Crown 35246 User Manual

126676-1 7/00

Crown International, Inc P.O. Box 1000, Elkhart, Indiana 46515-1000 (219) 294-8200 Fax (219) 294-8329 www.crownaudio.com

SECTION ONE

Microphone Technique Basics 3

How to: Reduce reverberation 3

Reduce background noise and leakage 3 Reduce phase cancellations between two mics 4 Reduce phase cancellations from surface reflections 4 Reduce handling noise 4 Reduce proximity effect 4 Achieve a natural tone quality 4 Achieve a bright tone quality 4 Achieve a good balance 5

SECTION TWO

Notes on Crown Mic Models

CM-200A 5 CM-700 5 CM-150 5 GLM-100 5 PZM-6D 5 PZM-30D 5 SASS 5

SECTION THREE

Specific Applications 5-10

INTRODUCTION

In this guide you’ll find suggestions on using Crown microphones to record music effectively. Whether you run a large professional facility, or a project studio, you’ll find useful tips here. We’ll cover some basics of miking, Crown mic models for studio use, and specific applications.

At Crown we’ve designed several mics specifically for studio applications. All these mics were field-tested in studios. Some were approved as is; others were enhanced with suggested improvements. We know you’ll like how they sound, and will appreciate their value.

MICROPHONE TECHNIQUE BASICS

How to reduce reverberation

Reverberation is sometimes loosely called “room acoustics” or “ambience.” It is a pattern of sound reflections off the walls, ceiling, and floor. For example, reverberation is the sound you hear just after you shout in an empty gymnasium. Too much reverberation in a recording can make the recorded instrument sound distant or muddy. To reduce reverberation:

• Place the mic closer to the sound source.

• Pick up electric instruments with direct boxes or cables.

• Use a room or studio with dead acoustics. The walls, ceiling, and floor should be covered with a soundabsorbing material.

• Use directional microphones. Hypercardioid and supercardioid patterns reject reverb more than cardioid. Cardioid and bidirectional patterns reject reverb equally well. Cardioid rejects reverb more than the omnidirectional pattern at the same distance:

Omnidirectional 0.0 dB Cardioid -4.8 dB Bidirectional -4.8 dB Supercardioid -5.7 dB Hypercardioid -6.0 dB

How to reduce background noise

• Stop the noise at its source: turn off appliances and air conditioning; wait for airplanes to pass; close and seal doors and windows; use a quiet room.

• Mike close with directional mics.

• Pick up electric instruments with direct boxes or cables.

• Aim the null of the polar pattern at the offending noise source. The null is the angle off-axis where the mic is least sensitive. Different polar patterns have nulls at different angles. Shown below are the null angles for various polar patterns (Figure 1):

Cardioid 180 degrees Supercardioid 125 degrees Hypercardioid 110 degrees Bidirectional 90 degrees

How to reduce leakage

Leakage (also called bleed or spill) is the overlap of sound from one instrument into another instrument’s microphone. For example, if you’re miking drums and piano each with its own microphone, any drum sound picked up by the piano mic is leakage. To reduce leakage:

• Mike close with directional microphones.

• When recording, overdub instruments one at a time on each track of a multitrack recorder.

• Pick up electric instruments with direct boxes or cables.

• Use a room or studio with dead acoustics. The walls, ceiling, and floor should be covered with sound absorbing material.

• Aim the null of the polar pattern at the undesired sound source. For example, suppose you’re miking two adjacent tom-toms with two hypercardioid mics. The null of the hypercardioid is 110 degrees off-axis. Angle each mic so that its null aims at the adjacent tom-tom.

How to reduce phase cancellations between two mics

If two microphones pick up the same sound source at different distances and their signals are fed to the same channel, this might cause phase cancellations. These are peaks and dips in the frequency response caused by various frequencies combining out-ofphase. The result is a colored, filtered tone quality.

To reduce phase cancellations between two microphones:

• Mike close.

• Spread instruments farther apart.

• Follow the 3 to 1 rule: The distance between mics should be at least three times the mic-to-sound distance. For example, if two microphones are each 1 foot from their sound sources, the mics should be at least 3 feet apart to prevent phase cancellations (Figure 2).

As described in the Crown Boundary Mic Application Guide, these situations can cause phase cancellations which give a strange tone quality. Solve the problem by using Crown PZM or PCC microphones mounted to the piano lid, wall, floor, or other large flat surface.

How to reduce handling and stand noise

• Use an omnidirectional microphone such as a GLM100, CM-150, or any PZM.

• Use a directional microphone which is relatively insensitive to handling noise, such as the CM-200A or CM-700.

• Use a directional microphone with an internal shock mount.

• Use a shock-mount stand adapter on a mic stand, such as the CMSM.

• Place the mic stand on foam or sponges.

How to reduce proximity effect

Proximity effect is the bass boost you hear when you mike close with a directional microphone. The closer the mic is to the sound source, the more bass you hear. To reduce proximity effect:

• Use an omnidirectional microphone.

• Turn down the excess bass with your mixer’s EQ.

How to reduce phase cancellations from surface reflections

Sometimes you must place a microphone near a hard reflective surface. Situations where this might occur are recording drama, musicals, or opera with the microphones near the stage floor, recording a piano with the mic near the raised lid, or recording an instrument surrounded by reflective baffles.

How to achieve a natural tone quality

• Use a microphone with a flat frequency response, such as: CM-700, CM-150, GLM-100, or a PZM30D or PZM-6D set to “flat” response.

• Move the mic around until you find a spot where the monitored sound is natural.

• Place the microphones as far from the sound source as the source is big. For example, the sound board of a guitar is about 18 inches long. Place the mic at least 18 inches away to pick up all the parts of the guitar about equally.

• If you must mike close to reduce feedback or leakage, use your mixer’s EQ to restore a natural tonal balance.

How to achieve a bright tone quality

A “bright” sound is crisp, clear, trebley, and articulate. To achieve a bright sound, use a microphone with a rising high-frequency response, such as a Crown

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