Assessments - 2, GPA: 5
(
)
)
|
Facilidade de uso
Also exported as Amcron® 126676-1 7/00 Crown International, Inc P.O. Box 1000, Elkhart, Indiana 46515-1000 (219) 294-8200 Fax (219) 294-8329 © 2000 Crown International, All rights reserved PZM® , PCC®, SASS® and DIFFEROID®,are registered trademarks of Crown International, Inc. Also exported as Amcron® 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 sound- absorbing 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. 3 How to reduce phase cancellationsbetween 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). How to reduce phase cancellationsfrom 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. As desc...