I don't have experience with big horns in MTM configuration, only with 2x 8" + dome.
For a start, this plot of two oscillating 15" pistons in infinite baffle and 25 cm distance (edge to edge) vertically, may shed a light (courtesy of FollGoTT):
For a start, this plot of two oscillating 15" pistons in infinite baffle and 25 cm distance (edge to edge) vertically, may shed a light (courtesy of FollGoTT):
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Perhaps you can get away with the woofers partly tucked behind the hornmouth.
You could apply felt to the rear of the horn > similar to the horns of the Bullfrog and the Oberton coaxial.
However, the roundover may complicate things.
Another aspect to consider is the distance between upper woofer and ceiling vs. lower woofer and floor.
You could apply felt to the rear of the horn > similar to the horns of the Bullfrog and the Oberton coaxial.
However, the roundover may complicate things.
Another aspect to consider is the distance between upper woofer and ceiling vs. lower woofer and floor.
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@camplo, I can't speak to the MTM, but my JBL 4722's are TMM and XO'd at 630 Hz to a waveguide on top. The virtual point source using DSP is at ear height between the top woofer and the waveguide. If I move the XO up to 800 Hz, the virtual point source moves up a bit closer to the waveguide, so I like the 630 Hz setting. I have had no issues with the bottom 15" woofer where the bottom lip is about 3" off the floor. A couple of pics and measurements here.
As I understand it, MTM has a narrower dispersion pattern and potential off axis lobing issues and is exacerbated by using larger woofers... That's from what I read, not based on any experience, so take with grain of salt.
Also, two woofers side by side is not a good idea as the moment you move your head, you will hear comb filtering issues, or at least that has been my experience when I tried that as an experiment. The psychoacoustics behind it from what I have read is that the ears are more sensitive laterally versus vertically when it comes to sensing location.
As I understand it, MTM has a narrower dispersion pattern and potential off axis lobing issues and is exacerbated by using larger woofers... That's from what I read, not based on any experience, so take with grain of salt.
Also, two woofers side by side is not a good idea as the moment you move your head, you will hear comb filtering issues, or at least that has been my experience when I tried that as an experiment. The psychoacoustics behind it from what I have read is that the ears are more sensitive laterally versus vertically when it comes to sensing location.
Yes since the average head size transfer function [HRTF] is ~800 Hz, so Google it if you want to fine tune it to you/whoever or otherwise just arbitrarily use 500 Hz.
GM
Re MTM, I believe the "read 'n heed, else you gona eat it" '60s slogan is apropos 😉: Biro Technology
GM
GM
Subaru, the questions you ask were good ones, you added to the whole, carry on! Lol
You guys are all golden, thanks for being such speaker nerds!
Mitchba - your answer was encouraging but “ear height” is a relative designation, I can look up the dimensions of the 4722 but where within the driver alignment “ear height” is, is obscure. I’m usually sitting in my computer chair and ear height is tangent on where I set the elevation of it....can be more specific? Do suggest that I place the top woofer or horn at ear height or maybe somewhere in between?
You guys are all golden, thanks for being such speaker nerds!
Mitchba - your answer was encouraging but “ear height” is a relative designation, I can look up the dimensions of the 4722 but where within the driver alignment “ear height” is, is obscure. I’m usually sitting in my computer chair and ear height is tangent on where I set the elevation of it....can be more specific? Do suggest that I place the top woofer or horn at ear height or maybe somewhere in between?
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It seems I missed some details in your response...����*♂️ You did say that at 630hz xover, the sweetspot is between the woofer and waveguide. Sorry I’m reading this stuff while at work. (75+ hrs last wk and that’s with a rain day on Monday)
I’d like to think that this design is somewhere between the 4722 and m2 with a little horn elitism thrown in. I borrowed from the 4722 xover choice. Since my horn drivers are of that era and the driver count and alignment are matching...it just made sense. I’ve actually seen those picks and read many of your threads that inturn lead me to choose certain products for this project.....I didn’t expect you to show up and actually help me finish it lol! Good Sht ��
I’d like to think that this design is somewhere between the 4722 and m2 with a little horn elitism thrown in. I borrowed from the 4722 xover choice. Since my horn drivers are of that era and the driver count and alignment are matching...it just made sense. I’ve actually seen those picks and read many of your threads that inturn lead me to choose certain products for this project.....I didn’t expect you to show up and actually help me finish it lol! Good Sht ��
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The principles remain the same, except we've got 'an extra obstacle' to deal with.
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In room (next to Cornscalas in the 2nd pic.):
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I am not sure this concept would work, considering the mouth diameter of camplo's horns is about 50% larger.
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