pine or oak for baffle?

[Binkstir]

See, We know that after you countersink a driver for flushmount and then you round over the back of your cutout for the rear wave, you aren't going to be left with a tremendous amount of material for your screws to grab.

What would be wrong with using solid woods for the baffle. Oak is really hard and it doesn't take much of it to hold a screw.

[leadbelly]

Originally posted by Binkstir
See, We know that after you countersink a driver for flushmount and then you round over the back of your cutout for the rear wave, you aren't going to be left with a tremendous amount of material for your screws to grab.

What would be wrong with using solid woods for the baffle. Oak is really hard and it doesn't take much of it to hold a screw.

I use solid woods for many of my baffles. The purists will say that resonance and directionality of the grain make it inferior to void-free plywood or MDF, but I personally am always willing to make that tradeoff because I hate veneering and hate anything other than a wood finish on a speaker.

HOWEVER, using solid wood for the reason you bring up, which is screw engagement, is a bad idea IMHO. Just use t-nuts if that's your only issue. A lot of people here ONLY use t-nuts to attach drivers, whatever the design.

http://www.partsexpress.com/pe/showd...umber=081-1090

[Cal Weldon]

I agree with leadbelly. T-nuts are your friend again and again.

[Binkstir]

Ok, guys thanks for the tip.

[Scottmoose]

The Japanese rate pipe & spruce very highly I understand, only just behind maple. I remember Terry Cain describing pine as 'dreamy' for speaker boxes, esp. horns, providing it's of the right quality.

[Dave Cigna]

Originally posted by Scottmoose
The Japanese rate pipe & spruce very highly I understand, only just behind maple. I remember Terry Cain describing pine as 'dreamy' for speaker boxes, esp. horns, providing it's of the right quality.

Interesting. Spruce and its relatives are what has been used traditionally for the tops (soundboards) of stringed instruments. Here, everyone is trying to make boxes and baffles that are dead. Makes you think....

-- Dave

[AuroraB]

Somehow I think that this solid woods story is based on misunderstandings and lack of knowledge. The fact that spruce is used as soundboards on acoustic guitars has nothing to do with solid wood in loudspeaker cab's. In a guitar top the thicknes is 3 mm or less, which of course wil make the panel resonate as it should, but if used in a loudspeaker, you would head for 20-25 mm, possibly even more in the baffle. MDF is not resonant free by far, and still needs damping. A solid wood cabinet will maybe need more damping, or at least more intelligent damping.

The industrial excuse for using MDF, and previoulsy chipboard, ( .. MDF is chipboard, too- just smaller chips..) has little to do with resonance, rather than material and production cost which would be extremely high using solid woods, and hardwoods in particular.

There may be an issue with solid woods in terms of expansion with temp and humidity, but I think this is possible to combat. There is a myth, or at least partial myth, that a solid wood cab will crack at the joints, but why doesn't all our table and bench tops, shelfs etc. etc crack?? OK- some of them do, but ususally after being exposed to fairly extreme temp and humidity variations. The issue lies with cross grain joints, where a possible expansion will have different coefficients in the opposing grain directions, but I still think this is possible to beat, provided the panel size is not extreme. As for any resonances, they will of course have to be dealt with, by damping and bracing. Intelligent bracing with the aim of reducing the resonance Q is the trick, not trying to remove the resonances all together.

I am possibly to embarc an a new project, most likely a full range, or treble assisted full range, like a BIB or a MLTL of some kind, hoping Scott could give me a hand, as I don't have access to MathCad.
The reason for using solid wood, is that I truly like to have a proper finish. Although I have no problems doing veneering and such, quality veneers are almost impossible to find in my corner of the world, in smaller quantities at least. A plywood- chipboard-MDF lamination with solid at the outsides is another posiibility.

[stroop]

Hi Folks,

I don't know if this is of interest.

One way to avoid solid wood from splitting due humidity etc. is to join the wood in strips about 5cms wide by a good tongue and groove joint or similar and then glueing. It works for parquette floors which are much greater in surface area and subjected to harsher conditions. I would not be too concerned with solid wood pieces up to around 6 inches in width though.

I believe the wood will still be affected by temperature and humidty(swell and contract) but the amount of expansion of each individual piece is much more consistent, because each piece is much narrower.

The changes in humidity are a major factor in how string instruments sound, also temperature. Double basses and cellos in particular for obvious reasons. I know I used to play viola for 10 years.....

Joining the wood shouldn't affect the sound either, a large number of stringed instruments have 2 piece backs. But the glue used is rather important indeed and is just important as the varnish.

cheers Stroop

[Dave Cigna]

Originally posted by AuroraB
Somehow I think that this solid woods story is based on misunderstandings and lack of knowledge. The fact that spruce is used as soundboards on acoustic guitars has nothing to do with solid wood in loudspeaker cab's. In a guitar top the thicknes is 3 mm or less, which of course wil make the panel resonate as it should, but if used in a loudspeaker, you would head for 20-25 mm, possibly even more in the baffle. MDF is not resonant free by far, and still needs damping. A solid wood cabinet will maybe need more damping, or at least more intelligent damping.

What do you suppose a guitar would sound like if it had a 3 mm thick MDF top?

Seriously, I think you underestimate our knowledge and understanding. I know that I understand the difference between the top of an acoustic guitar and a speaker baffle. I still think it's interesting that people with ears I respect find that spruce baffles sound good.

-- Dave

[Geek]

Originally posted by Dave Cigna
What do you suppose a guitar would sound like if it had a 3 mm thick MDF top?

This time of year, LOTS of stores are carrying $49 electric guitars made of just that

My advice to add to this thread is stay away from laminated pine. As pretty as it is, the adhesives used are always questionable and they definately expand/shrink at a different rate than the wood. I have yet to have one that didn't split after a few months in the house.