Digital recording levels - safe or pushing?

[hrn]

I wonder how you guys do it. What levels do you use as input to the soundcard...Just under the clip level or safely at the zero level. Do you think this will affect the sound?

I've heard of some kind of "digital limiter" and wonder if it's possible to push the signal as recording analog.

Hans,
www.hagen.nu

 

[pratt]

I wonder how you guys do it. What levels do you use as input to the soundcard...Just under the clip level or safely at the zero level. Do you think this will affect the sound?

I've heard of some kind of "digital limiter" and wonder if it's possible to push the signal as recording analog.

Hans,
www.hagen.nu

I tend to be a bit on the conservative side since digital distortion isn't pretty and isnt' something that you want to commit to disc (unless, of course, that's what you're looking for!).

 

[hrn]

pratt,
Do you think you get that ugly distortion even if it doesn't clip? Just wonder if it's possible to push it...

Hans

 

[Blue Bear Sound]

Digital 0 is digital 0 -- when you're out of bits, it's game over......

Be conservative - especially if you're using 24-bit -- there's NO NEED to push levels at all!

 

[pratt]

pratt,
Do you think you get that ugly distortion even if it doesn't clip? Just wonder if it's possible to push it...

Hans

nope, I'm specifically referring to clipping (as the awful distortion)...like I said (and bluebear there too), why push it and take a chance? I learned the hard way....

 

[hrn]

And how low can you go. There must be a perfect level...I know 0 level but I know 24 bit has a lot of headroom. The AD is still half analog. I tend to think that I get a better sound when I push things a bit. About highest -1 dB under clip. Yellow color on top.

Hans

 

[TexRoadkill]

On sources that stay pretty consistent like a distorted guitar I'll try to track to around -2 to -4. On more dynamic sources I'm happy with -4 to -8.

The only way you can limit before the ADC is with an analog limiter. If you try to limit after the ADC you are just limiting the digital signal and are not being protected against distortion in the convertors.

 

[Timmy2000]

Man, I'd go a little lower. If you're tracking things like snares at -24dBFS, there'll be transients that go up as high as -1 to -3 dBFS! I tend to track vocals to between -18 and -12 anyway as I'd rather play it safe. You can always lift the levels later and any alleged loss in quality due to not using the full range of bits available is something I'm willing to take a chance on.

 

[mrface2112]

i'm with Tex on this. on sources that are stable, like guitars where i've disabled the knobs on the guitar so the guitarist can't fiddle with em (heh heh), i'll track pretty hot--usually around -4 to -2. i'll keep an eye on it and ride the fader if i have to (or put a mild compressor in there), but usually it's ok.

on sources that vary widely like snare and vocals, i make sure to slap a compressor before the ADC just to ensure that i can't possibly go into the red, and then i track as normal.

and remember, when you're dealing in 24bit, your "ceiling" is higher than when you're tracking in 16bit. there's definitely not as much need to push the levels as much with 24bit, but still, the better sound going to "tape", the better the sound coming off "tape".


wade

 

[Timmy2000]

...still, the better sound going to "tape", the better the sound coming off "tape".

Just out of interest, why is it that recording near to zero means you're getting a better sound going in to your DAW?

 

[TexRoadkill]

Just out of interest, why is it that recording near to zero means you're getting a better sound going in to your DAW?

All electronics by their nature have a 'noise floor' that is the most quiet possible signal they can record before it get's lost in the hiss of the electronics. The spec is commonly referred to as the Dynamic Range or Signal to Noise ratio. The better the gear the lower the noise floor.

If you are using cheap or mediocre gear than you want to stay as far from the noise floor as possible for a clean sound. It's not a big deal on a couple tracks but when you add 24+ tracks with a high noise floor the hiss gets pretty loud. Anytime you double a track it gets louder so you can see how the hissy noise floor times 24 can become very loud.

The hotter you track the lower the noise floor during the mix.

 

[hrn]

This is very interesting, some more opinions? A DAC is not completely digital, it's analog too...it has to take care of the input before going digital.

Hans

 

[mixsit]

The hotter you track the lower the noise floor during the mix.

True. But if your digital noise floor is many db lower than your source, than you have many to play with.
In other words, most of the noise is apt to come from the instruments, room, mics, ect, right?

If you're curious, try a little experiment. Take one of your quieter high-output mics, optimize the level on the analog end, but attenuate going to the A/D and record it down at the lower end of the scale. Say something nice and clean and sparkly like an accoustic guitar at -60. At 16 bit you should be able to get enough clean analog gain on playback to hear the digital crap below the analog hiss. At 24 bit it should be quite a bit farther down.

Wayne

 

[Timmy2000]

True. But if your digital noise floor is many db lower than your source, than you have many to play with.
In other words, most of the noise is apt to come from the instruments, room, mics, ect, right?
Wayne

This was actually my point. People seem to think that you need to record hot in order to get better signal to noise ratio whereas in reality, the noise on your recordings comes from your surroundings rather than a poor audio interface.

Off the top of my head, 16bit gives you something like 96 dB of head room. If you consider that even in a treated room, the background noise level will probably be 30dB above this, you could theoretically afford to record in at -30dB and normalise to zero before hearing any digital noise from the card over the background noise from your room.

One thing I've seen people discuss is whether lower amplitude=lower bit depth but I never worked out whether that was true or not. This is not what we're talking about here though (although if someone who knows wanted to clear this up for me I'd me much obliged).

What I'm saying is the only way to make a noticeable difference in signal to noise is to sing or play louder, not turn up the gain.

 

[Blue Bear Sound]

What I never understood, is why the people are worried about it when in the end, they limit the shit down to a dynamic range of 1 or 2 dB anyways!

 

[Timmy2000]

Come on Blue Bear. Everyone knows louder is better right....?

 

[mixsit]

... One thing I've seen people discuss is whether lower amplitude=lower bit depth but I never worked out whether that was true or not. This is not what we're talking about here though (although if someone who knows wanted to clear this up for me I'd me much obliged).

...Again, just repeating what I've heard around town... at ridiculously low levels, the results is increased distortion, but as long as it resides well below your room/analog noises, nothing is lost.
Wayne

 

[TexRoadkill]

Off the top of my head, 16bit gives you something like 96 dB of head room. If you consider that even in a treated room, the background noise level will probably be 30dB above this, you could theoretically afford to record in at -30dB and normalise to zero before hearing any digital noise from the card over the background noise from your room.

One thing I've seen people discuss is whether lower amplitude=lower bit depth but I never worked out whether that was true or not. This is not what we're talking about here though (although if someone who knows wanted to clear this up for me I'd me much obliged

Lower recording level DOES equal lower bit depth. Normalizing is a process that can subtley alter your audio and should be avoided if possible.

If your preamp and soundcard operate at the same levels (-10 or +4) then a good level on the pre will give you a good level on the soundcard. If you are recording at a pretty low level then you are throttling back somewhere on the preamp gain stages and possibly affecting your audio there also.

 

[Timmy2000]

Lower recording level DOES equal lower bit depth.

Why? I swear I'm not trying to be facetious, it's just I've seen discussions run to 10 pages on this very issue, and what I got from it was that lower recording level doesn't equal lower bit depth.

Normalizing is a process that can subtley alter your audio and should be avoided if possible.

In what way does it alter it? These days any digital audio editor worth it's salt should be able to do something as mathematically simple as normalising without messing up.

If your preamp and soundcard operate at the same levels (-10 or +4) then a good level on the pre will give you a good level on the soundcard. If you are recording at a pretty low level then you are throttling back somewhere on the preamp gain stages and possibly affecting your audio there also.

Correct gain staging when using analogue equipment is something I would most definitely agree with. The whole thing about running levels hot when recording digitally though is actually just a hangover from this. Hotter is better just doesn't hold true for ADC's that are linear down to god knows where.

I'm not trying to do you down here Tex (and anyone else either) and I'm really hoping it doesn't come across that way. It's just the idea of high recording levels sounding better is a much believed myth that doesn't do anyone any favours (especially beginners) - your first priority when recording digitally should be to avoid clipping.

Cheers guys

Tim

 

[Krakit]

Just thought I'd give this thread 5 stars

As being the most useful thread in a long time.



Carl