A new Open Baffle project (lots and lots of pretty pictures)

Bob in St. Louis · « **on:** 23 Apr 2009, 01:33 am »

Here's what I've got so far. The project has slowed (all but stalled more accurately), but what you see isn't even 50% of the final project. I just thought I'd show you what I'm up to recently. At a couple points along the way I would mount the drivers on the baffles to see how things where sounding. Also, since I only build on the weekends I wanted the system to be operational during the weeknights. This constitutes about three weekends worth of progress.
Don't forget, there's a whole lot more in the works you can't see yet. Very little of what you see will be part of the final product. Only the basic shape, sand fill, and driver choice are permanent.

Bob

Blackmore · « **Reply #1 on:** 23 Apr 2009, 02:01 am »

So the project begins. I like having the Iris and Augie on one baffle. Nice clean look. I like your baffle shaping around the Iris too. How much do those triple thick baffles weigh?

I look forward to hearing them when you get it all finished. Way to go, Bob!

mcgsxr · « **Reply #2 on:** 23 Apr 2009, 11:14 am »

Cool, and a ton of work evident there Bob!

I know it is WIP, but I love the primer gray - reminds me of street rods done up in "suede", all the dough spent in the motor, nothing left for paint, so leave it in primer!

I am sure with your HT needs, there will be a final coat of a darker colour.

Bob in St. Louis · « **Reply #3 on:** 23 Apr 2009, 01:47 pm »

Hey Mark (Blackmore),
Yes Sir. The project has begun indeed. aa
I've always liked the two drivers on one baffle as well. In every occasion you saw my rig, each driver was on it's own baffle. That was never my intention or goal to have THAT many pieces spread across the floor. It looked pretty cool, but most likely sacrificed some sound quality as a result.
Since you asked about the weight, I've got some specs for you:

- The final dimensions are 19 3/8" X 33" for all three baffles
- The center channel holds 9.12 pounds (4.13 Kg) of sand.
- The center channel baffle is 26 pounds, 4.8 pounds. (No driver installed)
- Each baffle (main channel) holds 5.84 pounds (2.64Kg) of sand.
- One baffle is 18 pounds, 14.7 ounces, the other is 18 pounds 11.7 ounces. (No drivers installed) three ounce difference being the amount of epoxy, resin and Bondo?????

Hello Mark (mcgsxr),
Thanks for the complement. Yea, it is a work in progress and the final color will be quite a bit different. The "Hammer Paint" is all I had on hand in quantity large enough to cover the three baffles (for now). The baffles actually have a couple coats of fiberglass resin. This final goal here is to have an automotive body shop spray on an actual automotive paint. There's a couple colors I have in mind, but haven't decided which one I'll go with. But when all is said and done, the baffle color will have the same color code ("part number") as a vehicle manufacturer has on their line of cars.

Surprisingly the light shade gloss coat doesn't interfere with the HT. You can't see any reflections from the projector which is/was one of my concerns. Now that I know there's no reflection or interference, that expands my color palette a little bit. Might have to have them painted some eye opening shade of yellow.

So far they sound great and haven't heard any anomalies (buzz, rattle etc..)
They actually sound better than having each driver on it's own baffle. There's considerable more "weight" to the sound. Either due to the extra reinforcement of the drivers having twice the acreage or due to the sand filling. Not sure which, but the sound quality improvement is a welcome addition. aa

Bob

Mr Content · « **Reply #4 on:** 23 Apr 2009, 02:31 pm »

Come Bob, so wheres the Pics aa, Naw only kidding. My you have been busy. I look forward to your progress, with pics of course.

All the Best
Nig

ebag4 · « **Reply #5 on:** 23 Apr 2009, 08:30 pm »

Looking good Bob! How do you like working with bondo? Before your previous baffles did you have much experience using it? The reason I am asking is because I am considering using it on my next project, but I have never worked with it.

Best,
Ed

Bob in St. Louis · « **Reply #6 on:** 23 Apr 2009, 08:50 pm »

Hey Ed,
Yes, absolutely!! Bondo is great.
The last time I used automotive body filler was.....um.....1986.
In some of the photo's you can see gray putty. That was a "general home use" two part epoxy. It's very easy to work with. I've had that can for well over a decade, so I'm not sure how much it costs. The Bondo I bought last week (looks red/pinkish in the photos) is one gallon and cost $20 at AutoZone. You can buy a plastic "knife" (spreader thingy) for $1, but the fine sharp edge gets beat up which leaves high spots you'll have to sand down later. Something like pieces of thick poster board might work just as well and be a lot less expensive, although making these three baffles you might only go through three spreaders so it may not be a big deal anyway.

Regarding my previous baffles (back in 2007?) I was using fiberglass cloth and resin over a wire mesh with a wood skeleton. I'm NOT a real big fan of fiberglass cloth or resin. If memory serves, I filled in the low spots with the same can of household epoxy I used up on these.

But yea, Bondo is very easy to apply, very cheap, sands easily...and actually smells good (subjective, of course).

Bob

ebag4 · « **Reply #7 on:** 23 Apr 2009, 08:57 pm »

Cool, might have to give it a try. Thanks for the info Bob.

Best,
Ed

Quote from: Bob in St. Louis on 23 Apr 2009, 08:50 pm

Hey Ed,
Yes, absolutely!! Bondo is great.
The last time I used automotive body filler was.....um.....1986.
In some of the photo's you can see gray putty. That was a "general home use" two part epoxy. It's very easy to work with. I've had that can for well over a decade, so I'm not sure how much it costs. The Bondo I bought last week (looks red/pinkish in the photos) is one gallon and cost $20 at AutoZone. You can buy a plastic "knife" (spreader thingy) for $1, but the fine sharp edge gets beat up which leaves high spots you'll have to sand down later. Something like pieces of thick poster board might work just as well and be a lot less expensive, although making these three baffles you might only go through three spreaders so it may not be a big deal anyway.

Regarding my previous baffles (back in 2007?) I was using fiberglass cloth and resin over a wire mesh with a wood skeleton. I'm NOT a real big fan of fiberglass cloth or resin. If memory serves, I filled in the low spots with the same can of household epoxy I used up on these.

But yea, Bondo is very easy to apply, very cheap, sands easily...and actually smells good (subjective, of course).

Bob

Scott F. · « **Reply #8 on:** 23 Apr 2009, 09:00 pm »

Nice job Bob

I really need to make it over one of these days to give your OBs a listen

Bob in St. Louis · « **Reply #9 on:** 23 Apr 2009, 09:34 pm »

Go for it Ed. If you plan on making odd, swoopy, contoured shapes, this will help. Although, with your wood working skills, you've seemed to mastered that pretty darned well. I still drool over you "guitar" baffles.

Scott, yea come on over. That would be great.

I'm here 24/7 nowadays so there won't be any scheduling conflicts on my account.

Bob

p.s. Mark (Blackmore) To answer your question about the weight, with the two drivers included, the right and left channel baffles weight about 53 pounds each.
The center channel baffle with the single coaxial driver will weight about 41 pounds. But that weight doesn't include the SqueezeBox that fits in that little rectangular hole on top.

TRADERXFAN · « **Reply #10 on:** 23 Apr 2009, 09:38 pm »

Thanks Bob, this is inspiring.

I may dabble with some of that bondo on a DJ speaker I am building for a friend.

Question though: Why did you leave that lip on the front of coaxial?

-Tony

Bob in St. Louis · « **Reply #11 on:** 23 Apr 2009, 09:52 pm »

Good question Tony.
These speakers are not only for two channel, but also for home theater. The height of the speaker can't be too tall, other wise it will interfere with the projector. Therefor I had to make them as short as possible. Well, the bottom of the HT screen is 30" from the floor. The drivers I'm using are 15" each. The math doesn't work out very well for two stacked 15" drivers on a baffle and still stay under the height of the screen. The only "slop" I had was that in the seating chairs, in a slightly reclined position, I can get away with 33" tall speakers. That still doesn't leave much room for space below the bottom driver, space between the two, and space above the top driver on the baffle itself.

So, The Augie (on bottom) is mounted on the front (recessed) of the baffle. The Coax (on top) is rear mounted. The bottom bolt of the top driver is actually below the top bolt of the bottom driver. They overlap. The top driver being rear mounted behind 2.25" of wood created the horn flare. This of course creates that lip thingy. I struggled quite a bit with a design that would allow the two to "flow" together.

Kind of a long explanation, sorry about that.

Bob

PDR · « **Reply #12 on:** 23 Apr 2009, 11:01 pm »

Hi Bob, very nice design.....been looking in from time to time at Darrels site.

I used bondo to smooth the baffles of a sub project I did a while back....it worked well.
On my last project I also required some but this time I used glazing putty, its the stuff
they use on top of the bondo, it worked very well but was pre-mixed(didnt require hardener)
had a much longer working time and sanded like a breeze. It was about $10 a large tin.
I would highly recommend it if you havnt used it before.
Thought I would throw this out there

Perry

Bob in St. Louis · « **Reply #13 on:** 23 Apr 2009, 11:05 pm »

Yea, thanks for the heads-up on that Perry, I'll check it out.
Do you have a thread about your sub baffle build?

Bob

Bob in St. Louis · « **Reply #14 on:** 27 Apr 2009, 07:25 pm »

The white shelf bracket legs on the left and right baffles are temporary until the project gets resumes later down the road. However, the wooden legs on the center channel baffle are VERY temporary.

Here's what things look like presently:

Bob in St. Louis · « **Reply #15 on:** 27 Apr 2009, 08:17 pm »

I had to mount the SqueezeBox and hook the power cable to see what it looks like.
There's no sound yet but, damn......that's just cool. aa

mcgsxr · « **Reply #16 on:** 27 Apr 2009, 08:27 pm »

INSPIRATIONAL!

I still love the colour, I don't care what you envision! aa

ebag4 · « **Reply #17 on:** 27 Apr 2009, 08:31 pm »

They look great Bob

! Are they painted a bronze color now or is that a lighting issue? (I like the bronze if that is what they are now)

Best,
Ed

edit: nevermind,appears to be a trickof the light. I can tell you they look good in bronze...

Bob in St. Louis · « **Reply #18 on:** 28 Apr 2009, 12:00 pm »

Mark, thanks a lot!
The color is growing on me. I think I can deal with it for a while.

Ed, thank you!
You're correct the second time. The color in the last picture is incorrect. I was trying for some fancy camera tricks and well...that's what I got.

But the honest color is a medium silverish gray. It's Rust-Oleum brand "Hammered", so it's slightly textured. Smooth overall, but slightly bumpy, like hammered metal.

It's very nice watching the VU meters of the SqueezeBox staring straight ahaid as opposed to over to the side. Much more comfortable on the neck.
With the lights dimmed, the bouncing VU display appears to be hovering in mid air. Kinda cool. aa

Bob

mcgsxr · « **Reply #19 on:** 28 Apr 2009, 04:25 pm »

Bob, I know that you have plans for different cosmetics eventually - do those plans involve rounding over the edges of the baffle? At present I notice they are square. When I routed off the edges of mine, a few years ago, with a 3/4 inch, I found that it did a lot of good, for the minimal work.

Highs were cleaner, I think it has to do with treble diffraction.