[Invinsible]

Originally Posted by karankapoor

is this comes as sheet like mdf and what about the price can you share it.

6 years back I had bought the plexiglass for Rs.250 per sq.ft or a ft. (don't remember exactly) for a 15mm size. that time had got the complete parcel tray done up for a palio out of it so that it's ICE gear could be seen under neat it wear neon's hiding.

They are expensive but they also carry a lot of resonance in it if not build properly. Also, get one air tight would be a difficult job. But, there some who use in the box for a view of the magnet. It does look cool. But, still MDF are the best way to go, sound wise. I use to get my boxes build in High density fiber-particle board years back. They are stronger than MDF but are not easily available and was twice the cost of MDF. The advantage was it was stronger than MDF and one can go .50" of it against the .75" MDF. Building a box is an art, better you build better the results.

[low_bass_makker]

Originally Posted by sudev

A bit OT but...



LBM as a manufacturer of MDF I have interacted with lot of people here and abroad and essential concclusion is MDF also has much better acoustic charactertics. I am sure about Aluminum though.

Can you opine?

By a sub enclosure there is no need for acoustic properties which comes in the picture it is the stiffness and ability not to flex which is important and no air leak if it is a sealed one and if it is a ported one proper air channel is needed for the air to pass so that it does not add to distortion.

The Aluminum is stiffer and does not flex like MDF that is the reason I choose it. MDF is the best and cheapest alternative for a enclosure material. Even I use it and I am satisfied with it.

[navin]

Originally Posted by karankapoor

mdf boards are compressed particle board

Originally Posted by frankmehta

so basically chiragh needs to go for one inch think mdf board.

Originally Posted by chiragh_bir

what will go wrong with particle board?

Originally Posted by karankapoor

particle boards are not meant for sub enclosure, it is not as strong as mdf

Originally Posted by abhibh

Why not to use particle board:
- it will flex too much specially with the sub you are using
- it can contract and expand due to weather changes
- its is not as strong as MDF.

Originally Posted by low_bass_makker

I would go for Alternate material like....Aluminum.

Originally Posted by sudev

LBM as a manufacturer of MDF I have interacted with lot of people here and abroad and essential concclusion is MDF also has much better acoustic charactertics.

Originally Posted by karankapoor

guys what you say on Plexiglas

Originally Posted by frankmehta

my dad is into plexiglass, and he says the acoustic properties of plexi are brilliant.

Originally Posted by low_bass_makker

By a sub enclosure there is no need for acoustic properties which comes in the picture it is the stiffness and ability not to flex

1. MDF is not stronger than Plywood. Void free (Marine grade) ply wood is technically stronger. MDF is better damped due to the resin used to bond the "fibers" together.

2. MDF is not compressed ply wood. Ply wood is compressed "plys" of wood sheet bonded together with some phenolic compound such as "Urea Melamine Formaldehyde". UMF is made using Benzene and Polyproplene which is then decomposed in a controlled manner (using Hydrogen rich acids). A by prodct of UMF is Acetone - the kind your wife/GF uses to remover her nail polish.

3. thickness for thickness ply can bend more than MDF but if both are prestressed ply can infct withstand greater bending moments than MDF and is hence able to made much stiffer (if prestressed).

4. As far as alternate materials are concerned there are some I have tried.
a. Aluminum - resonant. you can damp Aluminum using rubber compunds which is what JBL did for it Pro III (now called the Control 1)
b. Stainless Steel - resonant but not as bad as AL. However SS is 3 times as dense as AL and hence the whole structure can become very heavy. Weight is not good (unless it's presennse can be justified by the material's ablity to be damped or stiff) as it stores more energy which is relased later
c. Fiberlgass - diffcult to work with. Needs some special tools to make it thick enough and not de-laminate under long term use.
d. Carbon fibre - expensive. Not WAF friendly in looks. This might be the best material for car subwoofers though.
e. Glass and Ceramics - stiff but resonant. Must be used along with a second non resonant material
f. Plexiglass - too much flex but can be used in small panels (20cm-30cm square) for looks.
g. Bitumen (tar) - used primarily as a damping compund for ceramic tiles but horribly messey to work with in liquid form. You can get Bitumen sheet (or bitumen soaked sheets) and many roofing companies use the same (in corrugated form).

Guys this might look authoritative but it is not. I am willing to stand corrected but what I have stated above is only from my personal experinces.

My choice of materials today is a laminate of MDF-FRP-MDF-FRP-Ply. MDF layers are 4mm, FRP 3mm, Ply 6mm. This gives me a total thickness of 20mm. This gives me a limited degree of mess, easy to DIY (no special tools required), and adequate stiffness, damping and weight. I am sure that using more modern techniques and materials can lead to better results.