Orban OPTIMOD-FM 8700, Operating Manual

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OPTIMOD-FM DIGITAL OPERATION
3-73
Look-ahead activates or defeats the look-ahead functionality in the multiband com-
pressor / limiter. Defeating look-ahead improves transient impact at the expense of
distortion, particularly on speech. To mitigate this tradeoff, a selectable “auto”
mode turns look-ahead on for speech material and off for music, using an automatic
speech/music detector. Switching is seamless and click-free because we change the
delay in the compressor control sidechains; this is not a way to reduce the 8700i’s
throughput delay.
Choices are L
OOK
-
AHEAD
I
N
, O
UT
, and A
UTO
.
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 back-
ground will usually be detected as “music,” or the detector may switch
back and forth randomly if the stereo content is right at 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 misdetec-
tion will never cause objectionable distortion on music.
Speech that is not located in the center of the stereo sound field will al-
ways be detected as “music” because the detector always identifies ste-
reo material as “music.” This can increase clipping distortion on such
speech.
If the B
ASS
C
LIP
M
ODE
is set to H
ARD
, the speech/music detector will auto-
matically set it to
M
EDIUM
when speech is detected and
H
ARD
otherwise
(unless
L
ATENCY
is
L
OW
, in which case
M
EDIUM
bass clipping is unavailable
and bass clipping will stay H
ARD
).
Speech always sounds cleaner with M
EDIUM
bass clipping and the in-
creased bass “punch” supplied by H
ARD
is irrelevant to speech.
This control does not affect the HD processing chain.
MB Speech Threshold
(
“S
PEECH
T
HR
,”
located in the Speech page of
A
DVANCED
C
ONTROL
) lets you set the increment (in dB) by which the setting of the
MB L
IMIT
T
HR
control is reduced when speech is detected (see Look-ahead , above). This control is
particularly useful in minimizing speech distortion when you use the
LLH
ARD
bass
clipper—it allows the main clipping distortion controller to work harder on speech
while preserving punch in music.
This control does not affect the HD processing chain.
Speech Detect (“ S
PEECH
D
ETECT
,”
located in the Speech page of A
DVANCED
C
ONTROL
)
allows you to override the automatic speech/music detector, forcing the processing
into
S
PEECH
or M
USIC
mode
.
The three available modes are S
PEECH
, M
USIC
, and A
UTO
.
To Override the Speech/Music Detector
It is possible to force your Optimod into “speech” or “music” mode via its GPI and
API. One can achieve this functionality by creating a “speech” preset and a “music”
preset and programming the GPI to recall these presets as desired. To do so:
A) Create a preset with the desired settings for the music-mode and speech-
mode controls. Set its
S
PEECH
D
ETECT
control to M
USIC
.
B) Save this preset as a User Preset.