There are a number of problems with tracking these very
low and often unwanted frequencies. Low frequency
problems can come from traffic or subway noise hundreds
of feet away. A concrete or wood-joisted floor is
essentially an enormous drum head and every footstep
creates low frequency energy which can easily travel into
microphones.
In a major studio that has been acoustically isolated and
has wonderful full-range monitors, these low frequencies
don’t often make it into microphones, but if they do you
can hear them with monitors that are capable of producing
the bottom octave (20Hz – 40 Hz). In home studios that
don’t have a perfect monitoring situation, the engineer
can’t hear that this low rumble is on the tracks. The other
problem with recording unwanted low frequency sounds is
wasting the available bandwidth on non-artistically
essential frequencies. If you are recording a female vocal,
for instance, you can be pretty sure that any frequencies
below 80 Hz are not part of the vocal performance. There
might be plosives from popped P’s and rumble from the A
Train or the HVAC system that will not only make your
bass muddy sounding in the mix, but will diminish the
intensity of low frequency transients.
How to use it:
After you have set your gain level appropriately, start to
turn the HPF knob clockwise until you can hear the low
frequencies start to thin out in the audio. Now back the
knob off counter-clockwise until you can’t hear the HPF
working. Now you have removed the unwanted and
unnecessary frequencies, but the filter isn’t affecting the
timbre of the audible frequencies of your source material.
1.5.4
¼
” Instrument Input Jack
The
¼
” Instrument Input Jack is specifically designed
to allow users to plug a guitar, bass or keyboard into
the front of the preamp. The signal from this jack does
not pass though the input transformer, but rather is
unbalanced. You must engage the
¼
” Button in order
