When calibrating in a small room (ie. not a film mixing room) you should not use full bandwidth noise and C-Weighting. Use band-limited noise and A-Weighting, since small room modes will completely screw up a full-range C-Weighting measurement.

Good stuff here guys. Calibrating for small rooms I am in agreement with. Jeff good tip on the Bluecat stuff thanks for that.

Thanks Steve - very helpful. When you say 

"you should not use full bandwidth noise and C-Weighting. Use band-limited noise and A-Weighting",


do you mean:


1) A-weighting on the sound level meter
2) I used the pink noise files from Bob Katz's web site, it's 500-2K -20 dBFS RMS


I did do one speaker at a time.


Sam

Yes, A-Weighting on the meter. And yes, that file on Katz's site is a great one to use. It's nicely band-limited. Just remember that it's at -20 dBFS RMS (so Sonar's RMS meters will read -23) and do your calibrations accordingly.

Corey  is completely wrong regarding the A weighting. This is where the forum is full of mis information. I was confused re which weighting to use. I did the research and it is actually on Bob Katz website where he says you must use a C weighting (it is not obvious and it took me a while to find it, also it is in his book on mastering believe me) with all your measurements, small or large size rooms. That is why you guys keep talking about 76 db SPL etc. You are obviously on the wrong weighting. If you switch it over to C weighting you will hear a very similar SPL will be 83-85 dB setting. A weighting virtually ignores the bass end. Bob says if the bass is involved then you need to use it, simple as that. Because the bass does add to our perception. 83-85 dB SPL C weighting with music is NOT LOUD! If it is so loud people how come it is the acceptable SPL limit for health and safely over an 8 hour period?

Now Sam. There is a version of the pink noise that has been band limited. You have to be careful with this one. Firstly I would use the full range pink noise first and do your measurements. (That is up on my Soundcloud if you need it)

The reason for the band limited pink noise is to avoid problems that may be caused in your room due to low end issues so it avoids them. But first as a lot of the spectrum has been removed, this signal plays back much lower so you have to compensate by pushing it up level wise so it also just shows 0 dB on your VU meter. (around 6 db from memory) Hence the importance of the VU meters showing 0 dB VU when you are at your ref level. There is not a lot of difference between the A weighting and the C weighting then with the band limited pink noise test. However I found I got identical results with either the band limited noise (adjusted for level) or full range pink noise. (at normal level. You must adjust for levels between these!!!, Another reason to start with the full range pink noise because it is already at the right level. Also the full range pink noise on the Katz website is at -20 dB FS and you have to add 6 dB to this if you are working at K -14)

It is a good idea to use the band limited pink noise but follow it with full range pink noise and music as a backup, because you don't listen to music that is band limited do you! That is why you should also do a final music test (full range material) set at your K level and your VU's should be around 0dB and your meter on C weighting and your SPL level around 83 to 85 dB.

The Sonar meters are true rms and hence they are the reason why they show -17db rms with a -14 dB rms signal level. But as I have said and no one is getting this, you need a separate VU meter (not peak otherwise it will move wildly to peaks and you don't want that) that is showing right up to 0dB VU while you are at the K level. If you don't have this you are sort of wasting your time.

On the Bob Katz website it says nothing about setting your SPL monitoring ref level to say 77 dB SPL A weighting. It only talks about 83-85 dB SPL as the ref monitoring level so therefore he is referring to the C weighting. You can do one speaker at a time but I find both at 85 is very similar to one at a time at 83.

This can all be a bit confusing and I can understand if you feel that way. The band limited pink noise signal is even more confusing because it is not even at the right level. It is simply full range pink noise that started out at -20 dB FS and has had everything below 500Hz and above 2 KHz removed from it but the level has not been adjusted. Bob is assuming you have a proper VU meter that is normally showing 0 dB VU when you are at your ref level so it easy to compensate for the lower level of the band limited test signal. Another reason to START with the sine wave signal I have put up first. Because then you can set your VU meter ref level easily. It is a bit harder with noise as it fluctuates a bit.

The A weighting and C weighting on an SPL meter are different things. The A weighting is good for things where there is not a lot of content in the sound you are measuring under 500Hz. It is also good because it avoids false readings due to any lower frequency sounds that may be around at the time of your measurements. But with MUSIC folks we have bass present so get your SPL meters off the bloody A weighting and start measuring things with the corrcet C weighting instead. You will see once you do that the bass has a very big influence on the reading hence it makes you keep the music (around 8 dB) much lower SPL level for the correct 83-85 dB reading on your SPL meter. Our work involves the full spectrum and that is the reason why we use C weighting in our tests. This is the result of some fairly in depth research.

Jeff Evans


Corey  is completely wrong regarding the A weighting. This is where the forum is full of mis information. I was confused re which weighting to use. I did the research and it is actually on Bob Katz website where he says you must use a C weighting (it is not obvious and it took me a while to find it, also it is in his book on mastering believe me) with all your measurements, small or large size rooms. That is why you guys keep talking about 76 db SPL etc. You are obviously on the wrong weighting. If you switch it over to C weighting you will hear a very similar SPL will be 83-85 dB setting. A weighting virtually ignores the bass end. Bob says if the bass is involved then you need to use it, simple as that. Because the bass does add to our perception. 83-85 dB SPL C weighting with music is NOT LOUD! If it is so loud people how come it is the acceptable SPL limit for health and safely over an 8 hour period?

 

No, I am not completely wrong.  Katz says to use band limited (500-2000 Hz) noise because it reduces the effects of the room and is thus more accurate. It also will give you the same reading regardless of weighting.  Do you know if Sam has a properly calibrated SPL meter that is accurate on the low and high end? I don't. He hasn't said if he does. Thus the most reasonable advice is to say to use A-weighting which is better at reducing inaccuracies in measurement. That is the most sound advice for Sam's situation.
 
83 dBC SPL for music is loud. Many people have found that out. If you like that level then that's fine. But as Katz points out, the "83" level was arrived at based on movie soundtracks in a large room. Music in smaller rooms is very different perceptually. I, and many other people that I know who work in the industry have chosed to help save our hearing by lowering the loudness. Just because some government agency says 83 or 85 dB SPL is safe for 8 hours a day doesn't actually mean that it is so. Or that I would choose to subject myself to it.  Again, if it's fine for you then I can't argue with it.
 

Now Sam. There is a version of the pink noise that has been band limited. You have to be careful with this one. Firstly I would use the full range pink noise first and do your measurements. (That is up on my Soundcloud if you need it)

The reason for the band limited pink noise is to avoid problems that may be caused in your room due to low end issues so it avoids them.
 

You say may. But all rooms have low end issues. It's just a fact. That's why Katz says "For the most accurate measurement, use narrow-band pink noise limited 500-2kHz, whose RMS level is -20 dBFS." Direct quote. No ambiguity. If you think it's out of context go here to read it: http://www.digido.com/level-practices-part-2-includes-the-k-system.html 

 
But first as a lot of the spectrum has been removed, this signal plays back much lower so you have to compensate by pushing it up level wise so it also just shows 0 dB on your VU meter. (around 8 db from memory) Hence the importance of the VU meters showing 0 dB VU when you are at your ref level.
 

Now you're talking about VU meters. I know what you're talking about, but to someone who is new to this and is just trying to set up Sonar to a calibrated system it's confusing things. To people following along, I'd suggest to ignore VU meter stuff for now.

 
There is not a lot of difference between the A weighting and the C weighting then with the band limited pink noise test. However I found I got identical results with either the band limited or full range pink noise. (you must adjust for levels between these!!!, Another reason to start with the full range pink noise because it is already at the right level. Also the pink noise on the Katz website is at -20 dB FS and you have to add 6 dB to this if you are working at K -14)

It is a good idea to use the band limited pink noise but follow it with full range pink noise and music as a backup, because you don't listen to music that is band limited do you!
 

No, forget the full range pink noise. Your room will screw it up.  As it will full range music when you're trying to calibrate.

That is why you should also do a final music test (full range material) set at your K level
 

Meaning, music that has an equal RMS measure as the noise you calibrated with.

 
 and your VU's should be around 0dB and your meter on C weighting and your SPL level around 83 to 85 dB.

The Sonar meters are true rms and hence they are the reason why they show -17db rms with a -14 dB rms signal level.
 

Sonar uses a mathematical Root-Mean-Square representation, whereas the AES referenced the dBFS RMS scale to a sine wave.  One is accepted some places, one in other places.  Neither is true in that sense. Katz follows the AES spec.

 
But as I have said and no one is getting this, you need a separate VU meter (not peak otherwise it will move wildly to peaks and you don't want that) that is showing right up to 0dB VU while you are at the K level. If you don't have this you are sort of wasting your time.

 
Not at all. You don't need a VU meter. You just need to know how Sonar's RMS meters are figured, and how they relate to your calibrated monitor level and SPL. I posted that information. If you want a "VU" meter of some sort then you can add one later. But it's not necessary.

On the Bob Katz website it says nothing about setting your SPL monitoring ref level to say 77 dB SPL A weighting. It only talks about 83-85 dB SPL as the ref monitoring level so therefore he is referring to the C weighting. You can do one speaker at a time but I find both at 85 is very similar to one at a time at 83.

As I said above. A "Katz" calibration is too loud for me and other people. That's why I went lower. All that Katz has done is to write up what have been standard practices in the film industry and labeled them "K". There are good reasons to deviate from them for music mixing.

You DO need some sort of VU meter to show you a 0dB VU full scale rms level while you are operating at a much lower digital level. It is vital! (BlueCat meter is OK and very good but a VU is easier to read and very simple) You cannot see things accurately down at -17db or -23 on Sonar's meters. As I have said, unless you have some sort of rms meter to show you  a 0dB VU FSD while at the ref level then you are not using the K system correctly. Studio One can put its (buss and master) meters into K system mode and then they all read right up to 0db VU with 14 or 20 dB of headroom above that. I wonder why they do it! It is because you NEED to see a 0dB VU meter while you are right down at -14 or -20 etc. Otherwise you will never get it accurate. Any advice contrary to this is incorrect. (the Bob Katz website talks about the meter big time!)

Example: If you are adjusting your track level or buss level how are you going to do it. By watching your DAW meter hovering around -17 db rms or watch a nice VU just peaking right up to 0 db VU. See what I am saying. You tell me which is easier. You know when your VU meter is right up to 0dB VU you have got either 14 dB or 20 dB of headroom above that.

My room gives an identical reading with the full range pink noise and the band limited pink noise (adjusted) so explain that one. It means my bottom end is very accurate here.

If you do find that 83-85 dB C weighting levels with music are too loud for you then fine adjust to suit. My speakers and room are set up so that the 83-85 dB level sound pretty nice.
 
Have any of you bothered to switch your SPL meters into C weighting and listened to music? I wonder. I get the impression most of you are stubborn and are stuck on the A weighting instead. The moment you switch over to C weighting the bass really moves the meter big time so you tend to pull the music way down to get the 85 db level reading. It still does not sound loud to me.

It does not matter how big your room is either because the 85 dB SPL signal is right where you are. It does not matter if your speakers are 5 meters away or 1 meter away, you are simply adjusting your monitor gain to get a reading of 85 dB SPL where YOU are. In a larger room however with the speakers further away they will obviously be putting out more sound in order for the correct level to arrive where you are. Very close monitors don't have to work as hard to get there.

You may not get all your answers here Sam due to confusion. To avoid that  I suggest you go the Katz website and carefully read the information that relates to all this.  K system is a great thing and it will standardise all your track, buss and master levels. All your mixes will come out at a very similar level. You won't clip your DAW anywhere to be seen and mastering is also a breeze and very consistent.

Go here are read articles 11 and 12 (Level Practices)

http://www.digido.com/articles-demos.html

The K system is about consistent SPL levels in your monitoring environment for sure but it also about keeping rms levels consistent right through the tracking, mixing, bussing and final master levels also inside your DAW. And to do that we work at a digital level that is lower so we can have headroom. But we need some form of meter to show us a 0dB VU FSD indication while we are down at those lower digital ref levels. You cannot use standard DAW metering when in K system mode, period. Of course we also use our peak metering to keep track of those very transient types of signals that won't move a VU very much but for the most part the VU works very well. Even if you cannot have real ones the Klanghelm meters are a very good option.

Everyone have a good Easter too from the K system guru!

Sonar's meters are accurate enough for K-Metering. Period. Just because Evans doesn't think so, doesn't mean they aren't. One of the goals of the K-System is to ultimately rely less on the meters and more on listening. Once you've got a calibrated system going and you get used to it, meters become much less of an issue. You can hear when the levels are there.

Room size has everything to do with the PERCEPTION of sound loudness. Even though the SPL meter reads 85 in a large room and a small room, the actual PERCEPTION of loudness is different. That's psychoacoustics.

Of course I have set my SPL meter to C weighting for various measures. It's condescending of Evans to suggest that I and others haven't. I'm sure we all noticed how the metering readout changes with the low frequency content. We're not all inept. But Katz himself says, as I pointed out, that for the most accurate measurement when CALIBRATING, use band limited noise. And then A- and C-weighting should read the same.

Evans has his opinions on the K-System, and I have mine. I've outlined facts, and my opinions. I'll leave it up to everyone else to sort that out.

The only signal where peak = RMS is a square wave

Or if you're a Guitar Center salesman.


Kind of refreshing to be debating weighting curves and such, rather than whether SONAR is only suitable for Motown.


Count me among the 76db crowd. What sometimes gets lost in discussions of K-metering is the main reason for employing any standard, which is to encourage consistency. The absolute level that you monitor at is far less important than simply sticking to one level. You ears will train themselves regardless, even if you're in the less-flat region of the Fletcher-Munsen curves.

Thanks for all the input. I can see I have a lot to learn and this thread has been very helpful toward that. While I keep moving forward, I think I've gotten enough to work (play) in a way that will help me make better recordings. Since this is only for enjoyment in my situation, I have room to experiment (do it wrong).

The general things I'm getting are:

* You don't have to record up close to 0 dBFS to avoid the noise floor.

* When you mix, leave headroom between the RMS value and 0 dBFS for peaks, so that:
     1) you don't clip. 20 dB seems to be about the max needed.
     2) you're not forced to use compression to lower the peaks.


* Compression is okay, but be very aware of what it is doing to the dynamics. This has been big for me. Listening to Bob Katz's CD honor roll really opened my ears !

* The RMS values, not peak vaules, on the meters are closer to what you hear when you mix.

* Meters help but mix with your ears.

* Be consistent in your monitoring volume.


While I can see varying techniques, (no surprise), it makes darn good sense for me to try to conform to the "standard", or "learned" ways ways of recording and mixing, so I try to learn as much as I can. The people on this forum have helped so much. Thanks.

Sam