Mastering 96kHz to 44.1kHz

pure export, track only?
no automation or busses on the export?

just guessing here.....

Thanks. 
Batsbrew - I'm just exporting the main bus (Master).  I get the same result if I use the Export Mix button as well. No effects, etc. other than the mastering tools.
Drewfx1 - intersample peaks is possible, but I get fluctuations of about 0.5db in one song (while the others are less).  Is this to be expected?

I get fluctuations of about 0.5db in one song (while the others are less). Is this to be expected?

It's mathematically possible to get up to 3db.

Rick O Shay


Yes, this is to be expected.  Save yourself the headache.  Mix down to 44.1kHz 24-bit stereo first and then use that file for mastering.  By doing it that way, any processing in the mastering stage (especially compression) will calculate it's bahavior based on the 44.1kHz representation of the waveform.  The final step can be the conversion from 24-bit to 16-bit and this will not affect your peak levels.

On a side note, if you plan to create any mp3 copies of your mix. mastering at -.2 or -.3 is a good practice because the mp3 encoding process often introduces peak levels that are .1 or .2 dB higher than the original.

Spot on reply Rick. This is exactly the way anyone without the ability to monitor in both environments at once should proceed. The rule of thumb is to process in the highest bit/sample rate possible. But once you convert sample rate, you're clipping. If you could monitor in the converted realm while still in the high sample rate realm, you would see where the overs would be. This is what is great about the PSP Xenon limiter. It allows you to do just that so you see where your overs would be. In my opinion as well as experience, it doesn't make that much of a difference to be honest.
 
I always do the mastering procedure in the highest bit and sample rate, but have at times converted the sample rate before dithering/limiting. This works perfectly. Bob Katz told me I should do the entire procedure at the highest bit rate, but because I couldn't monitor where the overs would be properly, it was nearly impossible for me to do it without guessing. He turned me onto the PSP and I was able to do everything correctly. However, after extensive testing, I found no difference between the two methods and find it easier to convert my sample rate and THEN dither/limit. When you stay in the higher sample rate mode, you constantly have to watch and adjust your limiter for the overs...this can take about 2 passes of the tune to get right. If you just CSR and then dither and limit, you don't have to worry about that and there is no audible difference in my opinion.
 
-Danny 

I'd suggest limiting peaks to no more than -1db (or even -2db) for MP3s. Here's a thread with some pictures.

Try this experiment: limit a song to -0.1db (typical for professional products) and then do it again but this time lowering the maximum to -2db peaks while keeping the average RMS the same. Listen to them side-by-side and see if you can tell the difference. I know I can't, and most people probably can't either. That's because we're sensitive to the crest factor (the ratio of peak to average), not peak values. Lowering your brickwall limit to -1db will not hurt your song at all or make it seem less loud.

Robb,

Most commercial CD's are mastered to a few tenths of a dB below full scale.  Through trial and error (mostly error) I've found that when mastering*, if I set my peak limiter to -.3 dBFS, the mp3's I encode will not have any clipping.

Best bet is to create an mp3 of your finished song,  load it into a DAW and look at the waveform to see if there is any clipping.  Some DAW's can also analyze the waveform and tell you if there are any instances of clipping.

Bitflippers approach will certainly work, but my thinking is that we're already smashing the life out of our music in trying to get it "louder" and I'd rather not squash the peaks another 1 or 2 dB if I don't have to.


*While I don't consider myself a mastering engineer, often a band has no budget for real mastering, so I have to do what I can.