Increasing or Boosting Volume

Audacity Help Forum Windows
1

Windows XP Professional, audacity 2.03 .exe file,

Hi,

I create compilations with very different kinds of music from a wide variety of sources. To match the volume between selections, I use normalization, extensive use of envelope tool, compression, and compression based on peaks.

At times, no matter what I do, how much I envelope, or compress (to the point of artifacts & distortion) the volume is still vastly different.

I read about making a duplicate stereo track and then combining and exporting it which results in a tremendous increase in volume. I tried this and it seems to work but also obviously results in a lot of clipping. When normalized, the peaks look like the flat waveform that is common in very loud commercial recordings.

My questions are:

Is this a viable way of increasing volume?

Am I creating even more distortion by clipping the signal before its normalized?

What does chopping or flattening the peaks do to the sound?

Is this better or worse than compression?

Thanks for your help,

Art22

2

Custom Compression is the hallmark of songs that need to sound louder than everybody else.

Given what you’re doing, you might make very good use of Chris’s Compressor.

http://theaudacitytopodcast.com/chriss-dynamic-compressor-plugin-for-audacity/

Chris’s reason for being is to make everything come out the same level. The defaults are graceful, but I increase the first value, compression, to 0.77 from 0.5 and that simulates the compression and volume management in the local FM station. It takes care of everything, peaks, normalization, etc. etc.

Koz

3

Am I creating even more distortion by clipping the signal before its normalized?

What does chopping or flattening the peaks do to the sound?

Is this better or worse than compression?

Worse!!! Clipping is distortion. If you get enough distortion, you’ll hear it. If you crank-up a 10 Watt amp and try to get 20W out of it, that’s clipping. If you want to know what digital clipping does to the sound, use Amplify and boost the peaks to +12dB or more. Then, save that as a “regular” 16-bit WAV file and play it back. (Audacity won’t actually clip internally because it uses floating-point, but WAV files will clip, or you can clip your digital-to-analog converter by playing a floating-point file that goes over 0dB at maximum volume.)

Clipping is a kind of dynamic compression… It reduces (compresses) the dynamic range by boosting the overall volume without boosting the peaks. But, it creates more audible distortion than “regular” compression.

It’s a matter of taste, but compression damages the dynamics! Music is supposed to have loud parts and quiet parts. By using compression, you can make it constantly-loud. IMO, most modern music is over compressed… This can make an “exciting” 1st impression, but it quickly gets boring and soon you are reaching for the volume control to turn it down. Compression in modern recordings is one of the reasons some people think vinyl sounds better than digital. (Not me… I can’t stand the “snap”, “crackle”, and “pop” of vinyl records!)

I create compilations with very different kinds of music from a wide variety of sources. To match the volume between selections, I use normalization, extensive use of envelope tool, compression, and compression based on peaks.

The basic problem everybody has is this: Many quiet-sounding songs have 0dB peaks. If you boost the volume (linearly without compression), you’ll get clipping. Since you cannot boost the quiet songs (or you can’t boost them enough) without clipping, if you want to match volumes (without compression), you have to reduce the volume of loud-sounding songs. Then, if you want to listen louder, you can turn-up the volume during playback time.

As you’ve found out, normalizing won’t work… Normalizing works on the peaks. Perceived loudness is more related to the average level and the frequency content. It’s best to match volume by ear.

Here’s the basic procedure when making a compilation:
1. Normaize all songs individually for 0dB peaks.
2. After normalizing, choose the quietest-sounding song as your reference.
3. Adjust-down the louder-sounding songs (by ear) as necessary to match the reference song.

There are tools such as [u]ReplayGain[/u] (and MP3gain and WAVgain) that try to automatically match perceived loudness. Of course they also tend to reduce the volume of most songs and on a compilation you could end-up with your quietest-sounding song not hitting 0dB. (For playback, I use ReplayGain with Winamp and it works great!)

4

Windows XP Professional, audacity 2.03 .exe

Thank you both very much for your responses. Sorry for my delay, I’ve been having problems with my old DSL modem.

I agree in principle with what you are saying. Of course, ideally any high quality audio would have as wide a dynamic range as possible - as close to the original as possible. I have some half-speed master “audiophile” vinyl discs from the ‘80’s and ‘90’s as well as some Mobile Fidelity and other high quality CD’s. I also have downloaded FLAC files that are as good if not even better than most of the discs.

However, in this case most of the music is downloaded in a lossy format (mp3) and the person(s) who is listening to these does not have very good home equipment or is listening in their car. That combined with the fact that in one compilation there may be classical, soundtracks, big band, jazz vocalists, folk music, pop, and even some techno, lounge, and hip hop. It’s a challenge to match all these.

That’s why I do the unthinkable and extensively envelope the quiet parts of classical music and movie soundtracks. And as I said, I also try to get the level of the different tracks as close as possible so that the listener is not engaged in the constant struggle of raising or lowering the volume every two seconds.

On one hand I agree that it would make sense to lower the volume of the louder tracks to more closely match the quieter ones. The problem with that is, if I lowered the volume of the entire compilation (which I burn onto CD) to match the one or two selections that are radically lower in volume - I would end up with an extremely low volume CD.

When I asked about duplicating tracks and saving/exporting the resulting higher volume file (with some clipping) I want to make it clear that I do import it back and normalize it. Are you saying that it’s too late then, and that the file will still have the distortion from the clipping even though after normalization it no longer shows clipping?

If that’s the case, then I have to assume that a certain number of the files I’ve downloaded already have this built-in distortion. I say this because it is common with many different types of music (with the general exception of orchestral) that the mp3 file often comes in with a fair amount of clipping (according to audacity). Of course I normalize it. But if I understand, it sounds like the distortion is there to stay.

It sounds like you are also saying that the best alternative may be Chris’s Compressor. (I was very sorry to read that he is no longer with us).

How is this compressor different or better than the one native to audacity? And do you think it will do what I need with the default settings?

Thank you so very much,

Art22

5

Audacity’s compressor was designed to solve a specific math problem. Chris’s compressor was designed so he could listen to opera in the car. Both succeeded.

Koz