MDF vs solid wood - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th June 2006, 02:19 AM   #1
diyAudio Member
 
Join Date: Jun 2006
Default MDF vs solid wood

Hi guys
I am very new to this forum. I am quite amazed at the knowledge base here.
I am a part time hobby wood worker with a full shop in my basement. I am in the process of completing my first set of speaker cabinets. As far as the design and style goes I am copying the Genesis 6.1 e, except I will be using a horn .
My plan for the cabinets is this. I have completed the MDF "inside cabinet" That is the actual cabinet that all the bracing and guts will go into. I am also going to use solid wood to cover the sides and the front. The sides will be Eastern Maple and the baffle will be a 1.5 " hunk of American Black Walnut on top of the 3/4 mdf inside baffle.
My question. Aside for the obvious cost savings of MDF and the ease of workability, would I not be better off just making the speakers out of solid wood?
I understand that MDF is dense but so are a number of good hard woods. Opinions?
Since this is my first project I did not want to shell out the bucks for a solid wood cabinet, but in the future I would llike to go with just wood. Is this a good idea or should I continoue to make a double box design? Sound is #1 but the appearance of a finely made cabinet is also very important to me.
  Reply With Quote
Old 7th June 2006, 02:45 AM   #2
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
Hi Paul,

You can make them from whatever you like. One of the reasons a lot of people don't use solid wood is that every wood will have it's own sonic character. Just like a violin or a piano sounding board, the cabinet will colour the sound. The idea of a speaker is to reproduce the input signal not introduce it's own qualities. MDF and plywood tend to have less affect and are easier to work with and often more stable. Your way is fine but I know someone in this thread will want to know how you are planning to bond the two so I'll be first to ask.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 7th June 2006, 02:53 AM   #3
diyAudio Member
 
Join Date: Dec 2001
Location: Earth
I have used couple of speakers that i "build"(ask a carpenter to built). The design were my own.
I notice MDF is not a great material sonically. Inherently dead but that the problem, it tends to muffle down on the bass and vocals and seems to limit the sparkle in the highs. They are also much slower
MDF may be dense but because of its molecular structure displays this effect.
However FOR box speakers and bright sounding speakers MDF is good to be used, esp speakers like fostex 206,lowther the mdf tameds them down.

FOr horn, avoid mdf at all cost. THe mdf really sucks out the life on horns.

If possible try to find either hard wood or marine ply. I love marine ply very lively and tunefull bass not deep and low like mdf but very tunefull with texture bass output. Also with marine ply the highs are sparkling. The ply i used is a hardwood from indonesia where the wood is dense. it is a 3/4 or 18mm ply with 13 pcs of ply used. This unlike normal ply wood where they used less pcs of ply. Also the marine ply i used is very much heavier than the normal ply and i beileve comparable to mdf
Hardwood i have only use oak before and i love it. However hardwood is too hard to use when making big speakers as they don't come in that size i believe.
MDF when cutted emits so much of dust. May not be worthwhile after the clean up. The dust lingers in the air after the cut takes placce. Very unsafe,
Again this my observation.
  Reply With Quote
Old 7th June 2006, 03:21 AM   #4
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Solid wood "checks" -- so you can get leaks -- this screws up the impedance of the air in the chamber. MDF had been preferred for its stiffness -- the only firm I know which utilizes the flexibility of real wood is the piano manufacturer Bossendorfer -- all of us mere mortals would prefer to have the speakers do the vibrating and the cabinet remain imobile.

I love MDF -- a suggestion -- get the MDF used for shelves or those already cut into 8 square foot dimensions --
  Reply With Quote
Old 7th June 2006, 03:43 AM   #5
diyAudio Member
 
Join Date: Apr 2006
Location: East TN
Any good cabinet maker knows that wood moves with seasonal variation. The whole concept of "wood working" is to allow a natural material to expand and contract with varying moisture contents. An acoustically sealed, stable enclosure with a consistent volume is in direct opposition to an enclosure with built in flux for panel movement. The built in flux is necessary for longevity if you are using solid wood.
You are welcome to try "hunks" or slabs of 1.5" thick solid wood in your design but be ready for gaps at the joints in time.

Some manufacturers (Sonus Faber) have been able to get away with solid wood in their enclosures by using highly dimentionally stable woods, i.e. quarter sawn walnut, but even these manufacturers do not typically use thick walls of solid wood on all 6 sides.

In addition, the best figured woods are typically sent to the veneer mills, so often veneer is your best choice for the prettiest woods. Finally, it is far more environmentally friendly to use a thin veneer of an exotic wood on a lesser substrate than to use a whole "hunk" of that precious wood.

I am biased towards MDF or baltic birch plywood covered by veneer for my speakers and with good reason. To me, the "solid wood 1.5 inch thick baffles" always scream amateur. Who said, "anyone with a table saw can build a pair of speakers, and most do."

Good luck, and be sure you've read Vance Dickason's book.
  Reply With Quote
Old 7th June 2006, 03:45 AM   #6
...truth seeker...
diyAudio Member
 
Ed LaFontaine's Avatar
 
Join Date: Feb 2004
Location: where the Appalachians rise from the Blue Grass
polvoson posted:
Quote:
the baffle will be a 1.5 " hunk of American Black Walnut on top of the 3/4 mdf inside baffle
I would have concerns for this construction & I'd like to offer them to you.
Mdf, in relation to a solid wood is rather inert: I mean dimensionally stable. With the mdf on the inside of your cabinet it is less exposed to ambient moisture changes. The suseptibility to movement of 1.5" of solid wood (due to seasonal moisture changes) will (I think) overcome the stability offerred by 3/4" mdf. This could lead to glue joint failure.
A more reasonable approach, one that I have had success with, is to use a thinner layer of select wood to overlay the mdf. I have used up to 1/2" over 1 " of mdf, more at the corners. This, I think, shifts the balance for stability more towards the mdf.
  Reply With Quote
Old 7th June 2006, 07:39 AM   #7
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
MDF will offer stability/reliability over solid timber, however I don't like the sound of MDF when it resonates.

All wood will resonate and you have two basic choices. Either you accept it and build out of something that sounds good when it resonates, or you brace (etc) until the resonances are quiet.

To saitsfy this compromise between stability, good sounding resonance and relative freedom from resonance, I choose to use plywood with bracing.

I have to say that your idea is intriguing. It almost sounds like it will be successful. I have often used real wood veneer to make beautiful cabinets, and find plywood to be even easier.

Good luck.
  Reply With Quote
Old 7th June 2006, 09:08 AM   #8
diyAudio Member
 
Join Date: Mar 2006
Location: The Netherlands, Arnhem
Send a message via MSN to Jamesblond
Quote:
Originally posted by NickC
I have used couple of speakers that i "build"(ask a carpenter to built). The design were my own.
I notice MDF is not a great material sonically. Inherently dead but that the problem, it tends to muffle down on the bass and vocals and seems to limit the sparkle in the highs. They are also much slower
MDF may be dense but because of its molecular structure displays this effect.
However FOR box speakers and bright sounding speakers MDF is good to be used, esp speakers like fostex 206,lowther the mdf tameds them down.

FOr horn, avoid mdf at all cost. THe mdf really sucks out the life on horns.

If possible try to find either hard wood or marine ply. I love marine ply very lively and tunefull bass not deep and low like mdf but very tunefull with texture bass output. Also with marine ply the highs are sparkling. The ply i used is a hardwood from indonesia where the wood is dense. it is a 3/4 or 18mm ply with 13 pcs of ply used. This unlike normal ply wood where they used less pcs of ply. Also the marine ply i used is very much heavier than the normal ply and i beileve comparable to mdf
Hardwood i have only use oak before and i love it. However hardwood is too hard to use when making big speakers as they don't come in that size i believe.
MDF when cutted emits so much of dust. May not be worthwhile after the clean up. The dust lingers in the air after the cut takes placce. Very unsafe,
Again this my observation.
I'm currently working on a design for a small "mini-monitor" - about 36 litres, fitted with original components and filter from the Tannoy Stratford speaker. The woofer is a 6.75" driver and the tweeter is a 0.5" horn. It is a ported design, with the port firing forwards. The original Stratford is tuned to 50Hz, in my room there is a conciderable boost around that frequency. Simulations show a similar bump at aroud 45 Hz. My goal in designing a new cabinet is to tame that bump and to enlarge the bass response downwards. Maybe tune to somewhere close to 36 Hz. That means deep bass, so I would need to use MDF.

The tweeter is a very lovely horn - fast, transparent. To keep it's quality, I'd have to use plywood.

Would it be possible to make the cabinet out of 22mm MDF and the baffle out of 22mm + 8mm Plywood screwed and glued together? That way I have the qualities of both Plywood and MDF. I want to heavily dampen the inside by glueing bitumen (carpet tiles) on all inner walls, and stuffing it with fiberglass. Also, I've seen monitors with felt fitted on the baffle to minimize diffraction. I'm not sure if I'll use that, too. I plan to brace the cabinet internally.

Any ideas? Any input is welcome. Thanks!

Oh, and by the way: I've only recently taken a serious interest in speaker building. I'm still quite a noob, but I want to learn. Please feel free to include as much info as possible
Attached Images
File Type: jpg tannoy_stratford-sml.jpg (53.1 KB, 668 views)
  Reply With Quote
Old 7th June 2006, 11:10 AM   #9
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
Quote:
Originally posted by Jamesblond
I want to heavily dampen the inside by glueing bitumen (carpet tiles) on all inner walls,
Any ideas? Any input is welcome. Thanks!
I have used lead to line cabinets, tacking it in places with glue (not just any glue). The lead really goes to work on resonances. It has done well to tame those I couldn't fix with bracing...

Quote:
Originally posted by NickC
...Inherently dead but that the problem, ...
...but after doing so, I seemed to miss the resonance. The speakers seemed somehow dead. No problem. Revoicing, or adjusting the crossover to change the tone slightly has brought satisfaction back.
  Reply With Quote
Old 7th June 2006, 02:50 PM   #10
RDV is offline RDV  United States
diyAudio Member
 
Join Date: Sep 2005
As a wood worker I'm sure you're familiar with Veneer. You can get some beautiful veneers to cover that MDF with and still not disturb the glue joint integrity as the expansion and contraction of veneer should not equal what a 1.5" piece of hardwood will have.

RDV
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
let's enjoy the solid wood speakers Jed2JJ Vendor's Bazaar 19 13th August 2009 04:13 AM
Solid Wood? Lewis Moon Multi-Way 15 29th September 2008 10:06 PM
Solid Wood Plinth jlsem Analogue Source 2 3rd August 2007 12:22 AM
using one piece of solid wood for an enclosure Jared Multi-Way 13 8th May 2003 12:45 AM


New To Site? Need Help?

All times are GMT. The time now is 07:06 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2