Ultimate Open Baffle Gallery

ScottG

Member
2003-02-04 12:23 am
US
Probably a bit strange, but this is my open baffle soundbar (and HT screen: 175" Silver Ticket Screen). This "bar" (though there are actually 2 sections with one section at the rear with the tweeters) is about 14ft wide (slightly wider than the nearly 13 feet of Screen). The "bar" is also almost 20"s high, and is open to the rear with cloth draping it. Further, the "bar" has 3 channels (left, center, and right) with each channel composed of 1 - 1.5" cone tweeter, 4 - 4" fullrange drivers up-firing, and 1" 10 pro woofer up-firing. Due to the "up-firing" orientation this is the only design I've ever seen that is both radial AND open baffle (though obviously the tweeters are "nude" dipoles). The left and right tweeters have some cotton rebond insulation covering most of their front output - this was done to decrease the output close to the near seats for each channel while still having good spl/output for the far channel (..in other words: so the person in the left seat wasn't hearing a great deal of left channel and the person in the right seat wasn't hearing mostly right channel). Sadly I still haven't gotten around to the tweeter "bar's" covering nor have I placed a curtain around the screen to limit light-bleed to the cabinet to the left, ceiling, etc..

(..and yes, I screwed up with the build in a few places, particularly the molding at the bottom and the joint spanning the front panel of the "bar". :blush: Still, it's been quite serviceable over the past few years.)
 

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ScottG

Member
2003-02-04 12:23 am
US
Also open baffle and again with some uncommon design elements, the 3-chair back-row platform is an open baffle subwoofer. There are two "slot" openings on the "front" and rear of the platform with rectangular "grill cloths". It's basically an "H" frame design (separating the phase difference between the woofers) that's coupled to the floor (through the sheer weight of cabinet and the chairs on it). There are *two 15" high "Q" woofers that are down-firing and "slot loaded" into a larger front chamber (the frontal part of the "H") with the rear out-of-phase open to it's side of the "H" frame.

*it should have been at least 4 woofers (and preferably 8), as it is - the woofers can still bottom out if I'm not careful with the sub-setting for the particular movie.

The platform is specifically designed to shake with loud bass transients.

Perhaps even more different than most designs, the rug-like platform (that has the two front recliners on it) has 2 **bass shakers and is also coupled to the floor in such a way that it shakes as well. (Note that structurally this rug-like extension of the platform is physically separate from the 2nd row platform, basically that 8" high second row platform/"H"frame/box is one piece and the rest of the rug including the surrounding edge is a different piece.)

**that little black puck you see under the right front recliner.

Finally (and most importantly), each recliner has 2 bass shakers installed - one in the lumbar area and one at the bass of the chair for the chair's bottom. This is actually more important than the subwoofer as it generates the sensation of bass even though it isn't something you hear (which is strange but true). Turning off the shakers while keeping the sub on is far less beneficial than having the bass shakers on and the subwoofer off - and I don't mean this as simply a tactile sensation, I mean this in regard to its "audible" character. Note: this is with the front "soundbar" having a 100 Hz high-pass from the receiver.

The subwoofer's most notable improvement is with respect to certain scenes having low-freq "hall-sound" that represents expansion of the audible space.

The net result is something that sounds far more like a movie theater than a home theater while ALSO having the physical impact that very few commercial movie theaters have. (..most large commercial movie theaters don't have that "boomy" character that almost all HT's have, because of course the room dimensions are so large that the modes are so low in freq.. This home theater is very much like a large commercial movie theater in this respect. It's also more like one with respect to the size of the screen and the placement of the chairs/viewing position - and this makes a (literal) HUGE difference.)


Note: This system even at fairly high listening levels with (literally) explosive transients is barely audible to the rest of the home despite being relatively near the adjoining family room.
 

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My latest hopefully last redux of these 12 inch full rangers. They rely on using the baffle as a highpass to meet the sub, which is lowpassed at a high 100 hertz 4th order slope.
It's a little rough, as everything was made from spare parts, but I like them.
The bit of extra centre fill from the angled 4 inch drivers ceiling reflections is subtle and welcome.
Crazy good for my 2.1 channel music and home theatre system.
Not as illusory at throwing sound effects around as the horn hybrid dipoles were, but I have no sense of loss from no surrounds.
 

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My latest hopefully last redux of these 12 inch full rangers. They rely on using the baffle as a highpass to meet the sub, which is lowpassed at a high 100 hertz 4th order slope.
It's a little rough, as everything was made from spare parts, but I like them.
The bit of extra centre fill from the angled 4 inch drivers ceiling reflections is subtle and welcome.
Crazy good for my 2.1 channel music and home theatre system.
Not as illusory at throwing sound effects around as the horn hybrid dipoles were, but I have no sense of loss from no surrounds.
I've always been interested in upward firing drivers. Audio kinesis had some very interesting models that utilised that technique a lot but quite a bit more sophisticated.
 
I've always been interested in upward firing drivers
I've tried them and they sound more bi-pole than di-pole to me. Ever since the OB bug bite, my mind "wants" dipole; the sound radiating backward must be 180 deg out of phase or "something's not quite right".

I'm sure if I built castles with one front, one up firing and listened to them for a couple years - anything else would sound a bit off too...
 
I've tried them and they sound more bi-pole than di-pole to me. Ever since the OB bug bite, my mind "wants" dipole; the sound radiating backward must be 180 deg out of phase or "something's not quite right".

I'm sure if I built castles with one front, one up firing and listened to them for a couple years - anything else would sound a bit off too...
I have since removed the upfiring drivers. Today I started making some U Frame bass bins/satellite stands, with dual ten inch woofers. At this point I'm planning top and bottom plates, with one wing.
Adding a shallow wing and a top plate to the satellites makes them fine for late night listening, or adding a sub at 70 hertz.
I haven't heard open backed bass with these drivers for years, and a full U Frame was done wrong last time, making a cavity resonance that needed to be EQ'd out.
Here they'll be bandwidth limited enough to just use the plate amp filter to add some heft without neighbour disturbing bottom octave bass.