Waterfall graph

[Wheelman76]

Hello,

I’m new to REW and I’m having an issue with my waterfall graph. I’ve taken a few measurements and most of the tabs look normal, the waterfall graph is showing a tonne of decay. So much in fact that the blue colour of the chart along the bottom never stops. I know that I don’t have anywhere near the levels of decay that this chart is showing.

Am I doing something wrong while taking the measurements, or do I have a setting wrong for this particular chart?

Any help is most appreciated
Cheers

 

[Wayne A. Pflughaupt]

No need for phone pictures. The camera icon at the top left of the graph will save it as a jpeg.

For starters, your bottom horizontal limit is too low. Few rooms have a noise floor as low at 30 dB, and that’s the reason the blue “never stops.” I.e. it never stops because the room background noise is steady-state. A 45 dB floor for the graph would be a more realistic setting.

Next, 600 ms is a more reasonable time /window length setting.

In addition, it’s generally accepted that waterfall graphs are only useful up to about 200-250 Hz.

Recommended reading:

Thread 'Adventures in Waterfalling: Understanding Signal Levels in Time-Domain Graphs'

Aug 14, 2020

Adventures in Waterfalling
Understanding Signal Levels in Time-Domain Graphs​

Once upon a time in a land far, far away, the capability to generate waterfall graphs was limited to expensive software programs available primarily to professional speaker designers and acoustics engineers.

However, the advent of affordable measurement platforms like TrueRTA, Room EQ Wizard and others has made these powerful analytical tools available to the general public, most of whom have no formal training or experience in the relevant sciences. As a result we now have a curious...

• Wayne A. Pflughaupt
• Replies: 18
• Forum: Tech Talk

• 

Thread 'Adventures in Waterfalling Part Deux: Multiple Subs, Free Bass Traps, and More'

Aug 17, 2020

Adventures in Waterfalling Part Deux
Multiple Subs, Free Bass Traps, and More​

NOTE: Readers are encouraged to wade through my previous article on waterfalls and signal levels before delving into this one, to fully understand the terms and concepts presented.


Do Positive-Gain EQ Filters Cause an Increase in Ringing?
It’s known that EQ filters cause ringing, especially positive-gain (boosted) filters. That’s because equalizers use phase shift (which is time-domain) to accomplish frequency response changes. It’s part and parcel to the...

• Wayne A. Pflughaupt
• Replies: 10
• Forum: Tech Talk

• 

Regards,
Wayne

 

[Wheelman76]

No need for phone pictures. The camera icon at the top left of the graph will save it as a jpeg.

For starters, your bottom horizontal limit is too low. Few rooms have a noise floor as low at 30 dB, and that’s the reason the blue “never stops.” I.e. it never stops because the room background noise is steady-state. A 45 dB floor for the graph would be a more realistic setting.

Next, 600 ms is a more reasonable time /window length setting.

In addition, it’s generally accepted that waterfall graphs are only useful up to about 200-250 Hz.

Recommended reading:

Thread 'Adventures in Waterfalling: Understanding Signal Levels in Time-Domain Graphs'

Aug 14, 2020

Adventures in Waterfalling
Understanding Signal Levels in Time-Domain Graphs​

Once upon a time in a land far, far away, the capability to generate waterfall graphs was limited to expensive software programs available primarily to professional speaker designers and acoustics engineers.

However, the advent of affordable measurement platforms like TrueRTA, Room EQ Wizard and others has made these powerful analytical tools available to the general public, most of whom have no formal training or experience in the relevant sciences. As a result we now have a curious...

• Wayne A. Pflughaupt
• Replies: 18
• Forum: Tech Talk

• 

Thread 'Adventures in Waterfalling Part Deux: Multiple Subs, Free Bass Traps, and More'

Aug 17, 2020

Adventures in Waterfalling Part Deux
Multiple Subs, Free Bass Traps, and More​

NOTE: Readers are encouraged to wade through my previous article on waterfalls and signal levels before delving into this one, to fully understand the terms and concepts presented.


Do Positive-Gain EQ Filters Cause an Increase in Ringing?
It’s known that EQ filters cause ringing, especially positive-gain (boosted) filters. That’s because equalizers use phase shift (which is time-domain) to accomplish frequency response changes. It’s part and parcel to the...

• Wayne A. Pflughaupt
• Replies: 10
• Forum: Tech Talk

• 

Regards,
Wayne

Thank you very much for the tips. Could you please tell me where I find the adjustments for the noise floor levels?

I’ve adjusted the frequency range to 300hz and changed the time rise to 600ms and it’s looking better, but can’t seem to find the other setting to change the coloured bar on the right, which I’m assuming is the one you’re referring to as the noise floor level?

 

[Wayne A. Pflughaupt]

Look for the “Limits” icon above the graph, top right. “SPL Bottom” will set the graph floor.

Regards,
Wayne

 

[Wheelman76]

Look for the “Limits” icon above the graph, top right. “SPL Bottom” will set the graph floor.

Regards,
Wayne

I had changed that already and the graph does look better now. However I thought I was looking for a setting to change the coloured bar on the right that I circled in my picture. ?

 

[Wayne A. Pflughaupt]

AFAIK that can’t be changed. It’s auto-generated based on the SPL level of your graph. To test it, take subsequent measurements at an increased or decreased volume.

Regards,
Wayne

 

[John Mulcahy]

I thought I was looking for a setting to change the coloured bar on the right that I circled in my picture. ?

That is controlled by the Colour scheme settings, button is in the graph controls, which are displayed by clicking the "Controls" button at the top right of the graph.