Well, if you try to narrow baffle width at max both distance between baffle edge and diver basket will be the same ( maybe 1,5cm / 3/4inch). It makes sense to limit diffraction effects to something close to your driver basket dimension.
The point is to not have this same distance to the top as diffraction is cumulative and issue could arise. So doubling this distance ( or even more) could lessen the cumulative effect ( by shifting it lower in freq). Here again if you prototype it's not difficult to test if meaningful or not.
As it's a coax with ( short) waveguide it might not be an issue (if diffraction happen at a point where directivity management from waveguide already take place) but it could be audible though.
An other way to approach things could be an MTM arrangement with torso shape ( but it'll be more difficult to shape rear of loudspeaker with two 'wings' rather than one as on Perry Marschall's 'bitch's brew').
Something with this kind of shape ( torso):
https://heissmann-acoustics.de/en/dxt-wave/
I hope it's clearer.
The point is to not have this same distance to the top as diffraction is cumulative and issue could arise. So doubling this distance ( or even more) could lessen the cumulative effect ( by shifting it lower in freq). Here again if you prototype it's not difficult to test if meaningful or not.
As it's a coax with ( short) waveguide it might not be an issue (if diffraction happen at a point where directivity management from waveguide already take place) but it could be audible though.
An other way to approach things could be an MTM arrangement with torso shape ( but it'll be more difficult to shape rear of loudspeaker with two 'wings' rather than one as on Perry Marschall's 'bitch's brew').
Something with this kind of shape ( torso):
https://heissmann-acoustics.de/en/dxt-wave/
I hope it's clearer.
Much more clear! I occurred to me a little too late to be more asymmetrical in my placement in the photo below but I catch your drift.
Kicked up some dust this weekend and decided these speakers are entirely too big for my apartment. Would love to hear them some day but a narrower baffle/smaller drivers are going to suit me better. Trying to return those and just pounced on a used pair of 10" Coaxial Radians (constant directivity within my reach!). I'm also looking to accompany them with a pair on each side of Visaton WS 25 E 10"—Qts 1.43! They are cheap so I might even be able to afford 4 per side... lol poor neighbors.
Mic and sound card are here but it seems that my order for the cables got messed up, so still waiting on that.
So narrow baffle it is...
What do you think of this baffle-less MTM: Baffleless Aesthetically more challenging, but maybe fun to build? I really like the MTM idea with narrow or no baffle, but I'm not sure about the spacing in that picture—shouldn't the drivers be closer together or since its mid to woofer 1/4 to 1/2 is fine.
Since I'm using a coax and the system is time-aligned what would the benefits be to MTM? If I go narrow baffle I might experiment with wings but really I want light bass (it's a loft apartment with no insulation between floors, a little in the walls and very uptight landlord). It does have carpet, though. Normally I hate living with carpet but the silver lining for me was at least something going for me acoustically. Like I said I plan on playing appropriate music through the system at a quiet volume in what will amount to the near field.
I appreciate your comments on imaging in regards to baffle size. I can always get more MDF and experiment in the future.
Kicked up some dust this weekend and decided these speakers are entirely too big for my apartment. Would love to hear them some day but a narrower baffle/smaller drivers are going to suit me better. Trying to return those and just pounced on a used pair of 10" Coaxial Radians (constant directivity within my reach!). I'm also looking to accompany them with a pair on each side of Visaton WS 25 E 10"—Qts 1.43! They are cheap so I might even be able to afford 4 per side... lol poor neighbors.
Mic and sound card are here but it seems that my order for the cables got messed up, so still waiting on that.
So narrow baffle it is...
What do you think of this baffle-less MTM: Baffleless Aesthetically more challenging, but maybe fun to build? I really like the MTM idea with narrow or no baffle, but I'm not sure about the spacing in that picture—shouldn't the drivers be closer together or since its mid to woofer 1/4 to 1/2 is fine.
Since I'm using a coax and the system is time-aligned what would the benefits be to MTM? If I go narrow baffle I might experiment with wings but really I want light bass (it's a loft apartment with no insulation between floors, a little in the walls and very uptight landlord). It does have carpet, though. Normally I hate living with carpet but the silver lining for me was at least something going for me acoustically. Like I said I plan on playing appropriate music through the system at a quiet volume in what will amount to the near field.
I appreciate your comments on imaging in regards to baffle size. I can always get more MDF and experiment in the future.
Benefits of MTM with a coax: if you choose xover freq wisely* it can help mitigate floor/ceiling bounce.
Another benefit is it will help to make the whole loudspeaker even more 'point source' in it's behavior.
If you go with 4x low end drivers in WW+coax+WW ( something like this but with a coax in place of horn: https://www.pinterest.fr/pin/pureaudioproject-quintet15--1125968643622624/ )i can see an advantage in the acoustic design over a WWT: coupling to floor help make thick bass/low mid but sometimes it is too much with outcome of unaturaly sounding voices, 'bigger than life'. This can be pleasing but not accurate in my view.
By lifting a couple of WW above coax you should have a bit less coupling from floor and it re-center low/low mid at same height than mid and high emmissing point.
That said i observed this with boxed drivers not with OB, but i'm sure it would happen too in that case.
Here again i think a bit of prototyping would help you define if it matter to you, suit what you are after.
Why bother with already made cables? A pair of Neutrik's xlr connectors, some meters of known brands cable ( Mogami, Canare, Belden,...) and a bit of soldering would be even better than commercial offer and probably less costly too (and as you built them you can fix them too if needed).
Radian over Eminence? Nice choice i think. I had mixed results with Eminence 12" coax i played with ( in a 'wedge' PA musician monitoring). We ended with something usable but it required a bit of tweak with dsp. And i'm not sure i would had liked them at home.
Radian 10" i've heard were 'good' to me ( but it's so subjective...). Heard them in studio monitors and was pleased by outcome but it was long ago, i've not heard recent one so can only suppose they are as good or better.
* the floor/ceiling bounce happen at frequency which depend from your listening position and drivers location. So something like this should help define what to expect ( simulate for each driver's own vertical location ): http://tripp.com.au/sbir.htm
From there you'll have an idea of which freq to locate xover freq. But i can tell that something in the 250hz range would help with coax's woofer part by lowering displacement and so intermodulation distortion of high ends parts ( even if waveguide loaded the woofer membrane play a role too so limiting displacement helps) and it should be high enough to have multiple notch happening for floor/ceiling bounce rather than a 'big one' (as i'm lazy i suggest you to read the discussion we had withe Tmuikku regarding this point: Post in thread 'MTM vs coax for point-source design' https://www.diyaudio.com/community/threads/mtm-vs-coax-for-point-source-design.386957/post-7044305).
Another benefit is it will help to make the whole loudspeaker even more 'point source' in it's behavior.
If you go with 4x low end drivers in WW+coax+WW ( something like this but with a coax in place of horn: https://www.pinterest.fr/pin/pureaudioproject-quintet15--1125968643622624/ )i can see an advantage in the acoustic design over a WWT: coupling to floor help make thick bass/low mid but sometimes it is too much with outcome of unaturaly sounding voices, 'bigger than life'. This can be pleasing but not accurate in my view.
By lifting a couple of WW above coax you should have a bit less coupling from floor and it re-center low/low mid at same height than mid and high emmissing point.
That said i observed this with boxed drivers not with OB, but i'm sure it would happen too in that case.
Here again i think a bit of prototyping would help you define if it matter to you, suit what you are after.
Why bother with already made cables? A pair of Neutrik's xlr connectors, some meters of known brands cable ( Mogami, Canare, Belden,...) and a bit of soldering would be even better than commercial offer and probably less costly too (and as you built them you can fix them too if needed).
Radian over Eminence? Nice choice i think. I had mixed results with Eminence 12" coax i played with ( in a 'wedge' PA musician monitoring). We ended with something usable but it required a bit of tweak with dsp. And i'm not sure i would had liked them at home.
Radian 10" i've heard were 'good' to me ( but it's so subjective...). Heard them in studio monitors and was pleased by outcome but it was long ago, i've not heard recent one so can only suppose they are as good or better.
* the floor/ceiling bounce happen at frequency which depend from your listening position and drivers location. So something like this should help define what to expect ( simulate for each driver's own vertical location ): http://tripp.com.au/sbir.htm
From there you'll have an idea of which freq to locate xover freq. But i can tell that something in the 250hz range would help with coax's woofer part by lowering displacement and so intermodulation distortion of high ends parts ( even if waveguide loaded the woofer membrane play a role too so limiting displacement helps) and it should be high enough to have multiple notch happening for floor/ceiling bounce rather than a 'big one' (as i'm lazy i suggest you to read the discussion we had withe Tmuikku regarding this point: Post in thread 'MTM vs coax for point-source design' https://www.diyaudio.com/community/threads/mtm-vs-coax-for-point-source-design.386957/post-7044305).
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OK, so the seller backed out of the deal for the 10" radian. I'll figure something out—even if it's a temporary solution of the 8" full-rangers I have on hand. Also the Biancos are out of stock until mid October...
Thank you for sharing the calculator, it's a very valuable tool. I found some high Qts 10" woofers on close-out that are just too cheap to pass on for experimentation purposes. I'm going to buy 8 to play with. My ceilings will be very high: 3.5 to 5 meters. The floor bounce from top to bottom will be very asymmetrical. I'm not sure yet if the land lord will let me put up treatment yet. Something tells me no.
I've been thinking for some time of lifting the woofer from the floor, so thanks for reinforcing that idea. I want to avoid boominess. With an 8" at ear height using four 10" woofers I estimate I have about a foot between the floor and the bottom woofer.
Thank you for sharing the calculator, it's a very valuable tool. I found some high Qts 10" woofers on close-out that are just too cheap to pass on for experimentation purposes. I'm going to buy 8 to play with. My ceilings will be very high: 3.5 to 5 meters. The floor bounce from top to bottom will be very asymmetrical. I'm not sure yet if the land lord will let me put up treatment yet. Something tells me no.
I've been thinking for some time of lifting the woofer from the floor, so thanks for reinforcing that idea. I want to avoid boominess. With an 8" at ear height using four 10" woofers I estimate I have about a foot between the floor and the bottom woofer.