It seems I've chosen one of the most difficult types of music to accurately and noiselessly capture. I'm old enough to remember when CDs premiered as a new medium. Many of us had our ears opened when we heard our first high quality CD.
The first thing I noticed was how far down the noise floor was. Prior to CDs, our best (and only) media for music reproduction were vinyl LPs and magnetic tape. At the time, many audiophiles thought that vinyl was superior to nearly all forms of magnetic tape available to consumers.
In the 1980's, a form of noise reduction called CX hit the scene. CX works by encoding a compressed audio signal to the medium. The softest parts of the program are kept at a higher level (above the noise floor) than they would be without CX. That is, the dynamic range of the music is compressed. When the program is played back, the compression is 'undone' by a separate box called an expander. What that does is to effectively lower the volume of the quietest parts of the recorded program compared to the loudest parts. The end result is that the noise of the medium (a vinyl LP, let's say) is rendered much quieter than it would be without CX, and the dynamic range of the source program is essentially retained. The noise is reduced, and the music program is presented unchanged.
Being fascinated with this concept, I bought and built a CX decoder kit. (I still have it, and it still works.) I can confess that it works as advertised. It wasn't flawless, but it worked. During silent passages between cuts on an LP, there was no noise to speak of. This was my first taste of a reproduction method that produced what we today have come to accept as standard. CX didn't do at all well in the market. CDs soon came out, and CX became unheard of outside of the LaserDisk.
With the CD being so new, most audiophiles welcomed it as superior to all that had come before, at least as far as what consumers could lay their hands on. I knew some people in the 80s that thought the high end of CDs was all wrong. "Too harsh" or something like that, they'd say. I thought they were crazy at the time. But now, I am not so sure!
Today, the CD has most certainly come of age. In fact, a CD with a capacity of 800 megabytes ( an hour or so) and an audio encoding of 16 bit depth is considered barely adequate. The industry knows this and has left the CD behind - most people don't know that DVDs have an audio word length of 24 bits.
Which brings me to my thought for today. Over and over again, I have lamented that so many recordings I've made suffer horribly when mastered to 16 bit CD when the program gets extremely quiet. What happens in that case, is that due to the extremely low audio levels, very few of the available 16 bits get used to quantify the signal. What I heard was an Aliased signal. There's nothing musical at all about an aliased signal. I'd rather hear vinyl groove noise with a quiet program than aliased signals. So I always try to make sure that whatever I am recording is modulated as high as possible. Then I have to worry about clipping! There's no way to win on either end; There just isn't enough room for the whole program at 16 bits.
If I was recording pop or rock, This wouldn't be any issue at all. But for me (and for you, too!) it is a serious issue. There is no more dynamic program material commonly recorded than sacred and classical music in churches or music halls. The recording engineer is faced with a program that at times can be as loud as any rock concert (if you don't believe me, then you've never been to a hymn sing with 500 lusty singers and a blisteringly loud pipe organ) Then at times, perhaps at the same event I must record a single person singing at very little more than a whisper from 100 feet away. The temptation to crank up the gain is powerful, but has to be avoided if some dynamic context is to be retained.
As a producer of audio media for my clients, I cannot wait for the 16 bit CD to go away. If you have some attachment to the CD as it is today, may I please suggest that there is something better waiting for you. In the mean time, I am going to suggest to my clients audio DVDs in place of the standard CD of their event.
