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Magnetic Tape 9-57

9.4.3f

Slitting

The web is slit into strands of the desired width, from 150 mils to 3 in (3.8 mm to 7.6 cm). Toler-
ances in width variation are about ± 1.0 mil to less than ±0.4 mil, depending on the application.
Edge weave, or width waviness (country laning) over extended length, should not vary more than
about 1 to 2 mils in 1-in video tapes and 0.4 mil in video cassette tape. Tape must be free from
jagged edges and debris. Additional tape cleaning processes are sometimes used to ensure that
loosely held dropout contributors are effectively removed.

9.4.3g

Testing

Professional magnetic tape manufacturers test every component of tape in every step in the pro-
cess, from individual raw materials through packaging. The most exacting specifications are set
forth and followed. Electrical tests, including those for dropouts, are especially stringent, and in
professional audio, instrumentation, video, and computer tapes, each reel of tape is tested, in
some cases end to end, before shipment. In addition, warehouse audits are performed to ensure
maintenance of quality.

9.4.3h

Assembly and Packaging

Tape is assembled in various formats but mainly in reels, pancakes, cassettes, and cartridges of
different sizes. The same standards of precision, cleanliness, and quality exist in these areas as in
tape making per se, and final assemblies of tape components and packages are all performed in
ultra-clean-room environments.

9.4.4

References

1.

Grega, Joe: “Magnetic and Optical Recording Media,” in NAB Engineering Handbook, 9th
ed., Jerry C. Whitaker (ed.), National Association of Broadcasters, Washington, D.C., pp.
893–906, 1999.

9.4.5

Bibliography

Bate, G.: “Recent Developments in Magnetic Recording Materials,” J. Appl. Phvs. pg. 2447,

1981.

Hawthorne, J. M., and C. J. Hefielinger: “Polyester Films,” in Encyclopedia of Polymer Science

and Technology, N. M. Bikales (ed.), vol. 11, Wiley, New York, N.Y., pg. 42, 1969.

Jorgensen, F.: The Complete Handbook of Magnetic Recording, Tab Books, Blue Ridge Summit,

Pa., 1980.

Kalil, F. (ed): Magnetic Tape Recording for the Eighties, NASA References Publication 1975,

April 1982.

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Magnetic Tape

9-58 Audio Recording Systems

Lueck, L. B. (ed): Symposium Proceedings Textbook, Symposium on Magnetic Media Manufac-

turing Methods, Honolulu, May 25–27, 1983.

Nylen, P., and E. Sunderland: Modern Surface Coatings, Interscience Publishers Division, Wiley,

London, 1965.

Perry, R. H., and A. A. Nishimura: “Magnetic Tape,” in Encyclopedia of Chemical Technology,

3d ed., Kirk Othmer (ed.), vol. 14, Wiley, New York, N.Y., pp. 732–753, 1981.

Tochihara, S.: “Magnetic Coatings and Their Applications in Japan,” Prog. Organic Coatings,

vol. 10, pp. 195–204, 1982.

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Magnetic Tape

10-1

Section

10

Production Standards, Equipment, and

Facility Design

The distinction between an audio system intended for production applications and a system
intended for the transmission sounds and other information is an important one. Because of their
closed-loop characteristics, production systems can be of any practical design. The process of
developing a production system can focus simply on those who will directly use the system. It is
not necessary to consider the larger issues of compatibility and public policy, which drive the
design and implementation of over-the-air broadcast systems.

Although the foregoing is certainly correct, in the abstract, it is obvious that the economies of

scale argue in favor of the development of a production system—even if only closed-loop—that
meets multiple applications. The benefits of expanded markets and interoperability between sys-
tems are well documented. It was into this environment that production systems intended for dig-
ital audio applications were born.

A system intended for broadcast applications must—by necessity—strictly adhere to estab-

lished standards and practices, usually determined by governmental licensing authorities. Pro-
duction-oriented systems, however, are not bound by such restrictions. This flexibility is a two-
edged sword. While it permits systems of any practical design to be implemented—the system
need only communicate with itself and the equipments that directly interface with it—this situa-
tion permits—and even encourages—a diversity of product development. In some cases, such
proprietary systems have benefited the end-user and the industry; in other cases, it has led to
wasted time and money through investment in a technology that held promise at the outset but
wound up going nowhere.

This issue is an important one as the professional audio industry moves ahead in the realm of

digital broadcasting. Audio industry organizations—most notably the AES and its members—
have devoted enormous energies to the development of standards that help end-users chart their
paths into the digital domain. With the AES’s historic focus on production issues, the Society’s
activities have naturally focused there.

Industry veterans will remember that in the not too distant past, standards were usually diffi-

cult to develop and often required many years to formalize. Standardization efforts in the digital
era are—in many cases—leading product development, ensuring that products will communicate
with each other and work as promised when integrated into larger systems.

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Source: Standard Handbook of Audio and Radio Engineering

10-2 Section Ten

In This Section:

Chapter 10.1: Audio Production System Standards

10-5

Introduction

10-5

The History of Modern Standards

10-5

American National Standards Institute (ANSI)

10-6

Professional Society Engineering Committees

10-7

Advanced Television Systems Committee

10-7

Electronics Industries Alliance

10-8

Institute of Electrical and Electronic Engineers

10-8

Society of Motion Picture and Televisions Engineers

10-8

Audio Engineering Society

10-9

AES Documents

10-9

Informational Documents

10-9

Project Reports

10-10

Standards and Recommended Practices

10-11

Bibliography

10-15

Chapter 10.2: Production Facility Design

10-17

Introduction

10-17

Project Management

10-17

Feasibility Study and Technology Assessment

10-18

Project Tracking and Control

10-18

Change Order

10-19

Electronic System Design

10-20

Developing a Flow Diagram

10-21

Estimating Cable Lengths

10-22

Signal Timing Considerations

10-22

Cable Loss and Equalization

10-22

Facility Design Process

10-23

Preliminary Space Planning

10-24

Design Models and Mockups

10-26

Construction Considerations

10-26

Component Selection and Installation

10-27

Technical Documentation

10-28

Documentation Tracking

10-29

Symbols

10-29

Cross-Referencing Documentation

10-30

Specifications

10-30

Working with the Contractors

10-30

Computer-Based Tools

10-31

Bibliography

10-31

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Production Standards, Equipment, and Facility Design

Production Standards, Equipment, and Facility Design 10-3

On the CD-ROM:

•

“Studio Production Systems” by Ernst-Joacham Voelker, an archieve chapter from the first
edition of the Audio Engineering Handbook. This chapter examines design principles and
techiques for a variety of audio studio facilities.

•

“Postproduction Systems and Editing” by Tomlinson Holman, an archive chapter from the
first edition of the Audio Engineering Handbook. This chapter provides a wealth of informa-
tion on audio postproduction equipment, systems, and techniques.

•

“Noise Reduction Systems” by Ray Dolby, et. al., an archive chapter from the first edition of
the Audio Engineering Handbook. This chapter explains the noise reduction techniques used
with analog audio systems.

•

“Film Recording and Reproduction” by Ronald Uhlig, an archive chapter from the first edi-
tion of the Audio Engineering Handbook. This chapter discusses original production record-
ing, postproduction editing, and duplication of film-based audio.

Reference Documents for this Section

DeSantis, Gene, Jerry C. Whitaker, and C. Robert Paulson: Interconnecting Electronic Systems,

CRC Press, Boca Raton, Fla., 1992.

Whitaker, Jerry C.: Facility Design Handbook, CRC Press, Boca Raton, Fla., 2000.

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Production Standards, Equipment, and Facility Design