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Can you hear me mother? – Some background on the loudness war

Thu 17 March 2011 | Arcam blog | Back to article list

One aspect of modern music reproduction has recently come under the spotlight in a rather negative light. Recording and mastering engineers are manipulating replay dynamics to maximize sales.

Before we discuss what the engineers are doing we should take a moment to explain what we mean by dynamics…

The human ear has an amazing ability to cope with huge differences in sound pressure level. The difference in level we can hear, from the quietest sound we can detect to the loudest we can tolerate is approx. 100,000 times! That said exposure to the loudest sounds would quickly bring on permanent hearing loss. For a more detailed explanation of this subject check out the Dangerous Decibels website.

So what’s the “Loudness War” and why should we be bothered?

Sadly, recording and mastering engineers have no idea who will be listening to the music they make or where they’ll be. We know that there is a maximum level that a human can comfortably tolerate and the difference between this and the quietest sound that can be heard (over any ambient noise) we call the dynamic range. The more ambient noise an environment has the lower the dynamic range that can be achieved.

Quiet listening rooms aren’t a problem for engineers as background noise levels are low meaning even the quietest sounds in the music can be heard above the ambient noise. In noisier environments though the possible dynamic range becomes quite small as quieter sounds are masked by the ambient noise.

To counter this engineers use a technique called “dynamic compression”. This turns up the volume of quieter sounds while louder sounds are left alone. We should point out that the compression we’re talking about here affects the dynamics of the music as opposed to data compression (e.g. MP3, AAC etc.), which is something different altogether.

Unfortunately dynamic compression is used on most recorded material these days. This means that those with good systems in quiet rooms can’t achieve anything like the dynamic range of the original performance, or that the system is capable of.

For music fans, some genres are affected more than others. Pop music, especially if it’s intended for mainstream radio, gets the shortest straw. It tends to be very heavily compressed so that “more” of the music is heard in cars, cafés and bars where system performance is poor and ambient noise is high. Why? To sell more music!

Other genres can be affected too. A little compression is used on most recordings simply to keep the dynamic range with the limits of the CD format it’s stored on. However, additional compression is normally kept to a minimum on genres like classical, folk and acoustic.

Over time the amount of compression used on popular music has been increased to the point that it uses just a tiny amount of the possible dynamic range effectively “squashing” music to the point where it’s almost unlistenable on a good system.

For a technical history of the loudness war why not take a read through its Wikipedia page. If you’d rather hear music with more of the original dynamics retained why not visit the Turn Me Up website.



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