[Zuman]

I built my first set of DIY speakers from a CSS Audio Criton 2td-x kit and flatpack, but I'm about to build a new pair of Criton 2td-x towers with the help of a friend who is a very experienced and skilled woodworker with a wonderful shop and every piece of equipment you could dream of.
I'm partial to maple, and I was hoping to build a pair of fine furniture-quality cabinets from solid boards that would stand the test of time.
However, my friend says he worries a bit about the "stability" of solid wood, noting that it's more reactive to environmental factors than MDF and plywood.
I'd really like to go with solid hardwood, but I don't want a pair of beautiful boxes that are compromised sound-wise. So my question is this: If I really want the best-performing cabinets for the design, do I really need to go with MDF, maybe with a solid wood front baffle? Or is there a solid wood that's inert enough, even if it's not maple, especially with well-braced boxes?
Thanks for your expertise!

[FullRangeMan]

Builders use MDF or HDF because the wood can warp in a few years.
I suggest a golden ratio Bass Reflex box for the bass only under 200/250Hz, and to midrange and treble go OB with a hi Qts FR as Visaton B200 or other similar.
Golden ration enclosures usually dont need bracing.

[S Clark]

Solid is prettiest, but usually reverberant and not stable.  Good quality MDF is cheap and good.  Good plywood is more expensive, and maybe better than MDF, maybe not.  Braces are your friends... skimp on bracing at your own risk, Golden Ratio or not. 

[FullRangeMan]

Have posted this many times here AC:
MDF:  detailed and bright.
Baltic Birch:  soft and warm sound.
Particle Board:  neutral, mid on BB/MDF.

[mresseguie]

Not that I have a ton of experience, but would you consider MDF with a 1/8" thick maple (or other wood) veneer? I've considered doing this in the past.

[Zuman]

Just to clarify, I've already committed to the CSS Audio Criton 2TD-x design. External dimensions are 44" tall x 8-1/2" wide x 10-3/4" deep.
It looks like this (exploded):

[Jazzman53]

I built my first set of DIY speakers from a CSS Audio Criton 2td-x kit and flatpack, but I'm about to build a new pair of Criton 2td-x towers with the help of a friend who is a very experienced and skilled woodworker with a wonderful shop and every piece of equipment you could dream of.
I'm partial to maple, and I was hoping to build a pair of fine furniture-quality cabinets from solid boards that would stand the test of time.
However, my friend says he worries a bit about the "stability" of solid wood, noting that it's more reactive to environmental factors than MDF and plywood.
I'd really like to go with solid hardwood, but I don't want a pair of beautiful boxes that are compromised sound-wise. So my question is this: If I really want the best-performing cabinets for the design, do I really need to go with MDF, maybe with a solid wood front baffle? Or is there a solid wood that's inert enough, even if it's not maple, especially with well-braced boxes?
Thanks for your expertise!

Natural wood planks contract/expand significantly with changes in humidity. If this movement occurred uniformly in all directions there would be no problem, but it doesn't-- the movement occurs predominantly perpendicular to grain and very little in the grain direction, and that is the major problem.  Another problem is that plain sawn planks also tend to bow and/or twist, and/or cup.   

Furniture builders use hardwood planks for box-like pieces, but they always incorporate a floating bottom/top or floating back/front to accommodate the movement (i.e. no planks glued or screwed together across the grain).  You can't easily use this technique on a speaker box.

If you must use planks, then use only quarter-sawn planks for the sides, top and bottom, and use veneered MDF or plywood for the front and back. 

Quarter-sawn planks are cut with the wood growth rings aligned perpendicular to the board face for greater stability to resistant to bowing/twisting/cupping.  But they still expand/contract across the grain with changes in humidity so you would need to join the box sides with finger-joints rather than internal gussets glued across the grain.  Quarter-sawn planks are very expensive though -- at least 4X the cost of plain-sawn. 

[FullRangeMan]

Always remembering that processed woods as MDF exhales carcinogenic formaldehyde vapors around 5 years, so heavy paint are mandatory IMO.

[WGH]

However, my friend says he worries a bit about the "stability" of solid wood...

Your friend is right. Solid maple is probably the worst wood for speaker cabinets. Besides ringing like a bell the wood is not stable, eventually there will be cracks. I've been a professional woodworker for over 40 years and have made almost every mistake possible.
http://www.wghwoodworking.com/

There are plenty of options, because maple is so dense let it air dry and acclimate for at least 2 years for each 1" of thickness. A 2" thick front baffle should air dry for 5 years, then will it will be stabilized to your climate. You were probably thinking of something quicker.

Lou Hinkley, owner of Daedalus Speakers, makes solid wood speakers, usually out of walnut. Walnut is a good sounding wood with natural resonance control, dries fast and is fairly stable. Daedalus speakers also have heroic overkill cabinet construction with full length dovetail construction, which is needed to keep everything together. Notice how the grain is laid out. The front baffle is solid wood but the back is walnut plywood. Ask Lou how long he ages the walnut planks before he uses them, I would guess at least a year.
https://www.daedalusaudio.com/

3/32"-1/8" wood veneer will work, any thicker will act like real wood and curl/delaminate/split like real wood. Wood moves with changes in moisture, you can't stop it. If one side has high humidity and the other side doesn't then strange things happen and none of it is pretty.

My speakers are 1" MDF laminated with 1/8" mesquite veneer. The front baffle is 1-3/4" thick solid mesquite. The only successful way to apply the veneer is with a vacuum bag veneer press. The box has to be strong or it will be crushed. The mesquite front baffle was air dried for 5-10 years, I forgot for how long but it was a long time. I have a huge inventory of ageing mesquite to choose from. I put together a "how to" thread:
https://www.audiocircle.com/index.php?topic=100672.0

Salk speakers use a commercially made very thin solid wood veneer with no backing (very important), Titebond Veneer Glue and a vacuum bag veneer press. The front baffle is veneered MDF with solid wood quarter round expertly stained to match the veneer. Getting the solid wood and veneer stains to match only takes 10 years of practice because veneer and solid wood stain differently. The cherry speaker for sale is a good example:
https://www.audiocircle.com/index.php?topic=183344.0

Hobby woodworkers usually end up using some sort of iron-on veneer. It's good enough but prone to chip at corners and will eventually delaminate but that can take years.

[simoon]

As S Clark says, solid woods are not good for speaker enclosures.

Every type of wood, due to its specific hardness, density, flexibility, will also have its own specific resonant frequencies and poor damping characteristics. The only probable way to improve those things, is with maybe constrained layer damping. Or similar technique.

But, if your going to go through all that effort, might as well start with something much less likely to have the majority of those problems in the first place, and still use CLD for amazing results.

A speaker enclosure is not a musical instrument.

You want the enclosure to be as inert, sonically speaking, aspossible. You don't want it to resonate with the music.

 

[Wayner]

Several of my guitars have solid maple necks. They have not warped or cracked. They do not ring.

The problem with solid boards is the expansion and contraction between warm, cold and humidity, not the wood itself. Many pieces of furniture are made from solid woods, but care has been taken to make sure that some pieces can move (and not cause cracks or gaps) from seasonal changes. Other pieces are glued (functional dependent). Since cabinets need to be sealed at the seams (vented or sealed), having joints that allow for movement would not be a good idea unless one is very creative with a sealing technique.

I had a pair of speaker cabinets made by an expert that builds cabinets for the University of Minnesota. These cabinets are MDF with teak veneer on both the outside and the inside. The veneer on both sides brings stability to MDF. The speaker pair (FYI) are Dynaco A25XLs made in mirror image, eliminating the lip on the outside of the cabinet, inverting the vent (to hide the ugly screen) and even veneering the back so they can sit out in the middle of a room if need be.







Wayner

[Zuman]

Thank you all for your wisdom and experience. I suspect I'll now be going with veneer on an MDF core for five sides and a solid front baffle made from well-aged quarter-sawn solid hardwood!

[WGH]

I suspect I'll now be going with veneer on an MDF core for five sides and a solid front baffle made from well-aged quarter-sawn solid hardwood!

Jim Salk posted how Salk Speakers choose, apply, and finish veneer for their speakers you will find helpful.

https://www.audiocircle.com/index.php?topic=74089.msg698935#msg698935

[doorman]

Having built numerous pairs of speakers over the years, Baltic birch remains my preference, one of the deal breakers for me regarding mdf is the seriously nasty dust generated. Wear a good mask if you choose to use it, your lungs will appreciate it.
- good luck with your project.

[WGH]

I used Baltic birch a lot in my projects, it weighs less than MDF and is dimensionally more stable although that doesn't matter with the CSS Criton 2TD-X Tower because the sides are so narrow. A Baltic birch cabinet will need extensive bracing and No Rez to keep it from singing along with the music.

The CSS Criton 2TD-X tower goes down to 30 Hz so there will be plenty of cabinet flexing going on. Since you are making custom cabinets there is no reason not to use 1" MDF, bass will be tighter, deeper and more tuneful. I would still use GR Research No Rez too.

I made an unscientific video to demonstrate the resonance qualities of three speaker cabinet materials including Baltic birch and MDF:
https://www.youtube.com/watch?v=SkSxH40x5SA

[mcgsxr]

For my own DIY explorations I have enjoyed cabinets built from a combination of mdf and baltic birch.

I typically used mdf for the face/other areas where I needed to round over or cut holes - and the bb for the braces or portions of the cabinet that needed less machining.

IF I had a proper setup (table saw, router table) I would be more likely to have used bb more.

[FullRangeMan]

+1 for the MDF on the Baffle. North americans have the habit of using BB 18mm for all the speaker which is insufficient for the Baffle that will warping or opening over time mainly on big woofers.

[Peter J]

+1 for the MDF on the Baffle. North americans have the habit of using BB 18mm for all the speaker which is insufficient for the Baffle that will warping or warping or opening over time mainly on big woofers.

Yeah, what dummies we are. Speakers falling apart all because we use 18 mm BB. Maybe someday we’ll wise up.

[FullRangeMan]

Yeah, what dummies we are. Speakers falling apart all because we use 18 mm BB. Maybe someday we’ll wise up.

To this day no improvement 3/4 inch yet the standard in low cost speaker brands.

[Peter J]

To this day no improvement 3/4 inch yet the standard in low cost speaker brands.

To this day, I'm baffled by many of your posts. That would appear to be conjecture on your part. How is it you come to the conclusion that 3/4" or 18mm is insufficient? Structural bracing and/or panel damping will do far more to damp a box than will sheer thickness of material.
Your assertion that warping of 18mm BB is commonplace is nonsense. Somehow associating this phenomenon with an entire continent is even further from reality.