I would have personally thought it had to do with the fact hardwood is more prone to resonate and transmit vibrations, more than softwoods. Due to their grain patterns and denisty, and are able to absorb and loose some vibration.

(I used to be a french polisher and worked in a wood working company in the Blue Mountains in Australia and handled softwoods and hardwoods daily.)

My understanding is that MDF is denser than most regular lumber, and thus somewhat less susceptible to undesireable resonance and vibration. I think also that since it is not grain oriented, it is less likely to warp.

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My understanding is that MDF is denser than most regular lumber, and thus somewhat less susceptible to undesireable resonance and vibration. I think also that since it is not grain oriented, it is less likely to warp.

I had learned it that way, too.

A speaker maker once told me that MDF is also more uniform, so there is less concern about sample to sample variation, as would be seen with using "solid" woods.

I think one of the reasons the "real" wood speaker makers go so thick with their wood (my inner Butthead is saying 'heh heh, heh heh heh') is to compensate/minimize this effect - I think some of the Chario speakers and Sonus Faber have done this with good result.

MDF isn't as dense as some hardwoods and as I said grain patterns and density in real hardwood, would, preclude them from being a good source of cabinet matieral. Softwoods like cedar is different and plywoods. Hence certain Italian manufacturers like of cedar and softwoods and old school British manufactures like of plywoods.

After all, MDF is a medium density fibreboard. Not a HDF. And made of softwoods not hardwoods. It is similar to ply and slightly denser than particle board.

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MDF isn't as dense as some hardwoods and as I said grain patterns and density in real hardwood, would, preclude them from being a good source of cabinet matieral. Softwoods like cedar is different and plywoods. Hence certain Italian manufacturers like of cedar and softwoods and old school British manufactures like of plywoods.

After all, MDF is a medium density fibreboard. Not a HDF. And made of softwoods not hardwoods. It is similar to ply and slightly denser than particle board.

Interesting!

Chario uses walnut in the Academy line, and I think Sonus Faber did on the Extrema (I may easily be wrong). Where does walnut fit in?

"I have done quite a bit of reading about DIY speaker building and one thing that is almost universal is the use of MDF or some type of higher quality plywood. Why isn't regular hardwood used? Why don't speaker manufacturing companies use hardwood? Almost all of the manufacturers use MDF. I would guess it's a matter of cost."

It is, both in raw material cost (hard woods are about 5x more expensive at least) and the fact that hardwoods require skilled workers, many more machines to mill it, cut it up, glue it up, account for expansion and contraction (which is a lot, hence real furniture cabinets use panels), variation in grain and colors... That's not even getting into dealing with resonance issues. Basically, in my mind, it could work, but it'd be more like designing an electro acoustical musical instrument. A cool idea to ponder actually, but a loosing proposition for a business I'd bet.

Plus, with MDF, shape is pretty much anything you want because you can mill it via CNC machines; not the case with solid woods. MDF is extremely hard over shorter distances (bookshelf sized speakers) and it's still fairly predictable over larger sizes but needs bracing and other damping. When it's cut into pieces it needs a very dry and stable environment or it can expand with moisture absorption. But then again so will hard woods too. It also has the benefit of weight- another good thing for speakers.

"After all, MDF is a medium density fibreboard. Not a HDF. And made of softwoods not hardwoods. It is similar to ply and slightly denser than particle board."

It's relative- and there IS no "HDF" that's widely avilable like MDF. It's more like Masonite, but that can get brittle and have problems of it's own. MDF is mostly glue and saw dust, in the same way Corian is like acrylic and ground up stone. It's much denser and stronger than particle board and harder/heavier than "average" plywood. Most plywood is softwood in it's core with veneered hardwood layers on the outside. The exception being Baltic Birch ply. That stuff is nice but many time more expensive than MDF. I believe that is what's used when speaker manufacturers use plywood instead of MDF...

I always thought that MDF was multiple density, not medium, so that throws out my whole idea that multiple densities would negate cabinet resonances?

Multiple density? Hmmm- that would not be the MDF used in cabinet building for sure. Multiple density could refer to a constrained layer damping system, usually a very expensive multiple material product. I made some DIY speakers last year Pro-Ac 2.5s and thought about the benefits of building using MDF board with layers of aluminum and polycarbonate materials. Even at a DIY level it gets expensive and time consuming.

The big guys like Wilson and such use all sorts of exotic and expensive materials and constrained layers. I'm sure it's the way to go, but obviously you pay big bucks for it.

MDF= uniformity and predictability in materials.

At the top of cabinet build considerations, as a point in manufacturing.

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"After all, MDF is a medium density fibreboard. Not a HDF. And made of softwoods not hardwoods. It is similar to ply and slightly denser than particle board."

It's relative- and there IS no "HDF" that's widely avilable like MDF. It's more like Masonite, but that can get brittle and have problems of it's own.

There is no problems obtaining High Density Fireboard, (HDF) and it is made in a similar way to MDF and differs in it's density level. Some loudspeaker manufacturers actually claim to use it over MDF. HDF board has a smooth, hard surface which makes it perfect for painting, staining, grain printing and laminating. It has a density range between 900-950 Kg/m3. The manufacturing process are more or less same as used in Medium Density Fiber Board. Its advantages include high strength Ease of machining, Good weathering properties, Low thickness swelling. So the HDF board can be used where higher strength properties or more specialized machining characteristics are required.

And It isn't anything like masonite.

Real wood is more resonant than MDF. MDF is more uniform and takes veneer really well. Real wood warps and cracks and with grain, it is inconsistant. Most speakers are made with MDF, even high end ones. It is interesting that the higher end the speaker, the more seriously they try to kill cabinet resonances. What do they know?

Also, I think there is some part in cost. I know a lot of fine cabinet makers lose a lot of wood with cutting errors or the wood chipping while routing. if the entire panel of a speaker were lost like this, the cabinet would be really expensive.

There are many grades of mdf, so that might be where the density thought comes in. But the grade is for the whole board, not just a part. I have to float around to HW stores to find the good stuff. They don't seem to care, but sometimes I can find really nice MDF and sometimes it is crap.

P
www.helarc.com my speaker site.

yes, you end up buying from one specific manufacturer of MDF-HDF if you can. If not, buy from someone who can guarantee the quality and consistency. Machining accuracy and repeatability is a huge issue.

Anyone finds this out on their first attempt to build their own kitchen cupboards.

Part of the fun of this hobby is challenging your own expectations and biases.

Perhaps maintaining "repeatability" is an idiosyncratic pursuit, and speaker builders who echew MDF may reject many cuts of wood before "allowing" a certain piece into the process.

That's a reproduceable as MDF, eh?

Any of us can buy a purple Iris, but how many can buy a white one?

I say, listen without concern for MDF.

Be it an Onkyo POS resonant cabinet or a Pioneer whiskey barrel - as George Michael would say...listen without prejudice.

There are some spectacular "whole wood" speakers out there.

The concept of rejecting "whole wood" on the premise that pieces of "whole wood" can vary forgets that the builder can select for parts!

N'est-ce pas?