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Progress ok? graphs inside..
Old 18th May 2009
  #1
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kraskland's Avatar
 

Progress ok? graphs inside..

Hey guys, I finally got around to installing REW and testing the room. How do things look so far? Am I on the right track? There is an increase in the 70-75 Hz range with the corner traps in. Also, the nulls at 245, 345, and 515 Hz are larger with them. Is this unusual?

As I mentioned in another post, the density (40Kg/m3) is not as high as I wanted but what can you do... details of the build are over here.

I'm in the process of making a large trap on wheels (thanks to Glen for that idea) to put in front of the door behind me in front of a door. It's about 45" wide and 6-7" deep, pretty much floor to ceiling. After that I might go with superchunks in the back corners with the same material. Is this a sound plan?

orange=untreated room
green=side traps
blue=front corner traps behind speakers
Attached Thumbnails
Progress ok? graphs inside..-graph4alltraps.jpg  

Last edited by kraskland; 18th May 2009 at 02:31 PM.. Reason: Replace graph
Old 18th May 2009
  #2
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All of these tests are from the same spot in the room? (just checking)
Can you just show the detail from 300 hz down? Also can you post a waterfall plot?

Glenn
Old 18th May 2009
  #3
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I saw the other thread, panels looks nice and well done!

Just a suggestion, considering you have some panels in the side walls: treating front "and/or" rear walls (lenght) and a cloud in the reflection point (height) (*maybe if you already have it) can help with the ~75 and 120 peaks (strange that 120 looks narrower than before).

Ciro

*(edit) not so strange, probably the corner traps (blue graphic) helped more one mode/dimension than other and they´re close for similar size (or multiple).A narrow peak is not good, altough this one is not a nasty (db) peak and can be improved with proper treatment/speakers placement.
Old 18th May 2009
  #4
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I just went back to your old thread to try to figure out how many panels and where you put all of them. Can you give us a layout?
Old 18th May 2009
  #5
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Quote:
Originally Posted by Glenn Kuras View Post
All of these tests are from the same spot in the room? (just checking)
Can you just show the detail from 300 hz down? Also can you post a waterfall plot?

Glenn
They were done from the same spot, but I had to move the mic in between to get the corner traps in. I marked the spot on the floor but it's very possible I didn't get it exactly the same. Maybe I should redo it. Anyway, here's the 300 hz detail with 1/24th smoothing. I'm not sure about the waterfall, does this look right?
Attached Thumbnails
Progress ok? graphs inside..-graph5alltraps300.jpg   Progress ok? graphs inside..-graph6waterfall300.jpg  
Old 18th May 2009
  #6
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Quote:
Originally Posted by ciro View Post
I saw the other thread, panels looks nice and well done!

Just a suggestion, considering you have some panels in the side walls: treating front "and/or" rear walls (lenght) and a cloud in the reflection point (height) (*maybe if you already have it) can help with the ~75 and 120 peaks (strange that 120 looks narrower than before).

Ciro

*(edit) not so strange, probably the corner traps (blue graphic) helped more one mode/dimension than other and they´re close for similar size (or multiple).A narrow peak is not good, altough this one is not a nasty (db) peak and can be improved with proper treatment/speakers placement.
Thanks Ciro! I should clarify, the blue line is both the side and corner traps together.

The ceiling is problematic. It's of poor construction and I'm not confident it will hold much weight. So what I've got there (and here's my dirty little secret) is a bunch of *cough* Auralex panels.
Old 18th May 2009
  #7
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Quote:
Originally Posted by kraskland View Post
Thanks Ciro! I should clarify, the blue line is both the side and corner traps together.

The ceiling is problematic. It's of poor construction and I'm not confident it will hold much weight. So what I've got there (and here's my dirty little secret) is a bunch of *cough* Auralex panels.

I understood about the side+corners.It´s a pity about the ceiling,but if you have the option of front wall/ceiling corner, it´s a great point too!

Software is REW?
Your waterfalls shouldn´t "explode". Set 40 or 30 db in the vertical graphic- 80/120db for what I see- you need to see the mountains... "foot"?heh damn (mine) english..heh

Set the time range for 600ms
(Some Ethan´s examples,take a look:RealTraps - EQ versus Bass Traps)).


Ciro
Old 19th May 2009
  #8
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Quote:
Originally Posted by ciro View Post
I understood about the side+corners.It´s a pity about the ceiling,but if you have the option of front wall/ceiling corner, it´s a great point too!

Software is REW?
Your waterfalls shouldn´t "explode". Set 40 or 30 db in the vertical graphic- 80/120db for what I see- you need to see the mountains... "foot"?heh damn (mine) english..heh

Set the time range for 600ms
(Some Ethan´s examples,take a look:RealTraps - EQ versus Bass Traps)).


Ciro
Yes, I'm using REW. I understand what you mean about the mountains, your english is fine. How's this waterfall look?

I'm going to try and do the measurements again today, and see if I can do it without moving the microphone. But first need to put the traps in sketchup and post for Glenn.
Attached Thumbnails
Progress ok? graphs inside..-graph7waterfall300.jpg  
Old 19th May 2009
  #9
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Quote:
Originally Posted by Glenn Kuras View Post
I just went back to your old thread to try to figure out how many panels and where you put all of them. Can you give us a layout?
Here's a pic. There are two floor to ceiling traps across the front corners and two on the side wall. They're the ones in red/maroon.
Attached Thumbnails
Progress ok? graphs inside..-studio5.jpg  
Old 19th May 2009
  #10
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Hi!

You could even try more 15 or 20db on vertical graph to see if lower frequecies will changes a bit (they seems controled , at least in this graphic) but what is clear is that ~120 peak is narrow (showed before with frequencie graphic) and decay is longer.

1)"If" your height is ~ 2,80m, may be a ceiling peak related mode.Not being possible the ceiling treatment, as you said, a panel on the front wall/ceiling corner could helps -
try with a friend holding (or yourself on the REW slow sweep mode 1M- be quickheh).And measure to see if helps.
Another thing is the monitor (woofer),avoid it at 50% of height,will put it (at least in theory) in the peak of second harmonic (as I said, around 120 "if" your ceiling is near 9').
2) 120 hz is the 3º harmonic of your lenght mode too (it can be strong near the mix position). I´d try panels on front wall to see if helps too.

This is just trying to tame the worst peak.You still with a big not treated area on the rear wall.6" panels + gap are usually recommended.
And more corner panels.


Ciro

*just to let clear, my experience is limited to treat my room and "helping" two other friends room.
Old 19th May 2009
  #11
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by kraskland View Post
Here's a pic. There are two floor to ceiling traps across the front corners and two on the side wall. They're the ones in red/maroon.
You are off to a good start but to be honest you are going to need a TON more treatment in that room. Take a look at the following set up to give you some ideas on other places
GIK Acoustics: Room Setup
Also Frank who I work with did a room case study that I think will shine some light on where you are at.
GIK Acoustics
Old 20th May 2009
  #12
Gear Nut
 
kraskland's Avatar
 

Quote:
Originally Posted by Glenn Kuras View Post
You are off to a good start but to be honest you are going to need a TON more treatment in that room. Take a look at the following set up to give you some ideas on other places
GIK Acoustics: Room Setup
Also Frank who I work with did a room case study that I think will shine some light on where you are at.
GIK Acoustics
Thanks Glenn, yeah I'm planning on much more treatment, like I said a 6" back wall and chunks in the back corners to start with. The curious part was that some nulls got worst when I put the front corner traps in. I've read Franks writeup, but what I didn't see were nulls that got worst as he went through the process.

No worry though, as I finally found a source for 110 Kg/m3 (6.86 lbs/ft3) Rockwool. So I'm going to replace the 40 Kg/m3 in the corner traps and use that for the chunks.

But now my question is... is 110 Kg/m3 ok for 4" or 6" traps?
Old 20th May 2009
  #13
Gear Nut
 
kraskland's Avatar
 

Quote:
Originally Posted by ciro View Post
Hi!

You could even try more 15 or 20db on vertical graph to see if lower frequecies will changes a bit (they seems controled , at least in this graphic) but what is clear is that ~120 peak is narrow (showed before with frequencie graphic) and decay is longer.

1)"If" your height is ~ 2,80m, may be a ceiling peak related mode.Not being possible the ceiling treatment, as you said, a panel on the front wall/ceiling corner could helps -
try with a friend holding (or yourself on the REW slow sweep mode 1M- be quickheh).And measure to see if helps.
Another thing is the monitor (woofer),avoid it at 50% of height,will put it (at least in theory) in the peak of second harmonic (as I said, around 120 "if" your ceiling is near 9').
2) 120 hz is the 3º harmonic of your lenght mode too (it can be strong near the mix position). I´d try panels on front wall to see if helps too.

This is just trying to tame the worst peak.You still with a big not treated area on the rear wall.6" panels + gap are usually recommended.
And more corner panels.


Ciro

*just to let clear, my experience is limited to treat my room and "helping" two other friends room.
Ciro, thanks for the info on room modes. My ceiling is 260cm and the woofer is centered at 110cm. I do plan on a 6" back wall floor to ceiling trap and chunks in the corners to start with. Luckily I found higher density Rockwool so I think I'm going to replace the insulation in the traps (glad I haven't put the backs on yet) and see how it goes.

I've been thinking about the ceiling traps. I may be able to hang one using cables attached to the concrete side walls.
Old 20th May 2009
  #14
Gear Guru
 
Glenn Kuras's Avatar
Quote:
But now my question is... is 110 Kg/m3 ok for 4" or 6" traps?
Go with 6".
Old 20th May 2009
  #15
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kraskland's Avatar
 

Quote:
Originally Posted by Glenn Kuras View Post
Go with 6".
Right on, thanks Glenn.
Old 21st May 2009
  #16
JWL
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Yeah, all else being equal, 6" is better than 4".

Bass trapping is in large part about coverage area, though. It's probably better to have 6 - 4" panels in a room than 4 - 6" panels.

Though it sounds like you are planning for a wide coverage area, so you'll be all set.
Old 21st May 2009
  #17
Gear Nut
 
kraskland's Avatar
 

Quote:
Originally Posted by jwl View Post
Yeah, all else being equal, 6" is better than 4".

Bass trapping is in large part about coverage area, though. It's probably better to have 6 - 4" panels in a room than 4 - 6" panels.

Though it sounds like you are planning for a wide coverage area, so you'll be all set.
Thanks jwl, I read that report Ethan did on trap thickness and coverage, excellent informative.

My question wasn't very clear. I was asking more about the density, whether 110 Kg/m3 was good for the traps I had already built. Anyway, sounds like they'll be fine.
Old 21st May 2009
  #18
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hmmm... if you´re avoing a cloud for problems with structure... less dense material like 32kgm/³ will works fine too.

Ciro
Old 21st May 2009
  #19
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by kraskland View Post
Thanks jwl, I read that report Ethan did on trap thickness and coverage, excellent informative.

My question wasn't very clear. I was asking more about the density, whether 110 Kg/m3 was good for the traps I had already built. Anyway, sounds like they'll be fine.
Those should be fine.
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