side of the ribbon produces a positive voltage on Pin-2, with respect to
Pin-3 on the output connector.
The sound of your A840 is slightly different between the front and the
back — subtle, but sufficient to offer two “flavors.” In addition to polarity,
this is the result of using two wraps of grille cloth on the back and only
one on the front. When using the rear lobe, remember to invert the
polarity on your preamp or DAW. This ensures your recordings with the
back lobe will be in-phase with other microphones.
Controlling Leakage
A significant and ever-present challenge in contemporary studio
recording is minimizing “bleed” (also called “leakage” or “crosstalk”)
from nearby instruments into the various microphones. The deep nulls
of bidirectional ribbon microphones provide good rejection of unwanted
sounds, which also can be beneficial in sound reinforcement situations
where feedback is always a threat. While gobos can be effective in
isolating performers from each other, they introduce their own set of
problems - not the least of which are reflections in close proximity to
the performers and/or microphones that result in comb-filter distortions.
Since gobos usually are bulky, they also inhibit the ability of the
musicians to hear and see each other easily. Such a setup requires
complex and often cumbersome headphone monitor mixes for the
musicians.
Since the A840 is bidirectional, it exhibit nulls at right angles to the
principal axis. These nulls produce a “plane of rejection” around the
sides, top and bottom of the mic that can be used effectively to reduce
leakage. Simply arrange the musicians so that nearby instruments are
placed in the “null” of their neighbor’s microphone, and vice versa.
Although this does not entirely eliminate the need for gobos, it can
significantly reduce their number.
Keep in mind that a certain degree of bleed does not necessarily have
to be bad. For some styles and genres it can in fact be beneficial to
embrace a little bit of bleed in order to create cohesive and natural
sounding recordings. The important thing to listen for is whether or
not other instruments that bleed into a specific instrument microphone
still sound natural. You will generally find that well-designed ribbon
microphones like the A840 capture a natural off-axis sound, which
means that bleed from other instruments can contribute to the overall
sound in a pleasing way.
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