Headroom

wave100

How much headroom to you peeps have on the master bus a) with no compression/limiting and b) with compression/limiting ready for exporting as an mp3?

guitarfishbay

-1db covers for most scenarios to my understanding. The issue is inter sample peaks, hence not doing 0, but maybe someone with a deeper understanding like @octatonic can explain better.

When I’m mixing I do a split approach - instrument bus and vocal bus, which then goes to my master bus.

I’m gain staging so that my master bus is hit at -6db when my mix is hitting my instrument compression bus to my liking and the vocals are balanced in nicely. I then have the option of a mastering chain where I can bring up the level into a limiter if it’s something I want to get loud myself. But personally I don’t export MP3s louder than -1db on a limiter.

octatonic

There is a useful article on inter-sample peaks here: https://www.musictech.net/2012/09/10mm-no211-inter-sample-peaks/

Personally I am of the school of thought that thinks it is less of an issue than some people, esp in the audiophile communities, seem to think it is.

I've not mixed anything without having something on the master bus in a very long time but the goal is fatness and weight, rather than loud.
Often there are two compressors on the master bus, something like a Crane Song STC8 and an SSL G Bus.
In addition to something like an API2500 across the drum bus.
But these are tonal treatments as much as levelling tasks.
They are also on the bus from the start of the mixing session- they aren't on during tracking because of latency issues- I'm using hardware compressors on insert and it messes with LLM.

But I give the mastering engineer room to work-  3db ish, or more.
If I am doing something that is not for commercial release then I might strap a limiter across the bus and set it to -0.5db but the aim is to keep a bit away from that, it is a safety net, not a target.
If it hits then I've fucked something up along the way and it allows me to see that to go and fix it, rather than just letting it go.

If the OP wants things to be LOUD LOUD LOUD then that is a bit of a different question.
I try to concentrate on things sounding balanced and enjoyable, rather than it trying to be the loudest thing possible.

spark240

I send groups to busses, such as Elec Guitar, Acc guitar; Keys, drums, percussion, vocal, Bv etc, I mix to Master Bus at around - 6dB,,,,then if I attempt to Master myself I set it at -1dB.

joeyowen

octatonic said:

it is a safety net, not a target.

So much wisdom in one small comment

So many meters are seen as targets, I am as guilty as the next

Stuckfast

How much headroom to leave depends what is going to happen to the file after you've bounced it. If it's going to be mastered, then it is a good idea to leave at least a couple of dB unused. If it's going straight to release, there is no need for 'headroom' as such, because no further processing is going to happen to it, but it's worth checking on a few playback systems to confirm that things like inter-sample peaks aren't causing problems.

FWIW I set the ceiling on my output limiter to -0.1dB and I'm hitting it quite often, and no-one has ever complained about distortion.

wave100

Thanks for the replies guys. The reason I am asking is that for 20 years, since I started recording audio on computers, I have used the strategy of :- aim for 6dB headroom on the master bus then use a compressor (recently the NI SSL imitation) then a maximiser, Waves Ultramaximiser, with the volume limit set to -0.3 dB with a maximum of 2 dB gain reduction on each plugin. This has worked perfectly so far until a song which I have just recorded which has horrible crunchy distortion when rendered as a 320 kbit/s mp3. Then I tried changing the processing to Ozone 7 which I also have, this made very little difference, still tons of distortion where none exists in the final mix. So I tried reducing the limiter max volume in 0.5 dB steps until I got to -3 dB, there is still perceptible distortion on the render, though admittedly not as much. Still not acceptable though. I would have thought that 3dB headroom was sufficient to avoid inter-sample peaks.

WTF is going on with this one song?

24 bit render sounds fine, identical to the mix. I am, I would say, pretty anal about gain structure throughout the recording/mixing process, I just don't understand why this one particular song is being so problematic.

andy_k

I'm usually mixing to allow for -3db before bouncing to mp3, someone mentioned that to me a while back, and when comparing Wavs to mp3s of the same render in Reaper, it always seems that mp3 version has something in the conversion that boosts the signal, the -3db seems to compensate for that conversion.
Im not doing stuff that has to go for external mastering, in that case i would be aiming for more like -10--- -12 to allow the mastering engineer to do his black magic.
YMMV
cheers guys
andy k

guitarfishbay

@octatonic what is your methodology with the dual comps? Different attack times/ratios etc?

octatonic

guitarfishbay said:

@octatonic what is your methodology with the dual comps? Different attack times/ratios etc?

I usually start with different attack and release times but as I said before it is often a tonal thing.

The API has a very different feel to the SSL or the Crane Song- much more forward sounding- super punchy and clear.
I mostly use that in series with the Crane Song now- the STC I can hardly hear working, even at pretty ridiculous gain reduction- something like 12db.

Sometimes I parallel compress with the API and then level the whole mix with the STC.