Open baffle suggestions

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#44
"...they fit under my bed. Woohoo."

Now, if you were married, that sub under the bed might enhance the WAF...a little Barry White in the background... 😀

I think I'm gonna end up building a coupla versions of this thing no matter what I do. I want to check out all the suggestions here and see if there's really an advantage to any of them. I'm really piqued about the slots in AJinFla's barn door and whether or not the MTM makes an objectionable difference. And I want to check out the hinge idea.

The slot thing's got me wondering because I've had the Audax drivers in narrow OBs in the past.

An externally hosted image should be here but it was not working when we last tested it.


Up tight against the bass boxes was noticably different than when I moved them away forming a gap. Don't ask me what the differences were exactly - it's been two years - but when they were up against the bass boxes, it effectively added 26 inches of baffle that the Audax was seeing. Something changed with the slot between them. Anyway, that's another thread. 🙂
 
#50
Okay guys, enough thinking about it. Here's what I'm gonna do for the first iteration:

An externally hosted image should be here but it was not working when we last tested it.


In the absence of any way to really accurately sim something like this, the only option is to build it. This gives me most of what the OB gurus here suggested and leaves the whole mess flexible enough to changes baffles easily for slightly different configurations. I've got the narrow baffle for the mids/highs, most of the woofers on the floor, and only a 40 inch width for the main structure. I'll add wings for the lower woofers and custom fit them when I see exactly how the main frame fits in the room. A quick estimate tells me I can add up to 45 inches of wing width, depending on the angle. I'll use piano hinges to attach them. The top baffle for the two lone woofers can easily be extended all the way to the ceiling if it looks like it may help and the drivers can be mounted inline vertically if it makes a difference.

Anyway, I wanted to thank everyone that responded - I appreciate the suggestions. Time to cut wood in the rain - oh joy. 🙂
 
#52
" Maybe consider some of John K's U baffle type arrangement for the LF drivers."

I'm gonna leave all the non-flat baffle stuff for last. There's so many ways to do this that I'll always be wondering about the things I didn't try. I'll run thru all the flat baffle options, within reason, before anything else.

"What about the shed?"

I don't want to get it dirty. 😀

I'll do the cutting outside and the layup inside.
 
#53
AJ said:
" Maybe consider some of John K's U baffle type arrangement for the LF drivers."

I'm gonna leave all the non-flat baffle stuff for last. There's so many ways to do this that I'll always be wondering about the things I didn't try. I'll run thru all the flat baffle options, within reason, before anything else.
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I keep forgetting about the TL's so you don't actually need deep bass from the baffles.

One thought, try to mechanically isolate the Audax/HF baffle.

AJ said:
"What about the shed?"

I don't want to get it dirty. 😀
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Is that a Man Card violation?
 
#54
PS: got the Behringer and the transformers and am waiting on Hebb's to get back so I can borrow his tools to make my new MF horns and the TH subs.

I'm going to build them in the living room. Bachelor pads are cool.
 
#55
"I keep forgetting about the TL's so you don't actually need deep bass from the baffles."

Actually, my beloved TLs are history. 🙂 I donated them, along with a pair of my better line arrays (peerless mids/PT2 planar tweeters), to my son-in-law's church group. He's a youth pastor there and they needed a sound system for a smallish room where they entertain the kids with music and movies. Since I didn't trust myself to pull off a decent passive XO, I threw in a coupla Behringer 2-channel amps, a Behringer 3-way active XO, and Dick C donated an old Adcom 555 preamp. They already have a Behringer Mixer with an integrated stereo 250watt amp for the TLs. They'll be stylin'. 😀

"Is that a Man Card violation?"

Nah, it's just that I've got so many tools and stuff on shelves, I just didn't want to have to go vacuum the whole place after the sawdust settles.

"PS: got the Behringer and the transformers and am waiting on Hebb's to get back so I can borrow his tools to make my new MF horns and the TH subs.

I'm going to build them in the living room. Bachelor pads are cool."

Excellent. I plan on replacing the TLs with THs. If I can get decent results from the OB, it's 40inch width will let me easily put a pair of THs on either side of the flat screen TV. Very uptown. 🙂
 
#56
I know it's a little late in the game, but from my personal experiences with OB's, I would say that you shouldn't have any problem reaching down to 40Hz with those sixteen 12's you've got there in the original 48" x 77" baffles. You may need a little EQ to help them out, but still.

My current OB's are a prime example of the wrong drivers for the wrong job. They have a decent Fs of 29Hz but their Qts is 0.30! My baffles are somewhat on the small side and even without EQ, they reach down into the mid-50Hz range on their own. With some stong EQ on the low end, I get solid output down to around 35Hz.

However, after seeing the drawing of your latest design, the baffle is rather small, too small in fact I think. Five of the six 12" drivers on the bottom baffle alone are only a matter of an inch or two away from the baffle edges. I would think that cancellations would come in sooner than expected in this arrangement. Likewise with the two woofers on the top, plus the fact that they are up in the air, definately away from the floor and a good distance away from the ceiling.

Just my own thing here, but I thought that #1 in your original post would be a pretty successful design. Since you would make them mirror imaged pairs, and are placing them in the corners of your room, you could have the row of woofers closest to the side walls. You would have the benefit of the corners and side walls reinforcing the output of those woofers. Who knows, they could possibly reach down close to 30hz! However, please keep in mind that I have no clue what the T/S specs are on those 12's of yours.

At any rate, good luck with your project and be sure to post some pics when you can! 😉
 
#57
Hey Chops

"However, after seeing the drawing of your latest design, the baffle is rather small, too small in fact I think."

I'll have a 30 inch wing on one side and a 15 inch wing on the other so there's a little more width than the drawing is showing.

" Likewise with the two woofers on the top, plus the fact that they are up in the air, definately away from the floor and a good distance away from the ceiling."

Yeah, those two lone wolfers up there bug the heck outta me too, but I bought 16 and I'm gonna use them all! 😀 Actually, I'm thinking I'm gonna run the top baffle all the way to the ceiling - couldn't hurt.

"Just my own thing here, but I thought that #1 in your original post would be a pretty successful design. "

I've been thinking about these woofers for over a year now, and my original thought all along was a line array - I still like #1 as well. I've just resigned myself to the fact that I'll build a dozen different baffles for these things before I'm done, so #1 is gonna get its chance eventually. 🙂

Here's the specs:

RMS Power Handling: 250 watts
TS Parameters
FS 41 hz
VAS 4.12
SD 95.033
Qts 0.649
Qes 0.681
Qms 14.01
BL 13.35
Re 6.83
Nominal Ohms 8
Le uH 420.26
Mms 69.06
X max 0.25"
X mech 0.5"
Peak Power Handling: 500 watts
Ohms: 8
Frequency Response: 40 to 5000hz
Sensitivity: 99 dB
Magnet: 50 oz.
Basket: Stamp
Voice Coil: 2.5" kapton
Cone: Paper
Surround: Accordion
Binding Posts: Clip Type
Pole Piece: .
Overall Diameter: 12 1/4"
Overall Depth: 5"
Mounting Diameter: 11 1/8"
Mounting Depth: 4 5/8"
 
#58
chops said:
I know it's a little late in the game, but from my personal experiences with OB's, I would say that you shouldn't have any problem reaching down to 40Hz with those sixteen 12's you've got there in the original 48" x 77" baffles. You may need a little EQ to help them out, but still.

My current OB's are a prime example of the wrong drivers for the wrong job. They have a decent Fs of 29Hz but their Qts is 0.30! My baffles are somewhat on the small side and even without EQ, they reach down into the mid-50Hz range on their own. With some stong EQ on the low end, I get solid output down to around 35Hz.

However, after seeing the drawing of your latest design, the baffle is rather small, too small in fact I think. Five of the six 12" drivers on the bottom baffle alone are only a matter of an inch or two away from the baffle edges. I would think that cancellations would come in sooner than expected in this arrangement. Likewise with the two woofers on the top, plus the fact that they are up in the air, definately away from the floor and a good distance away from the ceiling.

Just my own thing here, but I thought that #1 in your original post would be a pretty successful design. Since you would make them mirror imaged pairs, and are placing them in the corners of your room, you could have the row of woofers closest to the side walls. You would have the benefit of the corners and side walls reinforcing the output of those woofers. Who knows, they could possibly reach down close to 30hz! However, please keep in mind that I have no clue what the T/S specs are on those 12's of yours.

At any rate, good luck with your project and be sure to post some pics when you can! 😉
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I think number 1 would also be better too. Put the MMT on the inside mirrored left and right with the line arrays near the side walls. Better bass, better loading for the mid, correct height and ultra cool massive line array movement of the air

Maybe you can break them in New Years Eve... Cue up some Lombardo. grab a cold 1 and fasten your seat belts 😀
 
#59
"I think number 1 would also be better too."

Oh great. Now you tell me. That's the last time I ever ask you guys for help. 😀

I should've just gone with my first instincts and stopped making such a BFD about it; you can engineer an unknown quantity till the cows come and the bottom line is always in the listening. 🙂

Well, as fortune would have it, I went out this afternoon and cut the four woofer baffles according to the latest and greatest plan, but it turned out someone forgot to glue the center plys of the plywood. I ended up with twice as many baffles as I needed - too bad they were only 3/8 thick. Took 'em back, got the sheet exchanged, and figured I'd start over tomorrow.

I'm going back to my first idea and I'll have 'em ready for New Year's festivities. Line array it is. And I'm not talking to you guys until they're done. 😀
 
#60
AJ said:
"I think number 1 would also be better too."

Oh great. Now you tell me. That's the last time I ever ask you guys for help. 😀

I'm going back to my first idea and I'll have 'em ready for New Year's festivities. Line array it is. And I'm not talking to you guys until they're done. 😀
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Are you sure? #3 is growing on me, and #5 would be perfect half passed out over the side of the E-Z-Boy.
 
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