What IS Mastering?

cont' from PAGE 3

3) Now comes, normalizing, compression , and limiting. In short, these are ways to regulate and/or change the volume in your work.

First let's get this out of the way…

This particular topic is the most widely debated, discussed, and argued about over and over. It has spawned what mastering engineers call "the volume wars". I'll explain all this once you get a basic understanding of these tools and techniques.

So lets dig in.

Normalizing is simply the process of making the program material as loud as possible WITHOUT clipping or distorting. It gives the engineer the most efficient signal to work with. Now a lot of you out there who use any type of digital recording are aware of this function.

Now, remember, normalizing is NOT the same as compression. Normalizing simply finds the highest peaks in the material and brings up the volume to that peak, BUT keeps the proportion and ratios of all the signals in tact. Thus, it is the loudest a signal can get ''naturally''…that is without altering the waveform proportions. You will notice that a normalized signal still is nowhere nearly as loud as a compressed one.

Don't worry, I'll get to that.

Also as side note, some mastering engineers don't use normalizing.

They feel that every function performed on a mastering workstation uses mathematical conversions, thus any step is yet another ''generation''. So they avoid it all together to minimize even the slightest degradation. They get all the volume they want from their compression techniques. The debate on normalization is best left up to personal preference and beyond the scope of this article.

Moving on to compression.

Well, this is the tool and technique used to really turn up the volume as well as alter the waveforms' inherent ratios and proportions. Simply put, a compressor works by analyzing a signal and making the weakest part of the signal louder as well as making the loudest peaks quieter. This results in a signal that is more consistent and even in volume. This is referred to as reducing the dynamic range of a signal. You are reassigning that signal to a ''smaller sonic real estate'' if you will.

As a consequence, since you've managed to contain the signal in a smaller area, you can now bring up the whole thing and make it a lot louder over all. Now, all these parameters found on compressors called threshold, ratio, attack and release, are ways of manipulating how much, or even where the signal will be altered. Thus giving you complete control over how much change…from subtle all the way to an unrecognizable waveform.

Again, refer to the Mastering Resources link to learn the detailed scientific breakdown of all these tools.

Using compression can radically alter, not only the volume of the audio, but alter the balance and ratio of what you hear. For instance let's say your mix is really loud and heavy on the drums and bass, but on certain passages the vocalist sounds faint. Well with compression we can change the ratio of what is heard, so we can tame that overbearing rhythm section and give equal volume to the vocal range, so everything becomes clear and audible, even at low volumes where most things disappear.

There are even multiband compressors, which are 3 ,4 ,5 or even 6 part compressors which break up the audio into user adjustable frequency bands, which allow you to compress the vocal range for example, while leaving everything else untouched. Or, assigning different "bands" to different areas of the music, thus compressing the low end differently from the mid band and the high band. All kinds of possibilities are available depending on the needs of the music. With all the detailed control provided, multiband compressors are often used as sophisticated equalizers because of the dramatic alterations possible in both volume and tone.

Again, as side note, some mastering engineers do not like using multi band compression because of the same reasons stated above in the EQ section regarding "purity" and continuity.

Again I say, leave it up to preference and the needs of the project.

Alright, so your music has been compressed, it's sounding balanced, loud, punchy…all of the "audio buzz words" have been met….

So now what?.....

Now comes limiting.

Limiting goes hand in hand with compression. Limiting, you guessed it, limits the maximum level your music can reach. That's called a "ceiling". The reason for this is two fold.

First, to avoid clipping and distorting (in digital, these are ugly cracks and pops and even dropouts…digital distortion is in no way even closely related to the progressive saturating of analog signals which can yield a pleasant effect…on the contrary, digital clipping is hideous. I'm sure you've all experienced it at one time or another.)

Second, to squeeze out even a few more decibels of volume and density. Now this is where we get into a lot of debating. I'll try and suss it out for you. We will also discuss the "volume wars", as this is now relevant!

Let's see how limiting is used and in some cases, abused! As we compress the material and change the ratios and proportions, as well as make the work louder, some of those transient spikes in the audio can still hit "0" or the absolute digital limit (redline), causing nasty clipping.

Enter the limiter.

This tool in essence sets a maximum limit that the audio can hit, and no matter how much you push it, will absolutely not reach past that. This ensures no clipping, but also enables you to get more relative volume out of the material. See, since the audio cannot exceed the preset barrier, it is essentially trapped, because right behind it you have the compressor squeezing the music, and altering it according to your settings.

But with nowhere to go because of the limit "ceiling", and the fact that you are reducing the dynamic range, that limited space just gets crammed with more and more information, making the overall sound much more dense, and as a consequence…louder!

So with careful and repeated tweaking, program material can be made much louder and much denser. Now, how much of this is desired, is entirely up to the artist, or producer/record label.

Here is where we get to the "volume wars".

In order to fully understand this we must take a brief look at the history of mastering. (A very complete and detailed explanation is provided in "The mastering engineers handbook" by Bobby Owsinski and Sally Englefried.)

Years ago, a mastering engineer was a media transfer specialist. The engineer would take the master mix tape and transfer it to lacquer master, from which the replication facility would take the appropriate steps to create mass vinyl records. The engineer used what is called a cutting lathe, to cut the original lacquer. That, in and of itself required a great deal of skill, but once done, the engineer was basically out of the picture.

However, as time went on, mastering engineers used higher and higher powered lathes, and as a result started to use tube compressors to protect the cutting heads on the lathes from blowing up! Needless to say the heads were pricey. As a result of this practice, everyone started to notice something different in the audio as a product of the compressors.

The records were LOUDER.

The higher volume was an incidental byproduct of compression.

Needless to say, the recording industry as well as the public loved this.

The recording industry noticed that records played on the radio that were louder than their lesser volumed counterparts, actually sold better.

Obvious to say, the writing was on the wall. Louder records were now demanded from mastering professionals. No longer was a mastering engineer just a transfer specialist, now the job required volume control. Volume addition to be exact! Now, as we discussed above, compression alters a lot of things besides just volume. So to replace and compensate for the tonality that was altered or lost during compression, equalization was now employed. That corrected the tonal problems, but, it too contributed an added boost in volume.

Again, I don't have to elaborate on the effect that had on the industry.

So, more tools were added, things became more sophisticated, and of course the desire for more and more volume continued, and continues to this day. Now, the recording industry actually did conduct studies to determine who was buying the records, and what effect more and more volume had on sales. Suffice to say, volume was, and is perceived as "better" and the record sales reflected that. (For the full details of the studies, let me refer you again to "The mastering engineer's handbook" by Bobby Owsinski and Sally Englefried.

The actual findings are rather fascinating…even details on what type of mixes, and EQ curves men responded to, as opposed to women. Very informative reading…Highly recommended.).

So it goes…."MORE VOLUME PLEASE".

Unfortunately, there is a very NEGATIVE side to the absurd quest for more and more volume.

The number one negative side, is the blatant disregard for audio QUALITY and INTEGRITY.

With this unbalanced obsession, comes the sacrifice of dynamic range, the original balance of the music, and ear fatigue from way too much density in too small of a space.

Gone are the subtle details, the build ups, the peaks and valleys, the rollercoaster of soft, medium, and loud signals.

The kind of dynamics that make music, a tapestry of different colors.

Nowadays, you pop in a CD, look at the level meters, and see them glued to the max, not even budging. That's an awful lot of music signal crammed into small quarters. That's why a lot of CDs now cause ear fatigue. You can barely make it through a few songs before you have to stop listening. The information is just to overbearing and relentless. Now mind you, I'm not speaking of any particular type of music, but rather the fact that it's all been crammed into a minute sonic real estate, if you will.

Your brain cannot process the overload.

Here, let me use an analogy.

Say you own a 30,000 sq. ft. house. That space can easily accommodate 4 or 5 families, IF, they utilize ALL of the available space. With that amount of space, privacy is not an issue, so the chances of domestic squabbling are slim to nil. The families might not even see each other for weeks.

BUT….

Take these 4 or 5 families, and despite all of the available space, make them all live in 1 room in that house. So you have now reduced 30,000 sq. ft. of space into, let's say a 30 ft. by 30 ft. room to house 20-25 people.

It doesn't take a doctorate in astrophysics to figure out you'll have a full scale war within 15 minutes.

That's exactly what happens with excessive use of limiting and compression. You have all of this dynamic range available, but you're using only a sliver of it, and even that is pegged to the red at all times.

So are we to say compression and limiting are bad?

NOT AT ALL !!

What I AM saying, and I believe most mastering engineers will agree, is that music today is being pumped up to the point where it's all volume but nothing else. There must be balance…loud and punchy, but not so loud that it loses its musical value.

Please see the FAQ section for the most common complaint mastering engineers hear…

And please, also read the answer to why, unfortunately, you've been deceived.

I believe if most consumers understood this concept, it would end the volume wars. Again, that can be found at the FAQ section. Trust me, it's worth your time.

Anyway, with all that's been said, mastering engineers will gladly perform whatever action you want on your record. You just have to understand that there is a trade off for anything…yes, back to that order of priorities and compromise concept again. These are physics laws, and there's no way around them.

SO, if you want volume and nothing but volume, you must accept the fact that you will have to sacrifice dynamic range and that the music WILL ALL be dense.

However, if audio quality and purity are the premium in your work, well then, animal neutering volume will have to take a back seat. We can also work with all the in between points until we come to the point closest to what you want. Again, personally speaking, you are the client, so I'll do my best to get the results you want, but it will be a lot easier if you understand these concepts, so you can formulate an educated decision.

Remember, there's no way around the laws of sound physics!