# Best Settings for Waterfall Graph



## alpenpoint (Apr 27, 2011)

Hi,

can you say me what are the best settings for the Waterfall Graph?
A measure of my DBA with 4 Subwoofer.









What are the best values for "Total slices", "Time Range", "Window", "Rise Time" .......
What do you say to the waterfall?
I do not understand the long reverberation time at 33Hz . Should not be in a DBA?
What is meant by "use csd mode"?

thanks


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## JohnM (Apr 11, 2006)

There is an explanation of the controls in the waterfall help, the settings you have look fine. 

Everything below 60 Hz in the response looks great, wouldn't worry too much about the stuff around 30 Hz, it is well below the direct part of the response.


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## Wayne A. Pflughaupt (Apr 13, 2006)

alpenpoint said:


> Hi,
> 
> can you say me what are the best settings for the Waterfall Graph?


Adding a bit to John’s comments, I’d suggest lowering the graph floor down to the room’s ambient noise, ~35 dB is typical.

I typically just use the default settings. About the only thing I change is the Window (ms) Time. For instance, you could extend the window to 1000 ms to see how long the stuff in the 70+ Hz range is taking to decay down to the noise floor. IIR if you have everything except the lowest frequencies decaying to the noise floor in a 300 – 400 ms window, that’s considered pretty good.

The 30 Hz thing looks like some kind of steady-state (continual) noise, like the drone of a HVAC motor, etc. I’ll bet in a 1000 ms window you’d see virtually no decay.

Regards,
Wayne


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## alpenpoint (Apr 27, 2011)

Hi john

Thank you very much I have already tried to reduce the reverberation at 30Hz. Many people say that in a normal DBA is no reverberation.
You can see my measurements here:
http://www.beisammen.de/board/index.php?page=Thread&threadID=118166&pageNo=4
I do not hear the reverberation at 33Hz.
I'm going to read the manual.

thank you


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## alpenpoint (Apr 27, 2011)

I measure only 4 Subwoofer here as double bass array

"The 30 Hz thing looks like some kind of steady-state (continual) noise, like the drone of a HVAC motor, etc. I'll bet in a 1000 ms window you'd see Virtually no decay."

I do not quite understand, it could be the fan noise of the amplifier? Behringer iNUKE 6000DSP.
What is a "HVAC Motor".

Here are the measurements but scaled differently.

















What noise could it be?

thank you, Alpi


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## alpenpoint (Apr 27, 2011)

Hi,

here is the file.

View attachment Messung REW Forum.mdat


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## JohnM (Apr 11, 2006)

You are bound to have some residual modal behaviour unless you can arrange enough subwoofers at each end of the room to produce a true plane wave - minimum is probably 4 each end, positioned 1/4 of the width in from the sides and 1/4 of the height in from the floor and ceiling. With 2 each end they need to be positioned at mid height, but the DBA effect would not extend as far up the frequency range. There may also be other parts of the room that have some resonance that emerges in the response, such as floor or ceiling voids for suspended floors or ceilings, or even items of furniture like large cupboards.


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## alpenpoint (Apr 27, 2011)

I found it.
I have no "heating ventilation and air condition", in Tirol/Austria not the usual.
But it could be the fan of the amplifier really. I'll check that.

thanks


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## alpenpoint (Apr 27, 2011)

I have 4 LAB12 per wall but currently I run only two Lab12 per wall. With 8 LAB12 I have the same problem.
The room has only concrete walls, two windows and a door.


My Room:

























The door resonates at about 66Hz. The Helmholtz resonator, it is not - definitif!


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## Wayne A. Pflughaupt (Apr 13, 2006)

alpenpoint said:


> "The 30 Hz thing looks like some kind of steady-state (continual) noise, like the drone of a HVAC motor, etc. I'll bet in a 1000 ms window you'd see Virtually no decay."
> 
> I do not quite understand, it could be the fan noise of the amplifier? Behringer iNUKE 6000DSP.
> What is a "HVAC Motor".


Yes, it could be fan noise from the amp. 




alpenpoint said:


> I found it.
> I have no "heating ventilation and air condition", in Tirol/Austria not the usual.
> But it could be the fan of the amplifier really. I'll check that.


 If that’s not it, then household appliances like refrigerators, washing machines, etc. can generate noise when they are running. Also, if you live in a crowded city the noise source could be something outside the house.

As John said, it’s well below the signal levels so if you can’t figure out what it is, it’s not going to have any effect on anything except your waterfall graph.

Regards, 
Wayne


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## alpenpoint (Apr 27, 2011)

hello

I live in a very quiet area, it runs no fridge in the room, or the like. I forgot, i've also been measured with a fanless Amplifier and I had the same result as with the fan.
I'll make a measurement of ambient noise and post here.

"As John said, it's well below the signal levels so if you can not figure out what it is, it's not going to have any effect on anything except your waterfall graph."

That's good, but I am very interested why I have this long reverberation.

Regards, Alpi


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