dBVU vs. dBFS

[RideTheCrash]

This is in regards to the "recording volume" thread. I did a test today. I stuck a mic in front of a fairly constant signal and watched where it peaked. On my board's meters, I set it to peak at just about 0dB.

On my card's software (Delta 1010lt), which has meters on it, it peaked around -18 (dBFS?), and after it recorded in CEP, it peaked around -18 as well. So this sounds about right?

My stuff is in another room and it's usually just me, so I usually just turn some stuff up and go at it. I guess it's funny seeing such a small waveform, makes me question "was this recorded at a good volume?". It's all psychological.

[ikon]

from what i been reading and trying of this myself is dont use your eyes....use your ears

[tarnationsauce2]

Yes that sounds about right.
If you do any "boosting" with your board, you'll be going into the headroom where more noise and non-linearities exists.

Trust your ears always, but also trust decades of design and engineering.

Once you add some compression to something that was tracked in the headroom of your console you'll not have as much room to play as you would have if it were tracked at 0dBvu on your board, -18dBfs on your DAW.

This is where it is advantageous to use 24/32-bit recording. Even at -18db in the digital realm, you're still using more than 16-bits. Then once you are in the digital domain, you can change levels without any addition on noise from running into headroom. As digital technically has NO headroom, unless we give it to ourselves by increasing bit depth (24 or 32) and tracking at a lower dB value. In essency, giving yourseld 18dB noise-free digital headroom.

[Farview]

Yes, 0dbVU = about -18dbFS

There is probably a zoom control that makes the waveforms look bigger.

[RideTheCrash]

Yeah, there are zoom controls, I'll play around with 'em maybe.

Thanks guys.

I record everything dry through my board, no compressors or any of that. Funny how there is nothing past 0dB in digital. My meters on my board go all the way up to +18, and finally "clip".

[Farview]

Originally Posted by RideTheCrash

Yeah, there are zoom controls, I'll play around with 'em maybe.

Thanks guys.

I record everything dry through my board, no compressors or any of that. Funny how there is nothing past 0dB in digital. My meters on my board go all the way up to +18, and finally "clip".

Do you see why that makes sense? That means that your board has 18db of headroom, so you give yourself 18db of headroom in the digital world. That is the way it was designed.
0dbVU is line level. -18dbFS is line level

[RideTheCrash]

Man, I didn't even realize that. Makes total sense.

[Massive Master]

And one of the best ways to make your tracks sound "small" is to record them too "big" - Using the 0dBVU = around -18dBFS rule of thumb while tracking is one of the best things you'll ever do for your sound.

As that's the way it was all designed to work. "Getting the levels hot without clipping" is NOT.

[tarnationsauce2]

Originally Posted by Massive Master

And one of the best ways to make your tracks sound "small" is to record them too "big" - Using the 0dBVU = around -18dBFS rule of thumb while tracking is one of the best things you'll ever do for your sound.

As that's the way it was all designed to work. "Getting the levels hot without clipping" is NOT.

I have you and Farview to thank for revolutionalizing the way I track.
And opening my eyes to what I should have already thought of.
Though it took me a while before I "got it". LOL
Again, Thanks guys!

[RideTheCrash]

Okay, another question. This might just be related to me somehow losing decibels from how my stuff is setup, but:

I have a simple shaker track. It peaks around -12dBFS to -18dBFS (max), in Cool Edit. My Delta software meters tell me it peaks around -12dBFS, which is about right. If I send that track out to my board, the signal comes up at -24dBVU.

Shouldn't it be up higher? Or am I looking at this wrong?

[Farview]

You aren't doing anything wrong. The meters on you mixer are much slower than the ones on the computer. The computer meters measure peak signal, the meters on your board measure average signal. A shaker doesn't have any sustain, just a bunch of transients, the meters on your board are too slow to catch them. Everything is fine.

[RideTheCrash]

Oh, alright. I remember reading that in other threads now..'cause VU meters measure average volume. Thanks.

[Massive Master]

Try recording triangle some time - You'll get clips that your PEAK meters don't even warn you of.

And your VU meters won't even budge.

[RideTheCrash]

What is "triangle"?

[Farview]

http://en.wikipedia.org/wiki/Triangle_(instrument)

It is a percussion instrument. It's also that triangular thing you see in old westerns when the farmers wife is calling everyone to dinner. She hits this triangular piece of metal to get everyones attention.

[RideTheCrash]

Oh yeah, duh, how did that not click in?

I think I played one once in high school.

[Massive Master]

Triangle, cowbell, tambourine -

You can record them all from a block away and they sound like they're right in your ear.

[RideTheCrash]

I have a tambourine and a mounted cowbell. I should give 'em a go.

[Farview]

Originally Posted by RideTheCrash

I have a tambourine and a mounted cowbell. I should give 'em a go.

When you set the levels on these and most percussion, you need to set the levels in the software and be done with it.

[Eluzion]

I been hearing about the dBVU, but how do you record on that, you know I mean? Could somebody just clear that up for me?

[Massive Master]

Have you read anything on this thread...?

[imetmatthoopes]

ok so first off i dont know what the heck im doing!! i haev a line 6 toneport ux2 or soemthing like that and i've been trying to lay down some tracks with cool edit and when i select my driver it dont work ...i know its powered through the usb but my cousin had it working just on that with sonar ..but i dont understand why it wont work like that on cool edit ..any suggestions?

wes
PS ....im VERY new to this and am horrable with computers to begin with

[RideTheCrash]

You might be better asking this as a new topic in the Cool Edit forum.

[tangerine]

There is still the potential for ambiguity with RMS amplitude measurements, since some use the RMS value of a full-scale square wave for 0 dBFS (which corresponds with a 0 dBFS peak amplitude measurement), and some use a full-scale sine wave (which corresponds with typical analog RMS measurements).

* In the case of a FS square wave = 0 dBFS, all possible dBFS measurements are negative numbers. A sine wave of larger amplitude than −3 dBFS would be clipping by this convention.
* In the case of a FS sine wave = 0 dBFS, a FS square wave would be at +3 dBFS.

The measured dynamic range of a digital system is the ratio of the full scale signal level to the RMS noise floor. The theoretical dynamic range of a digital system is often derived by the equation

\mathrm{DR} = \mathrm{SNR} = 20 \log_{10}(2^n) \approx 6.02 \cdot n

This comes from a model of quantization noise equivalent to a uniform random fluctuation between two neighboring quantization levels. For instance, 16-bit audio has a quoted dynamic range of 96.33 dB.

To make an equivalent measurement of a system's noise floor, the full-scale square wave convention is used. A signal which fluctuates randomly between two neighboring quantization levels will measure at −96.33 dBFS with this convention.

[tangerine]

There is still the potential for ambiguity with RMS amplitude measurements, since some use the RMS value of a full-scale square wave for 0 dBFS (which corresponds with a 0 dBFS peak amplitude measurement), and some use a full-scale sine wave (which corresponds with typical analog RMS measurements).

* In the case of a FS square wave = 0 dBFS, all possible dBFS measurements are negative numbers. A sine wave of larger amplitude than −3 dBFS would be clipping by this convention.
* In the case of a FS sine wave = 0 dBFS, a FS square wave would be at +3 dBFS.

The measured dynamic range of a digital system is the ratio of the full scale signal level to the RMS noise floor. The theoretical dynamic range of a digital system is often derived by the equation

DR = SNR = 20 \log_{10}(2^n) \approx 6.02 . n
This comes from a model of quantization noise equivalent to a uniform random fluctuation between two neighboring quantization levels. For instance, 16-bit audio has a quoted dynamic range of 96.33 dB.

To make an equivalent measurement of a system's noise floor, the full-scale square wave convention is used. A signal which fluctuates randomly between two neighboring quantization levels will measure at −96.33 dBFS with this convention.