Hi everyone, I'm thinking about building my first kit.
https://www.madisoundspeakerstore.com/pdf/REDISCV-CAB.pdf
https://www.madisoundspeakerstore.c...j9nkk0Y6PBtefRbZlNF-0l3X48oIBDav1uDPnB6r7G293
I had a Fritz Carbon 7 speaker that I liked that used Scanspeak drivers and was a similar size, so this kit seemed like a good place to start and is in the price range I want. Problem is, the plans call for a 1" MDF front baffle and the largest options I have near me are 3/4" MDF and 3/4" Baltic Birch.
My thoughts:
1. Build out of 3/4" MDF and hope for the best.
2. Use 3/4" Baltic birch for the whole cabinet or just the front baffle.
3. Build from MDF, and glue two 3/4" or 1/2" panels together to create a 1" front baffle.
I have zero experience building a speaker cabinet and would appreciate any ideas for the front baffle. Thank you!
https://www.madisoundspeakerstore.com/pdf/REDISCV-CAB.pdf
https://www.madisoundspeakerstore.c...j9nkk0Y6PBtefRbZlNF-0l3X48oIBDav1uDPnB6r7G293
I had a Fritz Carbon 7 speaker that I liked that used Scanspeak drivers and was a similar size, so this kit seemed like a good place to start and is in the price range I want. Problem is, the plans call for a 1" MDF front baffle and the largest options I have near me are 3/4" MDF and 3/4" Baltic Birch.
My thoughts:
1. Build out of 3/4" MDF and hope for the best.
2. Use 3/4" Baltic birch for the whole cabinet or just the front baffle.
3. Build from MDF, and glue two 3/4" or 1/2" panels together to create a 1" front baffle.
I have zero experience building a speaker cabinet and would appreciate any ideas for the front baffle. Thank you!
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Baltic birch. A better option than MDF anyway. I'd double up the 3/4 pieces for the front baffle. Be sure to champfer the inside edge of the woofer hole with either a 3/4" champfering or roundover bit.
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You could do that with Baltic Birch as well, if you need the extra thickness for the woofer rebate.
jeff
Comparing BB, marine grade plywood to MDF
You can look up 1" MDF's MOE to get an exact comparison, but it's obvious that 3/4" BB, marine grade is your plenty acceptable choice, so a waste of time, $$ for any thicker.
You can look up 1" MDF's MOE to get an exact comparison, but it's obvious that 3/4" BB, marine grade is your plenty acceptable choice, so a waste of time, $$ for any thicker.
Bond two different types of materials together - .75" ply with .25" OSB, MDF (yes, I know the dust sucks, wear a good mask) or even K3 (blasphemy!) but there's a reason. If you're veneering, put your smoothest surface outside, if not, the birch ply goes out. Be warned birch ply is hard to finish other than natural (blotchy).
The plan details are rather sketchy. the cabinet is only 9 inches wide and the speaker hole only leaves a little over an inch on each side of it.
From an engineering standpoint, there isn't going to be much resonance in a 9 inch wide piece of any thickness of plywood. How are you planning to attach the baffle to the sides of the box? Usually, the baffle is slightly recessed into the box. In this case, if the box is made out of normal 3/4 inch plywood, the speaker is right up against the box sides. Once you cut the hole, there is not much left of the baffle. MDF is dense and its heavy, but not very strong. It may crack in two near the edges of the speaker. I would recommend 1/2 inch plywood for the baffle and place a 3/4"x3" solid wood brace on edge running side to side between the woofer and tweeter. You may also want to think about increasing the width an extra inch or two to accommodate installing the baffle and rear of the box.
From an engineering standpoint, there isn't going to be much resonance in a 9 inch wide piece of any thickness of plywood. How are you planning to attach the baffle to the sides of the box? Usually, the baffle is slightly recessed into the box. In this case, if the box is made out of normal 3/4 inch plywood, the speaker is right up against the box sides. Once you cut the hole, there is not much left of the baffle. MDF is dense and its heavy, but not very strong. It may crack in two near the edges of the speaker. I would recommend 1/2 inch plywood for the baffle and place a 3/4"x3" solid wood brace on edge running side to side between the woofer and tweeter. You may also want to think about increasing the width an extra inch or two to accommodate installing the baffle and rear of the box.
The drawing implies the baffle is inset flush with the sides, hence the 1" due to basically cutting it away to fit the driver and as I proved, 3/4" BB or marine grade is plenty sufficient WRT rigidity even completely cut away to the sides.
Kit price could be reduced for $200 by buying passive parts (no boards) at PE, with a bit of adjusting one inductor to a needed value.
Fritz Carbon 7 has got drivers placed on baffle in such way so it looks better.
I have done some basic driver loading sim (20 lit) and I could not get that Fb=32Hz of Madisound Impedance using 2by4 inch vent.
Must be the T/S parameters.
Judging by the SS spec sheet, there is room for another 10Hz lower cut-off in a larger stand alone cabinet.
I'd leave the baffle 0.75" and add a brace or two.
Fritz Carbon 7 has got drivers placed on baffle in such way so it looks better.
I have done some basic driver loading sim (20 lit) and I could not get that Fb=32Hz of Madisound Impedance using 2by4 inch vent.
Must be the T/S parameters.
Judging by the SS spec sheet, there is room for another 10Hz lower cut-off in a larger stand alone cabinet.
I'd leave the baffle 0.75" and add a brace or two.
Dont see bracing in that plan.
Most of the resonance issues are solved with bracing.
Baffle is on the small size, most the issues is larger side panels.
Stiffness is a different conversation if this was a huge enclosure for live sound drivers.
Even then more important, bracing would be a big part of that as well.
Either way one vertical brace I would see used for the large sides.
Very expensive wood goes so far, eventually they all need bracing.
Or fancy expensive wood has no benefit.
Birch is a generic word for many plywood so is oak.
Many times it is actually pine layers and the final layers is only Birch.
Aside from price making it obvious. even sanded pine with bracing has its place.
It will get pretty laminate regardless, bracing is the magic.
But " Baltic" can more imply less than origin or if all plys are actually birch regardless of origin.
And marine grade has no voids and uses waterproof glue.
So often your buying dirt garbage pine with knots and the final layers are really really pretty.
So is the price. lol
Many plys will still de laminate waterproof glue is not usually used.
Most the issue with MDF is the dust, mask is mandatory.
It is actually easier to machine and wont chip out like ply.
Depends what your doing, very large enclosures I am set on ply.
Small boxes and bracing MDF is actually easy depending on finish.
If painted.
Most of the resonance issues are solved with bracing.
Baffle is on the small size, most the issues is larger side panels.
Stiffness is a different conversation if this was a huge enclosure for live sound drivers.
Even then more important, bracing would be a big part of that as well.
Either way one vertical brace I would see used for the large sides.
Very expensive wood goes so far, eventually they all need bracing.
Or fancy expensive wood has no benefit.
Birch is a generic word for many plywood so is oak.
Many times it is actually pine layers and the final layers is only Birch.
Aside from price making it obvious. even sanded pine with bracing has its place.
It will get pretty laminate regardless, bracing is the magic.
But " Baltic" can more imply less than origin or if all plys are actually birch regardless of origin.
And marine grade has no voids and uses waterproof glue.
So often your buying dirt garbage pine with knots and the final layers are really really pretty.
So is the price. lol
Many plys will still de laminate waterproof glue is not usually used.
Most the issue with MDF is the dust, mask is mandatory.
It is actually easier to machine and wont chip out like ply.
Depends what your doing, very large enclosures I am set on ply.
Small boxes and bracing MDF is actually easy depending on finish.
If painted.
I never tried, to do this kind of sandwich but always wanted to ...
Plain ceramic tiles have almost the same property of aluminum (that is for example used in Magico).
The difference is mainly ductility : you can bend the aluminum but ceramic broke.
It is very chip and you can find it for 10/15eu per square meter. Leftovers are also easy to find.
It's difficult to make a nice cabinet, but making a 10mm MDF enclosure with 8mm Ceramic tiles glued inside would do a really solid and and resonant free enclosure...
Plain ceramic tiles have almost the same property of aluminum (that is for example used in Magico).
The difference is mainly ductility : you can bend the aluminum but ceramic broke.
It is very chip and you can find it for 10/15eu per square meter. Leftovers are also easy to find.
It's difficult to make a nice cabinet, but making a 10mm MDF enclosure with 8mm Ceramic tiles glued inside would do a really solid and and resonant free enclosure...
15mm quality plywood woukd do, 18mm should handily out do 1” MDF.
IMO, MDF ia only good for speaker building if it is all you can get.
If you want more overkill, stranded/fossilized bamboo plywood.
Where is the bracing in that box?
dave
IMO, MDF ia only good for speaker building if it is all you can get.
If you want more overkill, stranded/fossilized bamboo plywood.
Where is the bracing in that box?
dave
Dave, based on the plan, there is no bracing 🙂 It would probably solve this issue, but since this is a first kit for me, I was not sure.
I'm not committed to this plan, so maybe there are some other kits I could build instead.
I'm not committed to this plan, so maybe there are some other kits I could build instead.
Look on the internet for MDF cut to size. You’ll be able to get it in any thickness. You’ll also have a wider choice of materials than buying locally. It’s not a problem, I buy many types of mdf’s in various thicknesses all the time. Just to complicate matters, they all sound different, the better types sounding better than birch ply in my experience.
It needs at least one brace, vertical, from baffle to back (and top/bottom). Use it to brace the driver against the back.Make the brace about a third holes, add 2/3rds the panel material to the width.
dave
dave
I am inspired to focus on bracing.... a properly braced box can be made out of a plethora of materials, in just about any thickness.
