Ohm C2 Water Damaged Cabinets

[ouimetnick]

Hey guys,
So I picked up 2 pairs of Ohm C2s from Craigslist recently for $90. All woofers needed to be refoamed, so that's taken care of. One of the low tweeters is blown, but that's not a big deal, plenty of them available on ebay for cheap. I used Howard's Restor A Finish, and that cleaned the cabinets up for the most part except for the fact that 3 cabinets are water damaged. 2 are really bad, so I took them apart with a bit of force. I called John Strohbeen at Ohm, as I was planning on building new cabinets using MDF, but he shot that idea down. He said that MDF is the worst material to build a speaker cabinet out of, and it would be better to use particle board over MDF. He suggested using baltic birch, but I can't figure out where to find that locally.

I had a set of Ohm D2s from my grandfather, but one of those cabinets was damaged from water when I stored them in the garage, so I tossed it. The D2 is the same as the C2 except the C2 has a high tweeter, walnut veneer on the front of the cabinet and formica on the rear. The D2 is just painted black on the front and rear. The cabinet construction is the same though. Oddly enough, THREE of the C2s have 2 switches on the crossover (low and high tweeter) yet one has 1 switch for both.

Any ideas on building new cabinets?

 

[ouimetnick]

More photos. John said that MDF is not dense and will sound terrible... Thought MDF was more dense than than the particle board the cabinets were made of originally...?

 

[rvatfhunter]

Got a woodcraft near you? They have Baltic birch. Other than that, you'll just have to call around to local lumber/hardware stores in your area.

 

[homebrew]

MDF should be fine for your cabinets. Use 3/4" for sides, tops, bottoms, and backs. Use 1" for the front baffle. Use a brace between the woofer and tweeter. MDF takes veneer or paint very well. If you do decide to paint MDF, seal the exposed edges with a 1:1 mixture of yellow glue and water. Also, wear a good dust mask as MDF dust isn't good to breathe.

19mm Baltic birch is also an excellent alternative. It's dense, void-free, and very strong. Construction techniques should be the same as for MDF.

 

[ouimetnick]

Well there's a woodcraft about 30 minutes from me, so I'll have to check there. I'm still not sure what the big deal is with using MDF. Anyone notice a difference in sound with MDF vs baltic birch?

 

[Old Guy8]

I'm not familiar with cabinet material suitability. Personally I would not discount John Strohbeen's knowledge of speaker systems. He has been head of Ohm since late '70's. Not many speaker companies have survived that long in USA.

 

[Ghonk]

Particle board over MDF,that can't be right,could it?

 

[bshorey]

I got 3/4" Baltic Birch plywood at Home Depot, fwiw.

bs

 

[ouimetnick]

I got 3/4" Baltic Birch plywood at Home Depot, fwiw.

bs

Must be that only certain Home Depots carry it. Mine has birch plywood, but it's not baltic birch, its got poplar in the middle.

 

[loudnoises]

Must be that only certain Home Depots carry it. Mine has birch plywood, but it's not baltic birch, its got poplar in the middle.

The birch and poplar ply sold by home depot isn't "baltic birch" at all.

I go through 500+ sheets of it from them a year. It's the cheapest, crappiest finish grade plywood you can buy. it's the inferior grade refused by all other vendors, which is why they can sell it for 40% less than anyone else. At $35-49 a sheet it's $30 cheaper than the next product in line, which you can't get from home depot. They do not sell cabinet grade plywood. The birch is better than the poplar, but it has voids as well. You get what you pay for. It's such a bad product you can't even buy it anywhere else. They've a market monopoly on the reject plywood. That being said it's great for bulding scenery and furniture out of, it's cheaper than pine boards.

It might look ok, but don't do it. voids everywhere, thin and missing glue. overlapped layers. I've pulled entire sheets apart with my bare hands they were made so badly.

Just no. Not for speakers.

 

[TomReceiver]

The way I look at it is MDF = CHEAP FURNITURE..Cheap furniture always falls apart or if you stare at it too hard it gets insulted and falls apart. You try to clean said furniture it falls apart. Particle Board at least is chipped wood that has been glued and pressed under pressure which should make it stronger. Go with the real Baltic Birch for the project.

 

[Old Guy8]

Hesitate to make this suggestion. Look for some well made speaker cabinets, to retrofit your drivers in.
Just for instance, Sansui SP1200 are 10" woofer cabinets, with two front ports. A removeble double mid mount plate. A new mount plate could be made for Ohm tweeters. The back unscrews also. Ports could be tuned by plugging one or none.
IMO, these Sansui's don't sound that good as they are. Or some 60's 10" woofer, Pioneer cabs. Maybe some could be found locally missing components, discounted.
Not trying to sell mine. They were $80 at garage sale. A lot of them were made.

 

[Uncle Paul]

IMO MDF is just fine and very dead acoustically, which is what you are looking for in a speaker cabinet. Cheap for a furniture project, but an excellent material for speakers. I tend to go with 3/4 " everywhere except the baffle which I double to 1 1/2". Also, no butt joints which you shouldn't use for any woodworking project. The only drawback is the very fine dust when you start your router work. I wouldn't use particle board for any project. I have no experience with Baltic birch, but have read it is highly regarded.

 

[Blue Shadow]

Magnepan uses an MDF frame for their speakers and one upgrade is to replace that frame with real wood. Make a big difference.

 

[loudnoises]

There's more then one grade of what people refer to as MDF, and some are far denser than baltic. Furniture MDF is thin stuff, the thicker crappy stuff is particle board. The high density MDF can be 2-3 times the density of plywood.

I'd bet on a good, high grade MDF sub box any day. The finish means the surface properties are moot. the woodworker in me would love to believe otherwise, but natural wood isn't really the best speaker cabinet material. If resonance is part of the design (like a violin???) then maybe, but we all know it's not in 99% of cases. The two benefits to using plywood are less dust and better humidity handling.

For the sake of argument, what company is using birch meow?