SIMPLE BUGS

[Tassy]

WAVE SHOWING CLIPPING REMAINS SHOWING CLIPPING (RED PEAKS) EVEN AFTER GAIN CUT/BOOST APPLIED
http://screencast.com/t/B7iRWgUahx
Tassy

[the C.L.A.]

Well... Cutting the region gain doesn't change the fact that the audio is clipped.

Also no need to use caps lock when writing a message on the forum.

[Tassy]

in MB2 clipping dissappears by the same aact. only v3 shows the track clip mb2 and other daws not

[x42]

It was a bug in Mixbus2 (or Ardour2 for that matter) that has meanwhile been fixed.

As The CLA already mentioned: Mixbus is non-destructive. The data on disk won't change.
Adding a gain-factor cannot remove nor introduce clipping (internally Mixbus uses floating-point).

If other DAWs don't do that, they display misleading information. The original signal is still clipped, no matter how much you decrease the gain afterward.

[Studio Saturn]

Yap it won't make it go away. It is like you received a distortion insert included track and trying to remove it by EQ. What I don't understand is, How did you receive that kind of recording? clipping from start to end? intro, chorus, verse. At least if it was here and there, you could replace the clipped signal with the unclipped one. It is better for you to ask an overdub.

[x42]

One can configure the level above which the waveform is displayed red. IIRC the default is -1dBFS.

I usually track at around -20dBFS with spikes to -10dBFS (give or take a handful of dBs) and record to 32bit float (Session > Properties > Media) so nothing is lost nor do I have to worry much about things while tracking.

[smallbutfine]

The best recording level is the one that the manufacturer of your AD converter recommends.
They (normally) know the sweet spot of their converters and often a recommendation is found in the manual. Some can be calibrated to a value with precision pots, some can be switched from the audio standard (-18dBfs) to video standard (-22dBfs).
A very common value is -18dBfs and peaks should be not higher than -10dBfs for 24bit converters. Avoiding peaks any higher normally sounds better, because of the internal architecture of most converters, i.e. (less) power demand of chips, common psu weaknesses.
So the standard calibration (in the USA) is -18dBfs ~ +4dBu ~ 1.228 V (Ueff.) ~ 0 VU analog meter.
In the EBU (European Broadcasting Union) standard studio calibration is as follows:
-9dBfs ~ +6dBu ~ 1.55V ~ 0 VU analog meter (this is just the european broadcast calibration standard, so you know there are differences if you work in different studios, of course you should print your tracks at much lower volume in the DAW than -9dBfs...)
Of course, you have to watch out for peaks and stay quiet (in opposite to analog tape) also because of the possibility of overloading a plugin at some point along the road in your DAW signal flow/gainstaging, resulting in unintended distortion/noise.
Low levels in the DAW are totally ok. Too hot is not giving sound like in analog, but most of the time creating problems. Converters or digital levels clipping normally sounds very bad (distortion) and is irreversible. Well, there is a plugin in the net that claims to "unclip" clipped tracks, but it also just makes the clipping not sounding too harsh by trying to "guess" transient recovery.
I hope this is understandable.... ;-)

[x42]

@smallbutfine, good summary and recommendation.

One small correction. The EBU recommends -18dBFS for 0dBu or rather EBU R68 specifies +18 dBu at 0 dBFS.
There are however various older national standards, in particularly DIN (Germany) which uses -9dBFS as alignment-level for +9dBu (IEC 268-10).

[smallbutfine]

Oh, hm, yes, i relied on a summary that assumed EBU ~ ARD german broadcast standard...
Okay, to make the confusion complete, this is what i read today, and it shows that there are, obviously, some more, ehm, standards. :-)
In the end, if you can't calibrate the analog input stage of the converter itself, you have to stick with what the manufacturer gives you, essentially...(see "Rock and / or Radio")

BBC spec: −18 dBFS = PPM "4" = 0 dBu
American Post: −20 dBFS = 0 VU = +4 dBu
Orchestral −18 dBFS = 0 VU = +4 dBu
Rock and / or Radio −16, or −14, or −12 dBFS = 0 VU = +4 dBu
Digi 002 is only capable of −14 dBFS.
German ARD & studio PPM +6 dBu = −10 (−9) dBFS. +16 (+15) dBu = 0 dBFS.
(as of "mrholmes" @realgearonline.com)

---

D'oh!
x42, you are the guy who programmed all those meters, right?
Ha, sure you know the standards much better than me!
:-)

[x42]

Well, regardless of all these conventions, your statement "The best recording level is the one that the manufacturer of your AD converter recommends." holds true.
Rule of thumb while tracking aim for ~ -20dBFS on a digital-peak meter (not to be confused with pseudo-peak meters). That leaves plenty of headroom for peaks, but as you said, it really depends on the i/o box.

Those broadcast conventions for alignment-level are mainly relevant for mixing/mastering (PPM or RMS meters), but yes, if you're in some foreign studio double check.
I covered the IEC standardized meters in http://lac.linuxaudio.org/2014/papers/24.pdf and there's various literature out there as well.