24bit color depth picture
An Introduction to the Restoration of Old Vinyl Records at Home
Sound Editing with the best software - Cool Edit Pro
Bit Depth & Sampling Rate
Cool Edit Pro is the best sound editing software I've known so far. Just like photo editing, we need something to restore the original sound or add something extra in order to bring out the best result. The first step is to have the analog sound input put through the sound card to make it digitalized. Digitalizing an analog signal is known as the analog-to-digital conversion (ADC). To make it back to the analog sound is known as digital-to-analog conversion (DAC). Digital medium for photo editing or sound editing, all need a conversion scheme. The higher the resolution scheme, the closer to the original, although a low resolution scheme may catch the essential body of the picture but is incomplete with some lost fragments. The advantages of digitalization is the immaculate reproducibility and power of virtually unlimited rendering the original signals. In sound editing, we are dealing with 2 things basically. The bit depth which reflects the dynamic range and the sampling rate which represent the spectrum of frequency.
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24bit color depth picture |
8bit color depth picture |
The Bit Depth The 24bit for DVD Audio is better than the 16bit CD Audio by the ability to reproduce sound in much more contrasting volume from very low whisper to loud screaming without distortion. Just like a 24bit picture looks more vivid compared to the same picture with 16bit color depth.
44.1kHz sampling rate includes a narrow spectrum of frequency up to 20kHz, but enough to satisfy the human ear (just like the TV screen)
96kHz sampling rate presents a wider spectrum more than enough to fill our ears (just like the movie screen)
Although it reproduces a wider spectrum of frequency, it still has its limit.
The Sampling Rate The sampling rate of 96kHz for DVD Audio lets us reproduce sound from very low frequency from 4Hz up to >100kHz, more than the human ear can detect. The CD sampling rate is 44.1kHz which safely represents the frequency range within the human ear limit, any treble more than 20kHz is cut abruptly(just like a TV screen shown above). The point is, what is the use to include side views you won't be able to concentrate clearly? Some scientist argued that the unheard high or low frequency sound actually contribute to the finally feel of the sound through other sense organs all over our body other than the human ears. In order to reproduce the "true sound" the DVD Audio digitalization scheme includes a wider spectrum that is more than our needs for hearing. So it is obvious the 96kHz/24bit wins over the 44.1kHz/16bit format of recording...but just how much does it win? It's not ony the frequency spectrum has widened, the sound becomes more realistic just like seeing through a window with fine hairlines rather than the window-blinds.
After some listening experiments I've done with vinyl recording, I concluded that the DVD Audio is superior to reproduce with no obvious difference to the original analog. The CD Audio when you listen to side by side with the original or the DVD Audio (an A-B test), appears to be a little bit harsh over the highs. The choice is obvious for quality. But for the time being the Performance-to-cost ratio skews to the CD format when you can digitalize the vinyl with the CDR so cheap today. My protocol is to digitalize the original sound source with higher resolution and store them in .wav format. After elimination of the background noise, the .wav files are down-converted to the CD resolution, ready for the CD Audio transfer.