[tcarcio]

I was wondering what if any difference it makes when building a sub the type of wood used? I see most people use MDF but is there a reason or is it just price. Also is there a better wood to use that would render better results?

 

[robertcharles123]

I studied that question for quite a while before I started my build. Many different ideas were uncovered, but each has its benefits and shortcomings. after much research, I decided to go with an mdf structure with beautiful oak ply laminate. The main reasons were to save some weight and get structural rigidity. If I would have went with all mdf , my build would be 150-200 pounds more than current weight per cabinet. The end product is extremely rigid and heavy, but not as heavy as it might have been.

Mdf machines quite nicely, while the ply does not come out as pretty. Also, mdf weighs 90-95 pounds per sheet, ply 40-45 pounds.

What type of sub are you planning?

 

[tcarcio]

Thanks for the info, I am planning on a simple sealed 2.2cf sub to match the one I already have although it will have a different driver, the shiva X 12''. I can't go to big so I thought another small sealed would balance out the bass a little although I do get fairly flat response now according to my SMS1. It will be my first build so I will keep it simple. I guess MDF is going to be my choice unless someone changes my mind with a good enough reason.:yes:

 

[Kevin Haskins]

MDF is cheap and easy. People debate between the different materials but as long as you brace 3/4" MDF appropriately, it works great.

As robertcharles123 noted above, the void-free plywood is less wieght but cost at least twice as much. I've built both and I use MDF for all my prototype work. Baltic birch can be nice if you want a quick & easy sub because you can just sand & stain the surface and you don't have to do veneer work or have any painting headaches. It limits your finish choices, and you have to be creative with your cuts to get the right look but it can also look good.



Kevin Haskins
Exodus Audio
www.diycable.com

 

[tcarcio]

Thanks Kevin, and thanks also for the plans for the sub you sent me. I hope to get it done soon. So what I am not hearing is that there is an audible difference in wood choices which I guess might have something to do with mass or does that not play a role to a degree that it makes a difference?

 

[Bill Fitzmaurice]

So what I am not hearing is that there is an audible difference in wood choices which I guess might have something to do with mass or does that not play a role to a degree that it makes a difference?

What's required is a cabinet that doesn't lose energy or create spurious sounds due to vibration. That can be addressed via mass or via design, ie., bracing. Commercial designs tend to take the mass route, as MDF is cheap and the labor to build well braced cabs is expensive. Where DIY is concerned mass is fine if you never have to move the cab. But bracing works just as well and can give a far lighter cab.

 

[tcarcio]

Ahh, Got ya.:T

 

[SteveCallas]

To touch on this, if you wanted to go with really thick and rigid walls, but not necessarily have tons of weight, you could even use OSB for inner layers. Sandwiching layers of various materials might be your best bet, as you'll have the mass and rigidity as well as a varied density.

 

[tcarcio]

I am building the sub now and I am useing MDF for most of the enclosure except I used birch for the front and back.

 

[Warpdrv]

In my research I have found that for a very rigid structure, 3/4 Baltic Birch or void free plywood is very popular, if you can get it... I am getting it at a local supply house for @ $60.00 4x8 It still requires bracing just as any other product.

Just throwing that out there for anyone doing research.

 

[avaserfi]

Panel resonance is not a large issue with the typical passband of a subwoofer (xHz-80Hz). For such an application MDF with typical bracing implementation is a perfectly suitable material although it is heavier and less stiff, but cheaper, than a cabinet grade void free plywood. Now as the intended passband increases so does the need for more rigid materials, denser bracing and/or use of a constraint layer due to the exponentially increasing effects of cabinet resonance.

One of the most efficient methods of which I am aware for removal of cabinet resonance in a typical DIY environment is proper use of a constraint layer. For example, say one had a cabinet that was made from a high grade plywood with dense oak bracing such that there were no gaps in any direct XYZ greater than three inches and another person used the same bracing matrix and materials, but also included a proper viscoelastic constraint layer. The latter cabinet would be have a panel resonance attenuation about 8x greater (inaudible in most cases) than that of the former (lowered resonance than typical but still audible in many cases).

Of course, such dense bracing is not needed for a subwoofer, but if a loudspeaker is being built and optimal sound quality is a goal such bracing is necessary to remove resonances which have been repeatedly shown to lower listener preference of a loudspeaker in credible perceptual studies.