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First measurement - What to do with it?
Old 4 weeks ago
  #1
Here for the gear
 

First measurement - What to do with it?

Hi everyone!

Now that I have the opportunity to use a room for music production purposes exclusively, I'd like to do some acoustic treatment.

Unfortunately my room is nearly quadratic as it is 308 x 328 x 250 cm, except of one "cut out" in the corner and of course that isn't really big at all (see picture).

I would like to achieve a better sound for mixing and recording vocals.

I did a first measurement (or at least 3 of them, left speaker, right speaker and both together), the mdat-file and some graphs are attached.


Although I'm a total beginner to room acoustics (except reading some stickys and threads in boards or watching youtube), I tried to interpret things a bit:

- small resonance at 55 Hz
- very ugly resonance at 130 Hz (where the wave length fits in the cube/room almost perfect as it's about 266cm)
- the "impulse" graph to me seems, as if there's a lot of flutter echo


Is that correct or am I horribly wrong?


And: What to do now?

Again, my thoughts on this:

- diffusors at the rear wall to reduce/eliminate flutter
- bass traps at the corners of the front wall (on the right side - on the left side right in front of the "cut out" corner)
- maybe helmholtz resonator(?) to kill the 130 Hz resonance


Could that be useful in any way?
What would you suggest?

Thanks in advance for your help!
Attached Thumbnails
First measurement - What to do with it?-grundriss-studio_1.jpg   First measurement - What to do with it?-spl-green-left-blue-right-red-both.jpg   First measurement - What to do with it?-waterfall-30-20000.jpg   First measurement - What to do with it?-waterfall-bass.jpg  
Attached Files
File Type: mdat Messung Ausgangssituation.mdat (9.18 MB, 14 views)
Old 4 weeks ago
  #2
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Jason Foi's Avatar
 

Somethings wrong. That peak at 130hz has no decay. It would be a constant hum in the room. You dont hear anything? If not, its in your signal chain somewhere.

I would also set up on the oposite wall.
Old 4 weeks ago
  #3
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Thank you for your answer!

Quote:
Originally Posted by Jason Foi View Post
Somethings wrong. That peak at 130hz has no decay.
I just can't say, what could have went wrong here. The peak is equal in all measurements (l, r and both). If I'm right, there is a decay, but a very, very slow one. I've attached the spectrogram, what I would interpet like that.

Quote:
Originally Posted by Jason Foi View Post
I would also set up on the oposite wall.
Good point, thank you! I could try switching front and rear walls. The sides aren't an opportunity as the door and window still need to be opened.

[second try, this time with attachment ]
Attached Thumbnails
First measurement - What to do with it?-spectrogram.jpg  
Old 4 weeks ago
  #4
If you make a sweep with

https://www.szynalski.com/tone-generator/

Do you hear the resonance at 130 Hz?
Old 4 weeks ago
  #5
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Quote:
Originally Posted by Lilith View Post
If you make a sweep with

https://www.szynalski.com/tone-generator/

Do you hear the resonance at 130 Hz?

Just tested it (thanks for the link btw) and yes, at this frequency it gets much boomier than at any other.
Old 4 weeks ago
  #6
What are your speakers? Did you play with the speaker position and mic position already? When you walk around in the room does the 130 Hz volume decrease somewhere?
Old 4 weeks ago
  #7
Here for the gear
 

Quote:
Originally Posted by Lilith View Post
What are your speakers?
I have a pair of Samson Rubicon R6a, which I'm using for music production (and additionally a pair of passive JBL Control One's on a Yamaha AX-396, but they are just for cross checking sometimes).


Quote:
Originally Posted by Lilith View Post
Did you play with the speaker position and mic position already?
Not yet, but just like Jason Foi said, I will try to switch my working place to the wall on the bottom tomorrow and measure again.


Quote:
Originally Posted by Lilith View Post
When you walk around in the room does the 130 Hz volume decrease somewhere?
It's almost in the whole room, getting worse in the corners - except for exactly that wall at the bottom. In the middle of it, seems like the resonance is gone (almost) completely.
Is that a good sign for moving my working place over there maybe?
Old 4 weeks ago
  #8
Yes, facing the other wall would help, but wouldn't expect wonders. Bass traps (minimum 40-50 cm thick) will help to reduce the ringing time.

I wonder a bit why the decay time is so short for the other low freqs. Do you have a couch or something in the room? Maybe it's also because your measurement volume look quite low. You should measure at around 80dB. A cell phone app should do the job to roughly estimate the right volume.
Old 4 weeks ago
  #9
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Quote:
Originally Posted by Lilith View Post
Yes, facing the other wall would help, but wouldn't expect wonders.
Thank you, I'll try it and tell about the results.


Quote:
Originally Posted by Lilith View Post
Bass traps (minimum 40-50 cm thick) will help to reduce the ringing time.
I think I will build DIY traps and will give them a thickness of at least 50 cm.

What about the wall opposite to my working place?

The reverberation times in the mids and highs seem to be okay and absorbtion wouldn't be absolutely necessary, is that right?
I've read, that putting diffusors at the rear wall can make the room sound a bit "bigger", nicer/more natural and reduce flutter. So, for having a good sounding room, should I try putting some diffusors in the back or not?
Old 4 weeks ago
  #10
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Quote:
Originally Posted by Lilith View Post
I wonder a bit why the decay time is so short for the other low freqs. Do you have a couch or something in the room?
No, there's nothing like that in the room.
Could it be effacements maybe?


Quote:
Originally Posted by Lilith View Post
Maybe it's also because your measurement volume look quite low. You should measure at around 80dB.
I didn't have a dB-meter, so I set up the Volume to approximate the loudest level I would normally listen to whilst producing.


Quote:
Originally Posted by Lilith View Post
A cell phone app should do the job to roughly estimate the right volume.
Why didn't I think of that myself? Thank you! I'll do that from now on!
Old 4 weeks ago
  #11
I don't think it's effacements as it's quite even. Let's look at the new measurements. Flatter echoes, etc is easy to treat compared to the room mode(s), so I would first try to get the bass right.
Old 4 weeks ago
  #12
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Jason Foi's Avatar
 

Try playing that 130hz tone and walk around the room and touch everything, walls, furniture, etc, including the speaker cabinets. Something is resonating.
Old 3 weeks ago
  #13
As others have mentioned, the decay times are nice but there is little energy between 70-90 Hz so you'll still need some absorption to tame this (may be side wall interference), I think.
Old 3 weeks ago
  #14
Here for the gear
 

Thank you for your answers as well!


Quote:
Originally Posted by Jason Foi View Post
Something is resonating.
You were right. My fault: wrong settings in the DSPMixFX of my soundcard.


I have now fixed that and did a new measurement (and it really looks much better now, especially at the 130Hz resonance).

Afterwards, I moved my working place to the opposite wall (the one at the bottom of the picture) and measured again.


What do you think?

To me, somehow the first speaker position seems to work better even though they aren't placed symmetrically in the room, because of the cut corner.
Attached Thumbnails
First measurement - What to do with it?-bottom-wall-30-300.jpg   First measurement - What to do with it?-specbottom.jpg   First measurement - What to do with it?-spectop.jpg   First measurement - What to do with it?-top-wall-30-300.jpg  
Old 3 weeks ago
  #15
The second position looks a lot better to start with. You can see that the hole in the frequency response is narrowing a bit (less interference). Modal activity is higher up which is always good (less treatment needed).
Old 3 weeks ago
  #16
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Quote:
Originally Posted by johannburkard View Post
The second position looks a lot better to start with.
Just to make sure I'm getting you right (I'm a total noob in this whole thing):

The position at the bottom wall (attachment 1 [BOTTOM WALL 30-300] and 2 [SpecBOTTOM] in my last posting), which is the second position, is better?
Old 3 weeks ago
  #17
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akebrake's Avatar
 

Quote:
Originally Posted by knobsnfaders View Post
Just to make sure I'm getting you right (I'm a total noob in this whole thing):

The position at the bottom wall (attachment 1 [BOTTOM WALL 30-300] and 2 [SpecBOTTOM] in my last posting), which is the second position, is better?
(I'm not Johann) but if you upload the mdat from your measurements we can compare them (in several ways) to see which one is probably "better" in an untreated room (if that is important?)

The result (treated room) also depends on if there are space for treatment, desk and traffic etc

Best


PS If one file is too big for uploading, just make two or more files.
Old 3 weeks ago
  #18
Quote:
Originally Posted by knobsnfaders View Post
The position at the bottom wall (attachment 1 [BOTTOM WALL 30-300] and 2 [SpecBOTTOM] in my last posting), which is the second position, is better?
The filename is specTOP so I guess it's the top position.
Old 3 weeks ago
  #19
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Quote:
Originally Posted by akebrake View Post
(...) if you upload the mdat from your measurements we can compare them (in several ways) (...) PS If one file is too big for uploading, just make two or more files.
I tried to upload them here, but after the upload was complete it didn't paste the attachment in my post.


I uploaded the 2 measurements at a host now:

Position 1:
http://s000.tinyupload.com/index.php...14365265784821

Position 2:
http://s000.tinyupload.com/index.php...86536815050721
Old 3 weeks ago
  #20
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akebrake's Avatar
 

Quote:
Originally Posted by knobsnfaders View Post
...I uploaded the 2 measurements at a host now...
Seems to work OK

Small, (close to cube shaped) rooms are a challenge. Nearly all room modes have nulls i the middle of the room.
Unfortunately this is often also close the listening position/ (mic)... huh

Hunecke room mode calculator (Link) can demonstrate that.
Just insert room dimensions and step through the modal frequencies and watch the light areas. (No bass...)

That doesn’t prevent modes to have long decay. REW T60 graph gives an idea. Here the Topt values. At 125 Hz the 1/1 Octave band decaytime is around 1 second! Above 500 Hz around 0.35s. Pic 1

L& R Frequency Response of the Bottom wall loudspeaker (AllSPL tab)
Psy smoothing used to similate ”what it sounds like”. Around 15 dB more Low End would be nice... Pic 2

A lot of bass& low mid trapping is needed to attenuate 53-500 Hz reflections from the room boundaries (Walls, ceiling)
L & R Freq Response with more detail ( 1/24 Oct smoothing) Pic 3

So you have to decide how many, how big and what kind of traps you can build.
Soft or maybe Helmholtz for the rear wall.

Suggestion:
IMHO floor to ceiling corner traps in the front and a deep rear wall trap is a good start. Pic 4 sketch
Attached Thumbnails
First measurement - What to do with it?-topt-6-1-1-oct-plots.jpg   First measurement - What to do with it?-l-r-psy-bottom.jpg   First measurement - What to do with it?-bottom-wal-l-r-1-24-oct-allspl.jpg   First measurement - What to do with it?-knobsnfaders2.jpg  
Old 3 weeks ago
  #21
Here for the gear
 

Thank you for your detailed analysis, that makes it a lot easier for me to comprehend!

And again thank you for your suggestions where to begin with the treatment.


I'll start with making floor to ceiling hemp traps with a plane of 45 x 45 cm for the front corners, maybe even 50 x 50 cm if I have enough space to place them.


Afterwards, I will measure again and see, where to go from there on.
Old 3 weeks ago
  #22
What's the material you have in mind? This Thermohanf stuff?
Old 3 weeks ago
  #23
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Quote:
Originally Posted by johannburkard View Post
What's the material you have in mind? This Thermohanf stuff?
Yes, thought about that, the "Thermohanf Premium" with 40mm thickness* stacked into 2 frames with about 120cm height each per side.

*as i read, that this one has the highest density of the Thermohanf products with 40kg/m³. The thicker or thinner plates partly have only 35kg/m³.
Old 3 weeks ago
  #24
If the flow resistivity numbers are in here, plug the numbers into http://www.acousticmodelling.com/. Maybe you'll find a product that will work better at the depth you have in mind.
Old 3 weeks ago
  #25
Gear Maniac
 

Quote:
Originally Posted by knobsnfaders View Post
Hi everyone!

Now that I have the opportunity to use a room for music production purposes exclusively, I'd like to do some acoustic treatment.

Unfortunately my room is nearly quadratic as it is 308 x 328 x 250 cm, except of one "cut out" in the corner and of course that isn't really big at all (see picture).

I would like to achieve a better sound for mixing and recording vocals.

I did a first measurement (or at least 3 of them, left speaker, right speaker and both together), the mdat-file and some graphs are attached.


Although I'm a total beginner to room acoustics (except reading some stickys and threads in boards or watching youtube), I tried to interpret things a bit:

- small resonance at 55 Hz
- very ugly resonance at 130 Hz (where the wave length fits in the cube/room almost perfect as it's about 266cm)
- the "impulse" graph to me seems, as if there's a lot of flutter echo




Is that correct or am I horribly wrong?


And: What to do now?

Again, my thoughts on this:

- diffusors at the rear wall to reduce/eliminate flutter
- bass traps at the corners of the front wall (on the right side - on the left side right in front of the "cut out" corner)
- maybe helmholtz resonator(?) to kill the 130 Hz resonance


Could that be useful in any way?
What would you suggest?

Thanks in advance for your help!
That room is very small and very square. Can you not find another space to work from? In all honesty,you may never be happy with the results
Old 3 weeks ago
  #26
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Quote:
Originally Posted by eljefe View Post
Can you not find another space to work from?
As it's a rental flat (which itself isn't too big at all), I don't have any other room to work in.
I was already using this room before, but my girlfriend had her office stuff in it, too. So there was no space for doing any acoustic treatment. Now, that I have the whole room to work with, I'd like to try making it sound better, even though I know it'll never be perfect anyway. But hopefully somewhere between "less bad" and "quite good"
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