Normalize Vs Volume increase Options

[tinpanalley]

I'm having trouble figuring out which of the two is better for me to create a vinyl recording at the highest volume without clipping.

I capture a record via my preamp into Audacity, and I get what seem to be relatively low levels even though I make sure the levels are right when I record (Peak: -6.4db, RMS -24.6db). Am I doing something wrong? Or are those levels right? These recordings don't seem as loud as mastered CDs.

Anyway, to get the most accurate sound possible, should I use normalize or just increase the volume? If normalizing makes everything sound the same at a peak level, doesn't that completely screw with the dynamic range of the music?

Thanks!

[DVDdoug]

Audacity's Amplify effect has an option of setting the peaks to 0dB, which is the same as normalizing.*

IIRC, Audacity's Normalize, adjusts both channels separately which can upset the left-right balance. On the Audacity forum, they seem to recommend Amplify .

Normalizing or adjusting the volume doesn't affect the dynamics, unless you push it into clipping. With clipping, you are getting a nasty kind of dynamic compression where the average volume is increased without increasing the peaks (plus you're getting distortion).

If you've got some loud "clicks" & "pops", these defects may represent the loudest peaks. So, you'll want to normalize after de-clicking.

(Peak: -6.4db, RMS -24.6db). Am I doing something wrong? Or are those levels right?

That's about right (before normalizing). You can go a little higher, but if the peaks "try" to go over 0dB, the analog-to-digital converter will clip (distort).


The ratio** of RMS to peak is determined by the dynamics of the music & recording. I usually check the peak level after recording, and if it's at 0dB, I assume it's clipped, and I re-record at a lower level. (I use a different program, but I believe Audacity shows clipping as red in the waveform.)

These recordings don't seem as loud as mastered CDs. Most modern popular CDs are highly (dynamically) compressed to make them constantly loud (see Loudness War). Compression is a way of increasing the average/RMS level without increasing or clipping the peaks. This is why some people prefer older vinyl over the remastered & over-compressed CD version.

Audacity has a compressor, so you can get a "louder" or "more modern" sound if you wish. Or if you want it listen louder, you can crank-up the playback-volume a bit and enjoy the dynamics!




* You can actually "normalize" to other peak values, such as -1dB, but setting the peak(s) to the "digital maximum" of 0dB is the most common.)


** Decibels are logarithms. So the difference in dB is a ratio, and it stays constant when you amplify (multiply) or attenuate (divide). i.e. If you boost the peaks from -6dB to 0dB, the RMS level will also be boosted by 6dB from -24 to -18dB.

This post has been edited by DVDdoug: Jun 30 2011, 01:01