RMS metering inaccurate in Sonar?

The K-meter does not read RMS. It reads something else. RMS is a measure of the power of the signal. The K system measures how loud it sounds and involves psycho-acoustics. These are two different measures of signal strength and are not expected to give you the same result since they use different criteria.

The K meter does in fact measure rms voltage so fret_man is incorrect.  The Sonar rms reading is in fact 3 db lower and therefore is also incorrect.  But in a way the Sonar rms reading is also correct.
 
By that I mean that true rms readings are 3 db down from the peak or the very top of a sinewave which is actually right. (by electrical engineering standards) But the standard for rms readings in signal levels in DAW's is that the actual value of the rms reading for a continuous sine wave for example is the level right at the top of the very sinewave which is 3 db higher.  (DAW industry has agreed that this is so, nearly every other DAW measures the very top of the sinewave but Sonar has not changed this in years)
 
So to sum up Sonar's rms readings will always be 3 db lower than what they should be.
 
In order to get a more accurate rms reading you need to invest in a separate VU meter plugin such as the Klanghelm meter (or others) when set for calibration to a speciafic level eg -14 then the needle will show 0 dB VU when -14 rms signal is present.
 
I don't like reading rms levels way down a scale anyway it is not very helpful.  A VU meter translates the rms ref lel (eg -14) into an indication that is right up high on the scale (0 dB VU) and therefore is much easier to read.  It is good that you are interested in rms values of signals.  It is very important and actually tells you much more about the actual level of the signal.
 
But VU meters don't respond to fast peak transients so it is also important to use your peak metering in conjunction with rms readings especially on drums sounds etc..But for most signals the rms values are important and very useful.  Any peaks or attack transients will take care of themselves and be handled by the headroom you have chosen to work with. eg -14 ref levels mean peaks can go as much as 14 db higher than the rms level and it won't be clipped.
 

batsbrew is also correct. Mono test signals can cause grief as well when panned centre. I find it is best to always work with interleaved stereo test signals. It eliminates this issue but yes it is also another source of error. (if you are using a mono test signal try panning it to extremes and observe what you see, often it will change compared to pan centre)
 
But what I think you are seeing is the result of Sonar's rms readings are just 3 db lower than what the industry standard is.

I agree with Bill in that I also have a pair of high quality VU's outside the system and when I really want to know what is going on they are what I am looking at for sure.
 
But there are some great VST's out there that do it too.  I have invested in quite a few and done some rather exhaustive tests and found the Klanghelm VU meter to be pretty decent and close ballistics wise to the real thing.  Not perfect but very good.
 
The good thing about a VU VST is that all you need to do is set the ref level and away you go. The meter itself just takes in the spec to show the correct reading for the very tops of the sinewaves as the level, not 3 dB down from that.  And also you are looking at something now that is centering around 0 dB VU which is easier than trying to read rms levels low down on a meter scale.  Sonar pushes the rms mark a little lower.

Can the T-RackS Meter and/or the meters in O5/6/7 be trusted?  Or other metering plugins?

that's why,
if you simply ALWAYS record with ample headroom,
you will be alright.

Jeff Evans
What I would be wondering say using the console emulator meters   (and is that a good idea? Do you have to go through console emulation in order to get the use of meters)  is what ref rms level is required in order to get the meters to show 0 dB VU.  (with the Trim control set normal eg no Trim)  eg what is the rms ref level for the console meters.  Is it -20, -18, -14 etc...  Do they tell you?   Can it be changed?  If it is fixed then Sonar is expecting you to work at a certain ref level.  (at least if you use the console emulation)
 
I would be running some test tones at various levels to see.

Yes you can use the console emulators meters without engaging them...they only activate when you use the trim and the other knob.  I actually use those meters for setting up the gain stage when mixing, they are fantastic...for me I aim for around -6 for main tracks...and -12 for everything else.  They have helped sort out my mixing technique...amazing.  Oh in mastering invaluable too!  
 
Ben 

As I do not work for any of the named companies I can't tell you what they are doing with their metering.
 
What I can tell you is that there are very specific, and agreed upon definitions for most of the terms that get tossed around, and all of these definitions can be found in various standards from IEEE, AES, SMPTE, EBU, etc.

Before you go down that path you have to first appreciate that analog voltages are usually measured over time, while digitized signals lend themselves to instantaneous measurement. Both have appeal, and applications to music production. But they are different methods, with different results for the same signal. You need to know when to use one or the other regardless of the domain.
 
Other things you need to think about:

1. a sine wave is cyclic, music is not. nor is music completely random, it is, for our purposes, considered periodic, but that is stretching things a bit. This is one of the key factors, I think, behind different meters displaying different levels for the same material. There are others - for example a sine wave has a crest factor of 3 dB, a square wave has a rest factor of 0dB, and audio can have a crest factor anywhere from 0 (highly unlikely, more like 12 dB) to as high as 20 dB. All RMS level meters and many RMS power meters, can stumble over different crest factors. Put another way, the ratio of RMS to peak value needs to be taken into consideration!
2. dB is ratio, and if you want to be really pedantic, it is a power ratio, although it can be used to describe any ratio. For our purposes it really is not important that it is a logarithmic ratio, except to remember that it is logarithmic because our hearing is logarithmic.
3. dB is a ratio, so it you want to know amplitude or power or whatever you must have a reference
4. common references include dBu, dBV, dBFS, and dB-SPL, among others - each provides a reference from which the ratio is derived. For example, if 0 dBV = 1V the 6 dBV = 2V.
5. dB is an RMS measurement, by definition. You can man-handle it into representing peak values, but you must do so carefully, and document completely.
6. VU stands for Volume Unit, and is an arbitrary scale, based loosely on mechanical meter ballistics, that is intended to represent - very roughly - the way the ear reacts to changes in level. 0VU = +4 dBu in most professional audio applications, +8 dBu for broadcasters, and -10 dBV for semi-professional gear. They are NOT the same!
7. In general, when we are metering in the digital domain we really are interested in how many bits we are using, because if we use all of them for any period of time things start to sound really ugly. But that is a generalization, there is no reason why digital metering can't convey apparent loudness, for example. And there are a number of reasons why digital metering ought to be able to convey a whole lot more!
8. Metering, and measurement in general, REQUIRE that everything use the same reference in order to be meaningful. In the bad old days we would spend time before each session setting (or at least checking) levels so that 0 dBu at the tape deck outputs was 0 dBu at the console input, and 0 dBu at the console output was 0 dBu at the tape deck inputs. It did not hurt if 0 dBu at a channel output appeared as 0 dBu at the compressor inputs either!

It would be a very interesting experiment too see how different software tools I have at my disposal represent levels... I need to find time to do that again!
 

dubdisciple
I got sick of giving myself a headache every time so I follow batsbrew's advice and simply track conservatively. 

heheheh
 
it's just so much easier.
 
and cleaner.
with 24 bit recording, 
you are not losing anything by having plenty of headroom.

I had an epiphany about this a while back: http://forum.cakewalk.com/Hitting-the-red-I-was-wrong-about-this-m3065697.aspx