Orban OPTIMOD 5750 Operating Manual page 114

5-7
Orban 5750 Technical Manual Troubleshooting
Digital Radio Loudness Cannot be Set Using the Digital Output 100% Peak Level Control
When the BS.1770 Safety Limiter is ON, adjusting the HD-assigned 100% PEAK LEVEL CONTROL sets only the output
headroom, not loudness.
Loudness Drops Momentarily During HD Radio Analog/Digital Crossfades
The analog and digital channels in your transmission path have reversed polarity with respect to each other and a
phase cancellation is occurring in the radio during crossfades. You can correct this with the HD POLARITY or FM
POLARITY controls.
BS.1770 Safety Limiter produces too much gain reduction
Turn down the HD Final Limiter Drive control in the processing preset and save the result as a User Preset.
HD Frequency Response is Limited to 15 kHz
The HD BANDWIDTH control might be set to 15 kHz.
Even if the HD BANDWIDTH control is set to 20 kHz, bandwidth will be limited to 15 kHz if the HD output's sample
rate is set to 32 kHz and/or if the sample rate of the audio applied to the 5750's digital input is 32 kHz. 20 kHz
response requires sample rates to be set to 44.1 kHz or higher.
General Dissatisfaction with Subjective Sound Quality
The 5750 is a complex processor that can be adjusted for many different tastes. For most users, the factory presets,
as augmented by the gamut offered by the LESS-MORE control for each preset, are sufficient to find a satisfactory
"sound." However, some users will not be satisfied until they have accessed other Modify Processing controls and
have adjusted the subjective setup controls in detail to their satisfaction. Such users must fully understand the
material in Section 3 of this manual to achieve the best results from this exercise.
By comparison to competitive processors, the 5750 offers a uniquely favorable set of trade-offs between loudness,
brightness, distortion, and build-up of program density.
If your radio station does not seem to be competitive with others in your market, the cause is usually source material
(including excess use of lossy digital compression), overshoot in the transmission link (including the FM exciter)
following the 5750, or an inaccurate modulation monitor that is causing you to under-modulate the carrier. A station
may suffer from any combination of these problems, and they can have a remarkable effect on the overall
competitiveness of a station's sound..
Technical Support
If you require technical support, contact Orban customer service.
See http://www.orban.com/contact/ for contact information.