Fri 11 Feb 2011
How Do You Balance The Volume Level Of Your Songs Equally?
Posted by Lorenz under Mastering , MusicNo Comments
To get equal volume just by letting the computer do it is still almost impossible nowadays and can’t replace the ears. Reason being is that the perceived volume (so what your ears tell you how loud it is) is completely different from what meters can tell you.
A simple example would be this: take a sine-wave-sound at 50Hz and one at 5000Hz that have the same RMS. Now, while the meters do show the exact volume for both, they have a very different perceived loudness to you, right? The problem is that the human ears reacts differently to different frequencies, and even then, impulse sounds, lasting for short at a high volume on the meter, can still sound lower in perceived volume than a longer sound played back at lower volume. Many factors come in so that only the human brain in connection with your ears can correctly judge what the right loudness relation between the songs is.
However, there is an ongoing attempt (and I say attempt, because it’s far from perfect) to digitally simulate and measure the perceived loudness and tell you how you have to change the volume of each song in relation so they all sound equally loud. This is derived from the ReplayGain that you might know from MP3 Players.
Here is how you go about and initial measurement and then adjusting the volumes accordingly - the results are acceptable for a first start, but still you have to control and adjust the volume of each song by ear afterwards. But it gets you in the ballpark for a good start:
1) Download this and extract it: http://www.rarewares.org/files/others/wavegain-1.2.8.zip
2) Take each of your songs and reduce it to the chorus parts (the loudest parts of the song, or better said: the parts the listener has the most attention to in the end, this usually IS the chorus, right?). Then save each of the “reduced to chorus” versions of each song to a separate WAV file (use 24bit, or better 32bit float).
3) Now put the wavegain.exe from the archive you extracted above to the directory you saved your “reduced to chorus” songs.
4) Open a command prompt and type
wavegain *
Press ENTER
…and it will tell you how much you should adjust each song so that they get the same perceived loudness. So you now go back to your original songs and boost/lower so much dB as it tells you for each song.
Normally you can also simply do this on the “full song” instead of cutting it down to a “chorus only” version. But I found that it yields better results this way.
Still you will have to control and manually adjust afterwards, but it’s the best starting point a computer can make out of it, haven’t found any other tool that does it any better than this.
Of course the best point do to this process is prior to the final limiting stage, because if you do this on already limited songs that have no more headroom, it will not work to well, apart from that you will destroy the dithering you (hopefully) applied. So do this at the point where you are happy with the master so far but have not used the final peak limiter yet. After you have fnished this process and did the last adjustment by ears for equal loudness, you can then go to the limiter and use the same setting for each of the songs you’ve previously processed - you do want to do this, because limiting each song with separate values will of course also put off the volume-relations between the songs again.
Hope it helps and good luck:)
About the Author:
Lorenz Vauck is an Audio Mastering Engineer, Musician, and Internet Entrepreneur from Dresden, Saxony, Germany. He is the Managing Director and Chief Mastering Engineer of XARC Mastering, one of the world’s first online audio mastering studios established in 2003.