'YOU WON'T BELIEVE YOUR EARS'

The entire process of mastering is heavily reliant upon the skills of the engineer. In particular, the degree to which he or she can judge the music and its deficiencies, or in other words, how well he or she can analyze the recording through listening. Even for the most proficient of operators this task can be particularly difficult to do well and this in turn is a result of the way in which we perceive sound. Factors such as masking, poor monitoring acoustics, and poor speakers play a significant part but most importantly the issue of human loudness perception makes the task very difficult to do well. Of course this wouldn't be an issue if we all had unlimited funds. An FIR Digital EQ Designed Expressly for Mastering, with a Musician-Friendly Interface.

 Figure 1: Equal loudness contours for human hearing subject to pure tones in a free-field with the subject facing the source (from ISO recommendation R226).

At low volumes we find it hard to hear low and high frequencies but as the volume increases the spectrum extremes become progressively easier to hear as is illustrated in the equal loudness contours for human hearing shown in Figure 1. So much so that you might find that if you were to simply turn up the volume you may find that your mix sounds significantly better. So when you combine the effect of loudness sensitivity and equalization changes, how do you tell how much of the improvement was due to the equalization and how much was due to the overall increase in perceived loudness? For example, you might raise the mid-range by 6dB because it sounds better but do you know if this improvement is actually due to the equalization or just merely the fact that the effective loudness has increased by something less than 6dB? To accurately judge a process that involves changes in spectral balance requires that you account for the change in effective loudness. In the above example, to accurately judge the effect of the EQ change would require that you reduce the overall volume while boosting the mid-range but by how much?

SO HOW DOES HAR-BAL BALANCING HANDLE THIS PROBLEM?

Har-Bal is essentially composed of two parts : a spectrum analysis engine and a high-resolution linear phase digital filter. We handle the problem by first analyzing the entire recording. This gives us a measure of the average and peak spectrum content (displayed graphically) from which we can quickly and easily judge the spectral balance of a given recording. Then through a novel user interface, our software allows you to design a matching digital filter that produces the spectral balance that you want and without question. The designed filter can be tested by listening to the effect it has on the recording and comparing it with the un-balanced version in real time.