Dynamic Range

What is the dynamic range (DR) score at the bottom of your reviews?

The DR score is our way to objectively measure the level of dynamic range compression used in an album. Dynamic range is the difference between the softest and loudest sound in a track. Higher numbers indicate a wider range.

But I thought CDs were uncompressed?

A common mistake is to confuse dynamic range compression (done in the studio usually by mastering engineers) with file compression used by formats such as MP3 or AAC. The audio files on a CD are uncompressed in the sense that no file compression is applied. Copying these files to a computer will create WAV or AIFF files which are large and also uncompressed. Their size can be reduced in one of two ways: lossless compression (FLAC, ALAC, APE, WavPack) or lossy compression (MP3, AAC, M4A, WMA).  Lossless compression reduces file size without altering the audio data. Lossy compression removes the highest and lowest frequencies to achieve much smaller file sizes.

Dynamic range compression is done at the mastering stage or sometimes during the mixing process before the CD has even been pressed. Albums with high levels of dynamic compression (low DR scores) have very small differences between the softest and loudest sounds, and their waveforms appear as near solid lines instead of large peaks and valleys. A common term for this type of compression is “brickwall”.

Why do I need to know the DR score?

At Metal-Fi our passion is not just metal, but great sounding metal, and it’s impossible to have a great sounding metal record with extreme levels of dynamic compression. “Brickwalled” albums are a fairly new phenomena that began in the early ‘90s with the advent of new filtering and recording techniques that have allowed the overall level of recordings to get progressively higher, resulting in sonic abominations such as Death Magnetic and Californication. Unfortunately there’s no way to make these albums sound better, all you can do is demand that a new, less compressed master be released. This is why we report the DR score with every review. You can help fight the Loudness War by not buying brickwalled albums, or by contacting the band and letting them know that you don’t want albums that are compressed to hell.

Who started it?

Dynamic compression was not invented with the Loudness War. Radio stations apply their own compression, and heavy levels of compression were used before the CD was even invented. The ’60s Motown records for example were known to be heavily compressed. These factors don’t really apply to the current industry wide practice of excessive loudness though. From the CD’s beginning as a consumer format in the early ’80s until the end of that decade, CD releases had little to no dynamic compression applied, and recording engineers typically left several decibels of headroom under the maximum possible volume (known as zero decibel full-scale or 0dBFS) to allow for volume peaks in recordings without any risk of clipping.

The main driving force was record companies who wanted their artists to sound the loudest. Making your song louder than the next guy is more likely to get you noticed because of the way our ears perceive frequencies at different volumes. Indeed at first blush and especially to inexperienced listeners, louder usually sounds better. (Electronics sales people know this quite well). Industry executives also believe that louder records sell better. There is no data to support this assertion, but far be it from the industry to ever let things like data or facts get in their way.

Are all heavily compressed albums equally bad?

No. The quality of an album’s mix is largely separate from the amount of dynamic compression used. It’s possible to have a terrible sounding album with no compression at all  (…And Justice For All) and its also possible to produce a good sounding but heavily compressed album. Heavy compression limits audio fidelity in an absolute sense, but it does not ruin it. What truly destroys any chance of good sound is clipping. Clipping is what happens when the recording is pushed louder than the CD can support – 0dBFS as mentioned earlier. There is no argument, either practical or artistic, to have clipping in a recording.

How can I measure dynamic range?

We use software called the TT Dynamic Ranger Meter which measures every track’s individual dynamic range and computes a single average dynamic range score for the album. We list this value next to our subjective scores for artistic content and production quality.

Our Killing Technology article, Measuring Dynamic Range, shows you step by step exactly how to install and use the meter on your own collection of music.

What can I do about it?

Evangelize dynamics! Tell your favorite artists and labels (politely) that you value dynamics and are tired of listening to heavily compressed masters. Talk to headbangers at shows, in the mosh pit, wherever, about the value of dynamics in metal.