[fishboat]

I've been considering building a pair of Super V's.  I'm a woodworker and very familiar with MDF.  LOTS of dust, but smooth, flat, & dense.

According to wiki..MDF density ranges from 30-60 lbs/cu ft.  Many hardwoods (quarter-sawn white oak, qs red oak, hard maple...etc) run around 45-47 lbs/cuft.

Are there specific reasons why MDF would be better than a good, dense, hardwood?  Gluing up wide panels from hardwood would be no problem for me...and finishing..well..I like a clear wood finish rather than paint (honestly, paint is a lot more work).

Thanks,
Kevin 

[Danny Richie]

I've been considering building a pair of Super V's.  I'm a woodworker and very familiar with MDF.  LOTS of dust, but smooth, flat, & dense.

According to wiki..MDF density ranges from 30-60 lbs/cu ft.  Many hardwoods (quarter-sawn white oak, qs red oak, hard maple...etc) run around 45-47 lbs/cuft.

Are there specific reasons why MDF would be better than a good, dense, hardwood?  Gluing up wide panels from hardwood would be no problem for me...and finishing..well..I like a clear wood finish rather than paint (honestly, paint is a lot more work).

Thanks,
Kevin

Welcome to AC.

The reason MDF is preferred is that it is less resonant. Hard woods tend to resonant considerably more in some cases. Hard wood can also change its shape with changes in heat and humidity.

[fishboat]

Thanks Danny..

Forgive me as I may not be as well schooled as some here and I'm sure you're busy..so don't waste a lot of time on this...

I'm a chemist/numbers analyst & woodworker...but my physics training was a long time ago.  Is resonance a function of material density? or stiffness?..both?  Anyone have a laymen's equation for material resonance?

I know some use baltic birch ply for enclosures..it's stiff (though hardwoods are too), but the density has to be fairly low as it's made of softwoods (fir, pine, aspen..). 

Can the resonance be damped by into acceptablilty additional bracing?  Would very dense tropical hardwoods be acceptable?  Or is MDF + veneer (if I wanted wood grain) the only reasonable path?  I assume(?) an 1/8th to 5/32nds veneer is OK?   I cut my own and a little thicker is easier to cut & handle.  The rounded edges would have to be painted or trimmed out in wood edging(not easy on the curves..actually it could be pretty tough).

[Peter J]

Thanks Danny..

Forgive me as I may not be as well schooled as some here and I'm sure you're busy..so don't waste a lot of time on this...

I'm a chemist/numbers analyst & woodworker...but my physics training was a long time ago.  Is resonance a function of material density? or stiffness?..both?  Anyone have a laymen's equation for material resonance?

I know some use baltic birch ply for enclosures..it's stiff (though hardwoods are too), but the density has to be fairly low as it's made of softwoods (fir, pine, aspen..). 

Can the resonance be damped by into acceptablilty additional bracing?  Would very dense tropical hardwoods be acceptable?  Or is MDF + veneer (if I wanted wood grain) the only reasonable path?  I assume(?) an 1/8th to 5/32nds veneer is OK?   I cut my own and a little thicker is easier to cut & handle.  The rounded edges would have to be painted or trimmed out in wood edging(not easy on the curves..actually it could be pretty tough).

Just a small correction here, fishboat. Baltic Birch is birch plys through and through...all hardwood. Guess there's no other types of trees in Baltica 

[fishboat]

Forgive me..you're right...I'm thinking of birch veneer ply.  For the most part I don't use plywood in the woodworking I do.  It looks like european birch (similar to baltic I'd guess) has a density of 42lbs/cuft...about the same as oak(45). 

[nickd]

My super V's are built from 15 ply Baltic birch. They sound amazing and look beautiful. I'm not sure about the differences between MDF and hardwood as far as resonance is concerned. If you cut and turn the boards so the grain pull is cancelled, hardwood is seriously strong. All woods have a different sound / resonance (MDF included) I have even used solid white oak with good results ( :roll:it was trendy 30 years ago).

I don't think you'll regret using ply or a nice hardwood. Just plan on lining the H frame with No Rez (see Danny's web site for No Rez info). I even covered the bottom of the base and inside the crossover box with asphalt sound dampening sheets (sold at automotive body shop supply).

The beauty of MDF is the "flat pack". They were not available for my build. Makes the project go much faster for those of us who procrastinate.
 

[tg3]

Are Super-V flat packs still available? I thought they were sold out.

[Danny Richie]

Are Super-V flat packs still available? I thought they were sold out.

They gone.

[JoshK]

I recommend Baltic Birch (skip the crap at the orange box and get the real thing, you may have to look up a local lumber yard) as it is non-resonate (maybe not as dead as MDF, but that is both a plus and a minus in this case) and it isn't terrible to work with, and it doesn't warp with age like real wood. 

After working with BB and MDF, I am less prone to work with MDF, although I haven't built an entire enclosure of BB yet, only hybrids.   MDF is terrible terrible stuff to work with (for your health if you aren't careful).

[JerryLove]

MDF has the advantage of consistancy. Real wood can have pockets and voids and areas of higher and lower density. MDF (like most engineered woods) is also easier to find flat.

But one can certainly build out of hardwood, or most anything else.

[fishboat]

I agree MDF is less than pleasant  to work with.  I have adequate dust control in my shop and wear a respirator when milling any amount of MDF.  It is nice stuff, from a technical standpoint, but I like solid hardwoods a lot more. 

In general, sonic-resonance issues aside, wood movement in building furniture, cabinets, enclosures, I'm completing a dining table at the moment, can be easily controlled with good technique and starting with good quality, correct moisture content, lumber.

Anyone know where I can find some resources (that a laymen can understand) on wood enclosures & resonance.   Woods like Ipe, Jatoba(Brazilian cherry), bloodwood, bubinga, padauk...are like bricks when you pick up a piece...heavier than MDF.  I need to do some more digging...

[JoshK]

I have adequate dust control in my shop and wear a respirator when milling any amount of MDF.

So did I...but I had a less than ideal space....basement also use as laundry room.   Even with dust collection system, oshas facemask and overhead dust filtration system, I found a lot of fine dust on things the next day and hours later trips made me cough and sometime I'd just have bad days the next day anyway. 

Maybe I am sensitive...don't know, but I won't work with that stuff unless outside.

Beautiful wood is great....maybe talk to guys who have used it a lot.... I know Dale Ellis did... I am pretty sure Jim Salk does.   They might give you tips, even though they are the competition.   Dave and the rest are all good guys. 

[fishboat]

Fortunately my shop is in a building out back.  MDF dust is superfine and does go everywhere.  When I use it I run two dust collection systems and then once the dust settles..vacuum things up, start the dust collection again and pull out the compressed air.  Great stuff, flat, stable..but a PITA too.   That being said..I'll use it if I have to.

I was just searching tropical hardwood decking (plentiful..available..not too expensive..) the prices are not bad  for some really beautiful woods.

http://www.abswood.com/pages/deck-compare.htm

Looks like its available in 3/4, 4/4, 5/4, 6/4 thicknesses..hmmm 

[fishboat]

After studying the cabinet diagram and a few more pics..I see no reason to make the entire cabinet out of solid wood.  The internals (everything except the side "wing" panels and bow tie) would be fine in MDF and painted black.  The wings and bow tie could then be made from some interesting, super dense, tropical hardwood.  Depending on the thickness of the wings it looks like less than 40-50 board feet(4 wings).     

Any idea whether this path would address both resonance concerns and my desire(preference) to build with wood?  From an "ignorance is bliss" standpoint (that being me) it seems like a reasonable compromise.

[Danny Richie]

Building a speaker like the Super-V out of hardwoods would considerably alter the sound. This is especially true for the side panels. In all the builds of mine I used 1.25" MDF and still needed to line them with No Rez to further damp them.

You want the speaker to accurately reproduce the input signal. Building it out of hardwoods would shift it from music reproduction to production as it would in itself become its own instrument.

And MDF is not only the most ideal material, but it is about the least expensive and easiest to work with material out there.

[fishboat]

Thanks Danny..sounds like case closed.  I just needed a logical endpoint.  If you designed them around MDF then wandering into alternate materials leaves the design..which doesn't sound like a great idea.  Works for me.

If you'll bear with me for one more question..lets say I build completely out of MDF and add a 1/8 inch (or less) hardwood veneer to the outside of the side panels...will I impact the intent of what you've designed in a significant way?  If so, then MDF and paint seems to be the only-best option.

I've been researching materials used in cabinet construction...I guess it's really no surprise..it appears to be one of those topics of endless debate with followers & detractors on all sides.  I'm new here & it isn't my intent to stir up any dust..I'm just trying to understand the limits/options I have if I go forward with a build.

Thanks for your patience.
Kevin

[tasar]

Fishboat, I share most of your background. I too contemplated wood taking the middle road. There are products to satisfy the "wood" in you and provide stabilty. Franks Lumber Supply has arguably the largest selection of rare veneer grade, hi end cabinet and "apple ply" (heavy multi coursed hybrid) sheets. I sourced Rift sawn white oak, real eye candy, even for those "piano black" and GM paint pallet typos ! Glued up 90 degrees at 1 1/2" with similar top baffle and floor thickened to 2 1/4", my Vs don't sound like cellos, but they sure make cellos sound good ! I installed no Rez hesitantly, but aside from tad smoother LF, the sonics were unchanged. Bottom line, if you enjoy "healthy wood", this is a positive bent on the Hardwood/MDF camps. All said, I personally would spend much more time thinking out room resonances. Treatment variants make speaker builds look like "Childs play". Boundary layer, absorption/diffusion, Hemholtz, CBA, MLV, VPR, oh my ! These open baffles might not "load the room", but as velocity type sources, they still need a "good whipping" !!

[Danny Richie]

If you'll bear with me for one more question..lets say I build completely out of MDF and add a 1/8 inch (or less) hardwood veneer to the outside of the side panels...will I impact the intent of what you've designed in a significant way?

Actually using layers of MDF with other types of wood like Birch Ply or even some hardwoods works out pretty well.

[Danny Richie]

My favorite is layers separated by a sand filled space. If you use a layer of MDF and sand then your outer wall can be just about anything.

Check these out: http://www.audiocircle.com/index.php?topic=111180

http://www.audiocircle.com/index.php?topic=53675

[fishboat]

I saw PDR's 'sand trap' approach, but not the sub box...interesting builds. 

tasar..I've heard of Frank's, but I'm cutting my own veneer these days.  Rift-sawn oak does look nice with the right finish.  Most of the items (bath cabs, mantle, mirror frames, end table....) I've built for my home are quarter-sawn white oak.  I have a mission-type finish down pat..the flames in the wood tend to glow... Rift and qs also have less issue with seasonal movement, compared to flat-sawn (I not to thrilled with the look of flat-sawn oak..).



It's been a couple years since I dug into audio stuff...I've been happy with the system I've built and just listening/collecting music.  I have waay too many hobbies and there's only so many hours in a day...and then there's the full time+ job..minor detail.  But...lately I've been think about changing things up a bit..so here I am.  I have researched room treatments a fair amount in the past..it is a dizzying topic..another one of endless debate.  My system is located on a 12' x 16' loft over a great room.  Behind my head & 12 foot off the wall behind the speakers (speakers on the long wall, Snell Type AIII's) is the open space of the great room with the ceiling dropping off in a vault.   I think this addresses the reflections behind my head.  I have absorbers at the first reflection points, carpeted floor, speakers sit on 2x3 foot x 1.5 inch slate plinths, and I built 5 foot high 'superchunk' bass traps using 6# rockwool..one in each corner behind each speaker. 

No clue what the V's might require..I'm new the them...still trying to figure out which way is north...

I do have an unused 60W integrated tube amp that's looking for something to do...V's may be one answer..