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How I built my bass traps...
Old 18th February 2011 | Show parent
  #1021
Here for the gear
 
trafficarte's Avatar
 
🎧 10 years
Hi Paolo,
I paid 7,50 euros/sheet of Vital ( 120x60x4cm) and 15,50 euros for the 4 L-shaped profiles. 38,00 euros every bass-traps.
The bigger hacked-Ikea bass-traps costs only 4,00 euros more... :-)
As soon as I can I'll post the photos.
You can find the Vital at every RockWool reseller, and this is the brochure
Old 20th February 2011 | Show parent
  #1022
Here for the gear
 
trafficarte's Avatar
 
🎧 10 years
uploaded hacked-Ikea bookshelf bass traps on flickr...

Just for information,
I've modifided a pair of cheap bookshelves by Ikea, about 19,00 euros each, putting a couple of cellulose acoustic panel inside them.
I've uploaded a set of pictures on flikr with a brief description of every photo
Old 21st February 2011 | Show parent
  #1023
Gear Addict
 
PaulRain's Avatar
 
1 Review written
🎧 10 years
the Ikea Trap you did is basically empty inside.......maybe it's not so usefull, check this:
Insualtion FAQ
pay attention to the coefficents page.....what is more important in terms of absorbing bass frequencies is thickness....
I will suggest you to fill the ikea trap...any brand of glass wool or rockwool is fine
Old 21st February 2011 | Show parent
  #1024
Here for the gear
 
trafficarte's Avatar
 
🎧 10 years
I don't think that a completely filled trap is better than mine, because (can't find the right reference now...) I've read somewhere that a gap between two layer of high absorbent material is more efficient.
I've done some tests yesterday and seems that my resonance issues are gone. I need to test a lot more, but now is more pleasent to work into my studio...
Old 21st February 2011 | Show parent
  #1025
Lives for gear
 
ritelec's Avatar
 
🎧 10 years
Yet another bass trap post.

Rock wool, OC 703-705...... noticed density should be 3# or better. I clicked on a sight from this forum that has 8# x 2'' mineral wool. Should I be good to go with that or should it still be double to 4".


I also read covering more surface area with thinner is better than less surface area with thicker so hoping I get a thumbs up with 2" x 8#.




Thank you.

edit: after doing some more reading, I'm not sure if the 8# will be good, especially in the corners where 4# is recommended. If I slice the 8# in half, would that make it a 4# (that may sound ridiculous but...) ?

I will continue reading. Any comments appreciated.... Thanks again.

edit,edit: Let it go, the more I look into this the more I'm opting for the 703. TY
Old 24th February 2011 | Show parent
  #1026
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by AcousticsWizard ➡️
You have not demonstrated anything negative about the way i build my bass traps. The build can only amount to positive performance.

The tests will speak for themselves. Right now testimonials are amounting to more referrals - and increased trust in my claims.
I've scrolled through multiple threads that you've been posting on.

Anyone with $50 (for a Behringer SDC omni), an audio interface, and the internet (to download REW or something equivalent for free) can do (at least) simple measurements of rooms. I'm operating under the assumption that you have access to those things - why won't you use these tools to help verify and tune your work?

In any business, I would not want to rely on the salesman telling me "lots of other people (to whom I can't refer you specifically...) have told me they really like it" to prove that the thing fundamentally works in the manner described.

I don't think it's necessarily fair for people here to say "those diffusers/traps/etc. don't work" based on pictures. This is why everyone has been asking for data across all threads.

That being said, the burden of proof is on YOU (as the acoustician/seller) to show that your products work. Having clients tell you (to tell us, i.e. hearsay) that "it sounds great!" doesn't hold any credibility. I would argue that their decision to buy in the first place without any evidence was a ignorance-induced lapse in judgement - not because your products don't necessarily work, but because they aren't backed by data in any sense of the word (especially since a $50 microphone will get you pretty far in the hard-data department).

An example: I make diffusers. I claim that they will diffuse between 520 and 3000 Hz. I sell them to clients, who put them in their rooms and tell me "it sounds better". Therefore, my diffusers perform at my claimed specifications. =Doesn't work that way.

//

Additionally, assuming your clients are using decent speakers, the significant lack of low-end in their mix room(s) is not caused by your traps sucking up all the low frequencies (thus justifying the case for purchasing a subwoofer)... that's not quite how it works.
Old 28th February 2011 | Show parent
  #1027
Here for the gear
 
🎧 10 years
Hi All, sorry for the following lengthy post...if anyone has the patience to read it I commend you greatly.

I spent 8 hours yesterday reading through this thread and a few others and have made a few pages of useful notes....but I still have a few questions if anyone is up for it.

1. With regards to building my own absorbers, I have been looking around at suppliers in the UK for suitable absorption materials. Suitable materials within my price range are:

Rockwool:

RW3 - 60kg/m3
RWA45 - 45kg/m3

Knauf RockSilk:

RS45 - 45kg/m3
RS60 - 60kg/m3

From what I have seen the Knauf seems to be a better price for me but I was just wondering if these are both suitable and which density is more suitable. I get the impression that different densities may be suitable for different applications but not sure. I also want to check out prices for semi-rigid fibreglass boards as I understand these will be more lightweight.

Should I be looking at higher density materials?

Here's what I want to build:

Absorbers for first reflection points on side walls
Absorber for ceiling reflections
Superchunk style corner bass trapping
Additional absorbers for other locations in the room (where necessary)
Ceiling/wall corner bass traps (possibly of the panel variety)

At the moment I am only considering all this and getting prices and i'm definitely not considering getting all this built before I have carried out some measurements with Fuzz Measure. I know that many say that certain amounts of absorption are going to be necessary for a small room (even without checking it out on the graph) but the nature of my project means I need a before and after evaluation of the space so I will be testing this week.


If anybody is curious about the following info:

I have a Behringer ECM8000 mic and Fuzz Measure for testing.
I have built my own sturdy, strong and heavy speaker stands that put the tweeter at ear height and the woofer a couple of inches below half the height of the room.

Room Dimensions (m)

L 3.64m
W 2.44m
H 2.32m

I know that neither the size or room dimensions are ideal, but this is all I have to work with.

My last enquiry is this...my first step was going to be to measure the room at a selection of suitable listening/speaker positions at around 38% of the room length (untreated room) and analyse the data to see where might be a good listening/speaker position. Then throw up these absorbers in pairs and measure the difference. Is this a good way to go?

I have used formulas from Everest's book and Angus' book to calculate the likely modes of the room and where I expect there to be a build up/null and can confirm this all with fuzz measure.

So I was considering that the first reflection absorbers should be 4" rockwool and a 2" air gap behind and should not be 'faced' with anything to make them broadband (is this correct?).

Because of the size of the room I had assumed that this thickness absorber will be necessary on all absorbers but I suppose I don't know until I start putting them up which is why I was considering building them in pairs and then measuring the result. Then If I need to make any absorbers less thick/less absorbent at high frequencies I can address this as it arises. Does this make sense ?

As for placement of those absorbers other than at the first reflection points I had been considering using ETC measurements and calculating the distance of delayed reflections so i can attribute it to a wall.

I am not a professional engineer/musician but am attempting to make a space that (although will not be perfect) will be much better suited to the task than the room I am currently using (which I know is terrible).

Any advice much appreciated.
Old 28th February 2011 | Show parent
  #1028
Lives for gear
 
PaulP's Avatar
 
🎧 10 years
Quote:
Originally Posted by Caustin ➡️
My last enquiry is this...my first step was going to be to measure the room at a selection of suitable listening/speaker positions at around 38% of the room length (untreated room) and analyse the data to see where might be a good listening/speaker position. Then throw up these absorbers in pairs and measure the difference. Is this a good way to go?
Yes !

For the rest, you've done your homework and seem to have a good grasp of the basics. Welcome to the club.
Old 28th February 2011 | Show parent
  #1029
Lives for gear
 
johndykstra's Avatar
 
🎧 10 years
Good work Caustin.

Few things. Use the 60kg material for all of your 4" traps. 45kg is more suitable for the super chunks... even less dense if you can find it. Go with superchunks with 2' legs. Consider even an entire back wall false wall, and fill it with attic insulation, cover with fabric. Face size is nearly as important for trapping bass, if not more so. Particularly on the back wall. And essentially, the thicker the trap, the lower the density of your trap should be. When you reach around 1' of thickness, you want to start using the attic batt type.

Measuring. I would suggest one more type, and do it first. Place your speaker on the floor, pointing into the left corner, as close as you can get it to the corner without touching. Place the mic in the upper right hand corner by the ceiling, same deal, very close. This test will tell a lot about the modal activity of the room, while removing not only the direct sound from the speakers, but also any SBIR/LBIR issues at the mix spot. Then when you do place the test set up as you had described, certain anomalies will stick out as distinctly modal, as you can reference the corner test. New anomalies in the response (different frequencies) can now be attributed to SBIR/LBIR. Possibly some areas of the spectrum will be colored both modally, and reinforced by SBIR/LBIR, this scenario will show wild intensity variation in your graphs. I would say that your first objective would be to configure your listening position in an empty room... using minor tweaks in height, distance from boundaries, and distance from ear to speaker... until you find the best response on measure. Only then would I attempt to begin with treatment.

What kind of room response are you aiming for? (hint- "I want it to sound good" is not an answer.) There are particular acoustic models that fall into a precise criteria that we attempt to follow as best we can to mold the response in a particular way. Search LEDE/RFZ, Nonenvironmental, ... these are probably the best documented models here.

One aspect that will be pretty universal, is the early reflection control. Typically done with absorption as you had stated, but sometimes done with geometry of reflecting panels. You are right on the money in utilizing the ETC measurement for this, but something that is often over looked, is that you want to execute a number of ETCs, at various locations around the mix spot. This gives you a sweet spot of reflection free listening... allowing you to move your head while mixing. Kinda important.
Old 28th February 2011 | Show parent
  #1030
Here for the gear
 
🎧 10 years
Thanks for all the info guys thumbsup

As for what acoustic model I am aiming for, this is something I have come across while researching on this forum and will need to look into it more before I move too much farther forward.
Old 1st March 2011 | Show parent
  #1031
Gear Maniac
 
🎧 10 years
rockwool or alternatives germany?!

Hey guys,
here's another one trying to finsih his absorbers :D

I need a bit of help though....

anyone know where and what kind of rockwool or alternatives i can get in germany?!
i have been scanning the internet but to no avail.
Want to use the stuff with 100 kg / m3 for all of them. Anything wrong with that?
Somebody was trying to sell it to me for 20 € / m2. That seems pretty expensive to me...

I am making 10 broadbands (100 cm * 125 cm) with room for two pieces of 4 inch(10cm) rockwool.

6 for the walls behind speaker and 4 for early reflections next to speakers.
The corners have been treated and there already are some absorbers on the ceiling.
The back of the room has a big heavy curtain with storage behind it and reduces the ambience from the back of the room considerably.

Frames are finished but need to be painted. Will try to post pics next week.
I have ordered the behringer mic to use room eq wizard.

Am I on the right track?

Thanks for any help!
Old 2nd March 2011 | Show parent
  #1032
Gear Maniac
 
jaykay's Avatar
 
🎧 10 years
Quote:
Originally Posted by slimboyfat
anyone know where and what kind of rockwool or alternatives i can get in germany?!
I think you'll find all the answers regarding this question already in the forums, I personally used Gutex Thermoflex which I have also described on page 23 in this particular thread. The important thing is not just density but also gas flow resistance, so keep this in mind. Anyway, here are a couple of links I just dug up from a search in this forum:

Absorber / Bass trap supplies in Berlin Germany
Basstraps in Germany, suitable material?

Old 2nd March 2011 | Show parent
  #1033
Gear Maniac
 
🎧 10 years
Quote:
Originally Posted by jaykay ➡️
I think you'll find all the answers regarding this question already in the forums, I personally used Gutex Thermoflex which I have also described on page 23 in this particular thread. The important thing is not just density but also gas flow resistance, so keep this in mind. Anyway, here are a couple of links I just dug up from a search in this forum:

Absorber / Bass trap supplies in Berlin Germany
Basstraps in Germany, suitable material?

hey jaykay,

great thanks a lot!! all the answers I was looking for!
Old 2nd March 2011 | Show parent
  #1034
Gear Nut
 
🎧 10 years
should broadband absorber panels go directly behind the monitors, or the center between them? please someone answer that or i shall weep
Old 2nd March 2011 | Show parent
  #1035
Lives for gear
 
johndykstra's Avatar
 
🎧 10 years
depends.

sorry.
Old 2nd March 2011 | Show parent
  #1036
Gear Nut
 
🎧 10 years
Quote:
Originally Posted by johndykstra ➡️
depends.

sorry.
depends on what my young brother?
Old 2nd March 2011 | Show parent
  #1037
Lives for gear
 
johndykstra's Avatar
 
🎧 10 years
depends on what you are trying to do

length mode reduction?

sbir front wall reduction?

sbir side wall reduction?

lbir reduction?

flutter echo elimination?

a good place to place your star wars figurines?

If there was a specific blueprint to treat rooms properly, do you really think this forum would require so much discussion?
Old 2nd March 2011 | Show parent
  #1038
Lives for gear
 
johndykstra's Avatar
 
🎧 10 years
SBIR

Behind monitors--absorption, diffusion?

two really good places to start
Old 2nd March 2011 | Show parent
  #1039
Gear Nut
 
🎧 10 years
i appreciate the help, but you said it in kind of a mean way
Old 2nd March 2011 | Show parent
  #1040
Lives for gear
 
johndykstra's Avatar
 
🎧 10 years
if you thought that was mean, stay away from SAC.
Old 2nd March 2011 | Show parent
  #1041
Lives for gear
 
PaulP's Avatar
 
🎧 10 years
Quote:
Originally Posted by johndykstra ➡️
if you thought that was mean, stay away from SAC.


Old 4th March 2011 | Show parent
  #1042
Gear Maniac
 
🎧 10 years
me again,
bother! can someone please confirm or correct the following to eradicate my doubts before finishing the broadband absorbers?

True or False?

I gathered that the proportions of density to GRF are very important (kg/m3 - kPa*s/m²)
and the likes of 703 or 705 panels seem to have proven to be the most suitable for broadbandabsorbers.
Hence my conclusions:

1.The GRF and Density of:

· Rockwool Termarock 100 (≥ 43 kPa ∙ s/m² and density 100 kg/m3) has a too high GRF right?

· Rockwool Termarock 50 (≥ 16 kPa ∙ s/m² and density 50 kg/m3) is approx the same as 703 ?

· Homatherm Flex ( Cl (43 - 76 kPa∙s/m2 and Density 70 kg/m3) has a too high GRF?

· 703 Panels 16 kPa · s/m² · aprox. density 48 kg/m3

· 705 Panels 30 kPa · s/m² · aprox. density 90 kg/m3

2. I should purchase and then double layer 2" panels of the equivalent of 703 because it is more efficient than one 4" slab of 705?
This is because the density of 703 is more efficient than the density of 705?

3. If the Density (kg/m3) is too high then the panels reflect(?) too much?

Thanks!
Old 5th March 2011 | Show parent
  #1043
Gear Maniac
 
🎧 10 years
Red face on the road to absorbtion

hello,
here are some pictures of my frames. just finished the first paintjob. tomorrow the clear finish.
The frames are 12 cm deep, and 125*100 cm and made of birch multiplex.

I want the rockwool to be 1/2 way in 1/2 way out of the frame so that i have some space to light the frames up from behind. If I am right then this will also increase the absorbtion area and the frames won't be positioned too far from the wall.
haven't quite figured out how this is going to work. Maybe stiffen the fabric or some extensions at the sides. any ideas?

I'm going to put some white linen across the front to finish it.
Old 5th March 2011 | Show parent
  #1044
Gear Maniac
 
🎧 10 years
pics

forgot to attach heh
Attached Thumbnails
How I built my bass traps...-dsc04897.jpg   How I built my bass traps...-dsc04899.jpg   How I built my bass traps...-dsc04900.jpg   How I built my bass traps...-dsc04903.jpg   How I built my bass traps...-dsc04906.jpg  

Old 5th March 2011 | Show parent
  #1045
Lives for gear
 
PaulP's Avatar
 
🎧 10 years
Quote:
Originally Posted by slimboyfat ➡️
here are some pictures of my frames. just finished the first paintjob. tomorrow the clear finish.
The frames are 12 cm deep, and 125*100 cm and made of birch multiplex.
Nice woodwork thumbsup

What kind of joint did you use at the corners ?

I can see the mitered edges but not what's inside the joint.
Old 6th March 2011 | Show parent
  #1046
Gear Maniac
 
🎧 10 years
hey paul,
thanks, the frames were stuck with woodglue and fixated with straps. nothing in the joints. but I must admit that a friend of mine who is a carpenter, gave me a hand
Old 6th March 2011 | Show parent
  #1047
Lives for gear
 
PaulP's Avatar
 
🎧 10 years
Quote:
Originally Posted by slimboyfat ➡️
hey paul,
thanks, the frames were stuck with woodglue and fixated with straps. nothing in the joints. but I must admit that a friend of mine who is a carpenter, gave me a hand
Must have been tricky glueing things up. Sure turned out nice.

Looking forward to seeing them assembled.
Old 6th March 2011 | Show parent
  #1048
Gear Maniac
 
🎧 10 years
Quote:
Originally Posted by PaulP ➡️
Must have been tricky glueing things up. Sure turned out nice.

Looking forward to seeing them assembled.
its pretty straightforward if you cut the wood correctly and then strap round the outside. the frame is automatically 90 degrees all the way round. but as I said. I had help.

finished the clear paint today but my mobilephone didn't like the idea of storing the pictures. aaah! will post more when I put in the wool and the covering.
Old 6th March 2011 | Show parent
  #1049
Gear Maniac
 
🎧 10 years
Ooh and I'm getting some quotes on some rockwool tomorrow.
can anyone help me with these questions?

Rockwool Termarock 100 (≥ 43 kPa ∙ s/m² and density 100 kg/m3) has a too high GRF right?

· Homatherm FlexCl (43 - 76 kPa∙s/m2 and Density 70 kg/m3) has a too high GRF?


Would layering 2 Rockwool Termarock 50 (≥ 16 kPa ∙ s/m² and density 50 kg/m3) be the most affective?

Old 7th March 2011 | Show parent
  #1050
Gear Maniac
 
🎧 10 years
bump
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