[rajesh]

Has anyone used material other than MDF to make their speaker cabinet?

I'm asking because, dad of one of my friends owns a acrylic manufacturing factory and my friend has offered to make speaker box as per the given drawing. My doubts are:

1. Can Acrylic replace MDF as speaker buliding material?

2. Since the acrylic is much denser material, is it ok to reduce the cabinet wall thickness?

3. Are there any bracings required?

4. Are there any materials required like bitumen sheet (for cabinet damping) and / or fibre glass ( for arresting the standing waves)

[nickd]

Yes to all 4 questions.

However, it will sound like a nice kit in a "plastic" box. Acrylic looks good but is not famous for good sound. Phoenolic is better, crazy heavy, but better. Some plastic fab shops stock both.

[pureiso]

1. Plastics will work, you just have different design issues to deal with. 

2. If it is actually denser than MDF, you could reduce wall thickness but that would be a waste in my opinion.  You would just have a more inert box by leaving everything the same as the drawing.  If it is actually less dense, then more bracing and a thicker wall will be required.

3. Yes, more may be required but I would not stray from the amount in the original plans.  Your goal should be as per spec or better.  The nice thing is you may be able to create a curved speaker cabinet even easier using this material.  This design would be a good starting point: http://www.audiocircle.com/index.php?topic=79983.msg822776#msg822776

4. You will still want more dampening and absorption in the cabinet, the more the better as long as you are keeping the volume of the cabinet per spec.

More reading that may give you some ideas: http://www.audioholics.com/education/loudspeaker-basics/loudspeaker-cabinets

Also, if you do end up making it out of acrylic be sure to post  it up, the before and after pictures...

[FullRangeMan]

Has anyone used material other than MDF to make their speaker cabinet?

I'm asking because, dad of one of my friends owns a acrylic manufacturing factory and my friend has offered to make speaker box as per the given drawing. My doubts are:

1. Can Acrylic replace MDF as speaker buliding material?

2. Since the acrylic is much denser material, is it ok to reduce the cabinet wall thickness?

3. Are there any bracings required?

4. Are there any materials required like bitumen sheet (for cabinet damping) and / or fibre glass ( for arresting the standing waves)

I used (hard)MDF 30mm in 2003 and it is rock solid til today, also all MDFs are carcinogenic for about 5 years   for all the MDF life, due the use of formaldehyd and urea in the MDF manufacturing(the board will exhale formal and will kill termites and other insects), not to mention the MDF dust.
As you know the best sound is real wood, second is Baltic Birch phywood, 3º is MDF or HDF.

Omega enclousures use soft MDF in a sandwitch, I used hard MDF why it does not absorb water or moisture, and it is perfect already 9 years.
Below, 60mm baffle in 30 + 30mm:

P.S.:> Please note: you must paint inside the box, in mate black paint for long MDF life.

[srb]

all MDFs are carcinogenic for about 5 years   for all the MDF life, due the use of formaldehyd and urea in the MDF manufacturing

Although the majority of MDF is made with Urea Formaldehyde resin glues, many manufacturers have formaldehyde-free MDF products including
- UltraStock-FREE MDF from Temple-Inland
- Arreis, Medex and Medite II from Sierra Pine
- PureBond Classic Core from Columbia Forest Products

Many of these products may also use material that is from sustainable and/or recycled sources.

Same with plywood.  The majority of plywood uses formaldehyde based glues, but is also available in formaldehyde-free versions.  Bamboo plywood is the most sustainable and is offered as an option by some speaker manufacturers such as Salk Sound or as a standard material such as in the Ascend Acoustics Sierra line.

Fine dust is dust, and poses a health risk even from non-toxic building materials so appropriate dust masks should be used when cutting or sanding.

Steve

[jtwrace]

Has anyone used material other than MDF to make their speaker cabinet?

I like aluminum.   

[FullRangeMan]

Although the majority of MDF is made with Urea Formaldehyde resin glues, many manufacturers have formaldehyde-free MDF products including
- UltraStock-FREE MDF from Temple-Inland
- Arreis, Medex and Medite II from Sierra Pine
- PureBond Classic Core from Columbia Forest Products

Many of these products may also use material that is from sustainable and/or recycled sources.

Same with plywood.  The majority of plywood uses formaldehyde based glues, but is also available in formaldehyde-free versions.  Bamboo plywood is the most sustainable and is offered as an option by some speaker manufacturers such as Salk Sound or as a standard material such as in the Ascend Acoustics Sierra line.

Fine dust is dust, and poses a health risk even from non-toxic building materials so appropriate dust masks should be used when cutting or sanding.

Steve

Good to know your country had various types of MDF, no so lucky here.

Do you had any info about the Bamboo plywood sound quality??

[srb]

I like aluminum.   

So does Krell, when they built their Master Reference Subwoofer with a 2" thick aluminum baffle and 1" thick aluminum sides, top and bottom.   

I guess if you're making a 650lb. $30K subwoofer, you can afford to go big or go home.

Steve

[Hank]

Rajesh, it would be quite a bit more expensive.  It would most likely need to be opaque colors, as transparent would show the glue lines and internal damping material as well as drivers and crossovers.  Transparent might be a novel appeal to a very few people, but definitely not a WAF thing.  Acrylic would require very careful handling, since it scratches very easily.  And, I don't think Danny has had many customer requests for acrylic.
Corian or another brand solid countertop material equivalent might have some customer appeal.

[S Clark]

As you know the best sound is real wood, ...

This is incorrect.  Solid wood resonates more than plywood or mdf. 

Scott

[roymail]

Baltic birch plywood is a good alternative and lighter than mdf.

[Cacophonix]

Agreed. Baltic birch or any other void free ply is a much much better alternative to MDF. MDF is horrible ... unless you have a top notch dust collection system in your garage, i would strongly advice against this material.

[FullRangeMan]

This is incorrect.  Solid wood resonates more than plywood or mdf. 

Scott

MDF is less resonant than wood indeed, so it can be better suited to multi-ways boxed loudspeakers, where an inert or affordable material is wanted, but MDF has the known characteristic of the emduff bass, or duff.
However, the wood can warp, which does not happen with MDF.

In the 70 years my first bass guitar body was in MDF, and the tone was bad, non musical, I also already tested an e-guitar in transparent acrylic from Korea and the sound was horrible, just OK for glitter Rock Stars.

Then I came to conclusion that the resonance of well dry wood from a mature tree is very benefical to the sound of speakers, mainly no xover fullrange speakers, where the transparency is so sensitive.

I read on web about the HDF sound may be better than MDF thought, but I not sure.

[S Clark]

Baltic birch and mdf are the most commonly used materials for both manufacturers and DIY'ers.  Solid wood is not widely used because of its variable and unpredictable resonances.  Some prefer mdf, some prefer, ply, look around the web and you will find very few fans of solid wood for anything except instruments. If you are making a violin, piano, or guitar the resonance of wood is part of the signature sound of the instrument. Personally, I don't want my speakers to have a signature sound related to cabinet vibrations.

[FullRangeMan]

I myself only use MDF, real wood is expensive, can bend with humidity and be attacked by termites.
I think a good combination is to use MDF for the baffle and ply to the other sides.