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.
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
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
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.
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.
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.
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.
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.
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Like painting, all the work is in the prep. What do they saw about a painting job? "When you are all done, it is time to apply the paint. Veneer is not much thicker than paint.
The trick to making it look nice is getting a dead smooth (glass-like) surface with not even wood gain texture. The best, #1, first class thing is to first apply a Formica laminate and then veneer over that. But that doubles the work and triples the cost. The surface has to be 100% perfect BEFORE you apply the veneer. That is why people like MDF.
plastic surgery
My cutting tools and skill are not great.
But it is nothing short of amazing what a little Bondo and sandpaper will accomplish.
In the past I have relied on a flat black "theater" idiom for my creations.
Last week I purchased some very nice Mahogany veneered ply and built a pair of Brynn's. My joinery is primitive leaving a fully exposed square edge of non-veneered ply. I found 1" edge veneer in Mahogany from WoodCraft that is enormously forgiving. I purchased the iron from WallMart for about a ten spot.
For the front edge veneer I am likely ordering a banded veneer from one of the following sites. I admire natural beauty but for everything there is Bondo and veneer.
http://inlays.com/Custom_Inlay_Bandings.asp
http://www.inlaybanding.com/index.html
http://www.joewoodworker.com/
My cutting tools and skill are not great.
But it is nothing short of amazing what a little Bondo and sandpaper will accomplish.
In the past I have relied on a flat black "theater" idiom for my creations.
Last week I purchased some very nice Mahogany veneered ply and built a pair of Brynn's. My joinery is primitive leaving a fully exposed square edge of non-veneered ply. I found 1" edge veneer in Mahogany from WoodCraft that is enormously forgiving. I purchased the iron from WallMart for about a ten spot.
For the front edge veneer I am likely ordering a banded veneer from one of the following sites. I admire natural beauty but for everything there is Bondo and veneer.
http://inlays.com/Custom_Inlay_Bandings.asp
http://www.inlaybanding.com/index.html
http://www.joewoodworker.com/
Definitaive Reading
Please allow me to HIGHLY recommend this book:
"Understanding Wood Finishing - How to Select & Apply the Right Finish"
By: Bob Flexner
ISBN 0-7621-0621-2 (hardcover) also available in softcover.
It takes the reader through:
Preparing the wood
Tools for application
Staining
Oil & Wax Finishes
Pore Filliing
Film Finishes
Shellac, Laquer, Varnish, 2 Part (epoxy) & Water Based finishes
Finish selection
Colouring, caring & repairing.
One clever dude this Flexner bloke - goes on to explain the chemistry of finishes and how it applys to 'what's written on the tin' etc.
Only one critisim - it's an American Book (I'm from UK) and I have to 'translate' some of the terminology.
A definate must have book of you're 'into' wood finishing.
Cheers,
Andy
Please allow me to HIGHLY recommend this book:
"Understanding Wood Finishing - How to Select & Apply the Right Finish"
By: Bob Flexner
ISBN 0-7621-0621-2 (hardcover) also available in softcover.
It takes the reader through:
Preparing the wood
Tools for application
Staining
Oil & Wax Finishes
Pore Filliing
Film Finishes
Shellac, Laquer, Varnish, 2 Part (epoxy) & Water Based finishes
Finish selection
Colouring, caring & repairing.
One clever dude this Flexner bloke - goes on to explain the chemistry of finishes and how it applys to 'what's written on the tin' etc.
Only one critisim - it's an American Book (I'm from UK) and I have to 'translate' some of the terminology.
A definate must have book of you're 'into' wood finishing.
Cheers,
Andy
African Plywood.
Someone is selling it cheap in my area.
4 X 8 SHEETS OF HARDWOOD PLYWOOD - CHEAP
Is it any good? I guess for a prototype it's cheaper than MDF.
Someone is selling it cheap in my area.
4 X 8 SHEETS OF HARDWOOD PLYWOOD - CHEAP
Is it any good? I guess for a prototype it's cheaper than MDF.
5/8 hardwod? He is letting it go at 1/2 market value. It is MUCH more durable then MDF, much stronger. If you can use that much it it go for it.
I just built a speaker cabinet with 3/4 white pine. I did it on purpose because I wanted it to have a wood-like tone. Even with an intentional use of a very "springy" wood the direct sound from the driver (12" 98db) dominates so much I doubt I hear the wood, hard to tell.
So a 5/8 ply cab that is well braced will work fine and certainly it will be able to take massive physical abuse. QUality plywood like that is stiff.
That's exactly what they make guitar speakers with 5/8 hardwood ply. Because those guys move and transport their gear so frequently
This book is the bases of my knowledge of finishes. I read it 10 yrs ago and started using shellac. The dewaxed shellac is a great sealer also, as about anything will stick. It builds and dries fast. Forget the drip and brush strokes, just put on 4 -6 coats. You can put on a coat every 30 min. Just slop it on. Raw MDF edges take twice as much and can be coated an extra time between coats. Let it dry over night; then sand with 120 grit, backed by a block, and you can quickly level up the finish. Now see what you have and decide what you need to do next. You may need to put on another coat to level up the scuff marks and reveal your progress.
Now if you want a glass finish, just put on a couple more of coats of shellac and then began buffing out all imperfections. You will need to use some lubricant such as paint thinner to wash away the swarf. Start with 220 grit and finish with 600 or maybe even 1500 grit, as you prefer.This much shellac will take weeks to fully harden/cure. You may want to hold off on the final polishing grits for a month. Shellac dries hard and brittle, so it buffs very well. It also chips or can be damaged easily but repair is also easy. A drop of alcohol dissolves the layers and the chipped area and allows them to re-bond. Then you just buff out the area.
All of this is in this book.
Have fun.
Bob
Off topic digression split to here http://www.diyaudio.com/forums/full-range/170654-boxes-not.html
dave
dave
I am going to use some 3/4" Sandeply from Home Depot for my Lotus^2 build. Millstead 3/4 in. x 4 ft. x 8 ft. Sandeply Hardwood Plywood - 454559 at The Home Depot
No, it's not 9 ply BB or marine but it should be a good measure better than MDF. My only concern is the end grain and how strong the butt joints will be. I'll use yellow glue and clamps but I wonder if I'll need biscuits too?
It's raining here in Northern Minnesota today so I can't haul the material, otherwise I would be starting the project today.
Better than MDF is what way? It is hard to beat MDF if you want something that is sonically "dead".
If you are building a seaker that will see physical abuse, like for use with a guitar am then marine plywood with finger joint is best or even hardwood with figer joints and then cover it with black carpet and metal corners.
But it these will stay in one place and not get move every night MDF is good stuff.