Note: When using this application on the left and right masters, remember to turn off the enable button in the Pro Audio Lab GUI to disable the Tone Generation, as you simply need to see the meters. The Loudness Meter displays both a VU and a Peak Level meter on the same graph.

There is no absolute measurement for how the ear hears frequency response and consequently hearing can vary greatly from one person to another. Generally, hearing is much better in the high-midrange and less sensitive toward both extremes. For ex- ample, young children can often hear to above 20 kHz while older people often have difficulty hearing above 5 kHz. It is generally accepted that average resonance in the eardrum is most sensitive in the 2.5 kHz to 4 kHz regions. The human ear does not hear frequency response as flat and changes substantially depending on the intensity of the sound presented.

Very Important: With every 3 dB increase in output, double the amplifier and speaker power is required. Typically, the upper end of the ear’s intensity threshold is 140 dB SPL. This is where damage to the hearing starts to occur even with limited exposure. Sounds above this threshold, such as gunshots, jet planes, machines, and continuous loud monitoring, can be very damaging to the ear.

Sum/Difference

Sum/ Difference (expanded view)

The Sum and Difference meters analyze the sum of two input channels, and the difference between them in dB VU. This meter is useful in determining the association of two separate channels, or a stereo channel that is creating comb filtering caused when a stereo pair is summed to mono.

User’s Guide