Something that I've always wondered about MTM/d’Appolito configurations is why you don't see ribbon/planar tweeters coupled with them more often.
Pardon the dumb question, but given the default horizontal/vertical characteristics of a typical MTM design you'd think a ribbon/planar tweeter, with their particular horizontal/verical dispersion characteristics, would be a match made in heaven. Still, I don't recall every seeing a commercial or reputed DIY design using such a configuration.
Is this still a personal preference in regards to ribbon/planar tweeters, or does it have to do with the low crossover limits of ribbon/planar tweeters not conducive to a MTM design?
Pardon the dumb question, but given the default horizontal/vertical characteristics of a typical MTM design you'd think a ribbon/planar tweeter, with their particular horizontal/verical dispersion characteristics, would be a match made in heaven. Still, I don't recall every seeing a commercial or reputed DIY design using such a configuration.
Is this still a personal preference in regards to ribbon/planar tweeters, or does it have to do with the low crossover limits of ribbon/planar tweeters not conducive to a MTM design?
I think there are a few good explanations why MTM ribbons are not a good way to go.
1) Ribbons are usually quite tall (3"-5"+borders) so the midranges will be quite far away from each other which will result in bad imaging ja combing in the vertical axis. Something like LCY or BG Neo3 will do much better than Fountek NeoCd2.0.
2) Ribbons usually need to be crossed higher than dome tweeters, so the combing and imaging will be much worse. Very steep crossover slopes will help with this, but there's no way to cross a cheap ribbon much under 3kHz and still get low distortion. Also the steep crossovers have some weaknesses compared to basic ~2nd order stuff.
I like the RAW HT1 and HT3, but I wonder if the HT2 can give anything more and not have some major drawbacks of the high crossover MTM design.
1) Ribbons are usually quite tall (3"-5"+borders) so the midranges will be quite far away from each other which will result in bad imaging ja combing in the vertical axis. Something like LCY or BG Neo3 will do much better than Fountek NeoCd2.0.
2) Ribbons usually need to be crossed higher than dome tweeters, so the combing and imaging will be much worse. Very steep crossover slopes will help with this, but there's no way to cross a cheap ribbon much under 3kHz and still get low distortion. Also the steep crossovers have some weaknesses compared to basic ~2nd order stuff.
I like the RAW HT1 and HT3, but I wonder if the HT2 can give anything more and not have some major drawbacks of the high crossover MTM design.
Well I see the ribbons are a topic 
Those using them ion a MT or MTM we recommend the high order network.
As for issues with dispersion of a ribbon that all depends on the ribbon we are talking about.
Dan Wiggins and myself tested all the AC ribbons.
G1
G2
G2Si
Our RA104.5
G3
G3Si
Our G3 series ribbon (HT6 and line array ribbon)
G3Si-130
LCY ribbons
What did we find out .
Well why send the money on the G2 is my first point!
Anyway back to the point at hand here, using a short ribbon if crossed over correctly will have a lot more benifit that you would think.
And crossovers as low as 1800 on our long ribbon is not a issue with a high order network.
Dispersion of any tweeter come a issue both vertical and horizontal and ribbons just seem to be the pointing finger everyone uses.
Well I will offer up a pair of our RA104.5 ribbons to some with measument equipment we can confirm also knows how to use it.Why well cheap measuremnt equipment prices means every one can have the software but knowing how to use it is something else.
Now the ribbons I will reserve comment but have offered a pair of our ribbons for some to measure against well lets put it out to see what they want to compaire them to.
Say mabe Neo 3's or Excel ,and why not a Vifa XT or 2.
And lets see what comes out of a few tests!!
What must be recorded 0-45 both vertical and horizontal test, distortion test !
Can anyone offer up a day or 2 for tests!
Tests must all be done with a 10uf cap on all the tweeters.
Why? a simple cap will protect all the tweeters in the signal.And roll them off at the same rate!
As even as possible data test.
Here is a few graphs for you.
The waterfall is the RA104.5 against the G2
IEC baffle test panel
Data from Mark K site data he took not us the 9950 ribbon and the G2si ribbon.
Just tell us which has a dispersion issue!! 
Those using them ion a MT or MTM we recommend the high order network.
As for issues with dispersion of a ribbon that all depends on the ribbon we are talking about.
Dan Wiggins and myself tested all the AC ribbons.
G1
G2
G2Si
Our RA104.5
G3
G3Si
Our G3 series ribbon (HT6 and line array ribbon)
G3Si-130
LCY ribbons
What did we find out .
Well why send the money on the G2 is my first point!
Anyway back to the point at hand here, using a short ribbon if crossed over correctly will have a lot more benifit that you would think.
And crossovers as low as 1800 on our long ribbon is not a issue with a high order network.
Dispersion of any tweeter come a issue both vertical and horizontal and ribbons just seem to be the pointing finger everyone uses.
Well I will offer up a pair of our RA104.5 ribbons to some with measument equipment we can confirm also knows how to use it.Why well cheap measuremnt equipment prices means every one can have the software but knowing how to use it is something else.
Now the ribbons I will reserve comment but have offered a pair of our ribbons for some to measure against well lets put it out to see what they want to compaire them to.
Say mabe Neo 3's or Excel ,and why not a Vifa XT or 2.
And lets see what comes out of a few tests!!
What must be recorded 0-45 both vertical and horizontal test, distortion test !
Can anyone offer up a day or 2 for tests!
Tests must all be done with a 10uf cap on all the tweeters.
Why? a simple cap will protect all the tweeters in the signal.And roll them off at the same rate!
As even as possible data test.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here is a few graphs for you.
The waterfall is the RA104.5 against the G2
IEC baffle test panel
Data from Mark K site data he took not us the 9950 ribbon and the G2si ribbon.
Just tell us which has a dispersion issue!!
With the red waterfall plots posted above the upper Waterfall is the G2.
In these plots the red is the G2 and the yellow is the RA104.5
These are vertical tests taken on a IEC baffle taken 10ft off the ground.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
In these plots the red is the G2 and the yellow is the RA104.5
These are vertical tests taken on a IEC baffle taken 10ft off the ground.
I read John's article, and indeed he did seemed to come down heavily on the side of domes.
Which is fine and fair for both schools; con and pro, even though I have to admit I've never heard a bad ribbon while I've heard a lot of lousy domes that supposedly test out well.
As far as I'm concerned though we can we can post test graphs all day and it really doesn't tell us a darn thing about how the ribbon is going to integrate with other components. For that matter, let's order ten of the same kind and see just how much deviation there is in chinese manufacturing. Come on guys.....
Ultimately the ony thing I care about is -how does it sound-, and I'd love to hear some of the speakers posted above.
Which is fine and fair for both schools; con and pro, even though I have to admit I've never heard a bad ribbon while I've heard a lot of lousy domes that supposedly test out well.
As far as I'm concerned though we can we can post test graphs all day and it really doesn't tell us a darn thing about how the ribbon is going to integrate with other components. For that matter, let's order ten of the same kind and see just how much deviation there is in chinese manufacturing. Come on guys.....
Ultimately the ony thing I care about is -how does it sound-, and I'd love to hear some of the speakers posted above.
Hi I have built an Aria R, and MTM dsign using the Raven R1 with Focal mids. This is a D'Appolito design and details should be available on the Zalytron and Orca Sesign sites, I think. Speaker Builder carried an article a few years ago on it. Its a 95dB design and the Ravens are really good.
I agree with you as well good point.
Any tweeter can sound good bad or otherwize all depentant on the crossover as well as design.
Why I posted the above to look at vertical limits those have been asking about in a MT or MTM.
Anyone wanting to demo the speakers I info for that on our forum as well you can contact me and we can arrange to get out a pair.
We will have the HT2 going out on a demo run next starting the end of Feburary.
For those wanting to get a chance to listen to them.
Any tweeter can sound good bad or otherwize all depentant on the crossover as well as design.
Why I posted the above to look at vertical limits those have been asking about in a MT or MTM.
Anyone wanting to demo the speakers I info for that on our forum as well you can contact me and we can arrange to get out a pair.
We will have the HT2 going out on a demo run next starting the end of Feburary.
For those wanting to get a chance to listen to them.
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