Click here to purchase the entire book in PDF format. Loudness Although we rarely like to admit it, we humans aren't perfect. This is true in many respects, but for the purposes of this discussion, we'll concentrate specifically on our abilities to hear things. Unfortunately, our ears don't have the same frequency response at all listening levels. At very high listening levels, we have a relatively flat frequency response, but as the level drops, so does our sensitivity to high and low frequencies. (This effect was discussed in Section 5.4.) As a result, if you mix a tune at a very high listening level and then reduce the level, it will appear to lack low end and high end. Similarly, if you mix at a low level and turn it up, you'll tend to hear more low end and high end. One possible use for an equalizer is to compensate for the perceived lack of information in extreme frequency ranges at low listening levels. Essentially, when you turn down the monitor levels, you can use an equalizer to increase the levels of the low and high frequency content to compensate for deficiencies in the human hearing mechanism. This filtering is identical to that which is engaged when you press the ``loudness'' button on most home stereo systems. Of course, the danger with such equalization is that you don't know what frequency ranges to alter, and how much to alter them - so it is not recommendable to do such compensation when you're mixing, only when you're at home listening to something that's already meen mixed.