Measures of Volume
by Jonathan Wyner
"When I was a kid, I was filling balloons with oxy/accetaline (sic) mixtures and tying a firecracker fuse in the bottom of them and lighting them. I had one go off at point blank range as soon as I lit the fuse. That seemed pretty loud at the time. Of course, I've never been around anything really loud, just things that seemed loud at the time." - anon., Internet
"Music is the space between the notes" - Claude Debussy
"We think the record sounds pretty good, but really, we just want to be sure it's loud." - a renowned American string quartet that shall remain nameless
What is loud? This question is at the heart of so much of our work. How to measure volume, either in an absolute sense or a relative one. How loud should you listen, how loud should the vocal be in a mix, how loud should you record a track or a mix?
The related question, What is TOO loud, may in fact be more germane. If something is too loud, then something else gets lost. In a live sound reinforcement context, too loud might be described as a point when the level becomes painful. You lose your hearing.
Recording too loud is when unintended distortion takes place. You lose fidelity. In the context of mixing, too loud might be when one sound obscures others. You lose the balance. In mastering, too loud might mean that you lose the space between the notes.
In the days of analog recording and the early days of digital there was a relationship between the nominal level of a recording ('0 VU' or +4dbm or -20 dbfs) and the peak level ('+20 VU' or +24 dbm or 0 dbfs). In fact when mixes were heavily compressed you might see that 20db dynamic range shrink to 16 or even 14 db, though that was the extreme. So the loud part of a song would peak at a level at least 14 db hotter than the nominal level of the music. And the quiet sections of the music would reside lower than that. There were technical and aesthetic considerations that helped form this "equation."
Now, with our all powerful dsp chips, we can actually make recordings that have a nominal level of -8 or 9 dbfs or even louder. Often the quiet sections of the music are living in the area that was previously reserved for the med-loud sections. Have you ever compared two level matched versions of a mix, one at a mildly compressed volume and one at a highly compressed volume, to see which is louder?
The reasons for this? It could be that technology has improved and we simply can make hotter records. It could be that we live in a culture riddled with attention deficit syndrome and the only way to get people's attention is to yell all the time and hope to be heard. It could be that the typical MP3 playback system is poor and dynamics don't translate well on the poor equipment playing over the sound of a subway train. While it's not likely we can change the louder world, whatever the reasons for this phenomenon, we need to understand what the implications are.
The answers to these questions emerge in the context of every project and they bear asking. I leave you to draw your own conclusions.
What does it mean to music when the difference between loud and soft is disappearing? What does it mean when the average signal level presented to a D/A converter is so hot? What does it mean that the excursion of a peak of a drum hit is now only 3-6db hotter than the rms level? What does it mean when clipping distortion is an acceptable practice in recording? What does it mean when listeners are routinely subjected to high listening volumes and levels of distortion in the recording? What does it mean when engineers, producers and fans accept a hotter level as "standard"?
What does it mean when the level of a recording is sustained at a high enough level that you never get to hear the low level detail/ambience/etc.? What does it mean when you never get to hear the space between the notes?
Jonathan Wyner (www.m-works.com) has recorded, mixed and mastered more than 5,000 CDs during the last 23 years, spanning every musical idiom (and some nonmusical idioms as well!). He is a professor at the Berklee College of Music in Boston. His credits range from the extremely well known (James Taylor, David Bowie, Aerosmith, Bruce Springsteen, Kiri Te Kanawa) to the idiosyncratic and independent artists/labels. A 2007 Grammy nominee, his most recent work production will appear on PBS beginning in March 2007.
