Royer Labs SF-24 User Manual

Royer Labs

Model SF-24

Stereo Active Ribbon™ Velocity Microphone

Operation Instructions Manual
& User Guide

Made in U.S.A.

TABLE OF CONTENTS

Model SF-24 Ribbon Microphone

Revised 2009

Introduction! 3

Active Ribbon™ Technology! 3

Description! 4

Applications! 5

Ribbons in the Digital World! 5

User Guide! 6

Using the SF-24 Active Ribbon Microphone™! 6

Operation! 7

Using the RSM-24 Shock Mount Accessory! 8

Description! 8

Features! 8

Usage! 8

Properly Inserting the Microphone into the Shock! 8

Removing the Microphone from the Shock! 9

Connecting the SF-24! 9

Amplification Considerations! 10

Stereo Microphones and Ground Loops! 11

Equalization and Ribbon Microphones! 11

Hum, Noise and Mic Orientation! 12

Microphone Techniques! 13

General Tips for Using the Royer SF-24! 13

Specialized Stereo Recording Techniques! 15

Classic Blumlein Technique! 15

Mid-Side (M-S) Technique! 16

Care and Maintenance! 17

Care for the Optical Black Finish! 18

Features! 18

Specifications! 19

Wiring Diagram! 20

Polar Pattern! 20

Frequency Response! 20

Warranty! 21

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Introduction

Congratulations on your purchase of a Royer Labs model SF-24 stereo active ribbon
microphone™. The SF-24 is a handcrafted precision instrument capable of delivering superior
sound quality and exceptional performance. The SF-24 represents a new level of performance for
ribbon microphones, combining sophisticated technological advancements with old-world
craftsmanship. The SF-24 incorporates two independent head amplification systems that operate
on standard 48-volt phantom power, similar to standard condenser microphones. This enables the
SF-24 to deliver the same sensitivity that the recording industry has grown accustomed to with
modern condenser microphones. In addition, the active circuitry completely isolates the ribbon
element from impedance mismatches, short circuits and other anomalies that can degrade
microphone performance or damage the sensitive ribbon element. The SF-24 breaks the long­standing taboo associated with ribbon microphones and phantom power; it actually requires
phantom power to operate.

This instruction manual describes the SF-24, its function and method of use. It also describes the
care and maintenance required to ensure proper operation and long service life. The User Guide
section of this manual offers practical information designed to maximize the performance
capabilities of this microphone.

Royer Labs products are manufactured to the highest industrial standards using only the finest
materials obtainable. Your model SF-24 went though extensive quality control checks before
leaving the factory. Normal care is all that is required to assure a lifetime of trouble-free service.

Please read this manual thoroughly in order to become familiar with all of the SF-24’s
capabilities. It will assist you in making the most of your microphones’ superior acoustic
properties. This manual is a handy reference guide and we suggest you refer to it whenever
questions arise on the use and care of your SF-24 ribbon microphone.

Active Ribbon™ Technology

The heart of the SF-24 is its proprietary electronic system consisting of specially designed
toroidal transformers and electronic buffering stages. This system provides excellent frequency
response, extremely low noise and distortion, and high SPL handling (130 dB) without the use of
pads. It gives the SF-24 an output level comparable to that of condenser microphones, and its
buffer stages provide a low impedance output and present a perfect impedance load to each of
the ribbon elements. Unpowered ribbon microphones suffer substantially degraded frequency
response and lowered gain when they are paired to a preamp with too low an input impedance.
With the SF-24‘s active electronic system, the microphone’s frequency response and output are
much less affected by variations in the input impedance of the following preamp.

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Sonically the SF-24 differs from the unpowered SF-12 in one subtle way; due to the extra iron in
the SF-24’s much larger transformers, low-end frequencies sound slightly tighter and more
focused.

Key Points:

• No longer is it necessary to mate a ribbon microphone to an ultra-high gain, low noise
preamplifier for optimum performance. Any preamplifier of nominal gain will provide good
results with the SF-24.

• No longer is it necessary to carefully consider impedance matching characteristics when
choosing a preamplifier. Microphone loading is a non-issue and consistent performance is
assured, regardless of the preamplifier’s impedance characteristics.

• No longer is it necessary to be concerned about damaging the ribbon element with phantom
power. The active electronics need phantom power to operate - a first for ribbon
microphones.

• No longer is it necessary to worry about the effects of long cable runs degrading the
performance of your ribbon microphone. The active electronics provide a robust low
impedance signal that can handle long cable lengths with minimal loss of signal.

Description

The SF-24 stereo coincident active ribbon microphone™ is the only microphone of its kind
available, combining high audio performance with outstanding separation and imaging. It is a
modern ribbon design, with no audible diffraction effects or cavity resonance. The SF-24's active
electronics produce an output comparable to phantom powered studio condenser microphones
and because the ribbon elements are electronically isolated from the outside world, the
possibility of ribbons becoming damaged as a result of faulty wiring, brownouts or phantom
power supply defects is virtually eliminated.

The SF-24 is a compact, stereophonic ribbon microphone array consisting of two matched
microphone elements that are placed one above the other. Each transducer is positioned at 45¼ to
the left and right of center, or 90¼ from each other. When held vertically, connector down and
the “ROYER” logo facing the sound source, the upper element is the right channel and the lower
element is the left channel, from the perspective of an observer behind the mic. The microphone
elements are each bidirectional (figure-8) and may be addressed from either side with equal
sensitivity. The in-phase signals are achieved when the microphone is addressed from the front,
as indicated by the “ROYER” logo. If, however, the microphone is suspended upside down, the
connections to the preamplifier should be reversed since what was the left transducer is now
responding to signals from the right and vice versa.

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Your SF-24 is equipped with a 5-pin XLR type extension cable and a splitter cable that fans out
to twin 3-pin male XLR connectors. As shipped from the factory, the connectors are marked
“upper” and “lower,” since referring to them as "left” and “right” could lead to confusion.

The SF-24 is reasonably tolerant of shock and vibration, but care should be taken to prevent
accidental stretching of the ribbon elements. This is covered in the Care & Maintenance section
of this manual. The performance of the microphone is unaffected by changes in temperature or
humidity.

Applications

The SF-24 is a highly versatile microphone, ideally suited for a wide range of critical recording
applications. From drums, acoustic stringed instruments and stereo vocals to ensembles like big
band, orchestra and jazz groups, your SF-24 will capture performances with uncanny realism and
a beautifully full stereo image.

Because of the SF-24’s coincident crossed figure-8 pattern, M-S (mid-side) recording from one
microphone is easily achievable. Once a recording has been completed using the proper
orientation, the sound field can be adjusted from pure monophonic to “super wide.”

Although spaced microphones can produce similar stereophonic results, such recordings when
summed to mono can suffer from “comb filter” effects: peaks and dips in the frequency response.
When the SF-24 is used for M-S recording, the feeling of space changes but the sonic quality
does not. For more detailed information on the M-S technique, see the chapter Recording
Techniques: Mid-Side (M-S) Recording in this manual.

The SF-24’s small size and optical black chromium finish create minimal disturbance in the
visual field, which is especially important when the microphone must not obstruct the view of an
audience or of a motion picture or TV camera.

Ribbons in the Digital World

Digital recordings benefit greatly from the properties inherent in ribbon microphones. Since A to
D converters cannot distinguish between the sound source being recorded and the complex
distortion components often associated with condenser microphones, they sometimes have
difficulty tracking the signal, resulting in ringing and edgy-sounding tracks. With ribbon
microphones, ringing is almost nonexistent due to the ribbon’s lack of distortion artifacts and
high frequency peaks. A to D converters have less difficulty tracking the ribbon generated signal,
resulting in very smooth digital recordings free of microphone-related edginess.

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User Guide

Using the SF-24 Active Ribbon Microphone™

The head amplification system utilized in the SF-24 was designed to operate with standard 48
volt simplex phantom power sources only. The microphone will not work at all if phantom
power is not provided to the microphone! This aspect of an active ribbon microphone is in sharp
contrast to the common wisdom normally applied to ribbon microphones, in which phantom
power usually spells danger or destruction to the ribbon element. Royer’s active series ribbon
microphones require phantom power to operate.

To ensure long service life of your SF-24 active ribbon microphone™, care should be taken
when connecting the microphone to a phantom power source. We have prepared a few tips to
ensure that your SF-24 will perform perfectly for many years. We offer the following
information as a general set of good habits that apply to both active ribbon mics and solid-state
condenser microphones as well.

1. Always be certain to use the SF-24’s five-lead stereo cable, which splits out to two short 3­pin cables with male XLR connectors labeled “Upper” and “Lower.” Do not substitute
extension cables of unknown wiring! The SF-24’s pin-out is Pin-1 shared ground for both
ribbon transducers, Pin-2 signal hot (in-phase) for the upper transducer, Pin-3 signal cold
(reverse phase) for the upper transducer, Pin-4 signal hot for the lower transducer, Pin-5
signal cold for the lower transducer. If additional extension cables are used, be sure they are
in good serviceable order. Standard microphone cables provide a shielded ground carried
along to Pin-1 and a balanced differential signal carried along Pins-2 and 3, with Pin-2 signal
hot and Pin-3 signal cold.

2. Although it is usually safe to “hot plug” most phantom powered microphones to a
preamplifier or console with the phantom activated, we suggest that if it is possible to
deactivate the phantom power prior to plugging in the microphone, do so. This minimizes
any chance of random voltage surges entering the microphone. More importantly, it reduces
the possibility of loud pops being transmitted to your monitor speakers should the volume
control be raised. Serious damage to your speakers could result from this mistake.

3. Be certain that the input channel fader or volume control is set to minimum before plugging
in any microphone. Preamplifier gain trim should be set to minimum. Plug the microphone in
and activate the phantom power switch. The microphone’s electronics will stabilize in a few
seconds.

4. When the microphone becomes operational, bring the two channel faders to 0-dB (unity) and
use the trims to set the desired level. This technique maximizes the signal-to-noise
performance of the preamplifier or console input channel.

5. When disconnecting the microphone, bring the channel faders down and unplug the
microphone cable ends. It is also advisable to turn off the phantom power before unplugging
the microphone whenever possible.

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6. If the studio has the microphone lines brought to a patch bay (tie lines), never crosspatch a
microphone line when phantom power is applied or the monitor volume is raised. This could
cause damage to your microphone, preamplifier or monitor speakers.

Operation

There are a few important facts that are key to understanding how to use ribbon microphones
intelligently.

1. With ribbon microphones, rejection in the “dead” areas is very strong. Due to this
directionality, ribbon mics should be placed at 1.3 times the distance normally used with
omni-directional microphones, or at approximately the same distance used for cardioid
microphones. This method is used to achieve the same ratio of direct to reflected sound.

2. In the horizontal plane, ribbon microphones do not discriminate against the “highs” off axis,
nor do they boost them on axis. Therefore, several instruments or vocalists can be placed in
front of the microphone without favoring the performer in the center of the group.

Several performers can be grouped at both the front and the back of the microphone, with
one proviso: Since the outputs are out of phase at the front and back of the microphone,
cancellation can result if two tenors are placed on opposite sides at equal distances and are
singing in unison. Therefore, listen to the feed before committing to it.

3. The Royer model SF-24 is a phantom powered microphone and must be connected to a
preamplifier or console cable of delivering 48-volts at a minimum of 4-milliamperes per
channel. Faulty or improperly wired cables could cause your SF-24 to become inoperative.
Since the active electronics offer electrical isolation to each ribbon, miswired cables should
not cause damage to the ribbons themselves.

4. Never attempt to “test” the SF-24 (or any ribbon microphone) with an ohmmeter. Damage to
the delicate electronics could occur.

Always provide adequate protection for your SF-24 (or any ribbon microphone). If the
microphone is to remain set up on a stand when not in use, place a “mic sock” (provided)
over it until it is to be used. As even light wind can stretch the SF-24‘s ribbon elements, do
not carry the microphone around without placing a mic sock over it. Failure to follow this
commonsense practice may yield a stretched ribbon and compromised performance!

5. Avoid dropping the microphone. An accidental fall to a hard surface could stretch one or both
ribbons and, depending on the nature of the fall, possibly require a complete overhaul of the
microphone.

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