Audio Guidelines for Sound Design

AUDIO ASSET FILE GUIDELINES

The audio files that make up your sound design should all be of the highest quality possible. The sound file formats considered best to work with are:

• WAV or AIF Format
  
• Uncompressed
• 48 kHz Sampling Rate (44.1kHz is the lowest acceptable, anything below is not, anything above is unnecessary)
• 24-bit depth (16-bit is acceptable, 8-bit is not acceptable, 32-bit is unnecessary)
• Never, ever work with MP3, MP4 or AAC audio files. These use LOSSY compression formats that makes for poor editing and low bit depth, which is unacceptable quality for sound editing purposes.
  

AUDIO LEVEL GUIDELINES

Are your sound levels correct according to our audio level guidelines? Are there any sound quality issues? Review these guidelines and make adjustments accordingly. Apply the volume adjustments necessary to each clip in each category. Refer to the dB level guidelines in this document.

• AVERAGE levels range between -10 dbfs (loud) to -20 (quiet) dbfs

• LOUDEST PEAK (sound) no higher than -2 dbfs. This volume is only for momentary sounds, as it is quite loud.

• DIALOGUE averages between -16 dbfs to -24 dbfs, with the average being -18 dbfs, the lowest being -20 dbfs, and momentary peaks no higher than -10 dbfs (yelling, shouting)

• MUSIC averages between -18db to -22 dbfs. When music is playing at the same time as dialogue, aim for –3db to -9db below your dialogue audio levels as an average goal.

• SOUND EFFECTS range between -10 dbfs to -20 dbfs. There may be occasional spikes up to -8 dbfs. Momentary, loud sound effects (explosions, gunshots) might peak upwards around -3 dbfs to -2 dbfs.

These settings leave 2-6 dB of “headroom” in your mix, allowing some breathing room. This way your mix doesn’t sound clipped or harshly levelled off to a given threshold. If you mix beyond these standards, a technician will reduce your overall audio level, which could detrimentally alter the sound of your final output.

QUALITY CONTROL NOTES

• POOR QUALITY ASSETS?
  • If clips are recorded too quietly, and you cannot effectively increase volume, you may need to replace the clip.
  • If sounds were recorded too loud and they clip and burn, you’ll need to replace the clip.
  • If you’re using a file whose quality is below 44.1 kHz 16-bit you should replace it with a higher quality clip of 48 kHz, 24-bit.
  • You CANNOT use MP3, MP4, AAC files in your editing. If you are, you need to replace these clips. You may be hearing a “popping” sound as the timeline plays over editorial cuts, or just reduced sound quality range.
• There should be NO BLANK SPACES in your soundtrack. If there is “silence,” then cut in muted atmospheric room tone to buffer your other audio clip edits. (Make sure to not double up the layers of the room atmosphere sound. Use fades at the ends of clips to soften the edits and prevent doubled-up sound.)
• There should be NO HARD CUTS in your soundtrack, particularly if the sound is ongoing. Make use of simple FADES and CROSS-FADES to soften the head/tail of each clip. Layering in ongoing room tone underneath other clips helps. Layering and overlapping audio clips can also help.
• Rules on blank spaces and hard cuts can be broken, but only with a really good reason.

This image shows the basics of applied fades to soften the cuts, and layering of tracks. RT = Room Tone.