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How to Interpret the Graphs
As explained in
Things you can accomplish with this application
on page 2, you can use the graphs
displayed in this application to choose the optimum time period for auto EQ setup with the receiver’s
Advanced EQ Setup function, and to check the effectiveness of steps you take to improve the acoustics of
your listening room.
Note
• Acoustic Cal EQ of the amplifier adjusts five frequency bands of 63Hz, 125Hz, 250Hz, 4kHz, and
11.3kHz; however, the reverb characteristics are shown in six frequency bands of 63Hz, 125Hz, 250Hz,
1kHz, 4kHz, and 11.3kHz on the screen.
In automatic setting of Acoustic Cal EQ, it is designed so that the characteristics of the speaker and the
listening room are measured and analyzed in the six frequency bands including 1kHz, and then the
parameter of Acoustic Cal EQ in the five frequency bands is set based on the analyzed results. (The
relative balance of the six bands is designed to be adjusted using EQ5 bands.) The reverb
characteristics are, however, shown in the six bands, since all the data analyzed are designed for
display.
How to interpret reverb graphs
The graphs show changes in microphone input level along a time axis, beginning from a state of quiet at
time 0, when test tones begin to be output, and continuing while a constant level of sound is output from
the speakers.
• If there is absolutely no reverberation in your room, the graph will look like figure A below.
• If there is reverberation, the graph will show a gradual accumulation of acoustic power, as shown in figure
B.
Notes
• Due to an effect known as “group delay”, lower frequencies may take longer to be generated than higher
frequencies (this is most obvious when comparing the frequencies around 0ms).
• If a graph extends beyond the display range, or almost fills it, you can change the display by using the Z
(Zoom) control on the graph adjustment bar, adjusting the display range of the Level [dB] scale so that
the whole graph is visible.
•In the graphs, differences in channel level and speaker distance are taken into account automatically
(compensation is provided for comparison purposes), but the frequency measurements are always
shown without the equalization performed by the receiver.
• Even in cases where there is a great difference in the output levels of different frequencies (the frequency
characteristics of the room are poor), you can carry out ALL CH ADJUST with the receiver’s Acoustic Cal
EQ function to bring the frequency characteristics for each channel closer to a flat response. (For details,
see page 84 in the receiver’s Operating Instructions.)
• It is usually not possible to calculate the equalization values employed by the receiver’s Acoustic Cal EQ
function simply by viewing the graphs displayed on your PC. (This is because the automatic adjustments
made by Acoustic Cal EQ function take account of factors such as equalization band interference and
analytical filter characteristics, to achieve the optimum characteristic profile.)