Lets talk plywood and mdf

[The Dude]

So I may hopefully be building some speaker cabinets. I wonder what some of the pros and cons to some of the types of woods out there are. I was talking to Dana Moore about building a pair of Jamborees I asked if mdf would be all right. He recommended against it do to the weight and the dust. The weight came in at 96 lbs so I will give him that plus it is nasty to work with, I know MDF is nasty an heavy but how far can it be pushed does the cabinet design decide this.

So he recommended using Marine grade ply wood, which comes in at 72lbs a sheet and $70.00 which quite the increase.

http://www.menards.com/main/building-materials/panel-products/specialty-panels/specialty-sanded/3-4-x-4-x-8-marine-grade-plywood/p-1485663-c-13332.htm

Then I know a lot use Baltic Birch 83 lbs at $75.00 a sheet

http://www.menards.com/main/building-materials/panel-products/specialty-panels/hardwood-plywood/3-4-x-4-x-8-baltic-birch-plywood/p-1479674-c-13334.htm

Then there are a few others regular Baltic birch veneer core, when we looked it up it was around 65lbs and ran about $39.99

http://www.menards.com/main/building-materials/panel-products/specialty-panels/hardwood-plywood/3-4-x-4-x-8-baltic-birch-plywood/p-1479674-c-13334.htm

Last Arauco plywood or from Menards is ACX which runs 71 lbs at $45.00

Now I know the amount of plys are key, along with void free. But what does it really come down to, if the cabinet has short panels or well braced. I have seen some cabinets built or builders recommend each it just seems to be what the builder is used to. I do like the lighter ones better and are 11-13 ply and good prices.

[dtel]

I think your right, the amount of plys and lack of voids are the most important thing. IMO

For our MWM's I used some Oak ply from home depo, I have no idea of the weight but it was $49 a sheet, don't know if it went up since ?

I cut up 12 sheets and found very few voids and they were very very small, it also felt very solid compared to regular ply, better glue also, I think, I was really surprised. At 50 a sheet I measured 3 times or more before I cut

This is the edge.

Edited January 9, 2014 by dtel

[jason str]

If Auraco plywood is available i would use that, its priced cheap, void free & holds up well.

Stay away from plywood with a thin outer veneer, it dosent hold up to gluing well.

The Birch from Menards probably has a thin veneer, avoid it if it does.

The only time i use MDF is if i have too witch is rarely.

Edited January 9, 2014 by jason str

[toolz]

I was at the Arauco plant in Chile a few years back. The plywood is made from Radiata pine which is plantation grown. The materials manufactured at the Aruco coastal plant were of good quality and finish. At this plant they made various types of plywood used for furniture and other wood products. At the time it was the largest producer of wood products in Chile.

[ryanm84]

I've built bookcases and a tv stand out of the oak plywood from menards. Furniture that has been moved across the country twice. It holds up very well. I would personally use it again.

That said, while I lived in Phoenix and there was a woodworkers source a few miles from my house. 3/4 4x8 sheets of cherry, walnut and maple. Now you're talking!

[Thaddeus Smith]

Carl built my sub out of mdf. He doesn't mind the dust and it was his preferred material to work. The density and weight make this thing very inert even when playing very low frequencies at very high volumes. So can pretty much see that just about every material has its benefits and its fans.

[jason str]

Veneered plywood is great for making nice looking furniture, not good for a resonating bass cabinet.

The outer veneer will not hold up well.

Edited January 9, 2014 by jason str

[tigerwoodKhorns]

Veneered plywood is great for making nice looking furniture, not good for a resonating bass cabinet.

The outer veneer will not hold up well.

1/32" nowadays. Almost as thin as paper.

I hate cutting MDF, just nasty stuff, but sometimes you must. I am making shutter frames out of 1" thick MDF because I cannot find solid poplar that is not warped.

Most high end speakers are made of MDF because it is inert, but older Heritage are all ply.

Forget to mention, my favorite is the multi ply birch, comes in 5' x 5' sheets. Doesn't seem to warp and no voids.

Edited January 9, 2014 by tigerwoodKhorns

[Turbox]

I know MDF is good for Speaker Cabinets for its density, but i just prefer working with wood ply.

[The Dude]

The acx or auraco should be 7 ply, from what I can tell it appears to be more void free looking at the end grain. Same ply as marine grade same weight, but about $30 cheaper a sheet. So I would think if a speaker builder recommends marine grade the auraco would work fine.

In this case would we give up the amount of plies vs amount of void, I would think so as the voids could cause issues with sound and like Jason said after a while from flexing the glue would start to give and veneers would start to come apart( I know this isn't exactly what he said but that's how I interpreted it).

[tromprof]

Good quality Baltic birch. The stuff from Lowes is garbage BTW, I used it on my last project and regret it. My biggest fear with MDF is longevity. If it gets wet, bad news. If it gets bumped, again bad news. Plywood will shrug off what will kill MDF.

[CECAA850]

Plywood will shrug off what will kill MDF.

There's different grades of MDF as well. Cabinet grade is pretty tough is very durable and has an extremely hard surface. MDF from Lowes for example is much softer and flakes easily. When I get MDF, I always get it from a cabinet shop.

[Thaddeus Smith]

Good quality Baltic birch. The stuff from Lowes is garbage BTW, I used it on my last project and regret it. My biggest fear with MDF is longevity. If it gets wet, bad news. If it gets bumped, again bad news. Plywood will shrug off what will kill MDF.

You know that plywood has the potential to delaminate and warp and mold when it gets wet, right? And looks like *** with big gouges and chips and scratches, right? Along with everything else in your living room/music room that's not waterproof and affected by the same flooding force that ruins your speakers.

[tromprof]

Plywood will shrug off what will kill MDF.

There's different grades of MDF as well. Cabinet grade is pretty tough is very durable and has an extremely hard surface. MDF from Lowes for example is much softer and flakes easily. When I get MDF, I always get it from a cabinet shop.

I guess the moral of this story is whatever you use, don't get it from Lowes.

[tromprof]

Good quality Baltic birch. The stuff from Lowes is garbage BTW, I used it on my last project and regret it. My biggest fear with MDF is longevity. If it gets wet, bad news. If it gets bumped, again bad news. Plywood will shrug off what will kill MDF.

You know that plywood has the potential to delaminate and warp and mold when it gets wet, right? And looks like *** with big gouges and chips and scratches, right? Along with everything else in your living room/music room that's not waterproof and affected by the same flooding force that ruins your speakers.

I was thinking more in terms of spilled drinks, children, and other smaller mishaps. I don't expect any audio equipment to do well in a flood.

[CECAA850]

I was thinking more in terms of spilled drinks, children, and other smaller mishaps.

That's more a product of the finish than the MDF. Raw MDF does NOT do well even with a small amount of water, you're correct. You're also correct about wood products from Lowes. I'll buy fencing products from them but that's about it as far as it goes wood wise.

[Thaddeus Smith]

(self-censored for excessive snark and unhelpful commentary)

[The Dude]

(self-censored for excessive snark and unhelpful commentary)

I thought you wanted more of excessive snark, uh.

[Thaddeus Smith]

who died and made you the accountability-to-every-word-i-say police?

[The Dude]

This is what lowes usually carries, and what I meant to post in the first post. I would stay away from this, when I looked at it at the store you could see the voids. May be good for shop cabinets but not speaker cabinets. I think this is what Jason and Tom were referring to. The Baltic birch they offer seems to be better quality. May have the same quality as buying mdf at a big box store vs a cabinet supply store.

http://www.menards.com/main/building-materials/panel-products/specialty-panels/hardwood-plywood/3-4-classic-birch-plywood-wood-veneer-core/p-1480808-c-13334.htm

This stuff appears to all so have the thin veneers, the first link of actual Baltic birch appears to have equal thickness plys of veneer like what Dtel posted a pic of. Which I would think would be ok or better then the cheap thin veneered stuff.

My conclusion, top of the line would be 3/4" Baltic birch from a cabinet shop, if price was a concern and weight and dust weren't go MDF from a cabinet shop. Down from there I would go big box store for 3/4 Baltic birch(though I haven't had a chance to look at this since they don't stock it) or MDF. I for the most part like the Auraco 3/4" I think if the bracing is right or the panels are to long you would be fine. I know there a better products that could be used buy how much sound are we compromising when use the lesser.