Larry's Room

[LarryD]

Hello Everyone,

I just took my first measurements.

First is my room untreated with any acoustics.

[Wayne A. Pflughaupt]

Welcome to the Forum, Larry!

A few things: First, you should reduce your levels. Are you trying to blow up your sub?

Second, our standard 45-105 dB vertical scale is fine for basic frequency response plots, but not for waterfalls. You probably want to see your signal decay all the way down to the room's noise floor, which is significantly lower than 45 dB. Try changing the graph to a 30-35 dB floor, or perhaps even 25 dB if you have a room with extensive soundproofing.

Third, in addition to the 300 ms window, it's also useful to look at a longer-term 600 ms window as well.

Regards,
Wayne

[LarryD]

Wayne,

My levels were based on trying calibrating to the 75db level. And I was not using a sub at all, only 1 front speaker with a big driver. So, not sure why its showing so high.

Here is a graph with some of the changes you mentioned. It look really bad though



Larry

[brucek]

Here is a graph with some of the changes you mentioned. It look really bad though

Yeah, it's because of the scale you're using. It's basically a picture of your noise floor, which isn't the purpose of a waterfall plot. If you're interested in noise floors, check out the REW Spectrum Analyser.

Generally, a typical room in a home would have a background noise around 45dBSPL. If the furnace, air conditioner or refrigerator was on, it may raise to ~55dBSPL. With a waterfall plot we're interested in examining the decay of our REW signal, and with that as a reference, it's possible to examine how speaker or listening placement, (or EQ) affects that decay.

So, much like the average situation, we can see you have a noise floor that demands the standard vertical scale of 45dB-105dB. This is a reasonable scale for most users, and it compliments easy comparisons to the frequency response scale. I would also tone down the Y component on the chart. You have too much. A reasonable set of co-ordinates for a LOG waterfall plot would be x=1, y=100, z=150, with a vertical scale of 45dB-105dB and a horizontal scale (in your case since you're examining a single main) of 20Hz-200Hz. A time range of 500-600ms seems about right in your case.
Use an REW target of 75dB.

brucek