Ok....what do you call them with a top and bottom as well?.
<------as in my avatar, was always told they were H frames....trying to learn....🙂
<------as in my avatar, was always told they were H frames....trying to learn....🙂
agreed. whether 'reflex' 'qwtl' aperiodic or other, its certainly no kind of OB, slotted or otherwise.
to quote:
rjbond3rd
Speaking strictly as a newb: just consider the cabinet types as lying along a contiuum. Very simplistically and randomly:
OB (TL of zero length) -> TL (long straight vent) -> BLH (long expo "vent")-> BVR (bigger chamber, shorter expo "vent")-> BR (short straight vent) -> Aperiodic (resistive vent) -> IB (infinite volume, neglible vent) -> Sealed (no vent, shrinking volume) etc.
I couldnt have said it any more eloquently, if I had tried. Concise, direct, and astute.
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Hi mondogenerator, I am embarassed because it's really GM's ideas, horribly, horribly misquoted (sorry GM!) and almost completely beyond my understanding. But misquoting GM is not the worst one could do 🙂
Kind of U-frame at least. In fact you would be able to simulate such a beast with MJK's U-frame model. 🙂
/Erling
/Erling
All, at 6 Moons they cover a speaker that interested me as it uses 4 FR drivers and a ribbon tweeter:
6moons audio reviews: J.A.F. Bombard
The thing is, it is marketed as an innovative kind of open baffle.
Now, considering that there are 4 drivers, and a narrow open slit at the back, wouldn't it behave more like a bass reflex box?
Here is another product like it, also claiming to be an open baffle design:
Musical Affairs
ah yes, ocellia did a similar cabinet but used 1 phy driver.
http://www.wiredstate.com/forum/viewtopic.php?f=9&t=955
Norman
http://www.wiredstate.com/forum/viewtopic.php?f=9&t=955
Norman
Okay, that settles it, I'm moving to Holland. Folks that call a baffle a klankbord are my kind of people!
I think this thing belongs to the same category as console radios, guitar combos, and O'Conner's "detuned" cabs. I suspect it may work by canceling the resonance, rather than damping it. A big part of the appeal, though, is radiating mids and highs out the back (O'Conner's cabs are ported on the front), so yeh, it does function as an OB even though it's not very close to our definition of a "perfect" one.
I think that from 300-400 Hz (depending on slot measures) upwards it will have a cardioid polar pattern because the slot will be an acoustic LP filter.
/Erling
/Erling
You only need one "fullrange" drive unit per cab to make a close copy of the Musical Affairs Crescendo to test the Open baffle with wrap around wings concept.
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That is true, now in the originally linked speakers, having 4 fr drivers sharing roughly the same air volume as the one driver in the Crescendo is bound to have some influence on the sound, I would expect.
Only now i think about this design from Phy:
PHY-HP (Haut parleurs)® - Mini Kit 21
The idea being that you adjust the number of panels at the back to go from a folded open baffle to a BR.
Because of the 4 drivers in the original linked design, i still expect that it will act more as a bizarrely tuned BR, with each driver having a fourth of the narrow slit as opening.
PHY-HP (Haut parleurs)® - Mini Kit 21
The idea being that you adjust the number of panels at the back to go from a folded open baffle to a BR.
Because of the 4 drivers in the original linked design, i still expect that it will act more as a bizarrely tuned BR, with each driver having a fourth of the narrow slit as opening.
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Yes, there should be more pressure with the smaller opening and the increased output from all those drivers, but far less than in a traditional reflex cab.
Surely this speaker will act more like a monopole that a dipole, exiting more room modes than traditional dipole OB's, more like regular box speakers.
JAF Bassoon
Here's a 2nd offering from the same company with similar cabinet work. They are also planning a horn loaded option as well.
JAF bassoon
Here's a 2nd offering from the same company with similar cabinet work. They are also planning a horn loaded option as well.
JAF bassoon
4 x 8" per side = what, cone area of a 18" ?
That would certainly be fun.
Too bad the b20's arn't around.
I should have got them when they were discoing them away. Oh well.
Norman
That would certainly be fun.
Too bad the b20's arn't around.
I should have got them when they were discoing them away. Oh well.
Norman
SQRT[4]*~6" = ~12" effective diameter or about what a high excursion 15" has.
Indeed, I got an early Christmas present of several to add to mine for an 'el cheapo' HT project, but have enough old RS 40-1271s and 40-1272 8"ers I plan to try out as a free air [no baffle, only a tube frame, so to speak] four square with centered super-tweeter since their Qts is around 2.45 to see how close I can come to mimicking my dim memory of RCA's 'FR' 15" LC-1A except with HF out to at least 20 kHz.
I've been down the 'FR' vertical array path and it's not for me without acoustically response tapering of each driver, so way too much time/effort required for me.
GM
Indeed, I got an early Christmas present of several to add to mine for an 'el cheapo' HT project, but have enough old RS 40-1271s and 40-1272 8"ers I plan to try out as a free air [no baffle, only a tube frame, so to speak] four square with centered super-tweeter since their Qts is around 2.45 to see how close I can come to mimicking my dim memory of RCA's 'FR' 15" LC-1A except with HF out to at least 20 kHz.
I've been down the 'FR' vertical array path and it's not for me without acoustically response tapering of each driver, so way too much time/effort required for me.
GM
Hi GM, what if you angled each driver outward, e.g. 5 degrees (convex, not concave), like Don Keele's CBT line arrays? (I heard them recently and wow, really spacious and beautiful.)
EDIT: Oh darn, looking into those more closely, it would appear he does passively taper the output of the drivers. I had thought maybe you could just use the curved geometry to get the good results. Keele explaining it (6-part series, here's part 3): http://www.youtube.com/watch?v=0ucfyAeug8E
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