CD vs CDR Audio Volumes/Levels

[badobsession81]

I have a question about the volume of CDs vs CDRs...

I have noticed that CDRs always play quieter on my CD Player, even when burnt onto CD from official downloads that you assume have been mastered the same as the CD you can buy at the shop.

Is this just fact? Is this common? Or does CDR software change volumes? And why?

Any help would be greatly appreciated,

Rob

 

[MDS]

A waveform has an inherent average power. There are no standards for that level in the music world. Older cds were mastered very conservatively with average power levels of around -18dB, whereas newer cds are mastered much more aggressively with average power levels of -12dB or even higher. You can have two songs, by the same artist, on different cds, with vastly different power levels.

You cannot know the source of the song that was downloaded. If it was taken from an older cd with lower power levels or re-mastered from original master tapes, but you compare it to a newer cd that is hotter, naturally it will sound lower in volume, because it IS lower in volume.

Burning any track, whether ripped from a commercial cd, downloaded from an online music store, or ripped from a cd and then converted to a compressed format (mp3, aac, etc) will NOT change its average power level.

Converting to a compressed format may change the power level, but only by an infinitesimal amount. Just did that for a rock song ripped from a cd to give you a concrete example. The wav had power levels of -16.98 (L) and -17.41 (R); after conversion to 192 kbps MP3, the power levels are -17.13(L) and -17.57 (R).

 

[Rob Babcock]

Oftimes the software does in fact change the levels, and some suites will automatically "normalize" the levels. It's also almost always defeatable, although sometimes you have to root around in the settings a bit.

 

[dm_4u]

Which software can normalize the levels...that would be awesome.

I have Roxio 6 and it does not do this.

 

[MDS]

Nero has a few audio editing tools built in. I use Sound Forge, which is a wave editor, and even the Studio version ($70) is far more flexible and powerful than any of the tools in Nero.

A word of caution about Normalizing. Normalizing DOES NOT make all tracks the same volume, unless they were close in level to begin with. Normalizing does not increase signal to noise ratio or increase dynamic range or any other things that are often attributed to it. Normalization is a simple gain change, usually up, but can naturally also be used to lower the volume.

You should only Normalize if you have a track that is very low in average power (and don't normalize to 0dB - if the software let's you choose a point, use slightly less than 0dB - say -.5).

 

[djoxygen]

Apparent volume is not only subjective, but also entirely at the whim of the recording and mastering engineers. True normalization shouldn't actually do much to change apparent volume. Here's why:

Normalization should only find the loudest peak and, if it's not already at full code (all 16 bits at "1" on a CD) scale it up to full code and scale everything else by the same factor. Files you're downloading from legit sources and ripping off CDs should (if properly mastered) pretty much all be peaking at, or very close to, full code.

Now I've heard that some audio editing software is using the term "normalize" to describe something completely different, and something that *will* affect apparent volume. Probably some kind of peak-limiting and compression with gain compensation. I would never *destructively* apply this to any audio without actually knowing what kind of processing is taking place. As likely as not, it'll hose up the sound.

All that said, I sometimes use Volume Logic as an iTunes plug-in for casual listening. It's a multi-band compressor/limiter, works pretty well, is totally open about what it is doing, can be adjusted, disabled, etc... and is only real-time during playback - no destructive processing.

 

[MDS]

Now I've heard that some audio editing software is using the term "normalize" to describe something completely different, and something that *will* affect apparent volume. Probably some kind of peak-limiting and compression with gain compensation. I would never *destructively* apply this to any audio without actually knowing what kind of processing is taking place. As likely as not, it'll hose up the sound.

The full version of Sound Forge includes 'RMS normalization' which is exactly as you describe - it's compression. The only difference between that and using the compression tools is that the compression tool lets you choose the attack, release, threshold, and ratio values. RMS normalization allows you to set the rms power you would like the whole file to have and calculates the necessary values for the compressor for you.

Too often people confusing Peak normalization with RMS normalization/compression. Nearly all normalization tools I've seen in cd burning programs or simple audio editors are peak normalization.

 

[djoxygen]

The full version of Sound Forge includes 'RMS normalization' which is exactly as you describe - it's compression. The only difference between that and using the compression tools is that the compression tool lets you choose the attack, release, threshold, and ratio values. RMS normalization allows you to set the rms power you would like the whole file to have and calculates the necessary values for the compressor for you.

Too often people confusing Peak normalization with RMS normalization/compression. Nearly all normalization tools I've seen in cd burning programs or simple audio editors are peak normalization.

Cool that they're clear on what's taking place. I'm very wary of BBE-style magic black boxes. And I've had DJ friends try to "normalize" their music collections and ended up with everything sounding completely dull and lifeless because they went for "louder" and over-compressed everything.

I've got no problem with any of the tools as long as they're well documented and used wisely.