Pine Speaker Cabinets

[iep]

I'm thinking of building a set of speakers based on the M5 Classic Two at audioexcite:

www.audioexcite.com >> Classic Two – M5

For cabinet construction though I was considering something a bit more retro 70's (B&O BEOVOX kind of vibe)

BeoVox 1200 Passive Loudspeakers

I hate veneering though and was thinking about the possibility of using solid pine furniture board for the top, bottom and sides of the cabinet:

Wickes General Purpose Pine Timberboard - 18mm x 200mm x 2350mm | Wickes.co.uk

I regularly use this for furniture building as it gets round a lot of the problems with cut/planed pine. It is straight, temperature and moisture stable and has a more uniform density.

Question is whether, combined with an MDF baffle and plenty of internal bracing, it would make a decent loudspeaker cabinet.

Anyone tried anything like this?

Cheers.

 

[Scottmoose]

Providing you treat it like any other piece of solid wood and ensure that it really is stable, properly sealed and unlikely to move, then yes, it can be done (and has been). You'll need some decent bracing though, as it won't be sufficiently aged to have hardened to the extent pine can after a century or so. One suggestion: it might be easier to build an MDF or plywood box and laminate a thinner layer of the pine to the outside.

 

[turk 182]

aren't the knots a potential source of trouble? i once did make a speaker enclosure with pine boards only to discover that a few knots acted like kazoo's over time and had to shellac all the knots to seal it, problem was that wrecked the appearance and i ended up veneering it!

 

[Lojzek]

A suggestion, make your cabinets out of veneered particle boards. Exposed sides can be embelished with wooden slats.

 

[hifijim]

When you buy your material, select boards which have the straightest grain and the fewest/tightest knots. At your shop, you can test each knot for strength with a wood mallet or plastic hammer. Knots are usually harder and stronger than the straight grain... up until the point where they shrink and pull away from the surrounding wood matrix. As long as the knots have not reached the "shrink" stage, you will have no problems with them.

Any problem knots you find you can cut around them when you cut the boards to final dimension. Obviously you will need to make sure you have excess board material.

 

[puppet]

I agree with Scottmoose. Biuld a box and wrap it , sides, top and bottom. Slot your mounting screw holes from inside the box to allow the wood outer shell to move independent of the actual box. The baffle and back have to be separated from the rest. This will move and you need to allow for that.

Resonance of solids vary too much by themselves. An inner box allows more repeatable results.

 

[Mario Pankov]

Few issues to consider:

- the wood has to be super dry otherwise it will crack after some years
- pine is very soft so perfect finish will be somewhat a challenge
- when routing and sawing it there is a good chance of chips
- its light so the resonance of the box may be pretty high
- you have to look for eyes in it as they`re weak points so more material may be required

Good luck!

 

[boswald]

If you want to use traditional woodworking methods, it is easier to build your box the way you want, but oversized.
Then line with at least 2/3(the pine's) thickness of mdf and brace with intersecting struts.


You'll have a very nice box and it will be quite dead(no pining for the fjords here!).

 

[homebuilder]

pine boards

I'm thinking of building a set of speakers based on the M5 Classic Two at audioexcite:

www.audioexcite.com >> Classic Two – M5

For cabinet construction though I was considering something a bit more retro 70's (B&O BEOVOX kind of vibe)

BeoVox 1200 Passive Loudspeakers

I hate veneering though and was thinking about the possibility of using solid pine furniture board for the top, bottom and sides of the cabinet:

Wickes General Purpose Pine Timberboard - 18mm x 200mm x 2350mm | Wickes.co.uk

I regularly use this for furniture building as it gets round a lot of the problems with cut/planed pine. It is straight, temperature and moisture stable and has a more uniform density.

Question is whether, combined with an MDF baffle and plenty of internal bracing, it would make a decent loudspeaker cabinet.

Anyone tried anything like this?

Cheers.

iep:

To give a proper answer, we would have to know more about your situation, and your abilities. My read on your comment about hating to veneer SUGGESTS that you are not confident in your cabinet making abilities. Frankly, I'm with you on that score as far as veneering goes.....

Consider laminating a thinner layer of any solid material to the inside of your suggested pine boards, such as mdf or plywood. That way if any knots or gradual cracking show up down the road, it won't affect the sound of the box itself. I've laminated a lot of materials together, and my oldest one, 40 years, still has no apparent cracking or movement. (3/4 oak over particle board)

Have you considered gluing up solid wood, and running it through a planer? Personally, I despise the look of knotty pine, because for me it conjures up visions of cabins out in the woods, and funky bars. Not retro speakers.....

Good luck on your project what-ever you choose to do!

 

[iep]

Hi,
That is a ton of useful feedback. Thanks.

In particular the warning of 'knot kazoos' is the best argument against pine I have heard

So, trying to respond to all comments.

1. Lining the pine box with MDF is a fine plan. I was thinking of doing this with 9mm MDF. Hopefully enough to damp out any resonance but not too thick to dramatically increase size of cabinet.

2. Question on above is whether I go for 18mm pine and 9mm MDF or vice versa. I like the idea of panelling an 18mm MDF cab in ~9mm pine but I can't find a source of decent 9mm pine board. 9mm hard woods are available but they are pricey and not local.

3. Veneered particle board is good (i'v e use dit before) but I can't seem to find any locally these days.

4. As to my wood working skills, I'm pretty good. I just seem to be lousy at veneering. Certainly, the finish I can get on a solid wood box with visible jointing or mitres (I've don a few guitar cabs from pine) is far better than the finish I have got when veneering MDF. Maybe I just need to work on my veneering skills

Either way, from comments received, if I can avoid the 'kazoo effect' it sounds like pine might be a goer.

I actually popped into my local DIY store today. They have very little hard wood but have a couple of decent pine board options. Knotless pine or knotted pine are available. The knotless is more 'engineered' and is made up of many jointed sections. It's heavier and harder though so might form a decent starting place.

Cheers.

 

[planet10]

It is certainly doable. One needs to know how to deal with solid, and the humidity should move fairly slowly. Here is a set of Mar-Kel70wT built from solid Douglas Fir (a pine), that was built up out of the flooring Bernie lifted up during his house reno.

dave

 

[Scottmoose]

It'll work, no question, if you do it properly.

Incidentally, don't worry about panel resonance being 'higher'. That's a good thing for bass enclosures. You can never erradicate panel resonance, just move it about. Higher frequencies are good. The mode is higher Q (less likely to be activated), the available energy to excite it less, and it's easier to address with reduced quantities of damping material.

9mm MDF with the pine should be fine IMO, especially if the latter is properly dried, well sealed, tight / consistently grained & with a minimal number of knots. Solid itself is fine, but better left to experienced woodworkers with a reasonable knowledge of audio requirements (somewhat different to furniture).

 

[jtgofish]

If you are going to do it use quarter sawn boards[ribbon grain pattern with growth rings 90 degrees to the surface].
Although I think you would be better off using blockboard benchtop type material.Beech is commonly available and works fine.

 

[turk 182]

anecdotal box noise story....Martin single fifteen bass bin that whistled every time the kick drum was hit...turned out to be a leak around where the cable went into the driver doghouse, sealant was cracked and peeling and the top layer of the baltic birch ply was split and loose the damned thing sounded like a woodchuck in heat!
moral of the story, even choice materials can have flaws...common sense approach in choosing material and proper assembly (unlike some of my work at times) can yield good results.

 

[GM]

You'll need some decent bracing though.

Love this stuff, but for speakers recommend bonding cement board ~70% in area to all the inside panels including the baffle with a non hardening adhesive used for flooring in lieu of the mass quantity of bracing it otherwise requires beyond a driver support. Now it's well braced, super well damped and heavy enough to stay put. Use near continuous length [~70%] glue blocks to help keep the joints from pulling apart.

GM

 

[Scottmoose]

Sounds favourite.

 

[homebuilder]

pine boards

IEP:

Lots of good suggestions here. Solid wood gets a lot of undeserved negative attention due to the perception (many times true) that it will move all over the place and crack. I've restored many, many old buildings from the 1800's, and that was a common occurrence.

However, things change. Humidity levels in homes today are much more controlled than in the past. The quality of woods available to us on the open market has declined steadily for years, but there are many options for recycling materials that can yield fabulous results. I once purchased (50) 10' tall, x 18" deep door sets from a 1880's convent being torn down, for $50 each complete with doors, transoms and all brass hardware. I bought them for the 2" thick old growth wood. (Mostly birch, but also some maple and fir) I've also bought thousands of square feet of beautiful wood flooring to recycle.

It sounds like you have some good skills to put to the task, so why not expand your search for wood beyond the big box stores? Find some local woodworkers, and open up some new possibilities.

 

[rabbitz]

Here's a neat use of pine and MDF.

2way Speakers with SB Acoustics SB13PFC25-4 & SB26ST-C000-5

 

[bbe22]

example of pine (20mm) over MDF(6mm) project..

 

[GM]