cabinet materials

I believe quite a few people advocate .25" hardwood exterior on an MDF box. Should be fine.

--I believe quite a few people advocate .25" hardwood exterior
--on an MDF box. Should be fine.

reply

If you have the money, Birch or Oak wood is the very best,but it is very expensive,but makes a beautiful cabinet which is so strong and water resistant.
I prefer plywood to MDF because with MDF,there is the danger of inhaling fibers,unless you wear the suitable mask when cutting.
Also plywood sounds more natural,and doesn't resonant at 100hz-300hz like MDF does.With MDF you get hollow boomy sounding cabinets,unless you properly dampen the enclousure.
The plywood you buy doesn't have to be Baltic Birch or Marine grade,because marine grade is mainly for pa and disco cabinets.Normal 13 plywood[number of sheets '13'] would do.
Plywood is thin sheets of natural wood cermented together,where as MDF is sawdust fibres bonded together tightly with resin,and chipboard or particle board,is wood chips and saw dust loosly packed together with resin.
OFB, is Oriented fibre board,large wood flakes mixed with sawdust,stronger than chipboard but not as good as MDF.

I use plywood for pa/disco cabinets,and high quality hifi cabinets,MDF for cheap but strong hifi cabinets,and particle board for very small enclosures such as piezo tweeter array boxes.

The good thing about birch plywood is it looks so good,it doesn't need any covering such as veneer or black plastic vinyl or carpet.

I have compared the sound of different materials a while ago by building a number of speakers only differing in the material of the cabinet.

The only thing I found out is that there is no simple rule of thumb of which material to chose. Much to my surprise, I found myself preferring the cheap particle board over MDF in most cases. The first thing you realize is a slightly worse resolution in bass, but when listening longer, you will realize that voices sound MUCH better with the cheaper material (if the cabinet is constructed in the right way, that is).

For the good look, you can glue sheets of thin wood to the outside, as mentioned above.

My next experiment will be a carbon fiber cabinet

Regarding "My next experiment will be a carbon fiber cabinet":

What are your construction plans for the enclosures?

Are you planning on laying/bagging multi layers to form a carbon composite or are you going to bond carbon to some other substrate?

Also are you going to work wet, pre-preg or cold?

As a basic cottage project, that is one you can do I your garage, may I suggest the following:

Laminate a dry sheet of carbon fiber to a 1/8th sheet of acrylic that has been etched with an acrylic spray whilst it is still semi-tacky. Your choice of epoxy vs. ester based resin should be determined more by cost than performance for this example.

When cured bond the above composite to your substrate (carbon in) with a 2 part acrylic for a solid surface substrate (Corian, Fountainhead etc.) or with resin for a MDF/plywood substrate.

This can be done to a finished box or to flat sheets depending on your construction skills.

The inner surface of the enclosure will benefit from laminating at least one layer of carbon or carbon/Kevlar with care. When that cures laminate a 2nd layer with intentional disregard for surface irregularities.

Unless you are already experienced with carbon construction techniques and have your process worked out, the above example will give you balance of both the mechanical and aesthetic properties of carbon fiber used in a speaker building project.

Good luck and keep us posted,

Neil

biff584 said:

I was wondering if I could either glue MDF or some other material to the inside of a hardwood cabinet to improve it since I know that solid woods are not ideal.

Click to expand...

The Ellis Audio 1801 speakers, which are beautiful to lookat, are made by veneering the four sides, but the front is a piece of roughly 3/4" sold hardwood laminated to 3/4" MDF. If you don't expose the speaker to huge humidity swings this should work fine. and if you want to roundover all four edges to reduce distraction, it sure looks great.

FWIW, there's another thread on enclosure question that addresses a lot of the same issues as this one -- see for example my post there on the challenges of making hardwood speaker cabinets.

<url>http://www.diyaudio.com/forums/showthread.php?postid=140509#post140509</url>

I don't know the english words for all the terms to explain how I plan to do this (I'll look them up soon), but fortunately I can get all kinds of resin and carbon fiber for free and I have worked with these materials quite a lot (I'm member of a student group which is designing and building gliders).

@Arcdesigns: Have you tried making speaker cabinets from carbon fiber? How were the results?

I expect this cabinet to be as stiff as possible with readily available materials. I know that stiffer is not always better, but there is a factor involved and I like to experiment.

I'll start with a carbon fiber case for my next amplifier project to test some ideas how to get a good looking finish.

AMT-Freak:

Sailplanes, cool... I on the other hand am involved with Porsche race cars.

I did make a mid-bass enclosure however it was a different technique than the one above.

First, I made a plug of the final shape I wanted. Then I made a simple 2 part mold using a hi-temp resin. I laminated 4 layers of C/F with a layer of 2 oz matt between each layer. I than vacuumed bagged each mold and cooked at 150 degrees fahrenheit for 2 hours. At the bezel area I glued with methacrylate a 3/4 in piece of Corian. When cured I added 2 more layers of C/F and a final layer of C/K and attached the 2 mold pieces. The C/K layer was applied intentionally loose. I than milled the mid opening going thru the C/F into the Corian.

As a one off pair this is not a very cost effective way of doing things (even if your materials are of no cost) but you are able to make complex shapes and sonically dead enclosures.

I am currently looking for the right project to make full range C/F enclosures but have yet to pin it down.

Good luck, Neil

Cabinet Materials

I designed and built a very strong sounding bass cabinet using plain 3/4 inch plywood. It can be purchased at nearly any Home improvement store and can be purchased with a finished side. This means that you will have the look of real wood without the need of constructing a secondary cosmetic shell. Also, it will take most wood finishing products well so that you can have it in any color you want, (pine, oak, cherry, walnut, etc.). It is easy to work with and has certain interesting properties which can be used to make an otherwise inexpensive sounding subwoofer sound like high-end equipment.

how about something a little different?

hi!

i am a new user lokoing for a bit of help. i want to build a speaker cabinet for my home built amplifier and speaker combo. the head is going to go into a well venitlated metal box at this stage and i was wondering about the merits of constructing a speaker cabinet out of odd materials.

clearly the best option is using a good sturdy wood hat will not rattle or roll at all. however, i would like to make my cabinet out of perspex! maybe put some lighting in there for a cool on stage effect. i have built one cabinet before out of 20mm thick plywood and it held up well but, i was wondering if the perspex idea is a bit dodgy.

Is this going to be a substance that will kill the sound of my speaker?

For your reference, i am putting in a single celestion greenback 25W speaker.

Any thoughts?

Thnaks for the help!