Manley VOXBOX - MVBXA 4/2003 - Manual (Page 8)

EQ and DE-ESSER SECTION
O. EQ BYPASS: Switching this up engages the EQ section. This is a passive PULTEC MEQ style EQ with only
one capacitor, one inductor (coil or choke) a conductive plastic pot and a gold contact switch in the audio path for
each band of EQ. There are no tubes in the EQ and certainly no ICs or transistors. The tube circuit is only used
for flat, fixed make-up gain and is always in circuit. The EQ is before the de-esser / limiter and before the tubes.
P. EQ INPUT: Three inputs are available to feed the EQ / De-esser / Line amp. The LINE IN is a split from the
same LINE IN that can feed the mic preamp section. The PRE O/P is the output of the mic preamp / compressor
section and is not through the output transformer. When using a line input into the compressor, these two positions
allow you to compare compression to no compression without the drop of gain you get just using the compressor
BYPASS switch. The INSERT setting allows yet another line input to feed this section. It allows you to insert (or
bypass) an external device such as a noise gate between the preamp output and the EQ section. It also allows you
to use the VOXBOX for two different tracks. These 3 inputs are switched with high quality sealed relays near the
back panel & transformers for the shortest signal path.
Q. LOW PEAK FREQUENCY: This simply selects the center frequency to be boosted with the LOW PEAK con-
trol. The “Q” or bandwidth is fixed and consistant with the original PULTEC MEQ. There are now 11 positions
between 20 Hz and 1 kHz. The settings below 200 are new and were not on PULTEC MEQs. See page 14 for a
few tips if you want.
R. LOW PEAK: Adjusts between 0 or flat and typically up to 10 dB of maximum boost.
S. MID DIP FREQUENCY. 11 frequency bands between 200 Hz and 7 kHz (7,000 Hz). 1K5 is “British” for
1,500 hz or 1.5 kilohertz or kilocycles.
T. MID DIP: Adjusts between 0 (flat) and up to (minus) 10 dB of maximum cut. Many top engineers suggest that
by using cut EQ (mostly from 200 to 1K5) rather than boost reduces phase shift problems and improves the gen-
eral clarity and punch. Cutting a bit at 5 or 7 kHz can reduce the resonance of some vocal mics. (It helps to boost
16 or 20 kHz on the High Peak to compensate for lost brightness.)
U. HIGH PEAK FREQUENCY: Again 11 positions but from 1,500 Hz (1K5) to 20 kHz. The settings above 5 kHz
are new. Some frequencies may cause sibilance problems.
V. HIGH PEAK: Adjusts between 0 (flat) and up to 10 dB of maximum boost.
W. DE-ESS BYPASS: Switching up engages the de-esser or limiter. This function is also passive and can be
switched in silently during music!
X. DE-ESS SELECT: This rotary switch selects frequency band the de-esser will dip or notch. The 3 KHz posi-
tion is may be used for occasional de-essing or may help control sounds that tend to “hurt”. Our hearing is most
sensitive in that band. The LIMIT position removes the frequency selection and works as a “flat” electro-optical
limiter much like an LA2-A.
Y. THRESHOLD: This sets how loud an “ess” (or transient in Limit) has to be before it can be reduced. Turn
clockwise for more de-essing. Normally we try to make the sibilance natural rather than removing the ”esses”
entirely. A good way to set the threshold when limiting is to look at the tape machine peak meters and set it to
prevent overloads.
Z. POWER. The meter will light immediately. There is a relay that mutes the outputs for about 20 seconds after
power is turned on and immediately after power is turned off to prevent “thumps”. The LED marked READY
lights when audio can pass. This circuit will ignore quick “blackouts” for live sound work. This feature can be to-
tally bypassed (or the delay shortened). The VOXBOX should be turned off between sessions to extend tube life.
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