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OPTIMOD-PC
If processing for high quality is done carefully, the sound will also be excellent on
small playback systems. Although such a signal might fall slightly short of ultimate
loudness, it will tend to compensate with an openness, depth, and punch (even on
small speakers) that cannot be obtained when the signal is excessively squashed.
If women form a significant portion of the station's audience, bear in mind that
women are more sensitive to distortion and listening fatigue than men. In any for-
mat requiring long-term listening to achieve market share, great care should be
taken not to alienate women by excessive stridency, harshness, or distortion.
Speech/Music Detector
The Speech/Music Detector allows OPTIMOD-PC to change its processing parameters
depending on whether the input program material is speech or other material (usu-
ally music).
The algorithm is straightforward: Speech is detected if (1) the input is mono, and (2)
there are syllabic pauses at least once every 1.5 seconds. Speech with a stereo music
background will usually be detected as "music," or the detector may switch back
and forth randomly if the stereo content is very close to the stereo / mono detector's
threshold. Mono music with a "speech-like" envelope may be incorrectly detected as
"speech." Music incorrectly detected as "speech" will exhibit a slight loss of loudness
and punch, but misdetection will never cause objectionable distortion on music.
Speech that is not located in the center of the stereo sound field will always be de-
tected as "music" because the detector always identifies stereo material as "music."
Processing for Low Bitrate Codecs
V2 software employs Orban's PreCode™ technology to minimize codec artifacts. To
exploit PreCode technology fully, do not set up OPTIMOD-PC for very bright sound
(with large amounts of high frequency energy) because this is likely to exacerbate
codec artifacts. Some appropriate presets include J
S
, and the C
OFT
LASSICAL
bright-sounding presets and are more appropriate for uncompressed channels or
compressed channels with relatively high bitrates.
OPTIMOD-PC has several controls whose settings determine brightness. To control
excessive brightness when using the Five-band structure:
•
Use little or no high frequency boost in the equalization section.
•
Set Band 4>5 coupling to 100%.
•
Set the band 5 compression threshold to match the codec. Adjust the threshold
until you find a good compromise between presence and high frequency codec
artifacts. We find the range from –6.0 to +6.0 dB to be useful.
•
Use a moderate Band 5 attack time. 25 ms works well.
•
If necessary, lower the Band 4 compression threshold.
In addition, it is unwise to use stereo enhancement with low bitrate codecs. At low
bitrates, codecs use various parametric techniques for encoding the spatial attrib-
presets. Avoid presets like C
, S
J
, G
AZZ
MOOTH
AZZ
OLD
and E
; these are very
RISP
DGE
3-5
OPERATION
, R
OCK
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