1/2” birch ply sufficient for box build?

[Clifff150 10+ year member]

I ended up finding an 11 ply plywood board at my local Lowe’s. The exterior 2 layers are very thin so it’s more like 9 ply. I’m going to start the box tomorrow so I’ll report back. Going to do a window to show off the Brahma magnet

 

[Firewalker]

Oh you mean that Brahma that I will steal I mine borrow I mean be given when you are in Madison next time?

Sweet man thanks for doing all the work

 

[Buck 5,000+ posts]

I've never heard a sound difference between types of wood in non-walled enclosures. Usually it's a weight thing. It's usually a birch vs MDF comparison. Birch is just better quality, lighter, stronger. MDF will almost always work, but MDF can have symptoms that other wood types don't have.

Bracing is usually stronger than more layers of wood. Resonance is the killer. Resonance is why you need bracing on certain pieces in certain locations. Resonance can store energy and build up over time, and that constant vibration is what can break a box apart over time. Like I design my boxes to last, be durable. A lot of my designs could function without some of the bracing, but walls would flex and put a lot of fatigue on the glued joints and surrounding areas. Sometimes it doesn't matter quite how thick a wall is, if it's too long, it has to be braced. Like a side wall that's 40" long and fairly tall needs to be braced because that long distance is a lot of leverage and that piece will flex a lot. The fact that sounds waves are a mechanical (kinetic) AC wave means that the cycling can store energy into material it's being transferred too, as long as the wave is still currently active. Sometimes that energy can build up to a breaking point and cause a box material failure, same thing with the metal on your car. AC pressure is way different than you standing on the box and gravity causing your weight on the box. But that's why wood is used a lot for audio enclosures, it doesn't resonate very well, as a material. You're not making a tuning fork out of wood. Has to do with molecular composition and geometry

Sounds is a wave, and waves have certain lengths. Physical material also has certain lengths. When the sound wave's and material's characteristics match up, that's how you get resonance. The lower the frequency, the bigger the object you resonate with. The higher the frequency, the smaller of the object you resonate with. I'm saying all of this to try to explain why box bracing is important when it comes to wood thickness. If you study large bridge engineering, old bridges used to get knocked down because the wind would cause the bridge to vibrate at the resonance frequency of the bridge (long bridge, low resonance). The resonant energy would build up to a point that the bridge would literally start looking like a sine wave, and then it would completely fall apart. Just a little bit of wind could do that, and it's because of how resonant energy can become stored in physical material. And that's why bridges are braced like they are today, is because of resonance. You know, now imagine the wind from a 150db+ sound system. All that flexing to the box and to the vehicle causes fatigue and generally a loss of sound pressure.

 

[Clifff150 10+ year member]

Let’s make a deal, you can steal my icon and leave me a $200 spot LOL. I’m seriously thinking about doing 8’s in my truck instead of the icon.

 

[Bobbytwonames 5,000+ posts]

I ended up finding an 11 ply plywood board at my local Lowe’s. The exterior 2 layers are very thin so it’s more like 9 ply. I’m going to start the box tomorrow so I’ll report back. Going to do a window to show off the Brahma magnet

Is it ½" or ¾"?

 

[Clifff150 10+ year member]

3/4”

 

[Bobbytwonames 5,000+ posts]

3/4”

Just make sure that you glue and pre-drill for your screws. I usually glue and tack it together with a brad nailer and then pre-drill for the screws. No clamps needed.

 

[Firewalker]

100 bucks and the Dayton DSP, for the brahma ,lol. I have 2 FI 12" SSD4's coming later this month.

 

[Clifff150 10+ year member]

I actually don’t plan to use screws as I want it to look as seamless as possible

 

[Clifff150 10+ year member]

Those Fi SSD’s are on my short list for my collection lol. I let my brother in law go in my shop and look at my equipment and he quickly said I have a problem LOL. I totally forgot I had a JL W6 and some morel comps up there

 

[hispls 5,000+ posts]

3/4 Maple 5 ply
3/4 Red Oak 5 ply
3/4 Birch 5 ply

Those hardwood names are just the veneer coating. I can assure you that there will be no audible difference (and likely no measurable difference) between any of them if your box is assembled properly.
Pick whichever one looks like the best quality ply or if you plan to stain or leave unfinished, whichever has the nicer looking grain.

 

[Bobbytwonames 5,000+ posts]

Those hardwood names are just the veneer coating. I can assure you that there will be no audible difference (and likely no measurable difference) between any of them if your box is assembled properly.
Pick whichever one looks like the best quality ply or if you plan to stain or leave unfinished, whichever has the nicer looking grain.

The 5 ply stuff just warps compared to the 13 ply. The 5 ply is usually from China or Japan. @Clifff150 if you use the 5 ply stuff, then, I would definitely use some screws. Then, just use some wood filler over the screw heads.

 

[Clifff150 10+ year member]

I’m using an 11 ply wood I found at my Lowe’s. Literally the last piece they had and it was hidden in the back. Actually got most of the box built today

 

[Bobbytwonames 5,000+ posts]

I’m using an 11 ply wood I found at my Lowe’s. Literally the last piece they had and it was hidden in the back. Actually got most of the box built today

Good! I didn't use any screws on my box either. A lot of brad nails and glue. Then, wood filler and a lot of clear. I also siliconed the inside of the box. Just an idea.

 

[Buck 5,000+ posts]

Beetles get loud. I've done some of them before. We had a friend with a beetle with the like 4 foot long exhaust and spikes running down the center from front to back. He had 4 of something in there and it was super loud for what it was.