PDA

View Full Version : Fiberglass vs. MDF or HDF



spyd3r
05-12-2003, 09:16 PM
So,
Lets say we live in a world where space in your trunck ins't an issue and all you have to worry about is the acoustic performance of materials.

We all know that Fiberglass is very strong and can easily withstand the pressure inside a sealed chamber with a swoofer compressing the air ( if its layed with enough leyers ofcourse and ha some bracing inside ).

But when you but aside fuctionality and looks what creates a better tone? Or richer bass? I would lean towards a wooden enclosure like MDF (HDF for the lucky few that have access to it). Personally I feel the MDF enclosures ( if braced properly keeping in mind the braces acting as points to break up ressonant waves) would have a bit richer sound than a fiberglass enclosure with the same volume.

Any thoughts?

paikiah
05-12-2003, 09:20 PM
Originally posted by spyd3r
So,
Lets say we live in a world where space in your trunck ins't an issue and all you have to worry about is the acoustic performance of materials.

We all know that Fiberglass is very strong and can easily withstand the pressure inside a sealed chamber with a swoofer compressing the air ( if its layed with enough leyers ofcourse and ha some bracing inside ).

But when you but aside fuctionality and looks what creates a better tone? Or richer bass? I would lean towards a wooden enclosure like MDF (HDF for the lucky few that have access to it). Personally I feel the MDF enclosures ( if braced properly keeping in mind the braces acting as points to break up ressonant waves) would have a bit richer sound than a fiberglass enclosure with the same volume.

Any thoughts?

I sue MDF cause it's cheap and easy to build. HDF is heavy and not well-known for being easy to work with (as mentioned by Jmac some time back). I've always had the impression that fiberglass is, yes, strong, but also thin, leaving you with MROE internal volume than 3/4" MDF. You could also make curves with fiberglass. It'd be itneresting to see a fiberglass enclosure that FILLS the whole trunk.

About getting better tone or richer bass, I don't think the material is as important as the design and size of it. If it flexes, you lose out on SPL, probably SQ too. SOme people use an MDF box with a fiberglass lining inside the box, just to have a LITTLE more rigidity.

spyd3r
05-12-2003, 09:27 PM
Im not too concerned with strenght and design...Im assuming you already have this down....

Im more interested in opinion of the sound itself.

For example. You know how your voice sounds different in a metal room vs. a room with wooden panels or carpet. I mean theres reasons why some recording studios use wooden paneling. Im just curious if people can notice this difference in a car audio with a woofer.

paikiah
05-12-2003, 09:33 PM
Originally posted by spyd3r
Im not too concerned with strenght and design...Im assuming you already have this down....

Im more interested in opinion of the sound itself.

For example. You know how your voice sounds different in a metal room vs. a room with wooden panels or carpet. I mean theres reasons why some recording studios use wooden paneling. Im just curious if people can notice this difference in a car audio with a woofer.

SInce you put it that way...

I guess if fiberglass was the best option, most home audio mftrs would use it. Instead, they use wood(albeit different sort of wood, like oak, i think) to make their TL boxes. If OPTIMUM SQ is what you're going for, you COULD use erm.. what was the name of the wood again? I forgot, but there are some who use a very expensive type of wood to make thier enclosures.

paikiah
05-12-2003, 09:37 PM
oh, and about the wall surface of listening rooms...

that'd be your cabin, which you should plaster damping mats (contact ifandorabouts) all around, to try and achieve some sort of SQ listening confinements.

spyd3r
05-12-2003, 09:50 PM
See your reply on the oak boxes is more of what Im looking for.
As for the cabin of the car. Its far from being studio quality....but Im not really interested in hearing how soo many layers of dampner are going to bring it closer. In reality the dampner only makes a slight improvement in SQ, but I definetly agree its enoguh of an increase to pursue it........Once we get into dampening and everything the thread is reallly getting highjacked into a discussion of diminosing returns. errfffff:crazy:

spyd3r
05-13-2003, 12:18 AM
Good point

Never came to think of that. (dough! ;)).

So it really doesn't matter what the sound wave is bouncing off in a sealed enclosure because those waves inside the enclosure never really make it out side of it.

But then in ported applications the "texture" of the material inside the enclosure should make a difference on how it reflects the wave thats 180 degress out of phase with the front.

Hmmm
Paneling your trunk with acoustic material would seem an even further step in improving the quality of the bass wave we hear in the front of the car.
Wonder how much of a difference this would have on the sound. :confused:

awalbert88
05-13-2003, 03:40 AM
I think the single biggest advantage to sound damping in terms of SQ is killing rattle. My car rattles a ton thanks not only to the bass from the subs I've had, but also from the effects of PA roads on a suspension designed in the 1970's (thank you so much Ford).

As for material, in a sealed enclosure, it shouldn't matter. In a ported or TL-style enclosure, wood is usually preferred. I'm not sure what the high-end home audio speakers use... But I'd recommend just using 3/4" MDF if you're going ported. And if you want to make it look extra pretty, you can always build a fiberglass covering over it, but I'm not sure a ported fiberglass box would sound very good (might be wrong though). Definately stay away from HDF, however, as there is no acoustical benefit over MDF, and would just give you all sorts of headaches during construction. Not to mention the tremendous weight difference...

Cars are not the most ideal environment for sound quality, but with the right equipment and careful planning, it can match most high-end home audio systems.

paikiah
05-13-2003, 03:47 AM
Originally posted by awalbert88
I think the single biggest advantage to sound damping in terms of SQ is killing rattle. My car rattles a ton thanks not only to the bass from the subs I've had, but also from the effects of PA roads on a suspension designed in the 1970's (thank you so much Ford).

As for material, in a sealed enclosure, it shouldn't matter. In a ported or TL-style enclosure, wood is usually preferred. I'm not sure what the high-end home audio speakers use... But I'd recommend just using 3/4" MDF if you're going ported. And if you want to make it look extra pretty, you can always build a fiberglass covering over it, but I'm not sure a ported fiberglass box would sound very good (might be wrong though). Definately stay away from HDF, however, as there is no acoustical benefit over MDF, and would just give you all sorts of headaches during construction. Not to mention the tremendous weight difference...

Cars are not the most ideal environment for sound quality, but with the right equipment and careful planning, it can match most high-end home audio systems.

i say the best SQ cars (cars taht are running) still cannot match high-end home audio systems.. well, the definition of high is vague, but with my definition of high-end, I say it cannot be matched.



and thanks for pointing out that there's no acoustic benefit with MDF and HDF...:):) I wasn't really aware of that...

paikiah
05-13-2003, 03:51 AM
Originally posted by Jmac
Although if you use a soft damping material that absorbs sound, it should result in better sound quality. One of the biggest things in an automobile is that there are so many surfaces that sound can reflect off of and, in terms of sound quality (more accurately, imaging), that can be a bad thing. Of course, if you're smart, you can use those surfaces to your advantage (i.e. Placing tweeters on the back of your rear view mirror and reflecting them off the windshield towards you ... or making midbass enclosures on the floor and bouncing them off the windshield towards you) but, for the most part, you want to eliminate those surfaces ...

Oh, and there is an acoustical advantage to using HDF over MDF, but only in extreme circumstances (i.e. Where MDF would flex), but simply going to 1" MDF or doubling 3/4" MDF would solve that ...

jmac, i MIGHT need your help in about 2~3 weeks, deciding on whether to purchase the RE HC or not... i got in contact with the dealer, and he's agreed to give me a very attractive price on the 12"HC or 12"SE subs...

I trust your expertise on your deisgning of box volumes...
:)

paikiah
05-13-2003, 03:56 AM
Originally posted by Jmac
If I'm not on the day you get it, e-mail me ...

[email protected]

ok cool...

but i think talking over here would be good.. never know who else would benefit from our talk, and give suggestions on stuff...:):)

just my opinion...:)

paikiah
05-13-2003, 04:01 AM
Originally posted by Jmac
I also just realized that you probably want me to design the box before you get it ... am I right ?

(I'm tired so my thought process is off ... Also sick, which also affects my thought process ...)

nah man..
I've bothered you long ago with enough of my fantasies of owning power HX2's man...

this time, I'm goinna take things slow. I wouldn't mind for the sub to sit waiting, while I design a box... don't have much time anyway...:)