I have some extra 4" Mineral Wool 8lb density

brandondrury · Post by **brandondrury** » Fri May 28, 2004 6:17 am

Hello,

I know this stuff is hard to come by, but I have just found a batch of 4" Mineral Wool for use in bass traps and acoustical absorption panels. The batch is way more than I need for my studio treatment.

The stuff I have is 8lb density.

This is basically the same as the Owens Corning 703 as recommended by Ethan Whiner and Alton Everest.

The acoustical absorbtion is much greater in the low end than any foam product.

If anyone is interested, just let me know.
Brandon Drury

giles117 · Post by **giles117** » Sat May 29, 2004 1:27 am

8lb is too dense. You are looking for 4lbs at max.

Bryan Giles

brandondrury · Post by **brandondrury** » Sat May 29, 2004 2:59 am

I'm curious as to why 8lb is too dense.

http://www.roxul.com/graphics/rx-na/can ... t80oem.pdf

I'll be using the rockwool for absorbtion. As you can see from the link, the stuff I have has a 1.0 absorbsion coefficient at 125 Hz. I haven't seen a more even absorbsion through the freqency band.

Brandon

AVare · Post by **AVare** » Sat May 29, 2004 4:03 am

I'm curious as to why 8lb is too dense.

It is complex to answer, but basically the way absorption is measured on in a big room and the effect of adding the material is calculated.

This method does NOT show how much of the initial sound wave is absorbed.

The trade offs of density.thickness are not shown with this method.

This is one the parts of acoustics that people lean over the years.

Good luck with your project!
Andre

brandondrury · Post by **brandondrury** » Sat May 29, 2004 4:33 am

Okay, I just ordered quite a bit of this stuff yesterday.

Would it be smart to cancel the order and get the 4lb stuff?

Brandon

AVare · Post by **AVare** » Sat May 29, 2004 8:21 am

Okay, I just ordered quite a bit of this stuff yesterday.

Would it be smart to cancel the order and get the 4lb stuff?

We don;t know what you are going to with item the thickness, the room size, etc.

If you are going pm improving the acoustics, it will so that. Depending on the specifics, it may ne the perfect choice, or different materials may be better.

There are no salesmen here. Give us details and we will reply honestly, Not telling you what you bought is wrong because we didn't sell it, or tell tell you it you it is right because we sold it.

giles117 · Post by **giles117** » Sat May 29, 2004 3:07 pm

brandondrury wrote:Okay, I just ordered quite a bit of this stuff yesterday.

Would it be smart to cancel the order and get the 4lb stuff?

Brandon

Yes it would be wise.

The denser the material the more it will act like a solid wall... reflecting the sound instead of absorbing the sound, especially in the mid to upper frequencies. the 3 to 4pcf stuff will give the best balance between low end, mid and high end absorption.

Bryan Giles

chrisaiken · Post by **chrisaiken** » Mon May 31, 2004 10:12 am

[q[/quote]

Yes it would be wise.

The denser the material the more it will act like a solid wall... reflecting the sound instead of absorbing the sound, especially in the mid to upper frequencies. the 3 to 4pcf stuff will give the best balance between low end, mid and high end absorption.

Bryan Giles[/quote]

If he was only using it for bass trapping not mid or highs would it be ok?Or is there such a thing as to dense for bass trapping.
thanks,
Chris

AVare · Post by **AVare** » Mon May 31, 2004 10:55 am

If he was only using it for bass trapping not mid or highs would it be ok?Or is there such a thing as to dense for bass trapping.

Who knows what he is doing or what the room is like. The answer to your question is yes, 100%, it can't be answered whithout specifics..

chrisaiken · Post by **chrisaiken** » Mon May 31, 2004 8:45 pm

AVare wrote:
If he was only using it for bass trapping not mid or highs would it be ok?Or is there such a thing as to dense for bass trapping.

Who knows what he is doing or what the room is like. The answer to your question is yes, 100%, it can't be answered whithout specifics..

Yes 100% to my first or second sentence?Sorry it just wasn't clear how you stated it.
Chris

AVare · Post by **AVare** » Tue Jun 01, 2004 12:46 am

Yes 100% to my first or second sentence?Sorry it just wasn't clear how you stated it.

Hi Chris:

that is how much detail we have to work with. Without more detailed information, a more accurate answer can not be given.

chrisaiken · Post by **chrisaiken** » Tue Jun 01, 2004 5:50 am

AVare wrote:
Yes 100% to my first or second sentence?Sorry it just wasn't clear how you stated it.
Hi Chris:

that is how much detail we have to work with. Without more detailed information, a more accurate answer can not be given.

Ok I hear what your saying about his room(project),but let me rephrase....
Is it possible to have to dense of a fibreglass,rockwool, etc if you're bass trapping only?I was under the impession that the answer was no.
Sorry to be a pain,
Chris

giles117 · Post by **giles117** » Tue Jun 01, 2004 7:40 am

If the rockwool is exposed (coverd by fabric counts as exposed) in the room, then it will be none to effective at proper control of mid and high freq's. In other words they will bounce a bit.

Using this inside of a speaker soffit or as a replacement for hanging bass traps, would prove effective.

Bryan Giles

chrisaiken · Post by **chrisaiken** » Tue Jun 01, 2004 9:31 am

Ok thanks.
Chris

brandondrury · Post by **brandondrury** » Fri Jun 04, 2004 5:20 pm

Well, I called my dealer a few days ago and we switched the order out to get 4lb stuff.

Basically, I have a 15x20x9 room that is paneling, spackeling, hard wood flooring, and a drop ceiling. I've been using it for drums and such with no treatment whatsoever. The results are not terrible, but many pros on other forums have heard my mixes and instantly said that my room need "work". Currently, I have a 11x12x9 room that I've been using as a control room, but I think I'm going to swap these around. I've been recording in this setup nearly fulltime for about a year now and really haven't had much of a break from the recording to make changes to the acoustics of the rooms. I went the neutral path and did nothing for a long time. My skills have caught up with the limitations of my room as far as the live room and the control room.

My thoughts are to make the larger room the control room. Not only does it offer more volume, but it is nearly perfectly symetrical while the smaller room is not. While my situation is not ideal, I could also put drums in this room when I record full bands. The adjacent room (11x12x9) that I mentioned would more or less be a live room for guitars / vocals / etc.

I'm guessing a large portion of this is comb filtering and any other problems associated with my completely untreated rooms stem from the early reflections. I hope to minimize these reflections as much as possible using the Rockwool.

I can hear what is wrong with my room, especially when it comes to a loud cymbals or loud electric guitars. The problem appears to vanish when I build an acoustic fortress (blankets, unopened rolls insulation, old clothes, whatever I can find) around my loud guitar amps.

The aim in the larger control room is to get a room that is much more likely to give me more accurate monitoring. Like everyone, I've struggled with this.

To make a long story short, I'm basically looking for even broadband absorpstion. I'll probably have to come up with some bass traps. I'm sure the 8lb stuff will work better for those, but in general I'm just looking clean the acoustics up a little bit, if that makes any sense.

At this stage of the game, I'm trying to acoustically improve my situation. I'm unsure how long I'll be recording in my current location and I try to focus on things that I know I'll need in the future. (It's easy to get a microphone to work in a new studio location. It's harder to take a double layer of drywall with me.)

So that is the goal of the studio. I certainly did not need 1000 sq feet of the 4" 8lb stuff. I may consider tossing the 8lb stuff above the drop ceiling if see fit. I'm sure the 4lb stuff will do a sufficient job of trapping bass if I do it correctly.

Thanks for your help
Brandon Drury