Orban OPTIMOD 5750 Operating Manual page 24

Orban 5750 Technical Manual
With non-MX presets, the normal delay through the 5750 (from input to FM outputs) is about 18 ms when HARD or
MEDIUM bass clipping is selected, as it is in all nonMX factory presets other than those with "LL" ("low latency") or
"UL" ("ultra-low latency") in their names. An 18 ms delay is workable for most talent (although it may require some
acclimatization) because 18 ms is below the psychoacoustic "echo fusion threshold," which means that talent will
not hear discrete slap echoes in their headphones. This means that they can monitor comfortably off-air without
being distracted or confused. Moreover, off-air cueing of remote talent is routine.
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, which introduces 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, where the talent starts to hear slap echo in addition to frequency response
colorations.
Two lower-delay options are available. "Low latency" reduces input-to-FM-output delay to 13 ms and "ultra-low
latency" reduces delay to about 3.7 ms. The trade-off for this reduction is approximately 1 dB decrease in loudness
compared to the 5750's full look-ahead processing for low latency and about 2.5 dB loudness decrease for ultra-low
latency.
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When using a non-MX preset, you can invoke the low latency mode by setting the BASSCLIPMODE control (in
the CLIPPERS page of ADVANCED CONTROL) to LLHARD. You can also recall a preset with "LL" as part of its name.
LLHARD differs in two ways from the normal HARD mode of the bass clipper:
1) LLHARD automatically defeats the compressor look-ahead. (This action is functionally equivalent to setting
the LOOK-AHEAD control to OUT, except that it reduces input/output delay by 5 ms).
2) LLHARD prevents the bass clipper from switching to Medium mode whenever speech is detected. By
constraining the system in these ways, it ensures that the delay is always 13 ms.
Switching the BASSCLIPMODE to LLHARD (from any other mode) removes five milliseconds of delay from the signal
path. If it occurs during program material, switching can cause audible clicks, pops, or thumps (due to waveform
discontinuity). If you have some presets with LLHARD bass clipper mode and some without, switching between these
presets is likely to cause clicks unless you do it during silence. However, these clicks will never cause modulation to
exceed 100%.
One of the essential differences between the HARD and LLHARD bass clipper modes is that switching between HARD
and MED does not change delay and is therefore less likely to cause audible clicks.
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Ultra-low latency processing uses a separate, parallel processing structure and is invoked by recalling any "UL"
preset. This structure operates simultaneously with other code, so, unlike the similar structure in Orban's
OPTIMOD 8300, it does not require a code re-load and does not cause a gap in programming.
The only way to create an ultra-low latency user preset is to start with a "UL" factory preset and then edit that
preset. "UL" user presets cannot be directly converted to low latency or optimum latency presets because the
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Installation