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Baffled by baffle options (Read 3082 times)
Evo
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Baffled by baffle options
06/13/10 at 11:58:36
 
I am planning on building these relatively soon. One thing I was wondering about was how variations in the baffle material might affect the sound.

I could use plain MDF and veneer as Steve suggests, but in truth veneering is pretty horrible.  Having some difficulty finding pre- veneered MDF.

Another option might be use plywood and stain. Any ideas how this would affect the sound?

And finally a slightly more unusual idea would be to use solid wood (for the baffle only. MDF for the rest). I normally wouldn't even consider solid wood for speakers as the warping would cause all manner of problems, but given that with the ZOB I planned to place felt between the baffle and the speaker cabinet I thought that some warping might not affect sound. I figured that it would need to be hardwood in order to have the necessary density. Could be pretty expensive.....although I am pretty sure over here in Australia there a few affordable native hardwoods available. Also wondered what the sound would be like?

Any thoughts/suggestions re: best sound and easiest/best looking finish trade-offs?

Cheers,

Matt
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BoilermakerFan
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Re: Baffled by baffle options
Reply #1 - 06/17/10 at 04:59:11
 
In general, what I have been told for traditional box speakers is that a good hardwood plywood has better sonics than MDF.  

I will be using Baltic Birch plywood for my back cabinet.  I'll be using Bamboo and/or Walnut plywood for my front bezel.

Solid wood, if selected carefully and finished properly, should not warp a significant amount.  It will just be very expensive.  A butcher-block glue up would be a possibility  too, but I'd want to research the best glues to use to keep sonic performance intact.  

I'd use the densest, straightest, properly cut tone wood I could find.  Anything from the Rosewood family, hard Maples, Mopani, etc.  

That's just my opinion though, and based on comments from others I have received in the past WRT traditional speaker cabinets.  
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« Last Edit: 06/17/10 at 04:59:29 by BoilermakerFan »  
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Damien
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Re: Baffled by baffle options
Reply #2 - 02/12/11 at 02:10:50
 
I came here to ask this very question. I was thinking particle board for the cabinets. It's the hardest and smoothest unfinished non warping and cheap wood I could think of. OSB is the cheapest but it's not very smooth and has lots of air spaces in it

Then a solid hardwood exotic for the front baffle.

Flame Maple is my first choice but I'm betting that will be 15-20$US a foot! Ouch!

Anyway I am new to Decware and these forums but am very excited about the Taboo amp I ordered and my plans to build some of these ZOB's.
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Hotsauce
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Re: Baffled by baffle options
Reply #3 - 02/12/11 at 02:14:56
 
The problem with solid wood is that it shrinks and expands in width only as moisture changes.

John C.

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4krow
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Re: Baffled by baffle options
Reply #4 - 02/12/11 at 03:53:27
 
No doubt, wood does have those characteristics. In the 'old days' there were ways to accomidate this  problem. In the case of the ZOB, I see that the baffle is to be mounted on to the box by screws, and there is a felt gasket in between. In this case I can suggest that the baffle be mounted by the screws from the rear, and that holes in the box for the screws be be more like slots. It looks to me that this could be done both top and bottom. On the top, you would access the screws easily by using the brace on the top. In the case of the bottom, the rear panel of the box would have to be such that it could be removed in order to access the screws. Also, it should noted that not all woods expand and contract the same amount. Pine for example has a lot of movement as compared to walnut, oak or maple. You can find a chart of this in Finewoodworking if I recall correctly.
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ZYGI
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Re: Baffled by baffle options
Reply #5 - 02/12/11 at 15:18:13
 
Damien,

  I would not suggest particle board for the ZOB's as there are a lot of edges that would take way longer to fill and smooth with particle board than it would with MDF.

Jon,4krow,

Yes wood does expand and contract with the seasonal changes, and different woods do this more or less by species. But there are also different cuts that in the same species will also expand and contract more or less. Quarter sawn the least and flat sawn the greatest. Quartered is also less likely to warp than flat sawn. Rift sawn is in the middle with the best looking grain, and is easier to find than quarter sawn, and is less expensive than quarter sawn.

As far as using  solid wood for the baffle, the ZOB's can easily use solids for the front baffle, just do as 4krow suggests and slot the mounting holes. The only place you are going to have to be careful with is the driver mounting. I've seen a 5-1/4 driver mounting split the front of a solid would baffle right up the center of the screw holes. The baffle was fine until I moved from Virginia to Arizona which was quiet obvious why the problem arose. If you are using a driver with 4 mounting holes mount it square so the distance is the least in width. If you use a 6 hole mount, place 2 of the screw centered and this will give you the least width of driver mounting screws. With the ZOB being accessible to the driver, both front and back, you could used machine screws with nuts and washers on the back side, this would allow you to drill a larger hole, and allow some seasonal movement. You may also want to enlarge the driver mounting hole just a bit, so that didn't cause any problems. How much will depend on what time of year you build your speakers and if the wood has been in an environment long enough to acclimate to the room which the speakers will stay. If you build in the winter months you can usually build a little tighter as the wood will expand in the summer months. The opposite would apply if building in the summer. Just make sure you apply the same amount of finish to all surfaces.

MDF on the other hand doesn't really expand/contract in width or length but instead with its thickness. This was why when we build the ZOB's, on the sides panels the depth at the bottom from front to back and the height from the bottom to the port plate is made 1/4" bigger than the plans, keeping all other dimensions the same and rounding over both  inside and outside edges with a 3/16" round over bit. This is more for aesthetics, but it also doesn't allow the joint to get ugly over time, it always looks the same. We had to Lock miter the corners of the ERR's for this very reason, as we were having a lot of people wanting piano black and the joint would telescope the finish over time.    

Unlike the plans, when we build the open baffles we use cleats around the interior bottom to screw the bottom in after the front has been mounted, this allows us to finish everything, then mount the baffle and seal up the bottom of the cabinet, its the least obtrusive look, as you don't see any screws on the back of the speaker.

Hope this helps,
ZYGI 
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markm1111
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Re: Baffled by baffle options
Reply #6 - 02/21/11 at 04:17:41
 
Matt

Did you ever build these using Aussie hardwood? I am thinking of undertaking the project and would like some nice hardwood ftont baffles for WAF reasons

Cheers

Mark M
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