Help with room eq wizard understand the graph

[Glenn Kuras]

Can you post the REW file? Watch the following video which explains how to zip it and save it to upload here.
Room EQ Wizard Tutorial - GIK Acoustics

[jim1961]

Originally Posted by soundcard91

Hi,
i have measured my room acoustic using a behringer ecm8000 and room eq wizard.
The room is about 4x5x3 meters and is the room where i will mix (i have another room to record).

I would like to know how to interprete the graphics of rew.
I attach here THE ALL SPL and WATERFALL graphics.

I hope someone can help me!


Thanks

150dbSPL ?

[DanDan]

http://www.irishacoustics.com/index....oom-acoustics/
One Speaker. Waterfalls 20-300......
I think the SPL meter can be calibrated or miscalibrated so to speak.
Use the Input Level Meter and get close to FS. You probably already did. Zip and post the .mdat file or Export the IR as a WAV. Leave it at 32Bit resolution.

DD

[soundcard91]

I have already calibrated all, i have used the ecm 8000 calibration file and set up the volume till rew said they are ok.

In the attachments there is the rew file
I hope it is enough, if possible i would like to know what i should see to know what to correct in a room, because i will need to do it for different rooms in the next weeks.

Thanks!

[soundcard91]

Btw tomorrow i redo all the measurements to be sure that i have done all ok... I think i have done something wrong in db SPL calibration but in the meanwhile i would be happy to know how to evaluate the results of rew

[soundcard91]

Dear friends, please ignore my previous misuration file, i have redone the misuration now with perfect calibration of audio card and microphone.

I put it here attached.
I hope you can help me!

[JohnPM]

Your measurement is valid, but your soundcard calibration is wrong. You need to remove that soundcard calibration, it is a measurement of your room, not of your soundcard. As the measurement otherwise looks OK you can probably just skip soundcard calibration. You do need to go through the SPL calibration so that your graphs are shown at the correct level.

[soundcard91]

Originally Posted by JohnPM

Your measurement is valid, but your soundcard calibration is wrong. You need to remove that soundcard calibration, it is a measurement of your room, not of your soundcard. As the measurement otherwise looks OK you can probably just skip soundcard calibration. You do need to go through the SPL calibration so that your graphs are shown at the correct level.

Are you referring to my last post and attachment or to the first?
Because for the first yes i have done a wrong calibration of the soundcard, for the second all went ok i think...

Thanks!

[Glenn Kuras]

Also you want to measure each speaker separately.

See the following videos to help you with placement of your set up and also placement of treatment.
The Basics of Room Acoustics: Bass Traps, Diffusion, Panels - GIK Acoustics
Positioning the Listening Spot - GIK Acoustics

[soundcard91]

I have already measured the speaker alone, i am measuring now the right speaker only.
Btw here i have remeasured all without calibration of the audio card but with db spl settings.
It is attached.

I hope you can gimme some advices on how to improve the acoustics.
For what i see:
- In RT60 for me the reverb of the low frequencies is too high and the sound of the room will be not so clear...
- For what i see in the waterfall i probably need some bass traps, there are some peaks.

WHat do you think?

[JohnPM]

Originally Posted by soundcard91

Are you referring to my last post and attachment or to the first?

I was referring to the last post.

[soundcard91]

Originally Posted by JohnPM

I was referring to the last post.

ok thanks! I have posted in the very last post another measurement, i hope now is correct

[Glenn Kuras]

Like I said before I would look at where your set is and see if you can move to get the response better. From there start bass trapping in corners as much as possible with absorption in the early reflection points.

[soundcard91]

In the attachments the drawing of how is the room about...

[Glenn Kuras]

I would face the left wall (centered) and put the monitors close to the wall as possible. Having the mix spot the way you have it is going to really throw things off.

[soundcard91]

Dear Glenn the right speaker is there but the left one is already near the wall How you would put them?

[Glenn Kuras]

Originally Posted by soundcard91

Dear Glenn the right speaker is there but the left one is already near the wall How you would put them?

Turn the mix spot to face the left wall (centered). Put the monitors as close to the all as possible.

[soundcard91]

Originally Posted by Glenn Kuras

Turn the mix spot to face the left wall (centered). Put the monitors as close to the all as possible.

This is the measurement with the speaker facing the wall as you asked

For what i see i see also here that i need bass traps...
Strange is that around 60hz the graph is quite down...

What do you think?

[Glenn Kuras]

Every room will need bass traps. The point of moving is to the find the best location then treat the room.

[soundcard91]

but my question is i can add absorbing material and redo measurements but when i know on the graph when the room is ok?
What i must have in the graph for a good room?

[Glenn Kuras]

1)You are looking for the flattest frequency response as possible, but keep in mind that you will never get it totally flat.

2)Even decay times across the board (bass traps).
From an article I did.

Waterfall Graphs

Before we move on to the next set of tests, here is a little background on decay times and waterfall graphs and why they are so important to view (if not more important then frequency response). As sound plays through your speakers it doesn’t just get to you and stop but continues to bounce around the room and slowly fades away over time. This is sometimes referred to as ringing or reverb. A waterfall graph allows you to visualize how quickly or slowly a given frequency decays over time.

Low frequencies tend to be stronger and stay more intense longer than higher frequencies. Higher frequencies are also easier to control. Things like people, furniture, carpet, curtains, and even air tend to have a much more significant impact on the higher frequencies than lower ones. In addition, high frequencies are much more directional where low frequencies tend to spread like a sphere in 3 dimensions. In a bare room, there really isn’t much that has any significant impact on low frequencies which is why it is critical to have proper bass trapping . As the low end keeps bouncing around the room there are other things that you are trying to hear but the frequencies that are ringing are masking imaging cues, harmonic textures, and even cancelling and/or reinforcing themselves.

3)Knock down early reflections to about -20db to around 20ms. You would view the ETC graph

[soundcard91]

Ok! All clear, the only problem is i cannot find wher eis the etc graph in rew.... where is?

[Glenn Kuras]

Look under impulse

[soundcard91]

Ok!
Attached there is my impulse graph.
How to interprete it?

[soundcard91]

Should i have only the spike at 0 and nothing after ideally no?

[Glenn Kuras]

You want to view with a range from zero to around 60ms or so. The spikes between 0 and 20ms are early reflections and should be around -20db.
Video Early or First Reflection Points - GIK Acoustics