Orban OPTIMOD-AM 9300 Operating Manual Download

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OPTIMOD-AM DIGITAL

TROUBLESHOOTING

5-5

System Will Not Pass Line-Up Tones at 100% Modulation

This is normal. Sine waves have a very low peak-to-average ratio by comparison to
program material. The processing thus automatically reduces their peak level to
bring their average level closer to program material, promoting a more consistent
and well-balanced sound quality.

The 9300 can generate test tones itself. The 9300 can also be put into Bypass mode
(locally or by remote control) to enable it to pass externally generated tones at any
desired level. (See

Test Modes

on page 3-37.)

System Will Not Pass Emergency Alert System (“EAS” USA Standard) Tones
at the Legally Required Modulation Level

See

System Will Not Pass Line-Up Tones at 100% Modulation

(directly above) for an

explanation. These tones should be injected into the transmitter after the 9300 or
the 9300 should be temporarily switched to

YPASS

to pass the tones.

System Receiving 9300’s Digital Output Will Not Lock

Be sure that the 9300’s output sample rate is set match the sample rate that the
driven system expects. Be sure that the 9300’s FORMAT control (AES3 or SPDIF; in
System Setup) is set to match the standard expected by the driven system.

General Dissatisfaction with Subjective Sound Quality

The 9300 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

ESS

ORE

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 satisfac-
tion. Such users

must

fully understand the material in Section 3 of this manual to

achieve the best results from this exercise.

Compared to competitive processors, the 9300 offers a uniquely favorable set of
trade-offs between loudness, brightness, distortion, and buildup of program density.
If your radio station does not seem to be competitive with others in your market,
the cause is usually problems with the source material, overshoot in the transmission
link (particularly the transmitter/antenna system) following the 9300, or an inaccu-
rate modulation monitor that is causing you to undermodulate the carrier. A station
may suffer from any combination of these problems, and they can have a remark-
able effect upon the overall competitiveness of a station's sound.

Section 1 of this manual provides a thorough discussion of system engineering con-
siderations, particularly with regard to minimizing overshoot and noise. Orban's
publication

Maintaining Audio Quality in the Broadcast Facility

(available for down-

) provides many suggestions for maximizing source qual-

ity

Bear in mind that the average AM receiver has an audio bandwidth of 2-3 kHz and
relatively high amounts of nonlinear distortion. 9300 processing is specifically de-
signed to make the best of this class of receiver Nevertheless, even at their best, such
radios can never yield truly high quality sound.