mdf

home depot has 3/4" mdf and hdf. would high density be sonically better? what would you say? they are both around the same price.  for a new sub box.

                                                                                                   thanks!

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High density particleboard weighs more and is denser.  Medium density fiberboard is considered sonically superior.  You can build enclosures as well as a lot of other things with HDP, but if given the choice of both for speaker enclosures, choose the MDF.

To put this in another perspective, look at fiberglass insulation.  What is the insulator, the fiberglass or the air between the fiberglass?  It is the air that insulates.  The fiberglass just creates air pockets.  Look at MDF with that same understanding....less dense fiberboard allows for the damping of sound waves because of the very nature of its lack of density.  There is more air within the board.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

?

More air *in* the board?



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"I'm finished!" - Daniel Plainview

You answer it then.

i did not know that. i though that useing hdp or hdf makes it more riged so it is able to absourb more vibrations. are you soure that is the case. i have heard that the more dense the bord the better. but wy would the air in the board make it more absourbent. but wouldent the air in the board make it more flexible so it would case the bord to need more bracing.

i used hdp or hdf (i dont now witch one) to build my box and it dose fine i still dont get why the mdf would be better. do you want the box to vibrate cuse i think it would. and i have used it on the back of one of my boxes and it vibrated alot so i had to put extra bracing on it. i really dont get wy it is better. i thought that it was better to have a more riged material. and mdf has a bad tendincy to chip and crack. so wy would you use a weaker material. if sombody could elaberate on this to help me and this guy thank you

Aaron  

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Yeah I thought the denser material would help produce that dramatic difference in pressures between the inside and outside of the box.

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Tell the Snap-On guy I'm not here!

You could use it if you were building an SPL vehicle, otherwise it's probably just more expensive, heavy, overkill.  Usually, mdf will do just fine.

Steve, I'd have to disagree with you, buddy.  You logic could lead others to believe that something less dense than mdf would be ideal.  Why don't we all just use the cardboard box our subs came in then, as the enclosure?  (Kidding, obviously.)  I'm assuming you meant that mdf is ideal for most situations.  If this is the case, then I agree on that point.

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My ex once told me I have a perfect face for radio.

what about the power handling of the sub. if you build a box out of something that isent strong enough it will gust fall apart or crack. and what happens if you have a really big sub it will viberate the box to much if you make it out of something like mdf. so you have to use something more stronger and denser. i think that if you are runing a powerful sub you need a more sturdy material. but other then that you can gust use mdf. i still dont get wy you think it is better im about to do a seach and find out for my self but intell then i still would like to now from sombody of hear.

Aaron 

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youngone-thats why you use bracing and corner bracing.

stevdart-thank you i understand. mdf absorbs. unlike hdf which is "packed" tighter and reflects more.

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I've built boxes out of hdf. They sound great... They kill your gas milage.

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Tell the Snap-On guy I'm not here!

stevdart wrote:

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You answer it then.

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I think I need to you guys are in lala land.

Okay rather than address ALL the retarded statements in this thread one by one, I'll just tackle the original question head on.

MATTERS:
Rigidity
Air-permeability

DOES NOT MATTER:
Thickness
Porousness (....air in wood stevdart?)
Density

MDF is VERY strong. It isn't weak beacause it 'chips and cracks' whoever said that I'll spare you quotes... this demonstrates a fundemental lack of understanding of architecture and materials...

Take concrete for instance... VERY HIGH compression strength... Not so much TENSILE strength... which is why you can drop a concrete slab two feet and shatter it.... same with MDF... But try and compress concrete eh? Ya think standing on it will produce the same result?

This characteristic is why we line our roadways and buildings with steel cables... they provide that tensile strength. On the other hand, in car, we don't need that sort of strength. Your box should be bolted to your car nessecitating it only to withstand the *compression* waves from the speaker itself... which.. in all blindness to the design on the speaker box, are, obviously, uniform in dispersion into the enclsoure proper.

So with MDF... its rigidity.. particularly in subwoofer-box sized applications... makes it ideal for a speaker application... HDF will simply serve you more of the same.

In this case however, more isn't going to be any better, its just more. You will simply be adding another 1/3 or so to the weight of your box which is already quite hefty.. and then sticking it in your car. The idea that it is "better" here is akin to using 8-gauge speaker wire .... it doesn't functionally do anything 12-gauge doesn't, but theoretically in the numbers somewhere there's a gain. In this case it would probably be measured in microns. It would take a laser to measure the improvement.

It's the whole 'density' thing. We all use dense materials when making a sub-box, but not because they are dense, but because dense materials are inherently *rigid* ... the ultimate goal isn't to "absorb" or "reflect" or "suspend" or whatever the ultimate goal is to have no flexing of the enclosure while the speaker plays ensuring linaerity of cone movement....

In fact, I go a different route than most people.... I kinda dread those 75lb workout boxes that 3/4 MDF tends to produce so I use 1/2MDF and go hefty with fiberglass resin on the inside. The boxes are *much* lighter and at least *I* can't hear a different between those and much, much heftier 3/4" variants.

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"I'm finished!" - Daniel Plainview

Sedate, just a slight correction- you stated that thickness doesn't matter.  That's way too broad of a statement.  Yes, many of us have built boxes out of 1/2 inch as well.  But who hasn't seen a box that was ruined by using a material that's too weak, or thin?  I understand there are different ways to the same mean, but what you said could be interpreted that using a single layer of 1/4 inch would be okay to build a ported box for a couple 13w7's run by a 1000/1 a piece.  I'm sure that's not what you meant, but you shouldn't make such bold generalizations.

You're right that the goal is to minimize flexing.

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My ex once told me I have a perfect face for radio.

ok thank for your input sedate that was very helpful. but you could of speired to remark about what i said. im only trying to give an opinion, and i asked for help from somebody. did i say i was right noooo. i have work and do work with mdf and it dos chip and crack it chips when you cut it and it cracks and little cunks come off if you bump into stuff or if you acsidently scrape it on something. and im kind of pisset off that you called the statments people make retarded we are haveing a intelectuale argument we arent trying to put people down like somebody. and you also tryed put down stev. i realy dont like people that are smart but cant be polite and correct people in the right way. and i respeckd stevdart for his input and take it into acount and dayhon to they both now what they are talking about. and i know that mdf is strong. and i do know what im talking about in most cases and one of these days will correct you.

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geepherder wrote:

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Sedate, just a slight correction- you stated that thickness doesn't matter.  That's way too broad of a statement.  Yes, many of us have built boxes out of 1/2 inch as well.  But who hasn't seen a box that was ruined by using a material that's too weak, or thin?  I understand there are different ways to the same mean, but what you said could be interpreted that using a single layer of 1/4 inch would be okay to build a ported box for a couple 13w7's run by a 1000/1 a piece.  I'm sure that's not what you meant, but you shouldn't make such bold generalizations.

You're right that the goal is to minimize flexing.

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Exactly what I was thinking.

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Tell the Snap-On guy I'm not here!

see they were polite in corecting you thanks guys

Aaron

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sedate wrote:

[ I think I need to you guys are in lala land.

Okay rather than address ALL the retarded statements in this thread one by one.]

yes i am one of those retards in lala land!    ever been there?

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I sniff resin

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Tell the Snap-On guy I'm not here!

hahaha 5150azn. oooooooooyyyyyyyaaaaaaa

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I have to side with sedate. Thickness DOES NOT MATTER. You can build an enclosure with 1/4 inch material, but what kind of material are we referring to? He never said you could use 1/4 inch MDF, and get acceptable sonic characteristics, did he? Truly, the thickness does not matter, the MATERIAL matters. An infinitely rigid material could be infinitely thin, and still be perfect for an enclosure, right? (I'll save some of you the thought process.) Yes. And what is determined by the material? (let's see who's paying attention) That's right, class - rigidity and porosity. I have built enclosures with welded 1/4 inch aluminum plate, that rang like a bell at higher frequencies, but it WAS rigid at the frequencies a subwoofer would subject it to. To avoid or completely negate the ringing, a judiciously applied layer of Dynamat Extreme worked wonders.

This is the rigidity reference, people. Had I welded bracing onto that enclosure, I could have further improved the performance... If I had used steel, couldn't I have used thinner material stiil? Due to the RIGIDITY of steel vs. aluminum, I probably could have.

The gains in performance between MDF and HDP, are minimal, FAR beyond any point of diminishing returns. The only thing you will gain in a small enclosure (the kind specific to the autosound industry) will be weight and cost. MDF is a perfectly useable building matereial for <2 cu. ft. enclosures... hell, for that matter, 8 cubic foot enclosures. As your enclosures get larger, (and I mean LARGER) your point of diminishing returns gets closer to the trade-off between weight/cost and performance when you use HDP. There are advantages to using it in GIANT enclosures, although I do not believe for one second that the MATERIAL makes the acoustic difference, in and of itself. The difference comes from the rigidity and porosity of the enclosure, where the HDP can and will perform better in large pieces. The difference CAN be made up for using more bracing in a MDF enclosure, BTW...

Again, Dave can't keep his nose out of it, and there's my two cents. Take them for what they are worth.

(BTW, sedate, I have built enclosures from concrete as well... I don't recommend it.)

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Dave, you missed the point.  The point was that his statement was too broad, and it could lead someone to believe that you could use 1/4 inch mdf.  I understand that rigidity is key, that was actually part of my post.  In my original post I basically said that hdf would mainly be used in spl applications.

Apparently, Tom can't keep his nose out either.

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My ex once told me I have a perfect face for radio.

haemphyst i had heared that you could use metal. but i dident no it would work right. or that it would be good and solid. buy the way good post. at that note im going to do a searce.

Aaron


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Want to know some good equipment- JL,Adire Audio,Mcintosh,Brax,Helix,Eclipse,JBL,RE,Dimoand Audio,Zapco, pritty much anything DYhon,Forbidden recommend
On the12volt you give some info and you get in

geepherder wrote:

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Sedate, just a slight correction- you stated that thickness doesn't matter. That's way too broad of a statement. Yes, many of us have built boxes out of 1/2 inch as well. But who hasn't seen a box that was ruined by using a material that's too weak, or thin?

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Geepherder, just a slight correction- I was completely correct in this assertion. Your extrapolations from my statements do not make them mine. I correctly asserted that RIGIDITY matters, not thickness... you need to think more abstractly. The ONLY materials available that would be rigid enough to withstand the compression waves of a sub must be inherently thick.. this does NOT mean that they're for the proper functioning of a sub, simply that they are.

geepherder wrote:

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Dave, you missed the point. The point was that his statement was too broad, and it could lead someone to believe that you could use 1/4 inch mdf.

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Maybe if this someone was the same sort who needs the "Not for use in Bathtubs" sticker on the hairdryer or the "Do not Collapse while occupied" on the baby stroller..

youngone wrote:

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and im kind of pisset off that you called the statments people make retarded we are haveing a intelectuale argument we arent trying to put people down like somebody. and you also tryed put down stev. i realy dont like people that are smart but cant be polite and correct people in the right way. and i respeckd stevdart for his input and take it into acount and dayhon to they both now what they are talking about.

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Hmm. Okay its like this... I didn't so much put down stevdart as hold him accoutable for his "air in wood" comment. I'm sorry, I'll be the first to admit, stev is certainly a Jedi Master to my Padewan Learner, but he was seriously asleep at the keyboard on that one. He's gonna need to stand up and take one on the chin for that. Here, I'll call him on it:

stevdart: Your "air in the wood" statement was retarded.

I promise, he doesn't care.

See youngone, its not so much that I'm not able to be polite, its just that I find ascerbic mouthiness suits my personality so much more.

youngone wrote:

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see they were polite in corecting you thanks guys

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Oh come on just LOOK at my posts! Look at yours! I can't help but have a modicum of smarminess! Believe me its my only release! If it makes you feel any better, IRL, I'm totally miserable. I mean seriously look what the hell I'm spending my Friday night doing.

To be honest youngone, I actually kinda get a kick out'a ur earnestness..

hamfist wrote:

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An infinitely rigid material could be infinitely thin, and still be perfect for an enclosure, right? (I'll save some of you the thought process.)

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Ahh heamph! I was thinking earlier how cool it would be to invent this material and patent it! I mean, I really can't kid myself, I'm not that motivated... as much as I'd love to position myself competitively in the synthetic chemicals market and begin building myself a billion-dollar industrial empire with the "infithin-infirigid-inium"... eh..err... "sedatium" and begin selling like plastic and usher in an entire new era of synthetic materials.....
It'd be great and I'm sure enormously self-actualizing but I think I'd really just lazy myself out, whore the patent to DuPont for 8 figures a year and call it a day.. yea?



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"I'm finished!" - Daniel Plainview

sedate wrote:

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stevdart: Your "air in the wood" statement was retarded.

I promise, he doesn't care.

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Oh I assure you I am a living, breathing, social human being.  That's an offensive remark.  You can take that to mean I care. 

]I did wrote:

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't so much put down stevdart as hold him accoutable for his "air in wood" comment.

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The day that I should feel compelled to explain my posts to you will be the day when I believe that you actually possess qualities other than intellect;  beginning with showing a reasonable amount of humility.  It's easy to be a demeaning wiseguy when you're sitting at your computer.  In real life people walk away from one who talks to them like that...and then avoid him after it.  Count me as one of those who are tired of your "wit".  I'd like to be able to continue to post from time to time on this forum, whether my thoughts are written clearly or not, and worded as abstractly as I choose, without finding that I am insulted for it.  If you don't think my post is right, ignore it.  I'm not steering young minds onto the path of destruction here, I can assure you.  But to follow your example in how to address other people is surely that path.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

well anyhow stevdart thanks for your simple answer to my simple question!

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