Making Your CD Loud
This topic is one of the first items that is discussed before any mastering work is started. Many mastering clients have noticed that some CDs are louder than others but have not given it much thought. Others will demand that their CD be as loud, or louder, as the latest major label release in their genre. Still others understand the implications of the process and ask me to make their album as loud as possible, but not at the expense of dynamic range. Obviously, the latter approach makes the most musical sense but that does not always happen!
Our approach to mastering is to present and explain the positives and negatives of what can be done with your mixes. In other words, many mixes are compressed and equalized in such a way that allow us to raise the volume without doing serious damage to the dynamic range. On the other hand, some are not so easy! Occasionally its just one song on an album that defies all attempts to raise the level a hot as the others. In that case, if one wants the album aggressively loud, that song will have to suffer in order to not to bring down the overall level of the album.
After we point out the pros and cons, if the client wishes take a approach that we do not think is best for the mix, we respect their wishes. In other words, even if we think that your mix, or mixes, will suffer sonically when pushed to the level of the latest/greatest, we will do so as best we can!
If we need to explain the process of making an audio file louder, our favourite analogy is an old movie, with its whispers and screams. While watching such a movie, you try to set the TV's volume level to a point where you can hear the whispers but are not deafened by the screams, in other words, the average level of the program. If you are in a quiet environment, this will work pretty well until some outside noise intrudes into your space, thus covering the quiet passages, or until the commercial kicks in.
The commercial seems to be louder than the movie. Actually, it may not be any louder than the movie's peak point (the screams) but because the audio has been dynamically limited, it has almost no low points and therefore on average, sounds louder. In other words, through compression and limiting, the distance between the quiet and loud points have been reduced and the whole program has been raised so that what little peaks are left are at, or close to, digital zero.
Compression and limiting techniques are commonly used in mixing and mastering. In mixing, overdoing it will make the mastering either difficult or impossible (see A Guide For The Mix Engineer).
The mastering room is where most of the stereo compression/limiting techniques should be employed. There are exceptions of course, but generally, the mixer should stick to compressing individual tracks with possibly some light compression on the stereo buss, but only if it is understood how this will affect the mastering. Using mastering plug-ins is not advised unless you understand how they are going to affect our work.
In the early days the purpose of mastering was to fit a studio mix onto the medium of the day. For instance, if in the process of making a record, the bass was too heavy it would not fit on the vinyl medium and the needle would jump out of the groove. The solutions was to equalize and perhaps compress the bottom end.
Later, compression was used as a tool to enhance elements of the mix or master, i.e., giving the drums and/or bass more impact or "punch". This is referred to a "musical" use of compression as opposed to using compress strictly for getting more level out of a mix.
Eventually, as music began to be listened to in noisy environments, i.e., the car, it became necessary to reduce the dynamic range in order to hear all the elements of the music. For instance, when playing old jazz vocal recordings in a car, it was impossible to hear the bass without turning up the volume. Unfortunately, the vocals would then become too loud. So the mix balances that worked so well in a quiet home listening environment with a good stereo system didn't work in the car. So these days, even most jazz recordings use some compression and limiting in order to make the music listenable in more environments. With pop music, various types and levels compression are a given!
The reason for the next jump in compression and limiting to raise the apparent levels of CDs came with the invention of multi-disc CD player and continues today with the iPod. Many record companies, producers and artists did not want their album to sound quieter than the average and some wanted theirs to be louder than the average. This desire for one-upping the next guy has resulted in the biggest leap of volume over time. After all, if you want to be louder than the lastest/greatest, then you set the bar for the next one..and the next one, etc.!
As we are mastering the initial track of the day, we are able to demonstrate various compression/limiting techniques by comparing the master-in-progress to various major label CDs that the client and engineer are familiar with. Keep in mind that not all mixes will be able to be raised to the same level as your favourite CD, at least not without introducing some distortion! However, with the multitude of compressors and limiters we have on hand, we can usually get results that will satisfy those who want the volume of their CD to be aggressive!
After setting up the mix with analog and/or digital compressors, we finish with off a choice of the outboard Wave's L2 Ultramaximer or the TC Electronic's Brick Wall Limiter, or the PSP Xenon. Very occasionally, the L3 Multi-Maximizer or Sony Oxford Inflater (plug-ins) can also be useful.
If not overused, these limiters allow the waveform average to be raised with only a slight sacrifice of the highest peaks. Our technique at Silverbirch, i.e., using analog and/or digital compression before the final limiter helps it do its job without having to work it so hard, thus allowing us to keep more of the dynamic range of the track, if desired.
We often use our new Pendulum PL-2 Analog Peak Limiter just before the Lavry analog to digital converter and above mentioned digital peak limiters are used after the ADC. Again, a less intrusive way to avoid overusing the digital limiter.
The TC Electronic's Brick Wall 2 Limiter is probably the least intrusive limiter that we have and is often used on albums, or tracks, that don't need an aggressive volume level.
The Sony Oxford Inflater plug-in is yet another volume maximizer in our tool box. It has an "exciter/stereoizer" component built in that is only suitable for certain material. However, on occasion, it can be just the ticket to make something work when nothing else will do it.
And lastly, our new LavryGold Analog to Digital converter has a soft limiter on it which has proven to also be useful on more than a few occasions.
It seems pertinent to point out that the absolute volume level of the average CD mastered circa 2000 to 2009 is significantly louder than in former years although we are hopeful that most producers are probably going to settle for the current level or less! We have also noticed that a few new release are noticeably lower, which is a good thing, because if the practice becomes more common, it will relieve the pressure on labels, artists and producers to engage in the volume wars, i.e., volume over musicality.
At a recent session, in an attempt to establish where he should attempt to go with the volume level of CD about to be mastered, our mastering engineer asked how the client how they coped with the various levels of songs when listening to their iPod. The answer was "I keep my finger near the volume control". We couldn't have said it better ourselves!
Studios using inexpensive mastering plug-ins and programmes or all-in-one outboard boxes like the finalizer, are finding it increasingly more difficult to match the volume of professionally mastered CDs without losing too much dynamic range and introducing subtle digital distortion.
Over the years, we have learned to be sensitive to both the music and the clients and this applies to the absolute volume of your disc. For instance, a jazz album is approached with a more subtle compression approach than a "heavy" album. The tools that we have today give us just about every option we need to get your level just right.
There is more info here but you will have to scroll down as the first part of the linked section is the same as this one.