$250 MTM Vertically Oriented Measurements
What would happen if we
take that MTM speaker and turned it on its side? I did just that, by modifying my high-tech
stand with another piece of wood and some tape.
It may not be pretty but it’s for the science, right? I dropped a Center Stage acoustically transparent
screen down behind the speaker. It
didn’t affect the acoustics and I could get better photos.
In the 1/24 octave chart below, we can see the effect from rotating this speaker vertically. The horn tweeter isn’t as happy, exhibiting worse off-axis response from 4 k to 10 kHz, but you can see the frequency response from the midrange drivers shows much less wave interference.
If we look at the same slice at 1244 Hz to compare its lobing to the horizontal orientation, you can see from the below chart that for the specific frequency it was successfully eliminated. I won’t be showing any more of these charts because while they show the lobing shape more clearly, the 3D charts have more color. That must be a good thing.
To better gauge the audibility of orientating the speaker vertically, the chart below shows the measurements with 1/6 octave smoothing. The horn is clearly not designed to be rotated 90 degrees, but by not having horizontally arraigned redundant drivers, we have improved the smoothness of the speaker’s off-axis response a great deal. In the midrange drivers’ frequencies, the standard deviation improved to 1.19.
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TLS Guy posts on October 20, 2009 22:33
irish;637493
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 [madisound.com] 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.
irish posts on October 20, 2009 15:54
lsiberian;637476
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?
lsiberian posts on October 20, 2009 15:12
irish;637446
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 [avsforum.com] 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 [paradigm.com]. 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 [paradigm.com]
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
TLS Guy posts on October 20, 2009 14:30
irish;637446
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 [avsforum.com] 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 [paradigm.com]. 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 [paradigm.com]
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
irish posts on October 20, 2009 14:13
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 [avsforum.com] 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 [paradigm.com]. 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 [paradigm.com]
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 [avsforum.com] 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 [paradigm.com]. 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 [paradigm.com]
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