USL JSD-100 Manual - Manual (Page 25)

Page 24
Decode Option
Description
L_R The two channel source drives just the left and right speakers.
L_C_R The left and right channels of the source drive the left and right speakers. The center speaker is
driven with 0.707 times the sum of the left and right channels. The LFE channel is driven with
the center channel after passing through an 80Hz low pass filter.
Simple Matrix The front speakers are driven with the same signals as L_C_R, described above. The surround
speakers are driven with 0.707 times the difference between left and right (0.707(L-R)).
Active Matrix This option is only available if a DI-84 board is installed in the JSD-100. If the input is digital and
encoded with Dolby Digital® (AC-3), the signal is decoded to 5.1. If the signal is two-channel
analog or PCM (not encoded with Dolby Digital®), the signal is decoded to 5.1 using an active
matrix. If no DI-84 board is installed, the signal is decoded as L_R.
Equalizer
The JSD-100 equalizer allows the frequency
response of the JSD-100 to be adjusted for the
acoustics of the room. The RTA screen shows
the measured level in each spectrum band
along with the limit lines for the X-Curve for a
500 seat auditorium as defined by SMPTE
202M-1998. Using the internal pink noise
generator and the internal real-time analyzer
(RTA), the equalizer is adjusted so the RTA
shows the response specified between the limit
lines.
RTA Channel Select Buttons
Channel select buttons are along the top of the RTA window. These select which speaker the pink noise generator
is driving and which channel the equalizer controls are adjusting.
RTA Settings
When the mouse cursor is over the display area of the RTA, another row of settings becomes visible (as shown
above). Use the Source button to select whether the calibrate or PA microphone input is being used to drive the
RTA. The calibrate microphone input is on the 3.5mm TRS connector on the rear panel. The PA microphone input
is on the combination XLR ¼ inch TRS connector. Use the Zoom buttons to enlarge or reduce the text within the
RTA display area. Use the dB/step selector to adjust the vertical resolution as required to get all bands on screen
while providing the best vertical resolution. Make initial adjustments with a fast decay time. The fast decay time
provides a faster update, but a less stable display. As you close in on the final adjustment of the equalizer, increase
the decay time towards maximum to provide a stable display and precise indication of the equalization. Adjust the
gain control as required to place the mid-band signal level at 0dB.
Generator
Use the Generator button to turn the internal generator on and off. Use the adjacent buttons to select the type of
generator output: pink noise, various frequency tones, or a tone sweep.
Flatten
Pressing this button returns all the equalizer adjustments to 0.0dB.
Curve File
Press this button to load a curve file from the “My Documents” directory. The installer placed a file called “x-
curve.txt” there. It can be used as a template to create curve other limit curve files.