Royer Labs SF-24V - Manual (Page 13)

Unwanted magnetically induced noise (hum) can only come from external sources. Fortunately,
simply repositioning a ribbon microphone often gets rid of unwanted noise. If hum is detected,
the microphone is in the proximity of an alternating magnetic field. While listening (preferably
with headphones) to the mic, move it around. The mic will “find” the noise source quite easily.
For example, if you are miking a guitar amplifier and suspect the amplifier’s power transformer
may be the source of hum, move the mic around the amp. You will probably find that the hum is
louder as you approach the amplifier’s power supply and quieter when you move it away.
Eliminating the hum can be fairly simple and requires finding the “null” point of the hum. The
“null” point is the position that places the microphone’s magnetic components away from the
lines of the noise's radiation. Slightly rotating the microphone is usually all that is required to
cancel out the hum. This is similar to the procedure guitarists use to eliminate hum from single
coil guitar pickups: turning around slowly while listening for the hum. There will be a position
where the hum disappears completely.
Hum and other noises are often picked up in microphone cables. Since the output of a powered
Royer ribbon is 15 to 25 dB higher than with a traditional unpowered ribbon microphone, any
noise picked up in the mic cable will be at a corresponding lower level, and hence less likely to
be objectionable.
Microphone Techniques
General Tips for Using the Royer SF-24V
The following are good basic starting places for recording with the SF-24V. These positions are
known to produce good results, but experimentation is the key to getting the most out of your
recordings! Photographs of many of the following techniques can be found on our website --
www.royerlabs.com . It is important to remember that the SF-24V’s ribbon elements can be
damaged by wind. When the SF-24V is mounted on a boom stand, be sure the stand is moved
slowly. When the microphone is taken down, put it in its box immediately or, if it is to remain in
its shock mount, place the mic sock over the transducer end of the microphone. Leaving the
microphone out and unprotected invites an early re-ribboning job.
Ensemble Performances
The SF-24V records ensemble performances beautifully. Simply find the point in the room where
you hear the best blend of the instruments and room sound and place the microphone there, with
its logo facing the performers.
Strings
For stereo recordings of stringed instruments, start by positioning the microphone a few feet off
the body of the instrument. Depending on the acoustics of the room, you may want to move the
microphone closer to or further from the instrument to add or minimize ambience. For violin,
position the SF-24V horizontally, two or more feet above the instrument. For larger string
sections, try placing the microphone slightly above the instrumentalists and angled down; a
distance of three or four feet will do the job nicely.
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