I have read so many threads about enclosure materials and different points of view about bracing and damping, etc. I end up more confused than ever.
Question...........
I can buy 35mm thick MDF much cheaper than mediocre quality 18mm plywood. Will it be OK? Would it have better or worse sonic characteristics than ply? Quality birch faced ply with many thin layers is so expensive here it is often sold by the square metre rather than full sheets.
Question...........
I can buy 35mm thick MDF much cheaper than mediocre quality 18mm plywood. Will it be OK? Would it have better or worse sonic characteristics than ply? Quality birch faced ply with many thin layers is so expensive here it is often sold by the square metre rather than full sheets.
I'm not a specialist in speaker cabinets but since the MDF became available as replacement for chip-wood, I have used MDF. MDF should be acoustically more "dead" than chip-wood and in particular plywood. Plywood is very strong because it is flexible but that is a characteristic you don't want as it means that it can start vibrating. MDF is easy to work with and very homogeneous (another problem with plywood).
I normally use 22mm but if you can get 35mm at least the speakers will remain where you put them after a good Breton autumn storm, while the rest of the house may be gone.
I normally use 22mm but if you can get 35mm at least the speakers will remain where you put them after a good Breton autumn storm, while the rest of the house may be gone.
35mm MDF is surely sonically "better" than 18mm, whatever "better" might mean. However, I stopped worrying too much over MDF vs ply or whatever. Just add some bracing and the enclosure will become "dead". Using cheap 18mm MDF with some bracing may be "deader" 😱 than 22mm ply without bracing.
The german magazines Hobby Hifi and Klang & Ton has made several measurements and measurement wise there were hardly any differences between MFD and plywood. The big difference was braces and laminations. These realy altered the vibration patterns and decay times.
According to an earlier thread, you are contemplating building Tarkus speakers.
If you use 35mm MDF for the Tarkus, I suspect you will need a forklift truck to lift them!
Published plans of the Tarkus show 18mm wall thickness and, taking into consideration the considerable internal bracing included, this is quite thick enough.
If you use 35mm MDF for the Tarkus, I suspect you will need a forklift truck to lift them!
Published plans of the Tarkus show 18mm wall thickness and, taking into consideration the considerable internal bracing included, this is quite thick enough.
I have tended to use plywood with bracing as its lighter and I used to run a mobile disco. If you intend to just keep them in one place then MDF is the way to go.
Although I don't like to build with MDF anymore myself, as others have mentioned, make sure you're not going to have to move these puppies around. MDF does not like abrupt stops. Plywood is somewhat forgiving in that regard. 🙂
This debate just won't go away. I won't work with mdf because the dust is toxic and the panel stores energy, not to mention the weight of a 35mm sheet requiring two men and a boy to load on the saw. Suit yourselves; bracing and damping is what matters, mass not so much. JMO YMMV...
I haven't built a cabinet in ages but there are benefits in using different materials and glue.
Chipboard can be "improved" by using panels of MDF glued in place. I cannot afford to use 16 or 18mm void free plywood but I can afford to use 12mm plywood glue laminated to either MDF or Chipboard [ or both] to build up a decent thickness for the important front panel
Locally void free marine grade hardwood ply is cheaper than Birch plywood but it is heavier
There are many variations on the chipboard theme some "Very High Density" chipboard is excellent stuff, some of the stuff sold as "Shelving" or "Handy Panels" is rubbish but I can afford the rubbish stuff in pre-cut handy panels so often that is what I bought
Chipboard can be "improved" by using panels of MDF glued in place. I cannot afford to use 16 or 18mm void free plywood but I can afford to use 12mm plywood glue laminated to either MDF or Chipboard [ or both] to build up a decent thickness for the important front panel
Locally void free marine grade hardwood ply is cheaper than Birch plywood but it is heavier
There are many variations on the chipboard theme some "Very High Density" chipboard is excellent stuff, some of the stuff sold as "Shelving" or "Handy Panels" is rubbish but I can afford the rubbish stuff in pre-cut handy panels so often that is what I bought
It is interesting how neither the science behind speakers nor looking at what the professionals do seems able to overcome many DIY folks feelings about how to build a cabinet.
To the OP, all things being reasonably equal, a 35mm MDF cabinet is likely to be perceived as a bit noisier than an 18 mm MDF cabinet not quieter. The thicker stiffer walls may reduce deflections but they also raise the frequency of the main energy containing modes. The latter is a problem for two reasons: the first is that same SPL at a higher frequency requires less deflection (e.g. a woofer and tweeter of equal loudness) and the second is that at higher frequencies the audibility threshold falls. The latter tends to dominate although it is close and so about the same in terms of noisiness is perhaps reasonable. They are obviously not about the same in other respects like weight, cost and engineering cred.
It is of course possible to use science/technical knowledge to build quiet cabinets but thick walls everywhere is not how to do it.
To the OP, all things being reasonably equal, a 35mm MDF cabinet is likely to be perceived as a bit noisier than an 18 mm MDF cabinet not quieter. The thicker stiffer walls may reduce deflections but they also raise the frequency of the main energy containing modes. The latter is a problem for two reasons: the first is that same SPL at a higher frequency requires less deflection (e.g. a woofer and tweeter of equal loudness) and the second is that at higher frequencies the audibility threshold falls. The latter tends to dominate although it is close and so about the same in terms of noisiness is perhaps reasonable. They are obviously not about the same in other respects like weight, cost and engineering cred.
It is of course possible to use science/technical knowledge to build quiet cabinets but thick walls everywhere is not how to do it.
Dont know how many sheets of wood the Tarkus takes but a quick google suggests a single 8x4 sheet of 35mm MDF will be close to 80kg. I would cancel the gym membership during the build period!
I do not subscribe to the void free, marine grade, multi-ply cult. While it makes sense on paper, I've not seen any evidence that it is it measurably better (whatever that means) than regular G1S. I do prefer fir over spruce unless the cabinet is huge and then I make up for it with stick bracing. I don't bother with shelf bracing, I believe it is more for the believers than a necessity. It's also a lot easier.
OP’s sig address is Brittany France which is surrounded by ocean (basically a peninsula)
I’d go with plywood just for moisture issues and if your coastal definately use marine.
I’m coastal and even with constant climate control moisture is still a daily battle.
I’d go with plywood just for moisture issues and if your coastal definately use marine.
I’m coastal and even with constant climate control moisture is still a daily battle.
I've seen solid cabinets made from:
-hardwood
-plywood, all grades
-MDF
-HDF (DIY-laminated HDF is one of the best, but heavy)
-particle board/chipboard
-OSB (yes, even OSB!)
-Formica
-Plasti-board
The points are to the implementation. I prefer a hard 'clack' with a knuckle wrap test. Anything that goes bonk, or tonk has a resonance inside.
MDF is very porous, so you have to consider that it's not as strong physically. I have used a bunch of MDF. It machines very well. Best use? Well-braced, multi-layered, and soak some resin into the material for the most strength. Any glue will work substantially better than MDF alone. Double thick to 1.5" material steps up things considerably, especially in the bracing. HDF skinned MDF is better still. See Stance and Cecropia Supreme for examples.
Plywood is stronger, but flexes easier. Bracing is still required. Easier to finish, but it machines with splinters. Some boards have voids, but I've just filled them, or left them alone. I usually use the 5-7 layer ply variety. Occasionally you find a nice pre-veneered piece. It's all of no consequence really. My best use? use MDF/hardwood as bracing inside a plywood shell. The braces I used were half-cab-depth and solid without space removed. This also tied in all panels but the baffle. It is one of the best boxes I've built. Fenrir.
Formica over particle-board is a very good box material. Machines well, and edges are SHARP! I feel bracing is less of a concern as PB does not flex/bow like MDF or ply. Still required, but less of a concern. I've recently been told of laminating Formica alone, and it becomes something other-worldly. I've used ForPB mostly in baffles, but built the Vijon's main box completely of ForPB.
Hardwood can crack, expand, contract, splinter, ring like a bell, etc; but it looks great when finished and can be rewarding to work with. Be sure to damp it well. I done a few smaller projects or baffles of hardwood, and it's very pleasing to work with.
If you have or have access to a planar and drum sander, OSB can look very good with a stain or polyurethane applied. AND- it's a very solid material once it's finished/bound. Ed Lafontaine made 2 pair of these little hay-bails about 7 years ago, and they impressed me. Solid and dead.
HDF- This is a new frontier I'm exploring right now, but I've seen several made of layered HDF before, usually with curves of 3-5 layers applied one at a time. It started with me making my router circle jig of 4 layers of HDF, and then wondering what a speaker cab of it would be like. Sourcing thicker HDF is not easy to do for weight and shipping costs. It's also very hard material when multiplied, and the tools commonly used on the above tend to think twice about what you want them to do. Not only is it heavy, but it's also a laborious process to layer up to my chosen 8 x 1/8" or 1" thickness. More to come on this later...
Later,
Wolf
-hardwood
-plywood, all grades
-MDF
-HDF (DIY-laminated HDF is one of the best, but heavy)
-particle board/chipboard
-OSB (yes, even OSB!)
-Formica
-Plasti-board
The points are to the implementation. I prefer a hard 'clack' with a knuckle wrap test. Anything that goes bonk, or tonk has a resonance inside.
MDF is very porous, so you have to consider that it's not as strong physically. I have used a bunch of MDF. It machines very well. Best use? Well-braced, multi-layered, and soak some resin into the material for the most strength. Any glue will work substantially better than MDF alone. Double thick to 1.5" material steps up things considerably, especially in the bracing. HDF skinned MDF is better still. See Stance and Cecropia Supreme for examples.
Plywood is stronger, but flexes easier. Bracing is still required. Easier to finish, but it machines with splinters. Some boards have voids, but I've just filled them, or left them alone. I usually use the 5-7 layer ply variety. Occasionally you find a nice pre-veneered piece. It's all of no consequence really. My best use? use MDF/hardwood as bracing inside a plywood shell. The braces I used were half-cab-depth and solid without space removed. This also tied in all panels but the baffle. It is one of the best boxes I've built. Fenrir.
Formica over particle-board is a very good box material. Machines well, and edges are SHARP! I feel bracing is less of a concern as PB does not flex/bow like MDF or ply. Still required, but less of a concern. I've recently been told of laminating Formica alone, and it becomes something other-worldly. I've used ForPB mostly in baffles, but built the Vijon's main box completely of ForPB.
Hardwood can crack, expand, contract, splinter, ring like a bell, etc; but it looks great when finished and can be rewarding to work with. Be sure to damp it well. I done a few smaller projects or baffles of hardwood, and it's very pleasing to work with.
If you have or have access to a planar and drum sander, OSB can look very good with a stain or polyurethane applied. AND- it's a very solid material once it's finished/bound. Ed Lafontaine made 2 pair of these little hay-bails about 7 years ago, and they impressed me. Solid and dead.
HDF- This is a new frontier I'm exploring right now, but I've seen several made of layered HDF before, usually with curves of 3-5 layers applied one at a time. It started with me making my router circle jig of 4 layers of HDF, and then wondering what a speaker cab of it would be like. Sourcing thicker HDF is not easy to do for weight and shipping costs. It's also very hard material when multiplied, and the tools commonly used on the above tend to think twice about what you want them to do. Not only is it heavy, but it's also a laborious process to layer up to my chosen 8 x 1/8" or 1" thickness. More to come on this later...
Later,
Wolf
- Status
- Not open for further replies.