0dBFS and mastering levels....

[Gone To Lunch]

I am experiencing some confusion about mastering levels.

I have finished and mixed my track, and I want to achieve the best possible level for MP3 conversion. I am working in DP 7.24 at 44.1.

I have read in 'Sound on Sound' the advice that I should leave a db or two 'headroom' for the MP3 conversion process to do its best work. I am using the MasterWorks limiter.

Now here's the rub.

My master fader on the desk goes up to +6 db, and my track is dancing nicely round the 0 db mark. But in the MasterWorks Limiter, in the graphic display, both axes stop at 0, and also in Meter Bridge. Am I right in thinking that in both MW Limiter and Meter Bridge, the 0 is 0dBFS ?

And that therefore the 'headroom' required for the MP3 conversion should be referenced against 0dBFS and not the 0dB on my mixer fader ?

[Dan Worley]

Yes, just think of +6 in the mixer as digital zero (0dBFS). MOTU wanted to give the mixer an analog-board type of feel.

I'm no expert, but I like to mix down around -4 to -6 dBFS, and then do my mastering and leave about .3 on top for any crappy DA converters.

That's interesting about leaving a full dB of headroom for the MP3 conversion. I'm going to try that.

Thanks

[David Polich]

Yes, if you're peaks are hitting 0 on the Master fader in DP (prior to mastering), then you're good. I've had many mastering engineers tell me
that if I send them stuff to be mastered, the 2-track mix should not peak
higher than -3.00 from 0 dbfs, so that's what I've been doing for years.

I disagree with the caveat about maintaining 1 db of headroom in a mastered
track to allow for mp3 conversion. Why - because when I've done my own mastering, and sent clients an mp3 with peaks at -1.0 db from 0, they have
always complained that it "isn't loud enough". So here's my
take on that - mp3 is crap audio anyway, so if people are judging something
based on an mp3, they don't care about the quality or overs or clipping.
Go ahead and make it as loud as you want. Me, I usually leave my peaks at -0.03 from 0 when I master.

[mhschmieder]

OTOH, expect MP3 conversion with quality LAME encoders to still in many cases bring the peaks up about 0.1 to 0.2 dB above the WAV files, so I always leave 0.3 dB of headroom.

I'm talking masters though. If you're talking pre-mastering final stereo bounces, I leave 12 dB of headroom depending on genre and context (film/theatre/etc.).

[Phil O]

There seems to be general confusion about the scale next to the fader in the mixing board. That scale is for the FADER, not for the level bar. I've read many post where people refer to this scale as some sort of output scale, but if you use a test tone and measure the actual value (with the trim plug, the meter bridge, or some third party plug) you'll find there is no correlation, even if you subtract 6 db. This is the fader's scale, period. At least for audio tracks. I haven't tested MIDI track levels.
Phil

[Armageddon]

There seems to be general confusion about the scale next to the fader in the mixing board. That scale is for the FADER, not for the level bar. I've read many post where people refer to this scale as some sort of output scale, but if you use a test tone and measure the actual value (with the trim plug, the meter bridge, or some third party plug) you'll find there is no correlation, even if you subtract 6 db. This is the fader's scale, period. At least for audio tracks. I haven't tested MIDI track levels.
Phil

Yeah, I am completely with you on that point -- I never assumed the numbers on the side of the fader were meter levels and that anything below the red was below 0 dB. By the way, the numbers on the side of the fader ARE actually indicating a +6 dB (over 0 dB) boost, so you could theoretically max out at +6 dB.

MIDI track levels go by the 0-127 velocity scale rather than by MIDI volume (volume = audio meters).

I personally go by RMS over peaks, since most audio material nowadays consistently hits zero, anyway. I try to stay between -14 dB and -11 dB RMS (for a really heavy rock-with-full-orchestra mix) and always leave -.03 dB headroom. Not sure about the .mp3 level thing; load the next AAC file you get from iTunes into a wave editor and you'll see it probably peaks between -.01 and -.03 dB, just like the CD track it was probably ripped from. This might be a thing going around because iTunes, by default, has its Sound Enhancer switched on, and the Sound Enhancer is like a fixed-point multiband comp/limiter. If you have a crappy mix, especially one you might have mixed or mastered too loudly, it will sound ten times worse as an .mp3 in iTunes. If you're going to A/B roll against anything, make sure it's at least an actual commercial CD track (or a 44.1 kHz/6-bit .aif or .wav ripped from the CD), preferably one from between 1991 and 2003 (anything before that was mixed and mastered mostly for midrange and may sound thin by today's standards, anything after that is going to be a solid black waveform with no dynamics and a sound level you will achieve at the cost of a decent mix). A good mix will translate to .mp3.