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Need help with next steps for 15 m² room
Old 5th November 2019
  #31
@ johannburkard : Just wonder how big your ceiling cloud is as I also want to install basotec plates on my ceiling. I think I´m going for 2mx1m and 10 cm thick.
Does the basotec absorbers on the table have any measurable effect?
Old 5th November 2019
  #32
Lives for gear
Quote:
Originally Posted by Lilith View Post
@ johannburkard : Just wonder how big your ceiling cloud is as I also want to install basotec plates on my ceiling. I think I´m going for 2mx1m and 10 cm thick.
Does the basotec absorbers on the table have any measurable effect?
Need help with next steps for 15 m² room
Old 5th November 2019
  #33
Quote:
Originally Posted by JayPee View Post
thanks!!
Old 5th November 2019
  #34
Quote:
Originally Posted by Lilith View Post
Does the basotec absorbers on the table have any measurable effect?
Acoustically, they make a small difference, yes. It feels like the sound is coming only from the speakers instead of speakers + desk.
Old 5th November 2019
  #35
Quote:
Originally Posted by JayPee View Post
Waterfall before / after?
Sorry, my waterfalls always look really ugly in REW. Can you download the measurements above? Thanks.
Old 5th November 2019
  #36
Quote:
Originally Posted by Lilith View Post
@ johannburkard : Just wonder how big your ceiling cloud is
The ceiling cloud is 1,20x1,20 m. The thickness is marginal at best but it did remove two reflections (ceiling and side wall/ceiling corner).

I may extend it with Basotect behind it at some point.
Old 5th November 2019
  #37
Quote:
Originally Posted by johannburkard View Post
Acoustically, they make a small difference, yes. It feels like the sound is coming only from the speakers instead of speakers + desk.
That´s the theory, but I wonder if it is audible.
Old 5th November 2019
  #38
Quote:
Originally Posted by Lilith View Post
That´s the theory, but I wonder if it is audible.
It was for me.
Old 5th November 2019
  #39
Lives for gear
Sorry to ruin the party but your waterfalls look ugly for some obvious reasons...

These GIK Scopus tuned bass traps don't work according to your measurements.

It looks like a untreated room in the the bass region.

Any reasons you decided to buy these panels instead of DIY? You are familiar on GS, you should know enough to try
Old 6th November 2019
  #40
Isn't it looking less ugly than before @ JayPee ?
Old 6th November 2019
  #41
Lives for gear
 
akebrake's Avatar
 

Quote:
Originally Posted by johannburkard View Post
Since @ Soundman2020 suggested I treat the 33 Hz 1-0-0 mode, I bought four GIK Scopus bass traps, tuned to 33 Hz.
Interesting!
How big are these Scopus boxes? (Area compared to rear wall?)

Quote:
From the measurements, I've effectively lost 4 dB at 33 Hz, and decay times there went down from ~2 s to 750 ms.
Agree to that. The plots below are my "Scopus investigation"

I've compared meas 1 (No Scopus) to meas 7 (4 Scopus)
All SPL (Overlay) pic1

Need help with next steps for 15 m² room-allspl-meas-1-vs-meas-7-4scopus-.jpg

Also Waterfall (slightly angled and meas 1 yellow for more visible decay)
pic 2

Need help with next steps for 15 m² room-scopus-wf-meas-1-vs-7-800ms.jpg

Quote:
Not everything looks better though...
As the main change here is concentrated to the rear wall (mode 1.0.0) with tuned 33Hz traps one cannot expect much more to happen. Note the bumpy decay around 66 Hz which probably are closely spaced modes (freq.wise) beating. They need treatment at other positions. pic 3 Hunecke mode calc.
Attached Thumbnails
Need help with next steps for 15 m² room-allspl-meas-1-vs-meas-7-4scopus-.jpg   Need help with next steps for 15 m² room-scopus-wf-meas-1-vs-7-800ms.jpg   Need help with next steps for 15 m² room-hun-revised-johann.jpg  
Old 6th November 2019
  #42
Quote:
Originally Posted by akebrake View Post
Interesting!
How big are these Scopus boxes? (Area compared to rear wall?)
They're 60x60 cm. The coverage is 20 % of the rear wall.

Quote:
Originally Posted by akebrake View Post
As the main change here is concentrated to the rear wall (mode 1.0.0) with tuned 33Hz traps one cannot expect much more to happen.
Sadly, I don't really have much space at the front.

Quote:
Originally Posted by akebrake View Post
Note the bumpy decay around 66 Hz which probably are closely spaced modes (freq.wise) beating. They need treatment at other positions.
Right, there is a 2-0-0 mode in there, along with a 1-1-0 mode and the 0-0-1 mode (my current understanding).

BTW: Thanks to @ akebrake , @ Soundman2020 and everybody who contributes in this forum. I've learned a lot over time!
Old 1st December 2019
  #43
I would like to tackle the hole between 100-120 Hz. I assume this is some kind of interference. Just with what walls? Ceiling/floor or sidewalls?
Attached Thumbnails
Need help with next steps for 15 m² room-spl.jpg  
Old 3rd December 2019
  #44
Gear Nut
 

Do you know this chart? Might help in spotting the offending surfce.

Cheers, Peer
Old 3rd December 2019
  #45
Gear Nut
 

I'll chime in here as my room is very similar - hope that's cool. Main differences are the larger and much more offset window and the room being multi use, as well as the fact I didn't buy any absorbers yet. The guy at GIK recommended to just leave the nasty 30Hz 1-0-0-mode alone and use a high pass unless I wanted to put up 12 Scopus Traps tuned to 30Hz (that means covering 3,6m² or about 55% of the back wall).
That's quite contrary to this:

Quote:
Originally Posted by Soundman2020 View Post
In other words, if you want to get good frequency response in your room, start by fixing the lowest modal issues and SBIR.
So what would you recommend for a start then? I could see myself covering the full length of the back-wall / ceiling corner with one row of (DIY membrane?) absorbers, going down something like 60cm from the ceiling (i.e. an equivalent of 5 Scopus traps). Would that make sense? Could it even be sufficient 1-0-0-treatment to be able to play 30Hz properly?

Cheers, Peer

Last edited by PeerSoe; 3rd December 2019 at 09:52 PM.. Reason: correction
Old 3rd December 2019
  #46
Quote:
Originally Posted by PeerSoe View Post
Do you know this chart? Might help in spotting the offending surfce.
Did not know it, thanks. For one hole at ~110 Hz, there would need to be something 78 cm nearby but the side wall is closer, the ceiling and floor further away. Not sure.
Old 3rd December 2019
  #47
Quote:
Originally Posted by PeerSoe View Post
So what would you recommend for a start then? I could see myself covering the full length of the back-wall / ceiling corner with one row of (DIY membrane?) absorbers, going down something like 60cm from the ceiling (i.e. an equivalent of 5 Scopus traps).
You have seen the effect of four tuned membrane bass traps on my 1-0-0 mode which was measureable but not life-changing (not that GIK support claimed it would be). What I found odd is that I did not see much of any effect on 2-0-0, 3-0-0 and 4-0-0 modes (which GIK support claimed would happen).

Going back through my tests, using two GIK Monster Bass Traps with Range Limiters instead of Artnovion Wall Bass Traps on the first reflection side walls had a very strong effect between 90-300 Hz.

I have so far preferred treatment that's easy to move. I don't think you can go wrong with having let's say 20 or so 10 cm panels of something like Caruso Iso-Bond or Basotect that you can experiment with easily. Mounting my Artnovion Wall Traps made me realize that because installing them was a horrible experience compared to GIK.

Last edited by johannburkard; 11th January 2020 at 12:23 AM.. Reason: Expanding a bit
Old 3rd December 2019
  #48
I've done a test today where I moved the microphone up and down but the frequency of the holes did not change which means it's not a ceiling/floor reflection. When position the microphone closer to the side walls (but at the same distance to the speaker), one of the holes came up so I'm sitting in some modal nulls in that position.
Attached Thumbnails
Need help with next steps for 15 m² room-l-heights.jpg   Need help with next steps for 15 m² room-r-heights.jpg  
Old 4th December 2019
  #49
Lives for gear
....or SBIR
Old 5th December 2019
  #50
Quote:
Originally Posted by JayPee View Post
....or SBIR
Don't think so, especially not with ceiling/floor. When I moved the microphone closer to the side wall, the hole filled up again.
Old 5th December 2019
  #51
Lives for gear
This dip is very common but you have much bigger problems to deal with
Old 5th December 2019
  #52
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akebrake's Avatar
 

Testing

Quote:
Originally Posted by johannburkard View Post
I've done a test today where I moved the microphone up and down but the frequency of the holes did not change which means it's not a ceiling/floor reflection. When position the microphone closer to the side walls (but at the same distance to the speaker), one of the holes came up so I'm sitting in some modal nulls in that position.
Sometimes floor/ ceiling bouncing kind of cancel each other when moving the mic up/down. Just a shot in the dark...

In the photo (post 28) it looks like the speakers are close to the 0-2-0 and 0-0-1 mode nulls? (≈25% from the side wall. Half way between floor ceiling) Is it possible to improve speaker placement?

Tip: REW Generator: Pink PN (Pink Periodic Noise)
Display: RTA 1/48 Oct

IMHO Pink Noise is quite boring so I routinely band limit in order to save ears and tweeters. REW 5.19 Set Up Example below. (Note: This is not a room)

Move one loudspeaker up/down/ left right while watching the RTA and see what happens in ”Real Time”. Same method can be used for the microphone.

Best
Attached Thumbnails
Need help with next steps for 15 m² room-spkr-pos-rta-tst.jpg  
Old 5th December 2019
  #53
Thanks @ akebrake , yes, I wanted to play with the RTA tool for a while. The speaker position is a strange one. Moving the right speakers away from the side wall seems to introduce more holes, probably because the structure behind it (window) is not the same as for the left speaker (wall). I'm now sitting about 1,5 m away from the speakers which for me is quite far. I'd like to get a little closer but I still need to get to the window. What do you think about the equilateral triangle BTW? BS? I'm currently a bit "in" the triangle.
Old 9th February 2020
  #54
Desk vs. Workpad

In an attempt to go more minimalist, I am experimenting with replacing my desk with a workpad.

Need help with next steps for 15 m² room-desk-vs-workpad-l.jpg

Minimal changes to the amplitude response.

Need help with next steps for 15 m² room-desk-vs-workpad-etc-l.jpg

A deeper dip in the first 1 ms?

Subjectively, things don't sound any worse after GLM/SAM than before, maybe a bit better (I may be sitting closer to the front though).
Attached Thumbnails
Need help with next steps for 15 m² room-p1040482.jpg   Need help with next steps for 15 m² room-p1040483.jpg   Need help with next steps for 15 m² room-desk-vs-workpad-l.jpg   Need help with next steps for 15 m² room-desk-vs-workpad-r.jpg   Need help with next steps for 15 m² room-desk-vs-workpad-etc-l.jpg  

Need help with next steps for 15 m² room-desk-vs-workpad-etc-r.jpg  
Old 15th February 2020
  #55
I bought four of the new German Wunderwaffe: Caruso Iso-Bond WLG040. I didn't have any treatment at the moment that I could move around and experiment with easily and Iso-Bond is really good for that. This is all 10 cm depth each BTW.

Control:

Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-control.jpg

The first test was placing it on the floor along both front side walls (2*20 cm). This did improve the impulse response quite a bit and is also doing a lot to the spectrogram. I didn't expect this position to be this effective.

Need help with next steps for 15 m² room-caruso-iso-bond-front-side-floor.jpg

Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-front-side-floor.jpg

Then, I made another test and added two pieces of 20 cm depth to the parts of the rear wall that weren't treated yet. Another strong change, probably even bigger than the front side walls.

Need help with next steps for 15 m² room-caruso-iso-bond-rear-wall.jpg

Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-rear-wall-sides.jpg

What's impressive is that only 20 cm of WLG040 do something at 60 Hz and are pretty effective at 90 Hz. I may not need 40 or 50 cm depth really.

The measurements are here (20 MB).
Attached Thumbnails
Need help with next steps for 15 m² room-caruso-iso-bond-front-side-floor.jpg   Need help with next steps for 15 m² room-caruso-iso-bond-rear-wall.jpg   Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-control.jpg   Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-front-side-floor.jpg   Need help with next steps for 15 m² room-caruso-iso-bond-spectrogram-rear-wall-sides.jpg  

Old 15th February 2020
  #56
Lives for gear
 
Starlight's Avatar
 

Johann, I just wanted to say that I am so impressed at how much time you have invested to fully understand REW and experimented with a whole range of acoustic treatments. You deserve to end up with the best sounding studio on the planet.
Old 15th February 2020
  #57
Quote:
Originally Posted by Starlight View Post
You deserve to end up with the best sounding studio on the planet.
I'm just shooting for the best sounding ****ty 15 m² apartment room on the planet.

Thanks Starlight.
Old 16th February 2020
  #58
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akebrake's Avatar
 

Size of trap?

Quote:
Originally Posted by johannburkard View Post
I didn't have any treatment at the moment that I could move around and experiment with easily and Iso-Bond is really good for that. This is all 10 cm depth each BTW.
Just having a couple of movable, human friendly, absorptive panels for testing is a nice and educational way to find out:

"What happens if I add xx area of 20 cm trapping ..." !

What size is one Iso-Bond WLG040 absorber panel?
60x 120x 10cm (24x 48x 4 inch)?

Best

PS One can also use (small) reflective panels (plexi glass/ cardboard/ ply etc) to help identification of different boundaries in the ETC plot. If in doubt...
Old 16th February 2020
  #59
Quote:
Originally Posted by akebrake View Post
What size is one Iso-Bond WLG040 absorber panel?
60x 120x 10cm (24x 48x 4 inch)?
Yes, the standard size (kind of).

Quote:
Originally Posted by akebrake View Post
PS One can also use (small) reflective panels (plexi glass/ cardboard/ ply etc) to help identification of different boundaries in the ETC plot. If in doubt...
Good idea.
Old 21st February 2020
  #60
Lives for gear
 
akebrake's Avatar
 

Quote:
Originally Posted by johannburkard View Post
...What's impressive is that only 20 cm of WLG040 do something at 60 Hz and are pretty effective at 90 Hz. I may not need 40 or 50 cm depth really.

The measurements are here (20 MB).

Hi Johann,

Distortion window
When investigating mdats I usually start with the Distortion tab where one can see Fundamental (the sweep), Total Harmonic Dist. and the Noise Floor.
”Normal” Noise Floor (wind, rain, traffic, machinery... etc.) is usually around 30dB SPL (or more)
As your distortion figure looks OK, I have ”guesstimated” the peak level to be around 95dB. (I inserted that value in the Impulse Tab)

Pic 1 Distortion
Need help with next steps for 15 m² room-1.feb-15-dist.jpg

In order to compare your older measurement with the newer, I have first opened the nov 4 "Musikzimmer" mdat, (just kept one sweep), then opened the latest "caruso" feb mdat. (Kept one sweep)
Booth meas. are Left speaker.


Impulse window
Then I observed your earlier Nov. "musikzimmer" Impulse looks very different to the later ”caruso-iso-bond” Impulse... ? (Pic 2 & 3)

Need help with next steps for 15 m² room-2.musikz.jpg

Need help with next steps for 15 m² room-3.-caruso-.jpg

At a closer look I noted a different signal chain is used. (measurement Info)
Zooming in on the impulses. Pic 4 Overlay Clocking error?

Need help with next steps for 15 m² room-4.-impulse-ovly-zoom.jpg

pic 5& 6 Measurement Info from the two examples

If that strange Impulse ruins the LF measurement results I don’t know...
Finer ETC details possibly...

To find out, try comparing the two "methods" at the same occasion.

Best
Attached Thumbnails
Need help with next steps for 15 m² room-1.feb-15-dist.jpg   Need help with next steps for 15 m² room-2.musikz.jpg   Need help with next steps for 15 m² room-3.-caruso-.jpg   Need help with next steps for 15 m² room-4.-impulse-ovly-zoom.jpg   Need help with next steps for 15 m² room-5.-nov-4-17_16_01-l.jpg  

Need help with next steps for 15 m² room-6.-feb-15-18_40_44.jpg  
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