Gain Staging? help / discussion on volume levels

[Farview]

If the wave looks too small, there is a zoom control they will make the waveform look bigger. it is usually in the upper right corner of the workspace.

It really doesn't matter that sound looks like.

 

[Farview]

I have read many times about recording low with -db's and headroom. Not sure I understand the fundamentals.

Is the reason for recording low that digital is more sensitive to incoming signal than analog? Also I have not come across the need for headroom? I know that in photography it is easier to fix a snap that is underexposed vs. one that is overexposed. Assuming same principle.

"Set the amp so it sounds good. Set the input gain so you get a healthy signal but it's nowhere near clipping. There, you're done. It really is that simple."

The above quote is a slam dunk if you can get that to work. However, I have the same problem as the OP. With less expensive gear - it is impossible to get a healthy signal with nowhere near clipping.

The reason behind recording "low" is because the analog side of the equation wants to run at line level. That is the signal level that it is designed to work the best at. It just happens that line level in the analog world is roughly -18dbfs on the digital side. Digital is clean all the way up to clipping. But the analog signal path leading up to the converters will distort trying to push the signal all the way up close to digital clipping.
The confusion comes from people not understanding the gain staging between the two sides of the equation. -18dbfs is the correct recording level. There is nothing low about it.

 

[Bobbsy]

I have read many times about recording low with -db's and headroom. Not sure I understand the fundamentals.

Is the reason for recording low that digital is more sensitive to incoming signal than analog? Also I have not come across the need for headroom? I know that in photography it is easier to fix a snap that is underexposed vs. one that is overexposed. Assuming same principle.

Yeah. It's a bit like the photo analogy. If you underexpose a photo the detail is still there (up to a point at least) and you can bring it up, perhaps with the addition of noise, but it's there. However, if you over expose and burn out a highlight, you'll never get detail in the highlight.

With sound, the equivalent to the burned out highlight is clipping. That's where the system, be it analogue or digital, runs out of capacity to store a louder signal. In technical terms, the round-topped sine wave can't go high enough and gets square across the top, sounding crappy.

The big confusion of levels stems from the fact that, in their wisdom, the developers of digital sound chose to use a different scale when measuring their signals. In the analogue world, 0dB on a meter is equivalent to a specific arbitrary voltage. The amount of headroom in an analogue system is set so there's lots of space for peaks to go above the zero level. Exactly how much depends on the gear but typically you can safely go about 18dB above the zero level. (Worth saying here that in analogue clipping also comes on more gradually than in digital.) Anyway, in analogue you'd normally record so the average is around zero with peaks going higher--how much higher depending on the material. However 8 to 10 dB above zero on the analogue meter is pretty normal...and still far enough from clipping that you don't have to worry about clipping.

In digital, they used the "Full Scale" (dBFS scale for metering. In this case, 0dBFS is the exact point where clipping starts (basically every one of your 16 or 24 bits is a 1 so you simply can't go any louder). This means that if you take the clipping point in analogue as +18 on the meter, this becomes the equivalent to the 0dBFS point in digital--and the equivalent to 0dBVU in analogue. That's why the common advice is to record averaging around -18 on a digital meter with peaks going up 8 or 10 dB above this.

At this point, despite having suggested -18 myself, I'm going to at least partly agree with Greg_L. It's easy to get hung up on numbers. A lot of my recordings are hotter than that. Really, it depends on common sense and knowing the sort of material you're recording. If it's and instrument (or vocalist) known for huge peaks, I probably will stick to something near the -18dB advice, knowing there are going to be lots of peaks higher. However, if it's something or somebody with less dynamic range I'll let the levels go higher--just making sure it's comfortably below clipping.

"Set the amp so it sounds good. Set the input gain so you get a healthy signal but it's nowhere near clipping. There, you're done. It really is that simple."

The above quote is a slam dunk if you can get that to work. However, I have the same problem as the OP. With less expensive gear - it is impossible to get a healthy signal with nowhere near clipping.

It's a total slam dunk if you only have one level control after the guitar amp (or, for that matter, any source). However, on lots of systems there may be more stages each with its own gain control. Taking it to an extreme, how about if you have a mixer with gain on the input, then a fader, then a master fader, then an input to an audio interface with a hardware gain control, then a software gain control in the computer. My point was that, however many steps you have, you want to avoid having one gain setting cranking up the levels with the next one cranking them down again. You're best to have everything running near the middle of their range. Since there's not a meter on all these stages doing this gain staging is often a bit of trial and error but, with experience, you just do it.

Edited to add: Farview is more succinct than me...I was typing while he was posting!

 

[Greg_L]

Really, it depends on common sense and knowing the sort of material you're recording. If it's and instrument (or vocalist) known for huge peaks, I probably will still to the -18dB advice, knowing there are going to be lots of peaks higher. However, if it's something or somebody with less dynamic range I'll let the levels go higher--just making sure it's comfortably below clipping.

This was really my point. Not to say that anyone is wrong for strictly adhering to the semi-arbitrary -18dbfs rule, it's just that one doesn't need to be that anally retentive most of the time. In the case of distorted guitars (which I think was the original question here, but I genuinely don't remember and haven't looked back) there's not much dynamic range. Overdriven guitars are naturally squashed in the amp and there aren't huge spikes and transients like there can be with sparkling clean guitar tracks, or vocals, or drums. So track guitars a little hotter. It won't hurt anything. Be reasonable and don't let it get anywhere near zero, but don't spend an unnecessary amount of time micro tuning the input level. I'd personally rather slide a guitar track fader down into the mix as opposed to sliding everything else way down to match a lightly tracked guitar track.

 

[Jay C]

This was really my point. Not to say that anyone is wrong for strictly adhering to the semi-arbitrary -18dbfs rule, it's just that one doesn't need to be that anally retentive most of the time. In the case of distorted guitars (which I think was the original question here, but I genuinely don't remember and haven't looked back) there's not much dynamic range. Overdriven guitars are naturally squashed in the amp and there aren't huge spikes and transients like there can be with sparkling clean guitar tracks, or vocals, or drums. So track guitars a little hotter. It won't hurt anything. Be reasonable and don't let it get anywhere near zero, but don't spend an unnecessary amount of time micro tuning the input level. I'd personally rather slide a guitar track fader down into the mix as opposed to sliding everything else way down to match a lightly tracked guitar track.

awesome advise Greg. i think i sometimes get my head into this thing where i feel like there is a "rule" for everything and if i don't do things exactly it will be "wrong", i keep forgetting that there is still a creative side to it. i'm working through these tutorial videos called "rethink recording" . is anyone familiar with these tutorials? i like it b/c it comes with the track to a song and you work on the same song as in the videos. does anyone know of any others?

 

[Wonka]

Thanks for the responses. It is like I thought – digital is more sensitive to incoming signal than analog.

“The big confusion of levels stems from the fact that, in their wisdom, the developers of digital sound chose to use a different scale when measuring their signals.”

You have to wonder about this. Either they wanted everyone to have to buy new stuff or they knew that the speakers on digital devices would be dinky and they dumbed down the sound.

Going digital kind of reminds me of the super new light bulbs they have that are suppose to last forever and save lots of energy. They seems fantastic until you actually install one and turn it on and realize that for the first few mins you are almost in the dark. New and improved.

Analogue was, is, and will always be louder than digital. Well everyone will be in the dark with their new light bulbs but at least they won’t be deaf.

 

[Greg_L]

Thanks for the responses. It is like I thought – digital is more sensitive to incoming signal than analog.

“The big confusion of levels stems from the fact that, in their wisdom, the developers of digital sound chose to use a different scale when measuring their signals.”

You have to wonder about this. Either they wanted everyone to have to buy new stuff or they knew that the speakers on digital devices would be dinky and they dumbed down the sound.

Going digital kind of reminds me of the super new light bulbs they have that are suppose to last forever and save lots of energy. They seems fantastic until you actually install one and turn it on and realize that for the first few mins you are almost in the dark. New and improved.

Analogue was, is, and will always be louder than digital. Well everyone will be in the dark with their new light bulbs but at least they won’t be deaf.

 

[Bobbsy]

Well, just to clear up some confusion, the different scales have nothing to do with the eventual "loudness" of the signal when you finally listen to it. It's only to do with calibrating systems and allowing you to move signals from one system to another at a know level.

Despite my disparaging comment above, the dBFS scale makes sense for digital since the onset of clipping there is sudden and at a very specific point. It would be pretty well impossible to use clipping as a reference level in analogue though since different equipment clips at different levels--and the onset is often gradual so you'd also have to argue what percentage distortion constitutes clipping.

As for which system is louder, that has nothing to do with the digital vs. analogue debate. The loudness you listen to is determined by how you set the volume control on your CD or MP3 player. An analogue track mastered at +18dBVU will be exactly the same volume as digital mastered at 0dBFS.

 

[ecc83]

Thanks for the responses. It is like I thought – digital is more sensitive to incoming signal than analog.

“The big confusion of levels stems from the fact that, in their wisdom, the developers of digital sound chose to use a different scale when measuring their signals.”

You have to wonder about this. Either they wanted everyone to have to buy new stuff or they knew that the speakers on digital devices would be dinky and they dumbed down the sound.

Going digital kind of reminds me of the super new light bulbs they have that are suppose to last forever and save lots of energy. They seems fantastic until you actually install one and turn it on and realize that for the first few mins you are almost in the dark. New and improved.

Analogue was, is, and will always be louder than digital. Well everyone will be in the dark with their new light bulbs but at least they won’t be deaf.

Err? NO! Digital recording is essentially distortionless at all levels, -18, -30, -0.1dBFS. No matter.
Tape for instance is always "distorted". The "zero" level was chosen for a particular amount of distortion at a particular recorded magnetic flux (3%THD seems to stick in head?) but 6dB below that the distortion will be less but still vastly more than any decent digital system. At 6dB above (just off VU scale) it will be even worse but some folks like that! The point is the recording "zero" is an arbitrary level chosen as a convienience and compromise.

Many people in the "classical" field chose to record some 6-8dB under 0 when Dolby A came in because it resulted in much "cleaner" recordings and they thought the trade off for noise was worthwhile.

So they COULD have put 0dBFS at -10,-6 -18 and had everything above that as positive but what would be the point? Unlike tape, digital sounds the same no matter where on the scale you put the tracks!

Dave.

 

[RAMI]

Thanks for the responses. It is like I thought – digital is more sensitive to incoming signal than analog.

“The big confusion of levels stems from the fact that, in their wisdom, the developers of digital sound chose to use a different scale when measuring their signals.”

You have to wonder about this. Either they wanted everyone to have to buy new stuff or they knew that the speakers on digital devices would be dinky and they dumbed down the sound.

Going digital kind of reminds me of the super new light bulbs they have that are suppose to last forever and save lots of energy. They seems fantastic until you actually install one and turn it on and realize that for the first few mins you are almost in the dark. New and improved.

Analogue was, is, and will always be louder than digital. Well everyone will be in the dark with their new light bulbs but at least they won’t be deaf.

Man, I don't even know where to begin with how completely wrong this is.

 

[miroslav]

Analogue was, is, and will always be louder than digital.

How much louder is it?
Is it one louder?