Why Mastering?

It’s not loud enough. It sounds wimpy next to other commercially released music. Turning it up or mixing down at a higher level doesn’t solve the problem. It sounds louder, but not, well LOUDER. It sounds dull. Other CDs have a sparkle that cuts through with excitement. You try boosting the EQ at high frequencies, but now your song just sounds harsh and noisy. The instruments and vocals sound thin. Commercial songs have a fullness that you know comes from some sort of compression. So you patch in a compressor and turn some controls. Now the whole mix sounds squashed. The vocal might sound fuller, but the cymbals have no dynamics. It’s full…and lifeless. The bass doesn’t have punch. You boost it with some low end EQ, but that just sounds louder and muddier. Not punchier. You can hear all the instruments in your mix, and they all seem to have their own “place” in the stereo image, but the overall image sounds wrong. Your other CDs have width and image that you just can’t seem to get from panning the individual tracks.

You had reverb on the individual tracks, but it just sounds like a bunch of instruments in a bunch of different spaces. Your other CDs have a sort of cohesive space that brings all the parts together. Not like rooms within a room, but a “sheen” that works across the entire mix.

Don’t worry. It’s not that you’re doing anything wrong. The tracks need to get mastered in order to get that “sound”.


Why Mastering?

For musicians and home studio owners it is a well-known issue. After spending many hours on recording and mixing a song, the final mixdown cannot keep up with the loudness, punch and brilliance of a commercial production. While you may be well pleased with your mix when listened through your monitors, it just sounds unbalanced and dull over your home or car stereo.


Your songs don’t sound as good as the songs on the radio and the new album of your
favorite band. But why?

The answer is obvious. Professional music productions are mastered!


What is mastering?

Mastering is the final step of a music production that adds a professional, commercial touch to your mixdown. In the mastering process, tracks are refined to sonic splendor and adjusted to industry standards. Once your tracks are mastered, they will sound balanced, clear and precious — on your kitchen radio, in the car, on the club PA and your headphones. Mastering engineers typically work with a stereo mixdown provided by the producer or mixing engineer. Besides maximizing the audio quality, mastering also includes sequencing the tracks and preparing the pre-master used for replication and distribution. This process of taking a mix and preparing it for manufacturing involves the following:

The “Commercial Sound”
The goal of this step is to take a good mix (usually in the form of a stereo file) and put the final touches on it. This can involve adjusting levels and in general “sweetening” the mix. Think of it as the final coat of polish, or the difference between a good sounding mix and a professional sounding master. This process can involve adding equalization, multi-band compression, harmonic enhancement, loudness maximization, etc.

Consistency across the CD
Consideration has to be made for how the individual tracks of a CD work together when played one after another. Is there a consistent sound? Are the levels matched? Does the CD have a common “character”? This process is generally the same as the previous step, with the additional consideration of how individual tracks sound in sequence. The goal is to minimize the differences between tracks, which will most likely mean different treatments for different tracks.

Preparation for Duplication
The final step usually involves preparing the song or sequence of songs for manufacturing and duplication. This step varies depending on the intended delivery format. In the case of a
CD it can mean converting to 16 bit/44.1 kHz audio through re-sampling and dithering, and setting track indexes, track gaps, PQ codes, and other CD specific markings.

One of the most important steps in the mastering process is to enhance the loudness of a track. Loudness is the listeners’ individual perception of sound levels caused by an audio signal. In commercial productions, high loudness levels are an important factor. Unprocessed songs are likely to be too quiet, which is disappointing if songs are published on radio or TV, where louder songs might attract more attention. The loudness level is increased by using dynamic processors, such as (multiband) compressors and limiters, which reduce the dynamic range of an audio signal without affecting its dB level.

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Stereo mixdown — before mastering


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Stereo mixdown — after mastering

CD manufacturing
No matter if it‘s an album or a compilation, tracks need to sound as a whole rather than a bunch of songs stuck together. In the mastering process, songs are analyzed, equalized, compressed and shaped to achieve consistency and harmony between the songs. Via audio montage, tracks are brought into the right order, and indices, breaks and fades are set. The final step is the preparation of a Red Book compatible pre-master CD that is used for the manufacturing process.

Frequency Spectrum and stereo image
Mastering also adjusts the frequency spectrum to meet industry standards for audio CDs. Equalization is key to good sound. Low-end frequencies can be cut if a song is laden with bottom end and unwanted noise is eliminated with narrow-band notch filters and various special tools. Here analyzers provide detailed graphical feedback, making it easier to optimize the frequency spectrum. Comparisons with commercial productions of the same genre offer a good way to find flaws and detect differences. The same applies to the stereo image. The mastering engineer has to ensure a consistent stereo image along with good mono compatibility to achieve consistency among different listening environments.

Limitations of mastering
One final word of advice — mastering cannot work magic. It adds depth, punch, clarity and volume to your mixdown. Mastering may hone the overall quality, but you’ll never get a poor mix to sound like a high-end production. Here re-mixing the song will almost always lead to greater satisfaction. Each step in a music production requires great care and accuracy — with this in mind, along with some experience, you will be able to achieve good results.