stiffness...
I feel that horns need the extra stiffness of the ply.
the grain of real wood tends to be stiffer than particle board. add the crossgraining of a ply action, you have a substance of lower internal loss/higher relfection than MDF. the MDF "sings" MORE of its own sound than the ply, the ply lets you hear more of the initial energy of the driver.
the specific gravities of the woods are similar. that is BB to MDF. of around .6 while mdf has the "ideal" specific gravity for BLH construction, it just does not do the trick.
i am not a formal scientist about this stuff, but have tried both substances myself in identical horn enclosures. I use strictly birch ply with dense solids as driver mounts, but other woods work well.
lots of people tend to refer to MDF as emduuuf. it just kinda sounds like that too. BLH or bus reflex builds. duuuff dufffff duf duf duf duuuuuf duuuuf. I am hearing the basslines echo in my head from many a monkey coffin speaker. the bass is plump, and truely fat. and not with a PH. just an ufffey resonatey sound hanging over your entire consciousness while listening to the speaker. like the first few milliseconds of a cow getting hit by a car travelling 60 MPH. but less organic sounding.
note that not all studio monitors are made of MDF either. the world is filled with choices. I have seen people on this forum for years... I made my blh enclosures out of MDF... what is wrong with the drivers? I have all this damping in the horns... etc. etc. months later, they give up the progect or simply rebuild the enclosures out of suitable wood after being made aware of their mistakes by people on this forum.
I am not one to shut down the notion of science. we must always be experimenting, and there ARE applications of horns where MDF is called upon. it is just usually a good idea to start with plywood and go from there.
lighter specific gravity plywoods, like the poplar cores found in the us give a nice tonal sound. lots of flourishing. a nice effect. think of birch as more of a studio sound in the plywood arena.
Clark
blumenstein-ultra-fi.com
I feel that horns need the extra stiffness of the ply.
the grain of real wood tends to be stiffer than particle board. add the crossgraining of a ply action, you have a substance of lower internal loss/higher relfection than MDF. the MDF "sings" MORE of its own sound than the ply, the ply lets you hear more of the initial energy of the driver.
the specific gravities of the woods are similar. that is BB to MDF. of around .6 while mdf has the "ideal" specific gravity for BLH construction, it just does not do the trick.
i am not a formal scientist about this stuff, but have tried both substances myself in identical horn enclosures. I use strictly birch ply with dense solids as driver mounts, but other woods work well.
lots of people tend to refer to MDF as emduuuf. it just kinda sounds like that too. BLH or bus reflex builds. duuuff dufffff duf duf duf duuuuuf duuuuf. I am hearing the basslines echo in my head from many a monkey coffin speaker. the bass is plump, and truely fat. and not with a PH. just an ufffey resonatey sound hanging over your entire consciousness while listening to the speaker. like the first few milliseconds of a cow getting hit by a car travelling 60 MPH. but less organic sounding.
note that not all studio monitors are made of MDF either. the world is filled with choices. I have seen people on this forum for years... I made my blh enclosures out of MDF... what is wrong with the drivers? I have all this damping in the horns... etc. etc. months later, they give up the progect or simply rebuild the enclosures out of suitable wood after being made aware of their mistakes by people on this forum.
I am not one to shut down the notion of science. we must always be experimenting, and there ARE applications of horns where MDF is called upon. it is just usually a good idea to start with plywood and go from there.
lighter specific gravity plywoods, like the poplar cores found in the us give a nice tonal sound. lots of flourishing. a nice effect. think of birch as more of a studio sound in the plywood arena.
Clark
blumenstein-ultra-fi.com
Most commercial cabinets use it because it is cheap (to buy, to use, to finish), Manufacturers have propagated the MDF myth so far & wide, most of them believe it themselves.
Properly done, a plywood cabinet will be less "resonate" than MDF, and doesn't suffer the energy storage of MDF.
dave
Properly done, a plywood cabinet will be less "resonate" than MDF, and doesn't suffer the energy storage of MDF.
dave
Attachments
Thank you very much. I'll stick to birch ply.
Do you think thickness matters much? I'm going to use 1/2" for the internal walls and 3/4" for the top and bottom. Just not sure if I need 3/4" for the side walls.
BTW, I'm following the Z-horn Heruka plans on
http://www.audio-resolution.com/zhorn/herukaplans.html
I don't see a specified dimension for the side walls.
I appreciate all the help here
Do you think thickness matters much? I'm going to use 1/2" for the internal walls and 3/4" for the top and bottom. Just not sure if I need 3/4" for the side walls.
BTW, I'm following the Z-horn Heruka plans on
http://www.audio-resolution.com/zhorn/herukaplans.html
I don't see a specified dimension for the side walls.
I appreciate all the help here
Ply the music out..
I'm sorry I just don't subscribe to this "Ply is superior" notion.
Probably the reason why "factory" speakers are so lame is not that they use MDF, but they use MDF poorly, that is the construction techniques they use are haphazard at best.
I had a firsthand look at factory MDF construction when my prized "Real veneer" RS speakers toppled off the roof of my '70' Mustang........as the speakers hit the ground on the corner of the enclosure & broke apart into its component pieces, I got an eyefull of how NOT to build an enclosure.
The first and most important is panel thickness.........Use one inch......rarely less. Generously reinforce the inside (Whos' gonna see?)
Don't even get into radiasing(sp?) an edge of plywood.........all the voids in plywood make that nearly impossible.
Yes of course you can get the top grade plywood without voids...but it'll cost ya an arm and a leg!
What was once budgeted at $150 for wood, now has just tripled.
Just knock your enclosure with your knuckles.....Got a mic and a scope..what frequency was that?
If it is a high enough frequency then your drivers cannot excite the enclosure and then all of this discussion is moot.
_________________________________________Rick............
I'm sorry I just don't subscribe to this "Ply is superior" notion.
Probably the reason why "factory" speakers are so lame is not that they use MDF, but they use MDF poorly, that is the construction techniques they use are haphazard at best.
I had a firsthand look at factory MDF construction when my prized "Real veneer" RS speakers toppled off the roof of my '70' Mustang........as the speakers hit the ground on the corner of the enclosure & broke apart into its component pieces, I got an eyefull of how NOT to build an enclosure.
The first and most important is panel thickness.........Use one inch......rarely less. Generously reinforce the inside (Whos' gonna see?)
Don't even get into radiasing(sp?) an edge of plywood.........all the voids in plywood make that nearly impossible.
Yes of course you can get the top grade plywood without voids...but it'll cost ya an arm and a leg!
What was once budgeted at $150 for wood, now has just tripled.
Just knock your enclosure with your knuckles.....Got a mic and a scope..what frequency was that?
If it is a high enough frequency then your drivers cannot excite the enclosure and then all of this discussion is moot.
_________________________________________Rick............
'cause it sucks....
any number of reasons not to use MDF:
MDF can be used if finished on both sides (ie: painted) to help the breathing problem.
I think my second item in the list is enough reason to not use it.
I don't know of any musical instruments made with MDF. To me , that's a test of a suitable material. BB is easy to machine, looks good, is not a carcinogen (that I know of), and can have as "live" or "dead" sound one may want, based on panel construction techniques. It's also relatively inexpensive in Canada and much of the US.
hmmm, wonder why JBL(Pro) has almost always specified Baltic Birch ply as THE material when constructing JBL "approved" pro enclosures?
Every material has a sonic signature of some sort. I just find MDF's signature to take too much way from the music.
gnugear, look here
within the text is mention of the dimensions, which are 8.5 x 14 x 36 inches. Hope that helps.
any number of reasons not to use MDF:
- it has a "dead sound
- it's made using formaldehyde, a known carcinogen
- it breathes
MDF can be used if finished on both sides (ie: painted) to help the breathing problem.
I think my second item in the list is enough reason to not use it.
I don't know of any musical instruments made with MDF. To me , that's a test of a suitable material. BB is easy to machine, looks good, is not a carcinogen (that I know of), and can have as "live" or "dead" sound one may want, based on panel construction techniques. It's also relatively inexpensive in Canada and much of the US.
hmmm, wonder why JBL(Pro) has almost always specified Baltic Birch ply as THE material when constructing JBL "approved" pro enclosures?
Every material has a sonic signature of some sort. I just find MDF's signature to take too much way from the music.
gnugear, look here
within the text is mention of the dimensions, which are 8.5 x 14 x 36 inches. Hope that helps.
Re: Ply the music out..
You do need to use void-free plywood. That is all i ever reference (one should keep in mind too that MDF is all over the map, if you have to use it, then use the stuff better classed as HDF)
I'm guess i'm lucky here... The cost of good ply over MDF is negligable (even thou for small cabinets MDF is free) And given the labour involved the cost of the box material is actually small.
dave
Richard Ellis said:
You do need to use void-free plywood. That is all i ever reference (one should keep in mind too that MDF is all over the map, if you have to use it, then use the stuff better classed as HDF)
I'm guess i'm lucky here... The cost of good ply over MDF is negligable (even thou for small cabinets MDF is free) And given the labour involved the cost of the box material is actually small.
dave
hair splitting....
not really.
MDF cabinets often have a dull "thud" when slapped with the hand. The frequency is low, the amplitude is usually quite high. Baltic Birch is usually higher in pitch, but the amplitude is low.
recall that the speed of sound in solids is greater than that in air, and faster in dense materials than in less dense materials. It becomes a matter of energy storage, and the amplitudes of the energy release from these materials. Try it for yourself.
the higher pitch from Baltic Birch ply is a result of greater density. faster wave propagation and faster energy release than MDF.
As far as MDF breathing, it has been well documented. Even serious car audio guys know that if they want to get the most bass out of an MDF enclosure, it needs to be painted on the exterior and interior of the enclosure., whilst BB doesn't as it is void free and glued (layered).
But for the DIY community (where few if any use proper filtering masks etc), the health concerns of exposure to formaldehyde is greater. This in itself should make the case for DIYers to use almost anything else other than MDF
not really.
MDF cabinets often have a dull "thud" when slapped with the hand. The frequency is low, the amplitude is usually quite high. Baltic Birch is usually higher in pitch, but the amplitude is low.
recall that the speed of sound in solids is greater than that in air, and faster in dense materials than in less dense materials. It becomes a matter of energy storage, and the amplitudes of the energy release from these materials. Try it for yourself.
the higher pitch from Baltic Birch ply is a result of greater density. faster wave propagation and faster energy release than MDF.
As far as MDF breathing, it has been well documented. Even serious car audio guys know that if they want to get the most bass out of an MDF enclosure, it needs to be painted on the exterior and interior of the enclosure., whilst BB doesn't as it is void free and glued (layered).
But for the DIY community (where few if any use proper filtering masks etc), the health concerns of exposure to formaldehyde is greater. This in itself should make the case for DIYers to use almost anything else other than MDF
Re: 'cause it sucks....
Agreed re the finishing of the MDF, but then, this should be the case for all woods. If it ain't finished (sealed) then it'll absorb moisture from the air when it's humid and release when it's not. Not a good thing to have your wooden structure changing shape I guess that's what you mean by 'breathing').
Agree re the musical instrument theory. If it's used for making musical instruments then it will definitely impart sonic signature to the music from the speaker. AFAIK Birch ply and MDF are not used in the making of musical instruments and should be able to be used for speakers. Ditto Corian, concrete, granite, etc. Most single woods are out. All woods, and all wood'n'glues (which includes HDF, MDF, chipboard and all plies) will sing at some frequency - and you can reduce it by correct bracing, making it thicker, damping, or just finding a pleasant 'sing-along' frequency (think of those 'doof-doof' cars we sing along with every Friday and Saturday night
).
Nanook said:
Agreed re the finishing of the MDF, but then, this should be the case for all woods. If it ain't finished (sealed) then it'll absorb moisture from the air when it's humid and release when it's not. Not a good thing to have your wooden structure changing shape I guess that's what you mean by 'breathing').
Agree re the musical instrument theory. If it's used for making musical instruments then it will definitely impart sonic signature to the music from the speaker. AFAIK Birch ply and MDF are not used in the making of musical instruments and should be able to be used for speakers. Ditto Corian, concrete, granite, etc. Most single woods are out. All woods, and all wood'n'glues (which includes HDF, MDF, chipboard and all plies) will sing at some frequency - and you can reduce it by correct bracing, making it thicker, damping, or just finding a pleasant 'sing-along' frequency (think of those 'doof-doof' cars we sing along with every Friday and Saturday night
).by the way...
even though BB does not have any formaldahyde, I would still use a good mask, like the AOS safety #95
http://www.amazon.com/AO-Safety-Woodworkers-Respirator-95190/dp/B0000BYE9Q
cancer is real. critical levels of exposure happen quicker than you think.
i do not use MDF as well, because of the formaldyhyde (environmental sustainability, personal health safety) for a good plywood, and keeping in mind that nothing is perfect, BB is pretty decent, as far as forest sustainability goes.
also, from the standpoint of durability, BB ply is far superior. it is WAY more damp proof and ding proof. there is a reason that most self respecting PAs are BB.
again though, I think that everything is application specific. MDF has its place in audio, though admittably that place is probably a little larger than it ought to be.
yet another reason I love BB is that you can actually sand the stuff. the veneer is not hair thin like american finish grade plywood 4 by 8s.
even the lower grade birch plys (non marine grade) are decent sounding. the voids are usually minimal.
and yet another reason is that is is so sublime to build in metric. things just work out better. don't do the inches conversion, and the stanley 5m/16ft measuring tape is decently inaccurate. use an engineering ruler or better.
I actually like the look of the finished edge of the plywood too. it is one of the few plys you can do that with. though alot of the old fogeys would disagree with me.
what sucks about it? 5 by 5s are hard to tote around. truck beds don't fit them and they require a decent arm span to carry and not much equipment in america is sized to cut it. while cutting, it is easy to splinter off the bottom edge, and hard to fix it. proper saw blades/saw height is important, as well as feed rate. not too fast, not too slow...
the sound of BB is great and all, but, sometimes a lighter, heartier sound is nice. that is why I mention the poplar core plys. the blur the edges a little. a nice effect if you want it there. (which I usually don't). If I want a resonance somewhere, I vary the thickness of the panel to accomidate.
nothing has a set recipe. you have to know your ingredients and be willing to experiment. trial and error.
Clark
even though BB does not have any formaldahyde, I would still use a good mask, like the AOS safety #95
http://www.amazon.com/AO-Safety-Woodworkers-Respirator-95190/dp/B0000BYE9Q
cancer is real. critical levels of exposure happen quicker than you think.
i do not use MDF as well, because of the formaldyhyde (environmental sustainability, personal health safety) for a good plywood, and keeping in mind that nothing is perfect, BB is pretty decent, as far as forest sustainability goes.
also, from the standpoint of durability, BB ply is far superior. it is WAY more damp proof and ding proof. there is a reason that most self respecting PAs are BB.
again though, I think that everything is application specific. MDF has its place in audio, though admittably that place is probably a little larger than it ought to be.
yet another reason I love BB is that you can actually sand the stuff. the veneer is not hair thin like american finish grade plywood 4 by 8s.
even the lower grade birch plys (non marine grade) are decent sounding. the voids are usually minimal.
and yet another reason is that is is so sublime to build in metric. things just work out better. don't do the inches conversion, and the stanley 5m/16ft measuring tape is decently inaccurate. use an engineering ruler or better.
I actually like the look of the finished edge of the plywood too. it is one of the few plys you can do that with. though alot of the old fogeys would disagree with me.
what sucks about it? 5 by 5s are hard to tote around. truck beds don't fit them and they require a decent arm span to carry and not much equipment in america is sized to cut it. while cutting, it is easy to splinter off the bottom edge, and hard to fix it. proper saw blades/saw height is important, as well as feed rate. not too fast, not too slow...
the sound of BB is great and all, but, sometimes a lighter, heartier sound is nice. that is why I mention the poplar core plys. the blur the edges a little. a nice effect if you want it there. (which I usually don't). If I want a resonance somewhere, I vary the thickness of the panel to accomidate.
nothing has a set recipe. you have to know your ingredients and be willing to experiment. trial and error.
Clark
musicile
musical instruments are what we make. If you make a speaker, you make a musical instrument. to try to separate the two concepts is retarded. I don't care how much bracing you put in, the panels still resonate and the ear is more sensitive to this than anyone knows I think.
the important thing is to brace/damp to taste/whatever is appropriate for each design. there is a point at which a horn will just "click" when all the little components are doing the right things to tickle our BRAINS. this is what to strive for. stored energy or not. durable or not. music is fleeting. so is life. build with what you like, but be aware of the traits of each ingredient instead of stubornly self delusional - a force that perpetuates audio orthodoxy.
musical instruments are what we make. If you make a speaker, you make a musical instrument. to try to separate the two concepts is retarded. I don't care how much bracing you put in, the panels still resonate and the ear is more sensitive to this than anyone knows I think.
the important thing is to brace/damp to taste/whatever is appropriate for each design. there is a point at which a horn will just "click" when all the little components are doing the right things to tickle our BRAINS. this is what to strive for. stored energy or not. durable or not. music is fleeting. so is life. build with what you like, but be aware of the traits of each ingredient instead of stubornly self delusional - a force that perpetuates audio orthodoxy.
Ye gods..so technical.
I went over to my MDF towers & "knock three times" really is a high pitch........wish I could quantify the frequency.
So the theory is as a panel resonates it masks low level detail?
So as the panel is excited by the driver at the panels resonate frequency the panels "ringing" is of a relatively long time frame & that "ringing" masks other following musical passages within the "Ring" time?
If that is the case, we need to find materials which are outside the capacities of exitation, or those with short 'resonant' times.
__________________________________Rick.........
I went over to my MDF towers & "knock three times" really is a high pitch........wish I could quantify the frequency.
So the theory is as a panel resonates it masks low level detail?
So as the panel is excited by the driver at the panels resonate frequency the panels "ringing" is of a relatively long time frame & that "ringing" masks other following musical passages within the "Ring" time?
If that is the case, we need to find materials which are outside the capacities of exitation, or those with short 'resonant' times.
__________________________________Rick.........
Re: musicile
If I make a speaker to play my guiter through, I make a musical instrument. If I make a speaker to reproduce music through, I attempt not to make a musical instrument (ie, try not to add artifacts/distortions to the music I am reproducing). To do otherwise...
But you are welcome to your opinion. I just told you mine and did not expect you to question my intelligence. Apologies to others for being OT in this post...
blumenco said:
If I make a speaker to play my guiter through, I make a musical instrument. If I make a speaker to reproduce music through, I attempt not to make a musical instrument (ie, try not to add artifacts/distortions to the music I am reproducing). To do otherwise...
blumenco said:
But you are welcome to your opinion. I just told you mine and did not expect you to question my intelligence. Apologies to others for being OT in this post...
Re: Re: Re: Ply the music out..
That's the point!
I always did use MDF and I always will.
I'm absolutely shure, that most of the users in this forum couldn't say wich one is ply and wich one is MDF in a blind test.
Speakers are NO musical instruments! They should be able to reproduce all instruments, incl. the voice as good as possible.
The best thing an enclosure can do is to sound neutral.
Does the corpus of a cello sound neutral? Or how does a trumpet sound, when it's made of 18mm birch-ply?
It's like the CD-Vinyl-thing, the tube- or the cable-discussion.
Everybody prefers emotionally THE ONE AND ONLY thing and tries to put it into a scientific jacket...that's ok for me.
I read that stuff, lean back and have fun
Sorry for my lame english...
pinkmouse said:
That's the point!
I always did use MDF and I always will.
I'm absolutely shure, that most of the users in this forum couldn't say wich one is ply and wich one is MDF in a blind test.
Speakers are NO musical instruments! They should be able to reproduce all instruments, incl. the voice as good as possible.
The best thing an enclosure can do is to sound neutral.
Does the corpus of a cello sound neutral? Or how does a trumpet sound, when it's made of 18mm birch-ply?
It's like the CD-Vinyl-thing, the tube- or the cable-discussion.
Everybody prefers emotionally THE ONE AND ONLY thing and tries to put it into a scientific jacket...that's ok for me.
I read that stuff, lean back and have fun
Sorry for my lame english...
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