Network Library Services Home

This document outlines recommendations for digital talking-book production of analog-to-digital transfers  (A–D), including instructions for special A–D announcements, digital noise reduction recommendations, and suggestions for digital navigation.

Table of Contents

1. Requirements

All requirements of NLS Specification NS01 must be met.

2. Audio Recommendations

2.1 Excluding/Removing Cassette Announcements

Analog talking books contained numerous references to cassette sides and instructions for operation and navigation specific to the C-1 cassette player. Whenever possible, these cassette announcements should be excluded from the digital talking book. DTB authoring tools often contain features for editing the content of the XML control files so that portions of narration are not rendered by the playback device. Otherwise the cassette announcements can be deleted from the digital audio files themselves.

The following announcements should not be present in the DTB:

2.2 A–D Announcements

An announcement indicating that the recording was originally intended for cassette playback should be included in the opening announcement of the DTB. NLS recommends one of the following A–D announcements:

a. A–D Announcement 1 (Navigation)

The library may obtain from NLS the Don Smith narration of an A–D announcement that indicates the DTB contains navigation to major portions of the book. As stated in the announcement, the DTB must contain some navigation. Do not use announcement 1 if there is no navigation. See Appendix section (a) for the script of the A–D announcement.

b. A–D Announcement 2 (No Navigation)

The library may obtain from NLS the Don Smith narration of an A-D announcement that indicates the DTB does not contain navigation. See Appendix section (b) for the script for the A–D announcement.

c. Custom A–D Announcement

The library may record a custom opening announcement including an A–D announcement. This custom announcement should including the DBC number and other specific information regarding the book. See Appendix section (c) for the recommended script for a custom opening announcement

2.3 Audio Restoration—Noise Reduction

2.3.1 Analog Source

Analog recording is more susceptible to noise than digital recording. The most common noise that occurs in analog recording and reproduction is tape hiss.  Conversion from analog to digital will always contain some degree of tape hiss relative to the signal level of the original master. Proper cleaning, demagnetizing, alignment, and calibration of the analog tape machine is an essential step in noise reduction. In addition, specialized noise reduction systems can be inserted into the signal path to further reduce the noise prior to conversion to digital. Reducing noise at the source will result in a higher quality digital master.

2.3.2 Warning

Use caution when attempting to reduce noise in a digital audio file. Improper use of specialized noise reduction software may significantly reduce the overall sound quality of the audio file and introduce undesirable artifacts. Noise reduction software will not completely eliminate noise from an analog-to-digital transfer without adversely affecting the program material (i.e., the narration). Some level of tape hiss is expected in an A–D transfer; noise reduction is not a requirement.

2.3.3 Post-Conversion Digital Noise Reduction

Audio restoration processes may be applied to the digital audio files after conversion to remove any remaining noise.  Be aware that noise reduction may not completely remove all noise when the noise is very loud or variable, when the narration is not much louder than the noise, or when the noise frequencies are similar/identical to the narration frequencies.
The proper amount of noise reduction depends upon the type of background noise and how much loss in the quality of the remaining signal is acceptable. When applying noise reduction listen carefully to the unaffected rendition compared to the affected rendition. Is the noise reduced but at the expense of intelligibility and listenability? Find a middle ground between noise reduction and fidelity. Do not arbitrarily apply noise reduction without listening to the results.
When specially designed noise reduction software is unavailable, equalization and gating software may be used instead.

3. Navigation Recommendations

For A–D conversions NLS recommends the following navigation:

All navPoints should have a class attribute, text element, and an audio element, as required by NS01.
Whatever navigation is found in the DTB should be announced in the A–D Opening Announcement, Appendix section (c) below.
For more information regarding the basic components of a DTB, see “Draft NG04: Network Guideline for Digital Talking Book Mastering” and “Guideline for Appling Navigation Markers to Digital Talking Books (DTBs).”

Appendix—A–D Announcements

a. A–D Announcement 1 Location and Script

The following announcement should be inserted into the recording of the opening announcement. Place the recording after the narrator’s name and before the reading of page numbers. The audio recording of Don Smith reading this announcement may be obtained from NLS:
“This book was originally created for audio cassette playback. Any announcements concerning cassettes do not apply to this recording. This version contains markers allowing direct access to major portions of the book.”

b. A–D Announcement 2 Location and Script

The following announcement should be inserted into the recording of the opening announcement. Place the recording after the narrator’s name and before the reading of page numbers. The audio recording of Don Smith reading this announcement may be obtained from NLS:
“This book was originally created for audio cassette playback. Any announcements concerning cassettes do not apply to this recording.”

c. Custom A–D Announcement Script

 “[Title]”

“by [Author/s]”

The DBC Number [The assigned DBC number from the block of DBC number supplied by NLS]

“Copyright [date and holder(s)]”

 “Read by [name of narrator(s)]”

“This book was originally created for audio cassette playback. Any announcements concerning cassettes do not apply to this recording. This version contains markers allowing direct access to major portions of the book.”

“This book contains [number] pages.”

“Approximate reading time: [number] hours, [number] minutes.” Round to the nearest minute, keeping it within plus or minus five minutes of the value of dtb:totalTime.

Brief announcement describing the structure of this digital talking book. See Appendix 3 for examples.

“_______[Network Library Name]_______ Annotation”

“From the book jacket [publisher’s information about the book, excluding reviews].” This information may be given in several locations. The narrator should read the one most informative selection.

“About the author [. . . ]”

“Other books by [name of author or authors]: [titles].” The narrator should read all titles, unless they were previously mentioned in the book information or about the author. If only one title is mentioned, instead use “Also by [name of author or authors]: [title].”

Introductory items up to and including the table of contents, such as dedication, introduction, preface, foreword, acknowledgments, and other introductory items, in the order in which they appear in the print book. In the table of contents, include page references, preceding each reference with “page.”