Audio Mastering

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ON THE SUBJECT OF

MASTERING


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WHAT IS MASTERING?

| The Equipments | The Setups | The Science!

CD-Text vs. CD Database

There are two different sources from which CD Track information is obtained.

For less confusion, please note:

CD-Text shown on some CD-Players is inserted within the metadata (PQ codes) while

burning a Red Book CD. Specific software is used to insert this information (CD-Text, ISCR

Codes, Track Start/End…).

Since its release in 1996, CD-Text has been adopted (slowly) but not by all CD Players or CD-ROM

manufacturers.

CD Track information; shown on iTunes, Windows Media Player or other software media

players, is linked to an Online Database Server from which any user can upload or

download information regarding an Album (Track Title, Genre, Artwork, Comments,

Lyrics, Year...etc.)


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CraftLabMastering Setup

As Mastering is different than Mixing (room acoustic/structure, gears and ears), we, at

CraftLabMastering, have chosen to stick as possible to International Mastering standards.

Our reference room has:

An NC of 30, a result of an isolated machine room for less noise in the control room (for

delicate fadeouts).

An inclined ceiling that reflects mid/high frequencies behind the listening position and

produces a balanced tonality with a precise imaging.

A 32 ms difference between the direct sound and the early reflections; no obstacles

within the equilateral triangle!

Cables are kept as short as possible for minimum noise (no insert patch or useless

connections)

Custom designed hand-made tube and solid state Mastering Processors for a unique

sound character and maximum dynamic range! (no squashed sound yet competitive

results!)

All processors are analogue, no digital plug-ins.

Special Mastering DAW capable of inserting all metadata required for CD

duplication/replication (PQ, ISRC, UPC/EAN, text)

DDPi format for album delivery for minimum burning errors and more reliability.

3way wide band passive midfields to mimic best a home listening position and go down

to 25Hz!

Our fresh set of ears and experience in the audio field in London and Germany have let us

implement unique Mastering techniques with an advanced usage of the high-end gears we

have!

Verification Process @ CraftLabMastering

Digital media are subject to data dropouts and burning errors.

CraftLabMastering special measurements tools ensure through an internal media verification

test, the integrity of the disc surface with minimal C1 errors (BLER) and zero C2 or CU error.

Every single project then passes by a last auditioning quality control (QC) through different

playback systems and environments.

What is a DDP file?

DDP stands for Disc Description Protocol also known as DDPi as in image or DDP file set. It is a

delivery format that ensures an error protected audio material supplied by the mastering studio

and suited for CD/DVD replication.


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A DDP file contains audio as an image file with 3 additional sub-files that carry all other

necessary disc information.

CraftLabMastering includes an additional checking file to verify data accuracy between

transfers.

Nowadays, DDP is becoming the audio industry for optical discs replication due to their reliability

and the Robust-Data-Error (if any) Correction Algorithms. Audio CDs on the other hand,

introduce more errors on burning and playback with less reliable Error-Correction.

What is an ISRC code?

ISRC: International Standard Recording Code.

It is a 12-digits code that gets allocated (on the CD) to each track that goes out into distribution.

This is the code that identifies the owner of the track and country of origin each time it is

downloaded or played on the Radio/TV. The ISRC is free of charge and can be downloaded.

What is Dither?

Dither is a random low level noise (similar to a hiss) added to the signal to trim digital distortion

known as quantization error. Dither must be used when reducing word-lengths (mainly down to

16-bit).

There are different algorithms to accomplish dither but they all fall into two flavors:

Flat-shaped dither which is similar to white noise.

Noise-shaped dither which adds the noise to an unheard (by human) audio band.

All dither sounds different and every music demands specific dither type. Dither must be added

once and at the end of the signal chain. Therefore it is the Mastering Engineer's responsibility to

insert and choose the right dither type.

Try it yourself:

Start with a 32-bit sine wave.

Truncate it to 8-bit using dither.

Notice the added hiss (dither). It is gentle to our ear.

Truncate the 32-bit to 8-bit without adding dither.

Notice the unnatural digital distortion. It is unpleasant to our ear.

It is arguable that 8-bit file is a low quality sound therefore with a 16-bit Redbook CD there is no

need to dither. However, with some kind of music we clearly hear the difference (dynamic and

low level tracks for example), and generally on the fade outs (with any kind of music). Dither is

our friend while digital distortion is not!


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Now What is MASTERING?

Mastering is the final creative stage in the music production process. It is the bridge between the

final mix-down and the CD duplication/replication plant.

Mastering involves 3 stages:

1. Adjusting unpleasant sounds

2. Quality enhancements

3. Final output delivery

Stage one: Adjusting unpleasant sounds (the Lab part)

Through a careful and critical listening to the audio material, and by keeping up a good

communication with the client and his indications, most issues in the audio can be resorted,

whether it is in the frequency domain, level, dynamics, phase balance, disturbances or

noise. Over compressed material could also be surged to get its life back!

Mid field monitors set up is a standard in Mastering. It mimics a home listening situation. Near

Field Monitors are best suited for recording and mixing studios, not for Mastering. This is why we at

CraftLabMastering chose 3-way passive midfields as reference.

Stage Two: Quality enhancements (the Craft part)

This creative phase gives the project its sound identity and style by the use of the finest analog

and digital mastering processors in different approaches and techniques. That way, music clarity

is enhanced, a dimensional and airy sound could be created, warmth or punch is added (if

appropriate) and dynamic range is maximized.

Within the era of loudness war, a lot of commercial music suffers from hyper compressing and

hard limiting processes, which has a lot of technical and sonic drawbacks. i.e.: ear fatigues,

blurred stereo image and squashed highs, muddy smashed smeared pumping distorted edgy

sound, u named it!

Stage Three: Output medium assembly (the Logistic part)

In this last stage all the tracks are put together and exported as one complete project/file on a

specific medium (ex: CD) and format. The following tasks are done with a specialized high

resolution DAW (Digital Audio Workstation): Tracks sequencing with the appropriate gap in

between to create a smooth music flow throughout the whole album, editing fades/crossfades

with minimal calculation errors, choosing the right dither shape, inserting PQ codes (for track

start/end and program length timing), emphasis condition, UPC/EAN and ISRC codes, CD text,

EDL list, copy prohibit/permit. With a final quality check, a DDP file (recommended) or a Red

Book master disc is supplied to the replication/duplication plant.


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What shall i send to the Mastering Engineer?

Mastering should be taken into consideration while mixing for better results and time saving. Here

is a list of recommendations worth looking at.

Let your Stereo Bus peak at a maximum of-6dBFS (preferably at-10)

Don’t insert any processing or equalizing on the stereo mix bus. NO LIMITERS, No

Compressors.

Do not normalize

Any Lossless file is accepted with a Sample Rate of 44.1 KHz (or above), 16 bit (preferably

24 bit) burned as a wave file or a music CD. (We do accept mp3 if other format is not

available).

Make sure the format type is the same used in the recording/mixing session.

If your delivery is a physical disc, please burn the tracks as data and Not audio.

Leave a gap of one second before the start of the first track (glitches error) even if it is a

music file.

Leave some space before the start and end of the audio waveform while editing.

Name the tracks with their numeric order followed by their name (ex: Track_01_Me Amor)

Make sure that the total playing time does not exceed 74 minutes.

Label the disc using water-based markers and please do not use stickers.

Don’t hesitate to bring up or suggest any reference music that sounds appealing to you.

Provide us with appropriate ISRC codes. (Check "Notes" for more on ISRC codes)

Make sure that the bass drum and bass lines are well balanced.

Why should I have my tracks Mastered?

Have you ever wondered why your music sounds different in other playback systems

(nightclubs, car, TV, Radio, home) than in your listening room?

Have you ever tried to reach the same sonic results of other commercial releases?

Are you looking for a punchy tight bass, a warm deep spacious sound, or a loud and

dynamic track?

Do you need an assurance that your audio is problem-free and working well on any

extension format (mp3)?

Do you want your album/EP to have a consistent and smooth music flow with unified

tone and level?

Whether you're a Musician, DJ, MC, Producer, Composer, or Artist: Mastering is the key to get a

well crafted, clear, and defined sound, that takes your song to accepted high standards.


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For further questions, please feel free to send an email to [email protected] or [email protected], or visit the site.

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Audio Mastering