Rodriguez cartoon!