Peak Levels - Yet Another Thread

[Farview]

Right about the average to peak....though I still say it's the analog levels you need to set correctly...NOT digital levels. If you match the right reference (-10/+4) on both your analog front and your A/D converter...then set the levels at your analog front for good gain and good sound...the digital level really takes care of itself.
My converters don't even have the ability for input level adjustment...the input level at the converter is set by the analog front end output.

Correct. If you have both analog and digital meters, set the level on the analog side and glance at the digital meters to make sure you aren't clipping. That's all there is to it.

If you don't have analog meters, you just have to play the guessing game with the digital ones. What I do is set the level of a sustained note at around -18dbfs and then just make sure that it doesn't clip. For drums, I just set the peak around -6dbfs and call it a day.

 

[mixsit]

The need to build headroom into your digital recording has nothing to do with digital, it's all about the analog side if it. Digital handles levels all the way up to clipping very well. It's just the analog path leading to the ADC and the path coming from the DAC that tend to fall apart when they are run too hot. ...

Now, having accepted this I've sometime wondered, wouldn't there be a similar sonic hit on playback of finished/smashtered tracks with the whole program typically living crammed up into the last 5-10 db?

 

[Farview]

Now, having accepted this I've sometime wondered, wouldn't there be a similar sonic hit on playback of finished/smashtered tracks with the whole program typically living crammed up into the last 5-10 db?

Yes, there is. But that only happens once vs. having it happen on the way in on every one of the 42 individual tracks you are mixing together.

 

[bouldersoundguy]

Now, having accepted this I've sometime wondered, wouldn't there be a similar sonic hit on playback of finished/smashtered tracks with the whole program typically living crammed up into the last 5-10 db?

No, because the peaks are (should be) limited to below 0dBFS. I say below because there is a phenomenon called ballistics. If, for example, you have mastered a track to peak at exactly 0dBFS it does not mean that the waveform itself doesn't exceed 0dBFS. Since output voltage can't be allowed to make the sudden turns that going in straight lines from one sample to the next would do, so the DAC filter smooths it out to a nice curve with an LPF. If you have two consecutive samples at 0dBFS it's likely that the curve will rise past the first sample so it can fall through the second one.

By contrast, you can record audio to peak at exactly 0dBFS and play it back, unprocessed, without any issues. It's when you have to alter the track in some way, eq, mixing with other tracks etc., that you need headroom. You can even use cut-only eq and still end up with higher peaks, which is analogous to the DAC's filters creating peaks higher than the highest samples.

 

[Bobbsy]

Correct. If you have both analog and digital meters, set the level on the analog side and glance at the digital meters to make sure you aren't clipping. That's all there is to it.

If you don't have analog meters, you just have to play the guessing game with the digital ones. What I do is set the level of a sustained note at around -18dbfs and then just make sure that it doesn't clip. For drums, I just set the peak around -6dbfs and call it a day.

Well, really it depends on the ballistics...and the quality...of the meters. The trouble is, until you get to a certain level of DAW, they often don't specify the characteristics of the meters so you're left guessing.

I have the meters on both my DAW and my mixer set to PPM characteristics that roughly mirror the PPMs (BBC type) I was used to using at work. This gives me a fast rise, slow decay so I can monitor actual peaks. I also have the luxury of an inbuilt tone generator on my mixer so I tweak levels to 0dBu/-18dB(FS) on the mixer/DAW then control all levels on the mixer knowing the DAW will match.

Bob

 

[Farview]

Both bouldersoundguy and bobbsy are talking about metering vs. actual playback levels. I was attempting to address the 'running the analog side out of headroom' question. (I thought that was what was being asked)

To clear up my point: Playing back a song that only has a 5db crest and peaks at 0dbfs (and assuming line level is -18dbfs) is actually running the analog side at around +13db VU. Depending on the quality of the analog path in question, yes there will be a sonic hit. Whether or not that sonic hit is more noticeable than the sonic hit of turning the song into an mp3 and blasting it through cheap earbuds is another story.

 

[bouldersoundguy]

Both bouldersoundguy and bobbsy are talking about metering vs. actual playback levels. I was attempting to address the 'running the analog side out of headroom' question. (I thought that was what was being asked).

We were each using different meanings of the term ballistics, if that's what you're referring to. Bobbsy was talking about metering ballistics while I was talking about DAC filter ballistics. DAC ballistics matter because a processed digital signal with 0dBFS peaks can still overdrive the DAC. Meter ballistics matter because you need to know how to interpret a meter to properly set levels.

 

[Farview]

We were each using different meanings of the term ballistics, if that's what you're referring to.

No, what I was referring to was that I was answering a question about the effect a really hot digital signal has on the circuitry in the analog monitoring path. I was pointing out that it would have the same effect that running an input signal too hot has on the input analog circuitry.

I'm not discussing ballistics at all. I interpreted Mixsit's question differently than you guys did.