Has anybody here built various isobaric speakers?
I'm looking for information that's a bit more in-depth than the typical information. Specifically, nearly all configurations I see use the clamshell or back-to-back driver configuration. I'm looking for if anything special applies if the drivers are further apart, or if a driver at each end of a box tube wired out of phase can essentially be folded, much like DTQWT speakers are a folded horn.
What I've been looking to do is get particularly deep bass from a very small enclosure. I tried the Dutch & Dutch 8C and these have two 8" drivers in the back for boundary loading. I've looked around trying to find drivers that will get down to -3db @ ~30Hz (like the D&D 8C), and do so in approximately the size I suspect the bass portion of the D&D 8C uses, based on the dimensions given on their website for the overall speaker. However, I cannot find any configuration that would permit as small a volume as they use.
The only thing I know that could allow extra output from their drivers is the active amplification and DSP they apply, which would require the drivers to be high excursion.
Another way, which I thought may or may not work is to isobarically load the sealed enclosure. Since there are two visible drivers, I was wondering if they are wired out of phase so the internal air pressure remains constant and represent the aforementioned folded box tube - but then I was thinking the output might just cancel (?)**. If they are configured out of phase to keep internal pressure constant, then they meet the definition of isobaric, but I am not familiar with anybody or any article examining more elaborate configurations or 'folding' a box.
Any pointers/help appreciated.
**I can confirm that adjacent drivers in a folded box will cancel if out of phase, but still unsure if there could be hidden drivers on an internal partition within the enclosure of the D&D 8C. Also unsure about anything special if driver arrangement has some significant distance between clamshell or back-to-back isobaric arrangements. I assume that while common designs have the drivers touching, it is not actually necessary so long as their motion is synchronized to maintain equal pressure in the cabinet.
I'm looking for information that's a bit more in-depth than the typical information. Specifically, nearly all configurations I see use the clamshell or back-to-back driver configuration. I'm looking for if anything special applies if the drivers are further apart, or if a driver at each end of a box tube wired out of phase can essentially be folded, much like DTQWT speakers are a folded horn.
What I've been looking to do is get particularly deep bass from a very small enclosure. I tried the Dutch & Dutch 8C and these have two 8" drivers in the back for boundary loading. I've looked around trying to find drivers that will get down to -3db @ ~30Hz (like the D&D 8C), and do so in approximately the size I suspect the bass portion of the D&D 8C uses, based on the dimensions given on their website for the overall speaker. However, I cannot find any configuration that would permit as small a volume as they use.
The only thing I know that could allow extra output from their drivers is the active amplification and DSP they apply, which would require the drivers to be high excursion.
Another way, which I thought may or may not work is to isobarically load the sealed enclosure. Since there are two visible drivers, I was wondering if they are wired out of phase so the internal air pressure remains constant and represent the aforementioned folded box tube - but then I was thinking the output might just cancel (?)**. If they are configured out of phase to keep internal pressure constant, then they meet the definition of isobaric, but I am not familiar with anybody or any article examining more elaborate configurations or 'folding' a box.
Any pointers/help appreciated.
**I can confirm that adjacent drivers in a folded box will cancel if out of phase, but still unsure if there could be hidden drivers on an internal partition within the enclosure of the D&D 8C. Also unsure about anything special if driver arrangement has some significant distance between clamshell or back-to-back isobaric arrangements. I assume that while common designs have the drivers touching, it is not actually necessary so long as their motion is synchronized to maintain equal pressure in the cabinet.
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