Operating instructions

OPTIMOD-AM DIGITAL OPERATION
3-23
for various adult-oriented music formats where an easy, relaxed sound is considered
more important than the highest possible loudness.
MUSIC HEAVY is based on the Fast multiband release time. However, its tuning is very
different from GEN
HEAVY. It is tuned so that the AGC operates with a fast release
time, doing most of the work in compressing the program. This gives more of a
“wideband compression” sound than the other factory presets. Meanwhile, the
multiband compressor is operated lightly with relatively little gain reduction so it acts
more like a limiter than a compressor. Music Heavy is therefore an alternative to GEN
HEAVY, providing a different “flavor” of processing. Either preset could be used to
achieve a highly-processed sound with music programming.
The GREGG preset is designed for general-purpose voice/music programming,
particularly on music-oriented formats. Although not the loudest 9400 preset, it has a
smooth, well-balanced quality that keeps audiences listening. We tuned it to sound
very similar to the legendary Gregg Laboratories 2540 AM processor (designed by
Orban’s Vice President of New Product Development, Greg Ogonowski, in the 1980s),
using a direct A/B comparison with the Gregg processor to ensure accuracy. This preset
uses a 200 Hz B1/B2
CROSSOVER setting.
The PRESENCE preset, as its name suggests, emphasizes the spectrum around 3 kHz.
It is a very loud preset that emphasizes speech intelligibility. It uses H
ARD bass clip-
ping to maintain bass punch at the expense of some bass distortion. MW stations
seeking to increase their coverage and to cut through co-channel interference are
appropriate candidates for this preset.
This preset is tuned for the typical narrowband MW radio and will sound shrill and
unpleasant on wideband radios (of which there are very few in the market). If you feel
that the preset has too much distortion, feel free to turn it down it with L
ESS-MORE to
taste. The factory L
ESS-MORE setting is 9.0, so there is plenty of room to turn the
preset down without seriously compromising loudness and coverage.
You can also reduce the midrange boost if you feel this is excessive. Part of the boost is
implemented in the Equalization section and part is implemented by the compression
threshold controls, which are found in Advanced Modify.
HF GENERAL is a 4.5 kHz-bandwidth preset for international shortwave trans-
mission. In recognition of the severe noise and interference problems often
encountered in HF propagation, the HF
GENERAL preset has been ``tuned" to
emphasize loudness and intelligibility. By comparison to the medium-wave-oriented
presets, HF
GENERAL has a more ``forward" midrange balance and less bass. This is
because bass costs modulation without contributing proportional intelligibility (it
also can make intermodulation distortion worse during selective fading), and
because a boosted midrange can most effectively cut through noise to provide
intelligibility.
The 4.5 kHz bandwidth is coded into the preset, so the lowpass filter setting in the
active Transmission Preset will be ignored.
HF VOICE is a 4.5 kHz-bandwidth preset for international shortwave transmission.
Compared to HF
GENERAL, it emphasizes voice-range frequencies and has less bass.