New B&C dual 15" design

Ossian Ott said:
Why would this type of cab be preferable to using ground stacked sub/s benefiting from ground coupling run to ~100 Hz, and tops taking over from there? Would you not gain about 6 dB (or 3?) of free bass that way effectively needing half the volume of subs for equal output? Ty for any answer on this!
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The goal is to have the full frequency range, or nearly so (say, to 40Hz), be phase coherent with the rest of the mids/highs. Flown mains with subs on the ground can't do this. The goal is to have a single acoustic origin, or as close as possible, flat (no haystack) to 40-ish Hz, and then extra subs for the 20+Hz haystack.

It helps to think in terms of 'natural bass' vs 'effect bass'. Rock and roll kick drum and EDM is largely an effect; a natural sounding bass guitar is more natural, along with deep bass singers, detuned guitars, floor toms, etc.
 
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Ossian Ott said:
Why would this type of cab be preferable to using ground stacked sub/s benefiting from ground coupling run to ~100 Hz, and tops taking over from there? Would you not gain about 6 dB (or 3?) of free bass that way effectively needing half the volume of subs for equal output? Ty for any answer on this!
Click to expand...
Having full-range mains equals more options in terms of crossover frequency/slopes between mains and subs.
As an example, if I run mains L/R and center clustered subs, I usually prefer full-range mains. But not always.
Or, I can use my mains without subs.
etc....
 
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I'm possibly wrong, but that driver collection looks to me to be more expensive, heavier, and more prone to failure/operator error than a pair of 21s - imagine one of the 18s losing drive! I hope someone can explain the thinking and advantages behind driving non-identical drivers into each other, plus its disadvantages other than those I have noted.
 
Carl Klinkenborg said:
I'm possibly wrong, but that driver collection looks to me to be more expensive, heavier, and more prone to failure/operator error than a pair of 21s - imagine one of the 18s losing drive! I hope someone can explain the thinking and advantages behind driving non-identical drivers into each other, plus its disadvantages other than those I have noted.
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Generally speaking, isobaric boxes gives you high output with extended low end from a smaller box, in this case a equal 2x21" would be bigger than this 21"+2x18" arrangement.
IME I find that they also have less distortion, but this could be more about the designs that I've heard than about the isobaric principle itself.
 
Carl Klinkenborg said:
I'm possibly wrong, but that driver collection looks to me to be more expensive, heavier, and more prone to failure/operator error than a pair of 21s - imagine one of the 18s losing drive! I hope someone can explain the thinking and advantages behind driving non-identical drivers into each other, plus its disadvantages other than those I have noted.
Click to expand...
Compared to a pair of 21s in an isobaric configuration, the 21+ 2x18 configuration looks like it results in a shallower box with less of a need for internal bracing due to the configuration of the 2x18 baffle and the ports. There's also a possibility that the pair of 18s requires a smaller box than a single 21 would, further reducing the cabinet size (the cabinet volume is calculated only for the rear speaker(s) in an isobaric configuration), but I haven't checked that.
 
Peter Morris said:
I'm sure if size and weight are not an issue this will be a beautiful speaker, and I want a pair - but I also want B&C to release a smaller 90 degree version of this horn 15" wide for those projects that need a different compromise. :) There are lots of nice horns of a suitable size to match a 12" driver - B&C ME90, RCF HF950, Eighteen Sound XR1496 etc. but not many to match a 15" that provide good loading down to 600Hz or less.
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How about this new 500Hz. horn?
www.limmerhorns.de

Limmerhorns - 292

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www.limmerhorns.de www.limmerhorns.de
 
The Limmerhorn 292 is 18" (470mm) wide, Peter was looking for a 15" (381mm) wide horn.Screen Shot 2024-01-28 at 10.23.26 AM.png
The 292 is about halfway between the B&CME464's 22.6" (575mm) width and 15"...
 
The largest horn RCF makes is the HF950, 300 mm / 11.81 inches wide, like Peter said, a suitable size to match a 12" driver.
The Limmerhorn 250m is 390mm wide (15.34") close to 15".
How about that :sleep:?
 
So not to shoot down this box design too much since i don't have anything better to offer but one thing i dislike is the wasted space in that middle compartment.


215box.jpg
According to the B&C site the ME464 occupies 35.5L so that leaves very close to 100L of volume inside this box doing absolutely nothing which seems like an odd design choice to me. Opening up the middle section to be shared with the 15" drivers would also add some airflow via the ports for cooling the compression driver which seems desirable. Obviously would require a re-tune of the port dimensions and/or a different driver selection to go with the change.
 
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