Compression is just one technique in the tool bag of recording tools
What's pre-mastering and how, when, and why should I use compression?
Master VO,
Thanks for this opportunity (you may come to regret it !!)
Could you please have a go at explaining the art of “pre-mastering” and how, when and why to use compression.
I have Audition 2.0 and it is a monster that I only use to a fraction of it's potential; maybe there could be an offshoot forum for Q&A on how to maximize the potential of this remarkable software?
Martyn Lloyd- Australia
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Thanks Martyn,
Another Aussie chimes in.
My job here is to de-mystify a highly complex subject. I’ll start by saying that “Pre-Mastering,” in the sense of sending out voice files to clients isn’t something, as a “Grasshopper,” you really need to worry about a great deal. You’re not producing Snoop Dog’s tracks. However, you may be recording fully produced commercials that require music and sound effects. You may also wish to “enhance” your voice.
Let’s start with what our buddies at Wikipedia say:
Audio level compression, also called dynamic range compression, volume compression, compression, limiting, is a process that manipulates the dynamic range of an audio signal. Compression is used during sound recording, live sound reinforcement, and broadcasting to improve the perceived volume of audio. A compressor is the device used to create compression.
Adobe Audition, as well as every other major multi-track recording software, has a digital compressor with lots of settings built in.
Compression is often used to make music sound louder without increasing its peak amplitude. By compressing the peak (or loudest) signals, it becomes possible to increase the overall gain (or volume) of a signal without exceeding the dynamic limits of a reproduction device or medium. (I.e. your radio, i-Pod, or your computer speakers, known for their wonderful fidelity and frequency range) The net effect when compression is applied along with a gain boost is that relatively quiet sounds become louder, while louder sounds remain unchanged.
Got that?
Compressors usually have controls to set how fast the compressor responds to changes in input level, known as ''attack'', and how quickly the compressor returns to no gain reduction once the input level falls below the threshold, known as ''release''. Because the loudness pattern of the source material is modified by the compressor it may change the character of the signal in subtle to quite noticeable ways depending on the settings used.
A second control on a compressor is hard/soft knee. This controls whether the bend in the response curve is a sharp angle or has a rounded edge. A soft knee reduces the audible change from uncompressed to compressed, especially for higher ratios where the changeover is more noticeable. You need a chart to sort of show that.
http://alesis.com/support/notes/Signal_Processing/Compterm.html
An audio engineer might use a compressor in a subtle way in order to reduce the dynamic range of source material in order to allow it to be recorded optimally on a medium with a more limited dynamic range than the source signal, like a talking handheld device, or they might use a compressor in order to deliberately change the character of an instrument being processed. However, that has little to do with recording your voice for a documentary or a website Power Point (tm) or Flash presentation. Or does it?
It’s hard to explain without you actually hearing examples. One way I use compression is to emphasize the lower registers of my voice. I can play my voice louder, thus emphasizing the lower frequencies, which require more power, but keep the overall level from over modulating, or distorting. Compression lets you do that. That’s what many of the “Voice of God” radio imaging guys use. You know, the one who say “97 ROCK!” like it came deep from their gall bladder. My beloved agent refers to them as “Pukers.” I don’t do that type of stuff. I use it mostly to give my voice “presence.”
Another use of compression is to make your voice “float” over background music. By making your voice louder, it will overpower the music, even though they are at the same overall level or the music is complex and distracting. It’s a very subtle thing.
Remember that many times a producer just wants dry voice, and they will tell you so. Just record your voice with no processing. Let them handle that. However, if you do a great deal of business-to-business work, where you are the pro, you can enhance your audio using compression and the other fun stuff. Many clients who say “I’ve never done this before” will just say “that sounds great!” (Or not)
Some people need to read manuals on their software to learn all the bells and whistles a particular program offers. Most of these programs have factory “presets” that describe what that compression setting will do. As with many things in life, it is best to “go out and play!” Record something and change the compression settings. You’ll hear the difference. Learn what those changes are and what made them. You won’t learn that overnight. It takes years of listening and playing. Van Gogh didn’t learn his art overnight. He had talent but it took him years of torment to bring his colorful vision to canvass. He would have had trouble in VO however. He had no ear for it.
Compression is just one technique in the tool bag of recording tools. Play and learn. It’s a fascinating journey!
(((GONG))))





