Wood & Varnish - Page 9 - diyAudio
Go Back   Home > Forums > Design & Build > Construction Tips

Construction Tips Construction techniques and tips

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 20th August 2009, 09:33 AM   #81
diyAudio Member
 
hasaudio.co.nz's Avatar
 
Join Date: Aug 2009
I always like rimu wood from nz. Hard as hell and looks great when cut properly(which I can never do).
__________________
Hasaudio Speaker Components
  Reply With Quote
Old 20th August 2009, 05:44 PM   #82
ChrisA is offline ChrisA  United States
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by schn0354 View Post
...The loudspeaker should be viewed as a fine musical instrument. I wish more manufacturers would put the same emphasis on design and fine tuning as do musical instrument makers of violins, cellos, guitars, etc. There is a lot of math using the golden ratio in making a violin and few designs take advantage of tone woods like sitka spruce or maple....
HiFi speakers need to be "dead". and not contribute their own sound or color. The reason is that we listen to so many different kinds of music with the same speakers. I do think you could make an outstanding speaker for solo piano music from wood but it might not sound good if you played other music through it. The violin maker knows he is building a violin and he knows a violin will never be asked to make the sound of a bass drum. Speaker makers do not have such luxury.

This is why a live band can sound good live even when they are playing through speakers. What happens is each musician brings his own amp and speakers. Most of them will have spent years buying and selling amps and speakers until they found what they want (or more likely it's a continuing process.) But anyway the speakers are all very specialized to their intended use. No crossovers are used. The guitar speaker and the guitar amp are both designed for the exact frequency range of a guitar and so on with the others including vocals.

HiFi speakers are so hard to design because they need to be full range and general purpose. They have to be able to reproduce a violin, a bass drum sound and female vocals. No speaker can do this perfectly no matter the cost.

If you are a hobbyist and enjoy building speakers think about non HiFi speakers. There is so much MORE room for creativity when you design specialized speakers. For example let's say you want to design one to be used ONLY with a bluegrass violin. Let's say you know a "fiddler" who plays outdoor venues with a 250 to 500 people. Now you can think about "real wood" and how you can use it so that the sound does NOT sound like a stereo recording of a violin. Another example: I bet the best speakers for electro-acoustic guitar would look like an acoustic guitar and maybe be built with thin spruce and have compound curved sides and baffle. The low E-string is 82Hz so there is no need for the woofer to go lower and the highest harmonics is about 8Khz so it would not need a tweeter either.

I'm currently thinking about a design for a "piano speaker". One that will only be used to amplify a solo piano. After I have the design roughed out I will work on the amplifiers. These will be custom built, one amp channel per driver. Knowing that the amp connected to a given driver will never have to reproduce sound outside of the driver's range I can select component values without compromise.

All HiFi speakes and amps are compromises. If you build a specialized system there is no need to compromise.
  Reply With Quote
Old 4th September 2009, 03:37 PM   #83
diyAudio Member
 
aquapiranha's Avatar
 
Join Date: Jul 2007
Default 19 MM Oak veneered MDF?

hi chaps. I am about to start another build, this time OB's with 2 X alpha's and 1 x B200 per side. What do you guys think of 19 MM veneered MDF? Is it a suitable material? there will be bracing in the form of two supports, one either side at the back that will be linked with another piece of MDF at floor level/

Thanks!

Steve
  Reply With Quote
Old 4th September 2009, 04:24 PM   #84
ChrisA is offline ChrisA  United States
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by aquapiranha View Post
hi chaps. I am about to start another build, this time OB's with 2 X alpha's and 1 x B200 per side. What do you guys think of 19 MM veneered MDF?
You have to think in terms of the ratio of baffle thickness to baffle size. It's the ratio that matters. So 19mm might be very stiff or it might be to thin depending on the size of the OB. I said "size" but I meant "open span" of the size of the baffel between braces. Look at designs you know have worked and don't make the spans bigger then used on a known good design unless the goal is to experiment.

One problem with MDF is that is is not very strong. and very heavy. It is sonically dead but it's only strong when you build it into a box. You may want to add a hardwood frame to support and hide the edges. It could work if you design in some corners so the structure was stronger. 3/4 plywood would not need that but I think MDF might.

But I think OBs don't need to be so stiff because you can glue sound deadening material to them. With that stuff applied it does not really matter if the baffle vibrates it would not radiate sound.
  Reply With Quote
Old 4th September 2009, 05:12 PM   #85
diyAudio Member
 
aquapiranha's Avatar
 
Join Date: Jul 2007
Quote:
Originally Posted by ChrisA View Post
You have to think in terms of the ratio of baffle thickness to baffle size. It's the ratio that matters. So 19mm might be very stiff or it might be to thin depending on the size of the OB. I said "size" but I meant "open span" of the size of the baffel between braces. Look at designs you know have worked and don't make the spans bigger then used on a known good design unless the goal is to experiment.

One problem with MDF is that is is not very strong. and very heavy. It is sonically dead but it's only strong when you build it into a box. You may want to add a hardwood frame to support and hide the edges. It could work if you design in some corners so the structure was stronger. 3/4 plywood would not need that but I think MDF might.

But I think OBs don't need to be so stiff because you can glue sound deadening material to them. With that stuff applied it does not really matter if the baffle vibrates it would not radiate sound.
Hi Chris, and thanks. I do have some spare 19MM BB ply that I could use, but the finish is not too good... I could use it to increase the thickness of the baffle by glueing it on (?) assuming this would be OK? I would mind doing that since it would not be seen on the back in use.
  Reply With Quote
Old 4th September 2009, 11:00 PM   #86
diyAudio Member
 
raypalmer's Avatar
 
Join Date: Dec 2008
Location: Burlington
Hey all.

I've found this site but other than this where does one buy Veneer? I'd like to go into a brick and mortar shop to purchase rather than buying online.

I can find single ply (raw veneer) lots of places but I've used it before and am not in love with the final product. I can get paper backed and 2-ply veneer lots of places but only very small square footage. Obviously for speakers I need something more like 4x8 sheets...

Help.
  Reply With Quote
Old 8th September 2009, 01:37 PM   #87
diyAudio Member
 
Pit Hinder's Avatar
 
Join Date: Nov 2006
Location: Hannover, Germany
Send a message via ICQ to Pit Hinder
Ray, single ply is the way to go - if you are not afraid of burning midnight oil and elbow grease.

Buy it, it´s cheap. Cut to size+a bit. Now - normal carpenter´s glue. "Paint" the veneer and the box (one panel at a time) and let dry until transparent instead of white.

Now, the dangerous bit - you need a smoothing iron. Do NOT commandeer the one your Missus uses to iron your shirts, you´d risk civil war. Iron the veneer on - the glue on both surfaces melts and bonds. Allow time to cool, cut the edges to + ~1mm and sand down to flush. Repeat on next panel.

Tired and sick of it? OK, next job. What you´ve got now is real wood instead of some plastic crap, all it needs is finishing. Sand it. Water it. Sand it. Water it- Repeat. Now stain it and start lacquering.

Result? Nothing like you could buy in a chain store, rather something you´d never be able to afford paying an artisan´s hours for. Give it a whirl, if you have the time and enough trust in your tenacity.
  Reply With Quote
Old 8th September 2009, 02:41 PM   #88
diyAudio Member
 
raypalmer's Avatar
 
Join Date: Dec 2008
Location: Burlington
Quote:
Originally Posted by Pit Hinder View Post
Ray, single ply is the way to go - if you are not afraid of burning midnight oil and elbow grease.

Buy it, it´s cheap. Cut to size+a bit. Now - normal carpenter´s glue. "Paint" the veneer and the box (one panel at a time) and let dry until transparent instead of white.

Now, the dangerous bit - you need a smoothing iron. Do NOT commandeer the one your Missus uses to iron your shirts, you´d risk civil war. Iron the veneer on - the glue on both surfaces melts and bonds. Allow time to cool, cut the edges to + ~1mm and sand down to flush. Repeat on next panel.

Tired and sick of it? OK, next job. What you´ve got now is real wood instead of some plastic crap, all it needs is finishing. Sand it. Water it. Sand it. Water it- Repeat. Now stain it and start lacquering.

Result? Nothing like you could buy in a chain store, rather something you´d never be able to afford paying an artisan´s hours for. Give it a whirl, if you have the time and enough trust in your tenacity.

Excellent help Pit!

I've been impulsive and ordered a sheet of Ash paperbacked from the States last night. But next time I'll def use 1 ply again as per your advice. Just one further question for you though.

How do you deal with the curl?? It's vicious, I have a severely hard time laying down larger surfaces because of it.

Last edited by raypalmer; 8th September 2009 at 02:42 PM. Reason: grammar
  Reply With Quote
Old 8th September 2009, 03:46 PM   #89
diyAudio Member
 
Pit Hinder's Avatar
 
Join Date: Nov 2006
Location: Hannover, Germany
Send a message via ICQ to Pit Hinder
Risk civil war - steal the spraygun the Missus uses to moisten the flowers. Curl is the result of the veneer drying unevenly - moisten it and it lays down. Do NOT try a microsoft program instead of a cheap household tool.
  Reply With Quote
Old 16th September 2009, 06:48 PM   #90
diyAudio Member
 
chuyler1's Avatar
 
Join Date: Feb 2006
Location: Massachusetts
Is that oakwood site the best place to buy veneer? ...and I didn't see singly-ply as an option.

Lowes stocks 2'x4' sheets of iron-on red oak but that's the only thing I can find local.
  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
Varnish on old transformer duderduderini Tubes / Valves 12 19th May 2008 01:20 PM
Hot-Rod Varnish Formula John L Full Range 3 12th April 2008 09:03 PM
Recipe for Damar Varnish? bcherry Multi-Way 4 26th August 2005 06:09 PM


New To Site? Need Help?

All times are GMT. The time now is 05:47 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