Baffling question here?

[robertbartsch]

I'm currently building a (i) single HT center channel from an old JBL - L100 cab, and (ii) a pair of 3-ways with 15 inch LFD, large format compression drivers, and bullets.

Anyway, in making some construction modifications to the L100 cab, I have noticed that the baffle is made from very thick +1 inch material which gives me pause to think abut the construction of the pair of large format cabs.

Originally, I was going to build the 15 inch 3-ways with a 3/4 inch plywood baffle. Is this a bad idea and should I change my plans and use a much thicker material?

Why did JBL use such massive thick baffles on the L100? Was this just design overkill or was this needed and did it result in an accustic advantage?

[robertbartsch]

...so should I double up on the 3/4" baffles? ...what about adding only a 1/4" piece to the 3/4" piece and make a 1 inch thick plywood baffle?

...not sure why JBL used the particle board baffles in the L100 but that material does have some downside, so perhaps their responce to this was to use a very thick piece and, therefore, since I'm using plywood, I don't need to consider this.

[Mike Caldwell]

Particle board is actually denser than plywood making it a little better better choice acoustically. For durability birch plywood is the standard and it is available in one inch thickness. Cabinets of 3/4 inch ply that are well braced internally are the most common. If weight is not an issue a plywood particle board laminated combination has been done.


Mike Caldwell

[boputnam]

For durability birch plywood is the standard and it is available in one inch thickness.Yeah, I'd definately keep toward a 1-in baffle thickness, and certainly plywood versus particle board. Once you get all the drivers mounted on there, you'll be glad it's 1-in. Once you start drilling all the mounting holes, you'll be glad it's not particle board...

[duaneage]

I now use 1 inch double refined MDF for baffle boards and 3/4 MDF all around. I built a nice set of 4411 clones with 14 layer plywood sides, furniture grade stuff. I'd say it came out well.

MDF paints up better than particle board and is consistant all the way through. It has a higher modulus and is pressed at around 2.5 times the force of particle board. The MDF I use is also made without formalghyde. It's expensive, about 32 a sheet compared to 27 at HD but is higher quality and a bit safer to work with. The 1 inch is 38 a sheet.

The distributor I get my panels from can get MDF up to 2 inches thick. They stock 1.5 inch down to 1/2 inch thicknesses. You need to find a real plywood distributor for unusual stuff. Home Despot can order it for you but they are just going to call the distributor up, bring it in, and charge you a markup.

Of concern should also be the joints you use. I use biscuit joints and rabbit joints for the ends, I also have made spline joints. If you plan to hold a TV or entertainment devices up with it a strong box is essential. Brace the insides and consider that enough weight on top will eventually press down on the panels so you need bracing every foot or so.