Have anyone tried a wide band driver in a cardioid enclosure + waveguide/horn to control directivity in both the low and high end?
See the Directiva R2 plots from ASR forum:
In the above chart we can see cardioid behaviour from ~200 Hz to ~1000 Hz with the slots in the woofer enclosure.
Below 200 Hz we start to see cancellation which again governs the low end usability of the system.
Couldn't we then load the wide band driver in a waveguide to control directivity above 1000 Hz and get highly controlled directivity across the whole range?
See the Directiva R2 plots from ASR forum:
In the above chart we can see cardioid behaviour from ~200 Hz to ~1000 Hz with the slots in the woofer enclosure.
Below 200 Hz we start to see cancellation which again governs the low end usability of the system.
Couldn't we then load the wide band driver in a waveguide to control directivity above 1000 Hz and get highly controlled directivity across the whole range?
Look at Truefi, a front loaded midrange horn and dipole hybrid design for Tannoy dual concentric drivers. That's near to what you are proposing. But to be honest, if the cardioid approach only works down to 200 Hz, you might as well build a large front loaded horn that reaches below that. This will also give you directivity.
WG over what BW?
Note that WGs are 2x longer than same horn loaded, ergo bigger terminus also, so still want a WG?
Note that WGs are 2x longer than same horn loaded, ergo bigger terminus also, so still want a WG?
GM, perhaps you meant to say that the other way around or am I looking at this from a different angle..
For a given mouth size, the more curved the horn the less it tends to hold at lower frequencies and the more it will narrow at the top.
For a given mouth size, the more curved the horn the less it tends to hold at lower frequencies and the more it will narrow at the top.
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Allen, when somebody says WG, I think in terms of conical or parabolic which must be longer for a given loading cutoff (1 WL resonator*) whereas a horn is a 1/4 WL resonator. Your sketch shows me two vastly different horns, though as you've pointed out the short one has less control/wider directivity as it expands too quickly, so better to do as the pioneers and design a full size horn and cut a section out of it wherever it has the right specs, i.e. the famous A7 cab's 14" deep horns are a 55 Hz expo flare same as the much larger 'A' series cinema horns, though assuming for sales obfuscation the late Bruce Edgar called them half size 110 Hz expo.
Side note: one interesting thing is that I converted it to a round equivalent complete with rolled out end correction for several folks back early on the WWW which loaded lower at much less distortion overall, yet all swapped back to the original, so from that point on I've been pretty indifferent to all but the truly audibly distracting distortions.
If the pioneers taught us nothing (just mostly everything WRT the fundamentals of acoustics), its their 'don't fix what ain't broke', yet here we are nearly a century later still 'beating it to death'..............
Anyway, before I make any more errors, best at this point to fall back on Dr. Geddes' WP.
* Apparently I'm no longer able to respond to similar threads back-to-back at once, so misspoke in that a conical or parabolic must be 1 WL long IME for a given loading cutoff, so 4x longer and however big the terminus winds up being for a given directivity.
Side note: one interesting thing is that I converted it to a round equivalent complete with rolled out end correction for several folks back early on the WWW which loaded lower at much less distortion overall, yet all swapped back to the original, so from that point on I've been pretty indifferent to all but the truly audibly distracting distortions.
If the pioneers taught us nothing (just mostly everything WRT the fundamentals of acoustics), its their 'don't fix what ain't broke', yet here we are nearly a century later still 'beating it to death'..............
Anyway, before I make any more errors, best at this point to fall back on Dr. Geddes' WP.
* Apparently I'm no longer able to respond to similar threads back-to-back at once, so misspoke in that a conical or parabolic must be 1 WL long IME for a given loading cutoff, so 4x longer and however big the terminus winds up being for a given directivity.