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Calibration Clarification - K-System
Old 5th February 2009
  #1
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Calibration Clarification - K-System

Okay, so I need some clarification on how to calibrate my monitors. I've read many posts and I think I'm only getting more confused.

Here's what I've got in the chain: SPL meter, Apogee Ensemble, Event Precision 8 Monitors, -20dB FS test tones...I'd like to use a K-14 setup. Here's where I'm at:

1. Play the -20dB FS tone hard left (and later hard right) on a mono track
2. Set the Apogee Ensemble's output to 0 dB
3. Raise the output on my monitors until my SPL meter reads 83 dB [next repeat for right monitor]
4. To enable a K-14 setup, lower the Apogee Ensemble's output to -6 dB

Question #1: Does that seem correct?

Question #2: Am I correct to assume that a K-14 setup is "equivalent" to saying the loudess parts of my mix will have RMS levels around -14dB FS?

Question #3: If I'm using K-14, where do I want my input levels when I'm recording? Should they be close to 0 on the K-scale [-14dB FS]? Are we talking peaks or RMS?

Many thanks in advance.
Old 5th February 2009
  #2
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To use the K-14 alignment, you need -14dBfs test tones, not -20dBfs. Otherwise you'll be using the K-20 standard. Though it can be done, it's easier to use -14.

I'm assuming you're running directly from the Apogee to your monitors corect? The Events seem to be more like a -10 device so click your Apogee's ouput bubbles to read -10. When playing a -14dBfs RMS uncorelated pink noise file, set the monitors to reproduce 80dB from each speaker. When you have both speakers running, it should be 83dB. That's really all that's to it. Now your PEAK levels will be higher than -14dB obviously. The point is to make the -14dB RMS level translate to a comfortable but loud & clear level at your listening position. Anyways, tones are good for electronic alignment but useless for setting up monitors so that's why you use pink noise.

I started with -14dB also since I have a lot of tape equipment but I calibrated my decks to have 16dB of headroom and I mix a lot of movies so I switched to -20dB about 4-5 months ago.



Quote:
Am I correct to assume that a K-14 setup is "equivalent" to saying the loudess parts of my mix will have RMS levels around -14dB FS?
As I said earlier, your peak levels will be higher than that. NORMAL listening levels will be around -14dBfs RMS but it can drop below that or spike higher for intense passages. Your input levels will also be -14dBfs RMS. Peak levels are completely useless for anything other than making sure you're not overdriving your stuff. All loudness is measured in RMS.

Hope that helps. If you don't have any -14dBfs tones/noise, I can send you some.
Old 5th February 2009 | Show parent
  #3
kjg
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Quote:
Originally Posted by wado1942 ➑️
To use the K-14 alignment, you need -14dBfs test tones, not -20dBfs. Otherwise you'll be using the K-20 standard. Though it can be done, it's easier to use -14.
Not really. He could easily use the same -20 dB RMS test files, just calibrate to 77 dB SPL. That is the same as -14 RMS to 83 dB SPL.
If he'd calibrate -20 files to 77dB SPL he would have found the -6 monitoring gain. If he'd calibrate -14 files to 83 he would have the exact same monitoring gain: -6.

I find it easiest to remember it like this:

-20 dB RMS test signal @ 83 dB SPL per speaker = 0 monitoring gain. This is a given. Zero doesn't drift when you switch between working K20 and K14 for example. (You might attenuate a few dB more though, to compensate for midfield or nearfield monitors, but that is something else.)
You use monitoring gain 0 for K20, -6 for K14, -8 for K12
(OP: you already successfully did this - just set you monitoring gain to -6)

If you want to mark -6 as your personal "virtual 0", your personal anchor point, because you like to work on that monitoring gain, do that. But it is -6 monitoring gain in the K-system. There is only one K-system. It suggests three basic monitor gains, all based on one calibration: -20 dB RMS > into zero monitor gain > yields 83 dBSPL C/slow. Get your head around that and you can set up any deviation to suit your personal preference, sensitivity or working habits easily.

To the OP:

1: Correct

2: Yeah pretty much. Around -14dB RMS would be the level of an average forte section. Louder parts could still exist, but would be relatively rare.

3: You should set your input levels depending on the source. If it is very dynamic you need a lot of headroom to avoid cliiping your ADC. If it is more even you could get away with slightly less headroom. I routinely set input gains such that the loudest peaks the performers can produce are coming in at -10 to -6 dBFS. Might go lower just to be safe. As long as you are recording on 24 bit your resolution is fine anyway.

regards,
Klaas-Jan
Old 5th February 2009 | Show parent
  #4
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Quote:
Originally Posted by kjg ➑️
Not really. He could easily use the same -20 dB RMS test files, just calibrate to 77 dB SPL. That is the same as -14 RMS to 83 dB SPL.
If he'd calibrate -20 files to 77dB SPL he would have found the -6 monitoring gain. If he'd calibrate -14 files to 83 he would have the exact same monitoring gain: -6.
I think this is the quote that most other posts are missing and why so many newbies to proper calibration get confused. Thank You both for making everything clear!
Old 5th February 2009 | Show parent
  #5
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Well, as I said, you CAN do it with -20dB tones & noise but there's more to it. But yeah, 77dB will do just fine for the calibration if -20dB tones is all you have.
Old 5th February 2009 | Show parent
  #6
kjg
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Quote:
Originally Posted by wado1942 ➑️
Well, as I said, you CAN do it with -20dB tones & noise but there's more to it. But yeah, 77dB will do just fine for the calibration if -20dB tones is all you have.
I know you said it
My point is that if you actually understand what you are doing you can use pretty much anything to calibrate since you can then calculate what to measure for in SPL (or what monitor offset you are finding for a given SPL).

regards,
Klaas-Jan
Old 5th February 2009 | Show parent
  #7
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I won't argue with that.
Old 7th February 2009
  #8
Mastering
 
🎧 15 years
Quote:
Originally Posted by jaysunice ➑️
Okay, so I need some clarification on how to calibrate my monitors. I've read many posts and I think I'm only getting more confused.

Here's what I've got in the chain: SPL meter, Apogee Ensemble, Event Precision 8 Monitors, -20dB FS test tones...I'd like to use a K-14 setup. Here's where I'm at:

1. Play the -20dB FS tone hard left (and later hard right) on a mono track
What test tone is this? You need to have a calibrated pink noise signal. If you use the stereo uncorrelated signal you can download from our website in the downloads section at digido.com, then play it in stereo without adjusting the panning, at unity gain through your DAW. And either in the DAW or in your monitoring system, mute one speaker, please, play only one speaker at a time.

Quote:


2. Set the Apogee Ensemble's output to 0 dB
3. Raise the output on my monitors until my SPL meter reads 83 dB [next repeat for right monitor]
4. To enable a K-14 setup, lower the Apogee Ensemble's output to -6 dB

Or thereabouts :-)

Quote:


#1[/u]: Does that seem correct?

Question #2: Am I correct to assume that a K-14 setup is "equivalent" to saying the loudess parts of my mix will have RMS levels around -14dB FS?
Within reason. You're mixing by your ears and the high frequency content of the material and the transients and the distance of your monitors have an effect, but one thing's for sure, at that monitor gain, if it sounds "just loud enough for you", you'll probably be making a recording that is not overcompressed!

Quote:

Question #3: If I'm using K-14, where do I want my input levels when I'm recording? Should they be close to 0 on the K-scale [-14dB FS]? Are we talking peaks or RMS?

When you say "recording", do you mean tracking or mixing? I don't think the K-System is necessary for tracking. It's really a mixing and mastering approach. When tracking, really just keep your peak levels some points away from full scale and don't worry about RMS.

Hope this helps,

BK
Old 7th February 2009 | Show parent
  #9
Mastering
 
🎧 15 years
KJG's comments are great, spot on the money and very perceptive!

I see a lot of people beginning to "get" this system and what it does for them. Both mixing and mastering engineers.

Probably the most remarkable part of the system is mixing at K-20 monitor gains, closing your eyes and forgetting about the meters. They won't clip, I promise you! And even if you're done and the highest peak ends up at -6 dBFS peak, you've still got a perfect mix, it's got plenty of signal to noise ratio (at 24 bit) and it's just the sound you've been going for. You've just liberated yourself from meter reading entirely.

BK
Old 7th February 2009 | Show parent
  #10
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Thanks Bob. It's always refreshing to see you post on here. Everything's coming together for me now and I think I can finally say "I get it" with the K-System. I consider myself a young mixer and will try my best to serve as an ambassador in the K-System revolution...or rather, re-invention of music.

With any luck, we'll finally be back to making music that breathes with all the dynamic range and sincerity of the artform it's intended to reflect.
Old 7th February 2009 | Show parent
  #11
Mastering
 
🎧 15 years
Quote:
Originally Posted by jaysunice ➑️
Thanks Bob. It's always refreshing to see you post on here. Everything's coming together for me now and I think I can finally say "I get it" with the K-System. I consider myself a young mixer and will try my best to serve as an ambassador in the K-System revolution...or rather, re-invention of music.

With any luck, we'll finally be back to making music that breathes with all the dynamic range and sincerity of the artform it's intended to reflect.
Great. Or at least your raw mixes that do so, even if they are ruined in the mastering :-(.

BK
Old 8th February 2009 | Show parent
  #12
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Quote:
Great. Or at least your raw mixes that do so, even if they are ruined in the mastering :-(.
Ah but you'll still be able to do a remaster down the road when this loudness crap is at an end. Still one of the best sounding CDs I own is "Synchronicity" which sits around -24dBfs! And it's OLD digital too, not the nicer stuff we have now.

Thankfully, more and more people are adopting the -20 standard. A few months ago, I convinced one of the developers of a popular lower-end DAW to put the reference point at -20. It was in the next release just like he said it would be. I'm WELL pleased.
Old 22nd March 2010 | Show parent
  #13
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Quote:
Originally Posted by bob katz ➑️
KJG's comments are great, spot on the money and very perceptive!

I see a lot of people beginning to "get" this system and what it does for them. Both mixing and mastering engineers.

Probably the most remarkable part of the system is mixing at K-20 monitor gains, closing your eyes and forgetting about the meters. They won't clip, I promise you! And even if you're done and the highest peak ends up at -6 dBFS peak, you've still got a perfect mix, it's got plenty of signal to noise ratio (at 24 bit) and it's just the sound you've been going for. You've just liberated yourself from meter reading entirely.

BK
Bob,

Can you recommend a good step by step tutorial on using the K system? Like the OP, I have done a lot of searching, and simply do not have a grasp of how to properly calibrate my monitors. Until I found this post, I have just had my monitors plugged in and turned up to a comfortable listening level, not even considering the need for this kind of precision. This has forced me to be chained to my meters, and this post you made has me wanting to know more!
Old 23rd March 2010 | Show parent
  #14
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Bob,
After more digging around, I was pleasantly surprised to find that you introduced the K system of metering. When I asked for a tutorial recommendation I had no idea that you were the pioneer of this standard.

I found the settings in izotope ozone 4 for all three K system meters, and having no idea what they were for, I naturally turned to GS to find answers.

What a great community we've got here!

So then, I re-phrase my inquiry:
Is there a one stop shop somewhere for all of my Katz metering needs? I would really like to implement this in my studio, and share it with classmates at my university.
Old 23rd March 2010 | Show parent
  #15
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Red Mastering's Avatar
 
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go to amazon and grab Bob's 'Mastering Audio' book
you won't be disappointed, because it's like a Bible for any audio technician
you'll find there so many important information you weren't aware of....
Old 23rd March 2010 | Show parent
  #16
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Quote:
Originally Posted by tresperros ➑️
Bible for any audio technician
That would be Tremaine's Audio Cyclopedia.
Old 23rd March 2010 | Show parent
  #17
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Quote:
Originally Posted by Virtalahde ➑️
That would be Tremaine's Audio Cyclopedia.
Second Edition. But, Tremaine only gets a person to about 1970 technology, even in the late 1970's printings. PCM rec/rep is not really a thing in 1970 (Bell Labs and NTT were making some expensive recordings).

It is a basic book on analog electronics/studio standards, with a steep vintage purchase price (near $200 in 2009?) and even more valuable info.

The Ballou-edited "new audio cyclopedia" is also authoritative reading with similar very-long expiration dates on most of the material.

Cheers.
Old 23rd March 2010 | Show parent
  #18
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🎧 10 years
Quote:
Originally Posted by recordinghopkins ➑️
Is there a one stop shop somewhere for all of my Katz metering needs? I would really like to implement this in my studio, and share it with classmates at my university.
TT DYNAMIC METER is a good tool; from the anti loud , pleasurizemusic group. But they may now want you to join to get it for "free".
DYNAMIC RANGE | pleasurize music!

BUt I happened to get it bundled with the Brainworx demo , which is a supporter..
Brainworx | M/S Mastering Tools and Audio Plug-ins
Old 23rd March 2010 | Show parent
  #19
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Quote:
Originally Posted by Virtalahde ➑️
That would be Tremaine's Audio Cyclopedia.
That's an excellent place to start. I also highly recommend this one:

The art of sound reproduction - Google Books



DC
Old 24th March 2010 | Show parent
  #20
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Thanks for all of the responses!
Old 26th March 2010 | Show parent
  #21
Dos
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Quote:
Originally Posted by bob katz ➑️
When you say "recording", do you mean tracking or mixing?


Welcome to noobsville!
Old 27th March 2010 | Show parent
  #22
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Quote:
Originally Posted by dcollins ➑️
That's an excellent place to start. I also highly recommend this one:

The art of sound reproduction - Google Books



DC
as are the eargle books.. handbook of recording engineering and sound recording.

getting harder to find tho.
Old 27th March 2010 | Show parent
  #23
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Quote:
Originally Posted by Dos ➑️


Welcome to noobsville!
i take it that was sarcasm, and that you don't know who bk is.
Old 24th April 2010 | Show parent
  #24
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more books

Floyd E. Toole "Sound Reproduction: Loudspeakers and Rooms" Focal Press 2008 ISBN 976-0-240-52009-4 $50 at Powell's Technical Bookstore

Worth reading a couple times and returning to a year later. Indexed, Referenced, wide margins for notes. I've used soft pencil in case I turn out to be an idiot later.

I don't care much about "home theater" if sound in the good seat has to suffer at all for it. But, lots of people do.

The book has enough meat for a beginner and lots of insight that only comes with 4+ decades in an evolving field. Like a lot of specific application books, this one will save you piles of money and time, or merely add understanding of what you are paying a contractor for.

Cheers.
Old 25th April 2010 | Show parent
  #25
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Quote:
Originally Posted by Dos ➑️


Welcome to noobsville!
ehehhe right dude :D god...
Old 26th July 2010 | Show parent
  #26
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I want to clear this up as there is conflicting and unclear info on this thread:

In the OP it was asked if -20db rms should equal 83db per single speaker. (In a stereo system this will equate to more than 83db when both speakers are playing)

OR:

Is it 83db with both speakers on (and 80db per single speaker as suggested by the second post)

also, while I'm at it is this 83 db, c weighted, slow ?
Old 26th July 2010 | Show parent
  #27
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Quote:
Originally Posted by nomoreflakes ➑️
I want to clear this up as there is conflicting and unclear info on this thread:

In the OP it was asked if -20db rms should equal 83db per single speaker. (In a stereo system this will equate to more than 83db when both speakers are playing)

OR:

Is it 83db with both speakers on (and 80db per single speaker as suggested by the second post)

also, while I'm at it is this 83 db, c weighted, slow ?

85dB SPL, one speaker at a time, C weighted, slow average.

It's of little to no use for mastering, other than getting a feel for what 80-90 SPL sounds like, but those are the settings.


DC
Old 26th July 2010 | Show parent
  #28
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Re: K-System levels

Bob says to use 83 dB SPL-C "Slow" for calibrating the -20 dBFSD RMS pink noise for each soloed loudspeaker. The SMPTE's RP 200 said to use 85 dB SPL, but with a -18 dBFSD test tone.

From Digido.com:

(quote)

"...SMPTE Document RP 200, defines the calibration method in detail. In the 1970's the value was quoted as "85 at 0 VU" but as the measurement methods became more sophisticated, this value proved to be in error. It has now become "85 at -18 dB FS" with 0 VU remaining at -20 dBFS (sine wave). The history of this metamorphosis is interesting. A VU meter was originally used to do the calibration, and with the advent of digital audio, the VU meter was calibrated with a sine wave to -20 dB FS. However, it was forgotten that a VU meter does not average by the RMS method, which results in an error between the RMS electrical value of the pink noise and the sine wave level. While 1 dB is the theoretical difference, the author has seen as much as a 2 dB discrepancy between certain VU meters and the true RMS pink noise level.
The other problem is the measurement bandwidth, since a widerange voltmeter will show attenuation of the source pink noise signal on a long distance analog cable due to capacitive losses. The solution is to define a specific measurement bandwidth (20 kHz). By the time all these errors were tracked down, it was discovered that the historical calibration was in error by 2dB. Using pink noise at an RMS level of -20 dBFS RMS must correctly result in an SPL level of only 83 dB. In order to retain the magic "85" number, the SMPTE raised the specified level of the calibrating pink noise to -18dB FS RMS, but the result is the identical monitor gain. One channel is measured at a time, the SPL meter set to C weighting, slow. The K-System is consistent with RP 200 only at K-20. I feel it will be simpler in the long run to calibrate to 83 dB SPL at the K-System meter's 0 dB rather than confuse future users with a non-standard +2 dB calibration point.
It is critical that the thousands of studios with legacy systems that incorporate VU meters should adjust the electrical relationship of the VU meter and digital level via a sine wave test tone, then ignore the VU meter and align the SPL with an RMS-calibrated digital pink noise source."

(end quote)


If you use 83 dB/speaker, when you sum two such calibrated speakers together, you should measure approximately 89 dB SPL, perhaps taking off a dB, to several of them, for the real-world, bad acoustics that plague most rooms - including fancy control rooms.
Masterfonics sums at approximately +5.9 dB SPL, fwiw.

P. S., don't leave your monitor gain at a K setting all day. Use it to check your work and compare to others'. Wear earplugs outdoors in the city.





Andrew
Old 26th July 2010 | Show parent
  #29
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oh dear. more conflicting info.

we have one post suggesting that two speakers together should equal 83db and now a post suggesting that they should equal 89db

can I politely ask Mr Katz to make an unequivocal and succinct sticky in the mastering forum with the correct information for calibrating monitors to a system
Old 26th July 2010 | Show parent
  #30
kjg
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Quote:
Originally Posted by nomoreflakes ➑️
oh dear. more conflicting info.

we have one post suggesting that two speakers together should equal 83db and now a post suggesting that they should equal 89db

can I politely ask Mr Katz to make an unequivocal and succinct sticky in the mastering forum with the correct information for calibrating monitors to a system
83, slow, C, per speaker.
πŸ“ Reply

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