AirTools 6200 - DSP Module Configuration

6408 216th Street SW | Mountlake Terrace, WA 98043 USA
T +1.425.778.7728 F +1.425.778.7727 | www.SymetrixAudio.com
10
User’s Guide
To set the fine preamp gain (for Channel 1):
1. Press the HOME button to ensure that we are starting
from the top.
2. Press the NEXT button once, the display should read
“SectiontoEdit,-Channel1Menu-“.
3. PresstheNEXT button once, the display should read
“-Channel1Menu-,--Input--“.
4. Press the NEXT button once, the display should read
“Input Gain Trim, 0.0 dB“.
You can now use the ADJUST knob to dial in your fine gain setting.
Talk into the microphone as loudly as you think you will ever talk into it
whileturningtheADJUSTknobclockwise(increasinggain).Notewhen
the audio distorts and then turn the gain back down somewhat (maybe
6 dB or so). You should now be able to talk in a normal voice with
adequate level while still having enough headroom for loud passages. If
you find that the audio never distorts when turning the gain up, and you
reachthemaximumgainof31.5dBprovidedhere,youshouldreturn
this gain setting to 0.0 dB and then go back to reset the coarse gain to
a higher setting.
INPUT METERING:
You can monitor the input meters by viewing the “In LVL” menu
accessedbypressingtheHOMEbuttononcethenturningtheADJUST
knob clockwise once. A meter for channel 1 is displayed on the top
line, channel 2 on the bottom line. Unity gain is represented as an
“open square” symbol and corresponds to an input level of -20 dBFS =
+4 dBu = 0 VU.
Now that we have a basic signal through the unit, we can move on
to exploring the specific signal processing functions of the 6200 (EQ,
Dynamics, etc.).
DSP Modules
The following are the available DSP modules available in the 6200.
Each of these modules may be individually enabled or disabled. The
order of the modules is fully configurable. The modules are listed in
their default order.
SYMMETRY:
For broadcast applications, a switchable voice symmetry circuit helps
make speech waveforms more symmetrical, which makes better use of
the transmitter’s output power.
Human speech, particularly male human speech, contains a great deal
ofasymmetry.Inbroadcast(especiallyAMbroadcast),thiswastes
transmitter power because asymmetrical waveforms do not utilize the
full power of the modulator.
Controls:
Bypassed/Enabled - When bypassed, the input is sent unmodified to
the output. When enabled, the module processes the signal.
HIGH PASS FILTER:
High pass filters allow selectively modifying a signal by attenuating
all signals below a specified cut-off frequency. They can be useful to
remove noise or other unwanted frequencies. A high pass filter in a
voice processor is typically used to reduce rumble picked up by the
microphone. It can reduce boominess in a voice, noise from handling
the mic, fingers tapping on a desk, etc. The 6200 offers 6 dB/octave,
12dB/octave,18dB/octaveand24dB/octavefilters.Additionally,
“peak” versions of each filter are provided for further flexibility and
tuning. The filters with the steeper response filter more sharply.
Controls:
Bypass/Enabled - When bypassed, the input is sent unmodified to the
output. When enabled, the module processes the signal.
High Pass Frequency - Determines the cut-off frequency of the filter.
All frequencies below this will be progressively attenuated. Technically,
thisfrequencyisthe“3dBdownpoint”,i.e.thepointwherethefilter
responseis3dBlowerthanitisforunaffectedsignals.
HP Filter Slope - Determines the type of filter (slope) to use in order to
select how steep or aggressive the filter is.
Technical note: This module implements Butterworth filters which are
generally preferred for audio because of their flat frequency response in
the pass band.
DE-ESSER:
A de-esser is a frequency-selective compressor. It is used to remove
sibilance by detecting the presence of excessive “S” frequencies and
then reducing those frequencies in amplitude.
Controls:
Bypass/Enabled - When bypassed, the input is sent unmodified to the
output. When enabled, the module processes the signal.
De-esser (Response) - Determines the aggressiveness of the de-essing
(Gentle,NormalorAggressive).Thede-esserisadualbanddesign.
It compares the relative energy above the 2.5 kHz rollover point to
the energy below and limits the upper band when the high frequency
energyisgreaterthanathresholdamount.TheGentle,Normal,and
Aggressive settings determine how much relative high frequency energy
is required to start the high frequency gain reduction.
GainReduction(Meter)-Againreductionmeterisprovidedsothatthe
effect of the de-esser can be observed.
PARAMETRIC (1 through 4) EQ:
With parametric equalizers you can adjust center-frequency, gain, and
bandwidth of a filter band. Parametric EQ can be used to tailor an
overall sound quality or to more accurately boost/cut specific frequency
ranges. The 6200 provides a four-band parametric EQ. Each of the four
bands can be individually adjusted.
Controls:
Bypass/Enabled - You can selectively enable or disable a given
parametric band. If a band is disabled, it has no effect on the signal,
regardless of the other settings for this band.
Parametric (n) Freq - The center frequency of the equalizer band.
Parametric (n) BW - The bandwidth of the peak or dip applied to
the signal, expressed as the Q factor. Q is a dimensionless (unitless)
quantity used to describe bandwidth.
Parametric (n) Gain - The amount of gain or attenuation (boost or cut)
applied at the center frequency.
Note: Only one set of controls is outlined. Bands 1 through 4
are identical.
SHELVING FILTER:
High Shelf and Low Shelf filters are simple filters that can be used to
modify the treble or bass content of a signal. They are designed to
emulate traditional analog tone or treble/bass controls. If you need to
give a non-technical end user control over treble and bass, a shelf filter
is the way to go. The low shelf filter can be used to boost or cut the
bass from a signal. The high shelf filter can be used to boost or cut the
treble from a signal. The 6200 provides one shelving filter which can be
set as a low or high shelf. For a basic treble control, use a high shelf
filter and set the frequency between 2 kHz and 5 kHz. For a basic bass
control, use a low shelf filter and set the frequency between 200 and
500 Hz.
Controls:
Bypass/Enabled - When bypassed, the input is sent unmodified to the
output. When enabled, the module processes the signal.
Basic Setup