New speaker project (hardwoods)

[sugardawg34]

Hello, I have been wanting to build some speaker cabinets for some time now. I have been mainly looking at folded horn designs. However, for now, I have some much more general questions regarding building materials. Mainly I am wondering if you can use some type of hardwood to make the cabinets (the outsides at least) out of.

What woods have you used and been successful at? You don't see too many cabinets built out of solid wood. Is it even possible? I am guessing that I need a very hard wood. Also, since pieces too wide may warp (?) can I use pieces 5 or 6 inches wide and join them with biscuit joints to get the desired width?

Lastly, what are the differences in sound between using all MDF, plywood, or hardwood with MDF or plywood interiors (Folded Horn)? I know that Maple is a very hard wood used for fretboards for that "Poppy" sound. I guess what I'm getting at is, how much will tonalities change based on the wood used?

I am open to all suggestions. Thanks in advance for the help.

[mwmkravchenko]

THe basic reason why sheet goods or wood composites are used is to lessen or make more uniform the natural shrinkage and expansion that you get when you glueup large solid wood panels.

Get yourself a wood shrinkage and expansion chart off the net and you will see what I mean. Boxes made from large glued up boards will work themselves apart in short order. Sometimes as little as one year. There is no fastening method to counteract this either.

Short answer if you are contemplating boxes bigger than a small bookshelf speaker use the plywoods or MDF.

MArk

[kneadle]

Here is a thread which covers all the pros and cons.

Post 34 really gets things started.

Dave

[Jezz-the-Fezz]

Bloodyellfire kneedle!

Those links wrecked me up! I get your point though; it all depends on what you want out of your beloved, handcrafted audio talking point.

HiFi - High Fidelity; High Truth in otherwords, by definition means that you stay away from components that colour the sound. You are trying you re-create what's on your disc - vinyl or otherwise.

Musical instruments take advantage of mediums which positively add to the euphonic composition of the sound.

Solid wood is generally not used as it is inherently inconsistant in resonant characteristics - try matching two cabinets & they'll be all over the shop - not good for imaging. Plywood used to be the preffered medium as it had the advantage of composite strength and an averaging of these resonant inconsistencies.

Chipboard became a prefferable medium because it was:

a) consistent
b) cheap!

MDF is predominantly considered the most viable compromise as it is (relatively) neutral, affordable, and consistant. You have to ultimately strike a balance; are you looking for a HiFi component or do you want something that sounds good? If good is what you're after then knock up a pair of reasonable full bandwidth loudspeakers, and place a proffesional "oral exiter" befrore your power amp. I'll guarantee that everything will sound good, albeit the same.

[sugardawg34]

Wow, that is quite a thread there. Seems to be a devisive one as well (who would've guessed!). I think I may just end up using some high grade maple or birch plywood. It looks like many have had success using it, and the appearance is much more acceptable than MDF (I DONT want to veneer anything). Now, let me get back to reading that thread!!!

[pinkmouse]

If you have small boxes, you can always use mdf with an applied hardwood front, like I did here.

I must get around to taking better pics of those speakers, that one is full of jpeg artifacts and makes them look really messy...

[AndrewT]

Hi,
a French manufacturer has (continues to?) used hard wood for their boxes. Very good quality and look superb. Very sculptured=high cost. I think there is also an Italian as well.

Most manufacturers avoid real wood even for the veneer due to cost saving.
In my view the sound quality comes second in their priority over the ability to sell a product.

Some will use birch ply to ensure consistency but they tend to be expensive.

I used laminated (PVA glue) ash for the front of tower speakers. Absolutely no problem with dimensional stability.
Ash is very sensitive to warping in variable humidity.

[AndrewT]

Hi Pink,
have you replaced the screws with - black, raised head, cap screws (mushroom headed bolts)?

[Scottmoose]

Have a look at some of Terry's creations... drooling is not optional. It's a given. Pay particular attention to the Double BENs.

http://www.cain-cain.com/audio/

For what it's worth, I remember he advises the best woods for horns are Maple, Alder, Spruce and, believe it or not, the much laughed at pine! (I remember a comment noting that 'common pine is dreamy for speaker boxes') As I understand it, Terry suggests avoiding woods like oak etc due to the grain and ring structure. He knows more about natural woods and wood-products than anyone else I know or have heard of; however, he has been a cabinet maker for some 30 years, so his expertise in this regard is not surprising. He also takes the view that transducers should behave like musical instruments, which is the reverse of most people's approach. He's far from being alone in this belief, and it's a valid viewpoint, but it accepts that colouration is both inevitable and actually beneficial. So if you worship the God of neutrality (also a perfectly valid perspective) you might not agree with him. Me? I take no sides here. I can see and hear the benefits of both approaches. Suffice it to say, I hugely admire Terry and his speakers, but I also quite like the hyper-neutral stuff too. Depends on what mood I'm in, and what I'm listening to. However, if I was building a horn or some such variation, I'm with Terry. Plywood at least. They're unlikely to be entirely neutral anyway, and chances are, you won't want to be reproducing Pink Floyd in Pompeii very often: it's more accoustic stuff, right? Ergo, a 'perfectly' neutral enclosure can often rob wooden instruments, like cellos, of their natural sound and scale, when a wooden enclosure can correct this issue by providing a sense of that resonance that has either been lost in the recording, or is often robbed by a very rigid, dead enclosures common. Subjective of course, and open to oppinion.

Also, beware the assumption that MDF is acoustically dead. It is not. Plywood, for example, is on average rather stronger in both tension and compression. MDF has some nasty resonance issues at, if memory serves, circa 1Khz, though someone please correct me on this if I'm a long way out (I don't think so, but I'm going by fallible memory as to where this problem occurs). Also, when did you last hear of the moisture content of MDF being tested? It's not immune from such issues, any more or less than hardwoods. It's easier to work with in some ways, but it's also lousy for the health (the dust is carcinogenic), dulls the edges of your saws, router, planes etc as you're cutting glue, not wood and a host of other issues. I'm not knocking it: it's fine in some applications, but don't assume it's the universal panacea. Use the material best suited for the job, be it Alder, MDF, pine or even the cheap, derided chip-board (better than MDF on many occasions), and make sure your construction is as accurate as possible: that makes just as much difference as the materials used.


Best
Scott

[pinkmouse]

Originally posted by AndrewT
Hi Pink,
have you replaced the screws with - black, raised head, cap screws (mushroom headed bolts)?

Certainly have, those pics were taken at an early testing stage.