8
monitors that are capable of producing the bottom octave (20Hz – 40 Hz).
In home studios that don’t have a perfect monitoring solution, the engineer
can’t hear that this low rumble is on the tracks. 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.
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
and the HVAC system. That rumble will not only make your bass muddy
sounding in the mix, but it 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. 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.
1.5.3 The Gain Knob
The Gain Knob allows you to control
the amount of gain added to the input
signal. The knob is continuously
variable allowing a high level of
control over level. The gain should
be set as high as possible without
either seeing the peak indicator (*)
flask on the VU meter or hearing
audible clipping or distortion.
One common procedure for setting gain is to set the level while the
channel is muted. Turn up with gain until the peak indicator (*) flashes
during the loudest parts of the performance. Then reduce the gain by a
few dB. Then disengage the mute of the console or DAW and listen to the
signal. Note that many performers will be significantly louder and more
energetic when they believe they are recording compared to when they
believe that levels are being set.
