Table of Contents
Advertisement
2-8
Installation
preset customization controls are different—UL presets have fewer available controls because of the difference
in processing structure.
UL presets are the closest emulations of OPTIMOD 8200 processing available in the 5750. These presets differ
from OPTIMOD 8200 processing in two main ways: (1) the 5750 UL presets still use the 5750's stereo
enhancement, equalization section, advanced-technology AGC, composite limiter, and multiplex power
controller, and (2) the 5750 UL presets use anti-aliased clippers operating at 256 kHz sample rate.
Some talent moving from an analog processing chain will require a learning period to become accustomed to the
voice coloration caused by "bone-conduction" comb filtering. This is caused by the delayed headphone sound's
mixing with the live voice sound and introducing notches in the spectrum that the talent hears when he or she talks.
All digital processors induce this coloration to a greater or lesser extent.
Fortunately, it does not cause confusion or hesitation in the talent's performance unless the delay is above the
psychoacoustic "echo fusion" (Haas) threshold of approximately 20-25 ms and the talent starts to hear slap echo in
addition to frequency response colorations.
Low-Delay Monitoring: The 5750's analog outputs can be switched to provide a low-delay monitoring feed with a
delay of 5-10 ms. This uses a separate instance of the Ultra-Low-Latency structure to allow the monitor to provide a
"FM-processed" sound. You can adjust the amount of "FM peak limiter sound" via the MONITOR DRIVE control.
If the talent relies principally on headphones to determine whether the station is on the air, simple loss-of-carrier
and loss-of-audio alarms should be added to the system. The 5750 can be interfaced to such alarms through any of
its eight its GPI remote control inputs, cutting off the low-delay audio to the talent's phones when an audio or carrier
failure occurs.
PC Control
The OPTIMOD 5750 can be controlled via a web browser pointed at the address assigned to it. All system controls
are accessible there.
Racking the 5750
The 5750 is designed to fit in a standard 19' (inch) rack. While the 5750 is robust and can be used in situations that
are extreme, it is best that 1 rack space be left free above and below the processor to allow air to circulate.
The 5750 requires three standard rack units (5 inches / 12.7 cm). There should be a good ground connection between
the rack and the 5750 chassis—check this with an ohm meter to verify that the resistance is less than 0.5. Mounting
the unit over large heat-producing devices (such as a vacuum-tube power amplifier) may shorten component life
and is not recommended. Ambient temperature should not exceed 45C (113F) when equipment is powered.
Equipment life will be extended if the unit is mounted away from sources of vibration, such as large blowers and is
operated as cool as possible.
Using the power cable supplied (or equivalent), the 5750 should be energized. It cannot be stressed enough that
Orban Labs recommends the 5750 be energized via an Uninterruptable Power Supply (UPS) to prevent sudden
swings in voltage that may damage equipment. This isn't required because of a design flaw in the 5750 itself, it is
Advertisement
Table of Contents
