Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

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capracan
KVRist
72 posts since 21 Feb, 2010

Post Thu Nov 14, 2019 1:11 am

I'm confused by a production clue that says you need a VU meter.
i have the Youlean Loudness Meter Pro...i know there is a split around -23 dB. i can choose free...i know that -18dbFS is equal to 0 dBVU.
i also know that 0 dBVU is for analog Gear. So if you over, then it clips in analog Gear...or?

What is difference between dBFS and dB?
Is my Track/ STEMS to loud when a i have -14 LUFS for Analog Mastering?
Should i have -18 LUFS for analog post productions?

:cry:

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foosnark
KVRAF
4950 posts since 9 Jan, 2003 from Saint Louis MO

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Thu Nov 14, 2019 6:58 am

IMHO you can ignore VU in almost every case -- it's obsolete. LUFS is a better standard.

If you are doing the mastering yourself, you will probably want the final result to have a dbTP (true peak) somewhere in the -1.0 to -0.5 range at most so if it's transcoded to MP3/etc. the codecs don't wind up clipping. LUFS is up to you; some streaming services like -14dB LUFS but it's an arbitrary choice -- it just means pushing louder than that won't help. But you may want it louder for other purposes.

BEFORE mastering, you want to leave plenty of headroom in your mix. -3 dbTP is as high as I would go for the mix, which means less for individual stems. If you're at 24 bit float or better, it could honestly be much quieter as long as you're not burying it in whatever noise floor you may have.

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BertKoor
KVRAF
11335 posts since 8 Mar, 2005 from Utrecht, Holland

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Thu Nov 14, 2019 8:47 am

capracan wrote:
Thu Nov 14, 2019 1:11 am
i know that -18dbFS is equal to 0 dBVU.
Often close, but not nescessarily. It depends on specs of your DA converter (audio interface)
i also know that 0 dBVU is for analog Gear. So if you over, then it clips in analog Gear...or?
It depends on the gear's headroom. Some start clipping at +15dBVU, some at +30dBVU.
What is difference between dBFS and dB?
Just "dB" does not mean a lot. Decibels are always a relative thing, some reference level. FS is relative to Full Scale: clipping point of the DA converter. VU is relative to a healthy average level.
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Ploki
KVRian
994 posts since 17 Dec, 2009

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 15, 2019 4:50 am

BertKoor wrote:
Thu Nov 14, 2019 8:47 am

Just "dB" does not mean a lot. Decibels are always a relative thing, some reference level. FS is relative to Full Scale: clipping point of the DA converter. VU is relative to a healthy average level.
just dB actually means nothing except the math expression used to calculate its value in relation to the reference. so dB is just dB=10 * log10(x1/x2), x2 being the reference and x1 being the value it's compared to.
So without a reference (dB FS, dB A, dB SPL, whatever) it means nothing.
Also, dB full scale is not related to the clipping point of a DA, but to maximum possible digital level, which is when all bits in a sample are 1, simple as that. DA might actually have headroom. (it should, due to Intersample peaks, because as we all know, signal might be louder than 0dBFS at certain conditions)

0 VU is +4dBU and is relative exactly to 1.228V, and VU itself implies certain meter ballistics (how fast it takes meter to react, and how fast it takes for it to fall, how long does it hold its value when it reacts, etc) and not really any different relations.
capracan wrote:
Thu Nov 14, 2019 1:11 am
I'm confused by a production clue that says you need a VU meter.
i have the Youlean Loudness Meter Pro...i know there is a split around -23 dB. i can choose free...i know that -18dbFS is equal to 0 dBVU.
i also know that 0 dBVU is for analog Gear. So if you over, then it clips in analog Gear...or?

What is difference between dBFS and dB?
Is my Track/ STEMS to loud when a i have -14 LUFS for Analog Mastering?
Should i have -18 LUFS for analog post productions?

:cry:
dB FS is dB Full Scale. It's value in dBs in relation to maximum possible sample value in digital domain.
dB itself is nothing at all.

dB FS does not equal to 0dB VU in any technically significant meaning, it equals 0 VU because someone decided that -18dB FS should be 0dB. That means that if you connect an uncalibrated DA to an uncalibrated VU meter, it will likely not be the same.
Check this for reference:
https://en.wikipedia.org/wiki/DBFS#Analog_levels

If you work in the digital domain and send the mix out for mastering, the mastering engineer will do their own gain staging when going to analog gear, regardless of at which level you send your file out.

What kind of analog post productions? If you mean video (which generally post production refers to) then no.

Ploki
KVRian
994 posts since 17 Dec, 2009

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 15, 2019 4:53 am

Oh and LUFS are units that again, imply a certain behaviour of measurement ballistics (like VU, or RMS, or whatever else)

Ploki
KVRian
994 posts since 17 Dec, 2009

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 15, 2019 4:54 am

//

Ploki
KVRian
994 posts since 17 Dec, 2009

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 15, 2019 4:56 am

foosnark wrote:
Thu Nov 14, 2019 6:58 am
BEFORE mastering, you want to leave plenty of headroom in your mix. -3 dbTP is as high as I would go for the mix, which means less for individual stems. If you're at 24 bit float or better, it could honestly be much quieter as long as you're not burying it in whatever noise floor you may have.
ugh.
24 bit float is not common.
32bit float is common.
24bit integer is common.

if you bounce at 32bit FP you can clip at +60dBFS and it wont matter, but it's not good practice.

at 24bit integer however, your noisefloor is fixed at -144dB, so retaining a healthy level is good practice.

User avatar
foosnark
KVRAF
4950 posts since 9 Jan, 2003 from Saint Louis MO

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 15, 2019 6:42 am

My mistake, I was thinking I was using 24bit float, it's integer (S24_LE).

I tend not to worry about noise in the encoding, given much higher noise floors on the hardware that I use and the nature of the music that I make. Using reasonable gain staging on the input is more important to me than exact mix levels in the DAW, so long as clipping is avoided and there's headroom to play with.

heavymetalmixer
KVRist
491 posts since 8 Jan, 2017

Re: Need to know somethion about VU, db, dbFS, True Peak, LUFS for DAW

Post Fri Nov 22, 2019 11:20 am

Simple answer: Stop caring about how many LUFS or how loud the song is, mix/master it so it sounds the best to you in different devices. Also, never go above -1dB on True Peaks, so when converting to lossy, the True Peaks won't go above 0dB (unless it's REALLY LOUD, in which case -2dBTP is the maximum recommended).

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