[Christof]

Dayglow, you see any problems with solid baffles on the OB5's?  I've got a couple slabs of 8/4 Walnut sequenced off the same log waiting for a project like this.

Would there be problems if the baffles were rocked back, let's say 10degrees, like the front side of the C & C Abby's to give them a more casual posture?   Would a baffle change like this necessitate an XO change?

-c

[Daygloworange]

Danny can give you a more detailed answer, but no you can't. The drivers are time-aligned electronically, so you'd be throwing that all off by tilting them back. I love the look of that as well. I asked the question a long time ago, and found out why. Tilting the baffle back is one way of trying to get the mechanical centers of the drivers time aligned. The other way is to time align them with the crossover.

I'm not sure what to tell you regarding the solid wood for the baffle thing. I would be inclined to say no if you plan on gluing it on with carpenters glue. Solid wood will expand and shrink a lot across it's width. It might split. If you use a silicone type adhesive it would probably be OK. Something that will allow it to move across it's width.

I think 2" is a little too thick, as you'd be shrouding the back of the drivers quite a bit, even with a heavy roundover. But check with Danny, he'll be able to tell you better.

Cheers

[Danny Richie]

Dayglow, you see any problems with solid baffles on the OB5's?  I've got a couple slabs of 8/4 Walnut sequenced off the same log waiting for a project like this.

The way to do it is have it sliced down to a thinner thickness then laminate it to a sheet of MDF. Then fold over a short section of it on the ends to hind the MDF from view from the sides. And of coarse give the front edges a nice radius. 

You'll need to flare (radius) the back side of the woofer holes a little more the thicker the wood gets too. That way it won't start to load the woofers.

A slight tilt is okay but 10 degrees would be pushing it. It would make the lower woofer closer to you (in time) than the upper one. With this speaker it wouldn't be too bad as they are near perfect phase at the crossover point and it is a low crossover point.

See the vertical off axis measurements of the OB-7: http://www.gr-research.com/kits/ob-7vert.shtm

Tilted back 10 degrees your on axis response would look like something between the Yellow line and the Orange line and more like the Orange line to the Red line when you stood up.

Since the wavelengths of the lower frequency range are so long there will be little to no effect in that range.

[Daygloworange]

Tilted back 10 degrees your on axis response would look like something between the Yellow line and the Orange line and more like the Orange line to the Red line when you stood up.

Really?  I checked out the response chart. That's not a whole lot. I mean, with a 4" difference in axis, the red and orange lines are almost identical. Maybe I'll play with tilting the speaker back and see how much of a difference I can hear.

The way to do it is have it sliced down to a thinner thickness then laminate it to a sheet of MDF.

Yeah, that's a great alternative. The term is re-sawing . Try and find someone that offers that service, and ask if they'll stitch it for you as well. Then you'll have a bookmatched pair of speakers. If not you can still work around that. It's a lot better way to go, and if you have a really exceptional piece of wood, you could even sell the rest on Ebay.

Ah, man....here we go again, back to the ol' drawing board.

Cheers

[ebag4]

Just to throw my 2 cents in, I have been playing with OBs for a few months and one thing I noticed is that the height of the soundstage seems to drop when an OB is tilted back.  Of course YMMV.

Happy hoidays,
Ed

[Daygloworange]

ebag4,

Do you have a pair of OB 5's as well?

Cheers

[nodiak]

Hi, thought I'd put in here as I've used alot of resawn nice boards and glued to mdf for desk tops and side panels, and for speaker cabs. Typically I go over 1/8" thick up to 1/4" for the resawn pieces as they will have uneven thickness from the bandsaw, and are then run through a planer. I try to end up with 1/16 - 1/8 thick "veneer" that will avoid gouging. It's really important to laminate close to same thickness solid wood on the other side also to avoid warping. Can use something cheaper for that side
I don't have a large bandsaw so pay a local furniture builder $60 an hour, but if you prepare the boards first with a nice jointed edge and cut to length you'll save alot. He will run the thick board through a planer between each pass to keep one side reasonably flat. I try to start with as thick as possible boards, 1.5" or more as this method usually gives only 3 or 4 pieces per typical 3/4" thick board. I've never gone over one hour charge for 2 speaker cabs worth of resawing.
Kind of time consuming but really worth it! Good luck if you try it.
Don 

[Hank]

I second Nodiak's suggestion to use only thin resawn solid wood.  Thicker will possibly split with dimensional humidity-caused changes over time.  There are internal stresses in hardwood that may cause problems over time.  Seems that they are particularly exacerbated by ripping hardwood boards, which releases those internal stresses.  My bud built a grandfather clock from scratch out of walnut.  He used good, kiln-dried stock, but when he ripped boards down to use as stiles and rails, occasionaly the internal stresses released caused some of the thin rips to bend outward and result in curved pieces that were unusable.  Lesson:  you may have to rip several pieces if you're going to do things like corner inserts.

[ebag4]

D.O, sorry for the confusion.  No, I don't own OB5s (although I would like to hear a pair), my comment as meant to be a general comment based on my experimentation with Visaton B200s and Augies in an OB alignment.

Happy holidays,
Ed

[ewarren]

Dayglow, What is the maximun re-saw thickness that you could laminate to MDF, and not worry about cracking.  Also, how would you do the edge, so you could put a 3/4" roundover on it?  If you laminated the front and back of MDF with 1/8"- 1/4" veneer, wouldn't the MDF be exposed if you rounded the edge?  I am thinking of the OB5 cabinet style that you and Rocket Ronnie built.  I plan on building a pair in the near future, and have lots of 4/4 walnut, bubinga, maple, and cherry stock.


Thanks

[Daygloworange]

Dayglow, What is the maximun re-saw thickness that you could laminate to MDF, and not worry about cracking.  Also, how would you do the edge, so you could put a 3/4" roundover on it?  If you laminated the front and back of MDF with 1/8"- 1/4" veneer, wouldn't the MDF be exposed if you rounded the edge?  I am thinking of the OB5 cabinet style that you and Rocket Ronnie built.  I plan on building a pair in the near future, and have lots of 4/4 walnut, bubinga, maple, and cherry stock.


Thanks

That's a tough call. The thickest I've ever done re-sawn veneering on MDF has been less than 1/8th. A guy that is set up to do re-sawing can get it quite thin. If the saw is set up properly and has the right blade he can get it very thin. You have to get it that thin if you're going to get it to wrap around a round over. I think mine is a 3/8" or 1/2", I forget now. I still had to soak the veneer and use heat, as the veneer I had on hand was very brittle.

Or you could do the trick where you veneer the face and add solid strips to the edge and then round over only the solid wood portion. That's the second method. A variation on that would be to add solid strips to a piece of MDF, veneer over the MDF and solid wood with a 1/8" thick veneer and then do the roundover. My concern then is that the solid strips will expand at a different rate than the MDF, and you could have the joint lines telegraph through the veneer, although at 1/8" thick, it probably wouldn't.

Cheers

[ewarren]

Thanks Dayglow. 

[nodiak]

I use the second method dayglow describes. Often it will be a desk top with thicker edge that can be molded in various styles. And usually a different wood species for contrast - like Madrone with curly maple edge/legs, birdseye with cherry edge/legs (for one of my sisters).
I've never done the thin veneer wrap from "homemade" veneer. That's a skill level step up in care and attention to details.
Nice to hear these cabinet ideas, hope to see some pics when their done!
Don
 

[Daygloworange]

Thanks Dayglow. 

No prob. I hope that I'm explaining that well.

Good luck, and ya, post some pics when you're done. 
 
Cheers