Simple guide to Audio Mastering and how to get ready to manufacture

Adapted from Disc Makers Blog’s “Making A Great Master” guide, here are tips for preparing and uploading your audio master when you’re ready to make CDs.

by Andre Calilhanna of Disc Makers Blog

If your goal is to produce a killer-sounding CD, there are certain steps that must be taken in the preparation of your master.

First, your mix should come out of — and go back into — total silence. To do this, record for at least 15 seconds at the beginning and end of the song (for individual tracks) or audio program, with levels set at minimum. Check each track for clicks, bumps, thumps, and other strange sounds that sneak into almost every recording.

Make sure your mixer’s output is as clean and quiet as possible by listening to each track open all the way on headphones. Is there a hum or hiss that could be reduced or removed with proper grounding or a cleaner power supply? Experiment to find the optimal output level for your mixer.

Audio files via upload

While there are several format options to choose from when deciding how to prepare and submit your master for manufacturing, most are provided to us via upload, as individual files, through our website.

Our web interface allows you to upload audio files of varying sample rates and bit depths. One important feature of our web interface is that it allows you to stream your uploaded files for a proof before you finalize the submission of your master.

The two most frequently used file types are WAV and AIFF. They are identical in audio fidelity, and both are almost universally supported by any audio software package. Both WAV and AIFF files can be created in various levels of quality. At minimum, these files should be 16 bits with a sample rate of 44.1K. This is the industry standard “CD quality” audio.

FLAC files are also accepted, which are reduced-size lossless audio files, but you should avoid using lossy files (e.g., MP3) as significant audio content will be absent from the file.

When submitting WAV or AIFF files, name your files with the track number (01, 02, 03, etc.), based on the song’s position in the final order of your album, and the full song title. For example: “01 Silent Night.WAV.”

DDP masters

DDP stands for Disc Description Protocol. It is an image file format that was specifically created for use as a manufacturing-ready master to be provided to CD replication facilities. A DDP master can be easily and securely uploaded through our website.

A DDP master is typically created by a mastering engineer using special software after the mastering of your album is complete and you have given final approval. Though there are some low-cost software options available for creating a DDP master, we highly recommend you have your DDP produced by a professional to ensure it is prepared correctly.

A DDP master contains your audio master, laid out exactly as you specify to your mastering engineer, with all song-to-song spacing, song order, and CD-TEXT information encoded. A DDP master also contains robust error-checking features that allow us to ensure the master file we receive via upload has not suffered any data corruption.

The Disc Makers Master Uploader App

Our Master Uploader App is an app you can download from our website that allows you to create a manufacturing-ready master from individual audio files or a physical CD. You can import individual audio files or a physical audio CD master, adjust the song order and spacing (for individual audio files only), add CD-TEXT information, and proof your master before uploading to us by playing the album back in the app or burning a test CD. Once you are satisfied with the layout of your master, an image file is securely uploaded to us and stored on our servers for use in the manufacturing of your CDs.

CD-R masters

If you have a physical CD master that is laid out exactly how you want your final manufactured CDs to play, you can mail that to our facility. Due to the additional costs of processing a physical master, there is a small charge incurred for this master format.

DAT and analog tape

While these formats are increasingly rare, we do still get masters sent to us on tape. Note that these formats require additional care related to packaging and shipping and will incur additional costs to prepare the files for mastering. Always make a backup! Never send your only copy of your master analog or DAT master.

What to provide on a digital master

Before you submit a final master to Disc Makers, listen to it from beginning to end. If there is anything you want to change, go back to the studio and fix it. Whatever is on your master will be on your finished product.

Make sure that all songs are in the proper order with the correct spacing between them. Decide now whether you are satisfied with the way the master sounds, taking into account the acoustics of the room in which you are listening. Any unexpected post-production required at the mastering and manufacturing stage will add to the cost of your project and the time required to complete it.

CD master preparation

When you submit a CD master to Disc Makers, you want to submit an audio CD that sounds just like you want the final CD to sound. The songs must be in the proper order, with the desired spacing between them.

Be sure to place a CD track or “index” marker at the start of each selection on your CD. These index markers will be transferred to your CDs and will make it easy for listeners to jump to each selection as desired, including songs that fade into one another or have no discernible break.

• Listen to the CD carefully. It should sound exactly the way you want your finished product to sound.
• Make sure the disc surface is clean and scratch-free. Use only a soft-tipped marker to label the CD, never a ballpoint pen.
• Place a CD track marker at the start of each selection.

Handle all masters carefully, both before and after recording. Touch CDs only by the edges and keep them free of fingerprints and scratches that can cause data errors. Make sure your master is clearly marked with your contact information.