Premaster Editing and Analysis before Audio Mastering with Ozone

First and foremost, after installing iZotope Ozone mastering plug-in, launch Sony Sound Forge and load your pre-master audio file. To load Ozone, do the following:

You need to make it accessible on the DX Favorites menu. Click on the Recreate by Plug-In Name… command. Click Yes on the next dialog box. The next time you click on the DX Favorites menu, you should see the Ozone command – launch it.

Before you start the mastering session, close all applications and set the wave editor application’s priority to “high” or “realtime” (this will guarantee a glitch-free audio processing). To view the processes taking place in the system, press [Ctrl][Shift][Esc]. The Task Manager will appear; from here, click the Processes tab to see all the programs and system processes that are currently running:

  1. Right-click the forge110.exe process – for Sony Sound Forge.
  2. From the context menu, scroll to Set Priority and then select either High or Realtime.
  3. Confirm this setting by clicking OK button from the Task Manager Warning message dialog.

Setting Sony Sound Forge's CPU priority to High Ethereal Multimedia Technology

Figure 1: Setting Sony Sound Forge’s CPU priority to High.

DC Offset Removal

DC offset is a phenomenon whereby the hardware (soundcard) adds the Direct Current to the sound signal thereby causing the waveform to be off centered. This occurs as result of electrical mismatches between the soundcard and the input device. This phenomenon causes glitches and degrades audio quality when effects are applied to audio files that contain DC offsets.

Note: Back up the premaster audio file before you start making changes to it.

DC offset Ethereal Multimedia Technology

Figure 2: DC offset.

To remove DC offset, do the following:

  1. Click on the DC Offset… command on the Process menu.
  2. Choose the Automatically detect and remove option; then click the OK button.

CD Offset removal in Sony Sound Forge Ethereal Multimedia Technology

Figure 3: CD Offset removal in Sony Sound Forge.


Most musical tracks start playing softly and gradually become louder with time. Likewise, towards the end of the track, the sound gradually becomes soft to silence. To do this to your track, you need to use the Fade [Graphic…/In/Out] commands from the Process menu. To fade in (out) the track, select a portion from the beginning (or at the end) of the track; then apply the Fade In (Out) commands.

Adding graphic fade in with Sony Sound Forge Ethereal Multimedia Technology

Figure 4: Adding graphic fade in with Sony Sound Forge.

Track Pause

If you are mastering a song album for the Audio CD, there is a need to add standard CD 2-second pause in the beginning of the premaster audio file. To do this:

  1. Click on the Go to Start button to move the cursor to the beginning of the audio file.
  2. Choose the Silence… command from the Insert menu.
  3. From the Preset dropdown list, select [Sys] 2 second standard CD pause length at start of file option. Then click OK button.

Adding standard CD 2-second pause in the beginning of audio file Ethereal Multimedia Technology

Figure 5: Adding standard CD 2-second pause in the beginning of audio file.

Spectrum Analysis

Before you start tweaking your mastering plug-in, it would be best if you analyze the spectrum of the waveform of the premaster audio file. This is very important, as it provides you with the avenue to compare the premaster with other professionally mastered track in order to spot out the areas that required more attention during mastering. To do this, you need the Spectrum Analysis tool located on the View menu. To perform spectrum analysis, you need to select the entire waveform of the premaster audio. Once you have started the Spectrum Analysis tool:

  1. Click on the Settings… button.
  2. Select the [Sys] Audible range (20 to 20,000 Hz) option from the Preset dropdown list. Then click OK.
  3. Click on the Refresh button to run the analysis.
  4. Once the analysis is completed, click on the Set button to create a referential snapshot.
  5. To set the first snapshot (of your premaster), click on button 1.
  6. Without closing the Spectrum Analysis window, minimize the premaster file and load your preferred professionally mastered track; and click on the Refresh button again to run the analysis for this file.
  7. Then you’ll notice that both snapshots are displayed (note that the first snapshot is lighter in color). But in order view these snapshots distinctively, use the various options from the Normal Display function (together with the Hide active plot function).

 Premaster Spectrum Analysis Ethereal Multimedia Technology

Figure 6: Premaster Spectrum Analysis.

From the analysis in Figure 6, it is clear that the premaster lacks low-end punch, body/warmth, consistent dynamics and top-end air and brilliance.

Tools of Trade

Some common all-in-one Mastering Suite Plug-ins/Standalone applications include iZotope – Ozone ( and IK-multimedia – T-Racks( Thus, in order to master the premaster audio file, a typical mastering suite plug-in should provide the following tools: Multiband Equalizer, Mastering Reverb, Multiband Compressor (Dynamics), Multiband Harmonic Exciter (Enhancer), Stereo Imager, Loudness Maximizer/Limiter, Phase meters, Mono/Stereo channel indicators.

Izotope Ozone Interface Ethereal Multimedia Technology

Figure 7: Izotope Ozone Interface.

It is one thing to have all the tools at hand and another thing to properly arrange them without destroying the sound. In Izotope Ozone, for instance, the default processing chain is EQ → Reverb → Dynamics → Harmonic Exciter → Stereo Image → Loudness Maximizer → Spectrum Meter (analyzer) → Phase Meter. However, you are at liberty to change this arrangement to get the type of sound desired. Nonetheless, the Loudness Maximizer/Limiter should always be placed last in the processing chain. See Table 1.

Table 1: Typical mastering processing chain.

Typical mastering processing chain Ethereal Multimedia Technology

Your monitoring system should be well set. One thing to avoid is the use of effects (reverb, etc.) shipped along with your soundcards because the mastered audio may sound okay (on your system); but it will certainly sound differently on other playback systems.

Premaster Editing and Analysis before Audio Mastering with Ozone culled from an eBook: Digital Audio Mastering with Ozone by E. J. Garba

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