Not sure I'm following the question raised but this may help:
http://www.fabfilter.com/help/pro-q/using/analyzer
 

I lost my brain earlier - it doesn't show the levels correctly because of windowing.
 
And if you are going to compare sine waves, then you need to set the slope to 0dB to get an accurate comparison of relative levels.

drewfx1
I lost my brain earlier - it doesn't show the levels correctly because of windowing.

 
Hmm.  Well, this explains why the amplitudes change based on the window/block size.  Voxengo Span definitely performs consistently across a broad range of block sizes.
 

drewfx1And if you are going to compare sine waves, then you need to set the slope to 0dB to get an accurate comparison of relative levels.

 
I'll have to try that. Thanks for the tip.

Overall, it seems that the Groove3 tutorial is lending misleading advice, or maybe I'm just interpreting it wrong.  I'm not advocating that people go out and buy the series, but I bet some folks here have yearly subscriptions to Groove3 via their All-Access Pass.  So all they'd have to do is cue up the aforementioned video series and chime back to this thread.

drewfx1
I lost my brain earlier - it doesn't show the levels correctly because of windowing. And if you are going to compare sine waves, then you need to set the slope to 0dB to get an accurate comparison of relative levels.

I was referring to the level meter on the right being accurate. Not what the spectrum display itself is showing level wise. Although I do get the fact that the spectrum level is referring to a particular frequency band. That seems to be low compared to the actual (total) level of the signal. I would not be using that as a basis of accurate level measurement.

That begs the question: how often does one even need accurate level measurements? I'm thinking it's just once, in mastering.
 
Most of the time we're relying on spectrum analyzers solely for relative levels. One of the reasons I've liked MAnalyzer (and MMultiAnalyzer) is that it has a normalization feature (now SPAN has it, too) that lets you ignore absolute levels entirely and focus on relative amplitudes.
 
On the subject of slope, that's partly a genre-specific decision. For Top-40 pop, a 3 dB/octave slope works well. For acoustic genres, traditional jazz and classical music, 6dB/octave works better. Choosing -4.5 dB as the default for SPAN was a middle-ground compromise.
 
One way to settle on a slope is to determine the slope of your reference recording(s) that you want to emulate. Let's say you think Eclipse from Dark Side of the Moon best matches the project you're working on. Import it into SONAR and insert SPAN on the track. Choose "Master" as the mode (you want a slow-moving average). Now adjust the Slope knob until the low and high frequencies are at about the same level. (For that particular song, the slope is about 3.5 dB/octave on average, but brightens significantly to 2.5 dB/octave during some parts.) 

Jeff Evans

drewfx1
I lost my brain earlier - it doesn't show the levels correctly because of windowing. And if you are going to compare sine waves, then you need to set the slope to 0dB to get an accurate comparison of relative levels.

I was referring to the level meter on the right being accurate. Not what the spectrum display itself is showing level wise. Although I do get the fact that the spectrum level is referring to a particular frequency band. That seems to be low compared to the actual (total) level of the signal. I would not be using that as a basis of accurate level measurement.

Hopefully my brain is better today. 
 
The levels between meter types should be at least somewhat similar for isolated sine waves (i.e. a single sine wave with nothing else present), but obviously if you take a single -10dB sine wave at one frequency it will have a lower total level than two or more -10dB sines at different frequencies combined. And if you know you have an isolated sine wave, there's really no reason to bother with two different types of meters, right? 
 
So yes indeed, you're right - spectrum analyzers are only good for comparison between frequency bands and you can't really compare individual band levels to the overall level, at least not in most practical applications with a DAW.
 
 
In terms of the slopes, the difference between pink noise and white noise (and associated slopes) is that pink noise distributes the noise so that it's equal by octave (like our hearing) whereas white noise is equal by frequency.
 
FFT's do their thing by dividing things into equal frequency bands rather than equal octaves, so for "exactly how much at this individual frequency vs. that frequency" we want a 0dB slope (white noise appears as a horizontal line), and for "how much in each octave" we want pink noise to be the horizontal line - which corrects for the FFT dividing things into equal frequency bands vs. octaves.

Hello All,
 
I need help with calibrating my mixing position using pink noise.
 
I've read that one should use pink noise from 500 Hz to 2.5 K. The pink noise files I've seen are full spectrum.
The Pro-Channel has a low pass and a high pass filter with a roll-off choice of 6 dB, 12 dB, etc. What is correct slope of the roll off?
 
Thanks in advance for your help,
 
Ray (aka Oluon)

Here's an in-depth and excellent tutorial on the subject:
 
http://www.soundonsound.com/techniques/monitor-wizard
 
Here's a source for noise calibration files (there might be better ones out there but this is the first I found):
 
http://abluesky.com/support/blue-sky-calibration-test-files/

Thanks dmbaer,
 
Looks like that's just what I need.
 
I'll stop for an SPL meter at Radio Shack, too.
 
The info in the other posts is also very interesting.
 
Ray (aka Oluon)