The coffee cup analogy to audio headroom

Today I was reading a post on a facebook group from a guy, let’s call him Jack, concerned with a master that was clean in the DAW and clipped when it played streaming from Soundcloud. He checked for intersample peaks and left some headroom (0.3dBFS) but still it clipped when streaming.

Then I went to get my afternoon coffee.

As I’m filling the cup I realized that I can use a cup of coffee to explain headroom. Bear with me a sec.

coffee cupHere’s the cup. It only holds so much. Pour the coffee in, leave some room for cream and sugar, and some extra room to stir and to walk from the kitchen to the studio. Don’t leave enough room in the cup and it spills.

The coffee is the mix, the cream and sugar is the mastering, and the walk from the kitchen to the studio is the SoundCloud encode (or any lossy format conversion) and streaming. There wasn’t enough wiggle room in Jack’s master for the conversion to mp3, so some coffee got spilled while the drink was being delivered.

When I’m mastering I set my limiter ceiling to -0.7dBFS which is pretty close to the recommended -1dBFS level for Mastered for iTunes albums. I’d much rather have slightly lower peak levels for a cleaner master without any crunchiness on various playback systems.

Makes sense right?

Tasty.

BTW, if you’re interested in having me master one of your projects I can be reached at www.epicsounds.ca, I do free test masters.

 

16 thoughts on “The coffee cup analogy to audio headroom”

  1. Hello, the coffee cup analogy is good. Basically, the headroom of any piece of analogue circuitry is dependent on the maximum swing of the power supply voltage. For, example a 500 series rack runs on + & – 16 volts so the audio can swing 32 volts which would be the limit of the cup before it overflows and caused distortion. Running on + or – 18v like my Trident Series 80 console or my new Sony MXP3036 would be like going to a larger Grande cup and using a Neve 1073 modules is like going to a Venti cup.

    Thanks for pointing out that analogy.

    Cheers, Dave
    aamicrophones.com

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