Metric Halo SpectraFoo - Manual (Page 44)

Instruments
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2. Dual Trace: Two traces, one corresponding to each of the input channels, are displayed on the scope.
3. Subtract Second Channel: One trace, corresponding to Channel: Channel 2, is displayed on the scope.
4. Add Second Trace: One trace, corresponding to Channel + Channel 2, is displayed on the scope.
5. Multiply Second Channel: One trace, corresponding to Channel * Channel 2, is displayed on the scope.
Selectable trigger channel
The trigger channel is now user selectable. This allows you to run the trigger off of Channel 1, Channel 2,
or Either input channel. You select the trigger channel with the Trig. Chan pop-up menu in the Oscilloscope
Controls window.
Power History
This instrument allows you to see the history of the information displayed by the Peak and RMS meters. The
light grey “tick” marks indicate the passage of one second of time, and the height of the color for each time
“slice” indicates the Peak (yellow) & RMS (purple) power levels of the program. The ratio between these two
levels is responsible for the “perceived” volume” of program material. When there is a large difference between
the Peak and RMS levels of program material, the perceived volume will be low as compared to the peak levels
on the tape. Conversely, when the difference between Peak and RMS levels is small, the perceived volume will
be louder. This instrument can help you determine how much compression and limiting is needed for specific
program material. If you have a full-featured mastering compressor, this display can also help you determine
whether the compressor should be set to react to Peak or RMS levels.
Figure 3.46: Power history
Note: This meter is scaled logarithmically in decibels. When the average level is high, the signal can change
relatively dramatically in level without creating a large change in the display. In this situation it is useful to
refer to the envelope history display which is described below.
Envelope History
This instrument is a sample–editor–style scrolling envelope overview. It can help you calibrate your eyes if you
are experienced with DAW-style displays. Because it uses linear scaling, it is useful for identifying large level
changes when the average level is high. It should be used in conjunction with the Peak and Average History
display to obtain a good view of the overall dynamics of program material.
Figure 3.47: Envelope history