Room EQ Wizard Tips

[soundslikejoe]

My measurement depict some dramatic combfiltering. I've read mention of 1/3 octave smoothing for frequency response curves. Is this a setting I can apply to my measurements?

Are there any other tips or tutorials for using REW to take measurements?

[Bguzaldo]

Check Ethan Winer's stuff out he has like a step by step for Room EQ softwares.

RealTraps - Optimizing Acoustic Treatment using ETF

hope this helps,
-Barrett

[jwl]

joenovice, you definitely don't want to set it to 1/3 octave smoothing. That will gloss over much of the comb filtering that exists in your room, since it averages all the energy in each 1/3 octave frequency band.

Even 1/12 is too much filtering, but at least that setting will give you a rough idea.

[soundslikejoe]

Originally Posted by jwl

joenovice, you definitely don't want to set it to 1/3 octave smoothing. That will gloss over much of the comb filtering that exists in your room, since it averages all the energy in each 1/3 octave frequency band.

Even 1/12 is too much filtering, but at least that setting will give you a rough idea.

That makes total sense. What doesn't make sense is frequency response curves I've seen for untreated small areas that don't display much comb filtering at all.

Like this for example.... Room EQ questions

Our room are about the same size but mine displays much greater comb variations in mid-high.

Here is Frank's test case.... GIK Acoustics

Out rooms are also similar in size but his baseline is very smooth in comparison. Not much comb there.

So.... Should any smoothing or filtering be applied or do I just have very unusual problems?

[Ethan Winer]

Originally Posted by joenovice

Should any smoothing or filtering be applied or do I just have very unusual problems?

My preference is no smoothing and a 200 millisecond gate time for frequencies below 300 Hz, and third-octave averaging at higher frequencies. This is for the raw response only. Then you need to display a waterfall plot to see low frequency ringing, and RT60 for mid/high frequency decay times. Between those four graphs you'll know pretty much everything you need. There's also a graph to view individual reflections, though the result of reflections shows in a response graph.

--Ethan

[soundslikejoe]

OK.... I found the Filtering section and have graphs with a similar apperance.

I got decent RT60 results but the Waterfall plot is a bit messy. I guess I still need to figure that one out.

[Weasel9992]

No argument intended here, but the issue of smoothing is a debated one. Yes, a plot with no smoothing shows the naked truth of the room, but it's not all relevant, audible information. Some level of smoothing will show you in a visual way what you're actually hearing in the room. That's why I used 1/12 smoothing in the plots in that report.

Frank

[Ethan Winer]

Originally Posted by Weasel9992

a plot with no smoothing shows the naked truth of the room, but it's not all relevant, audible information.

Agreed, especially at higher frequencies where what looks like humogous comb filtering might not really be so bad at all. That's why I use averaging above 300 or 400 Hz. But the commonly repeated notion that we hear at no better than third-octave resolution is just wrong, as debunked and explained here:

Audibility of Narrow-Band EQ

--Ethan

[DanDan]

Use the smoothing when you want to. It's like sunglasses....:-)
I got REW going recently on my Macs. It seems like the choice is 1/3 or none, with some workarounds.
FuzzMeasure has the full range of choice in a menu. 1/3 2/6/ 1/12 1/24 1/48 None.
I think that pretty much illustrates why there is a sort of debate on smoothing or not.
In FM I regard it a s Zooming.
DD

[Weasel9992]

Originally Posted by Ethan Winer

But the commonly repeated notion that we hear at no better than third-octave resolution is just wrong...

Totally agree.

Frank

[soundslikejoe]

Originally Posted by Weasel9992

No argument intended here, but the issue of smoothing is a debated one. Yes, a plot with no smoothing shows the naked truth of the room, but it's not all relevant, audible information. Some level of smoothing will show you in a visual way what you're actually hearing in the room. That's why I used 1/12 smoothing in the plots in that report.

Frank

Hey Frank,

What settings did you use for your waterfall plots?

[Weasel9992]

Originally Posted by joenovice

Hey Frank,

What settings did you use for your waterfall plots?

If you mean smoothing, 1/12 for everything.

Frank

[JohnPM]

Originally Posted by DanDan

I got REW going recently on my Macs. It seems like the choice is 1/3 or none, with some workarounds.

The choice is 1/1, 1/2, 1/3, 1/6, 1/12 or 1/24 octave (the setting is in the "Trace Adjustments" task pane). There is a keyboard shortcut to apply 1/3 octave smoothing listed in the Graph menu (Ctrl+Shift+3) which is probably what you came across. There are also shortcuts to remove smoothing (Ctrl+Shift+0) or apply 1 octave (Ctrl+Shift+1) or 1/2 octave (Ctrl+Shift+2) smoothing.

[DanDan]

Thanks John, I haven't had time to really investigate all the controls in REW. I will say that, in FM, I use all of those settings as appropriate to what I want to see. I am glad that you have provided them also.
DD

[hereticskeptic]

Bump. This thread may be useful to those with Mac computers, as well as those looking for REW tips. Promotion of the search function! : D

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