Audio Specifications and Standards
The following provides a brief overview of our standard audio specifications.
Default File/Output Settings
- masters: .wav/WAVE at 24-bit/44.1khz
- note: IASA TC-04 calls for a minimum sampling rate of 48kHz (preferably 96kHz). We will discontinue use of 44.1kHz sampling rates pending confirmation of appropriate storage space as 24/48 vs 24/44.1 should yield only an 8% increase in space requirements. Projects already underway at the 24/44.1 spec will maintain that specification. - arora, 062910. Update: given remaining storage concerns, we will continue with 24/44.1. - arora, 030911.
- typically, 2s of silence is left or created at the beginning of each .wav, with 1s at the end.
- RMS levels are typically set fairly low, to -25db
For information on derivatives, see For_Creating_Derivatives
Care, Handling, and Storage of Analog Audio Materials
Audio preservation Potential degradation issues:
- Open Reels
- Obsolescence – lack of equipment being manufactured of available to play the format
- Cellulose acetate base – Cellulose acetate degrades in water so tapes with a cellulose acetate base are susceptible to hydrolysis which creates vinegar syndrome. Vinegar syndrome occurs when acetic acid is released and accelerates the degradation process.
- Sticky shed syndrome – polyester based tapes have a urethane binder that when subjected to hydrolysis sheds the backing when played across the guides.
- Fungus – tapes in high temperature and humidity causes tapes to grow mold or fungus.
- Laquer discs and aluminum discs
- Plasticizer exudation – failure of the coating and loss of content
Casey, M., & Feaster, P. (2009). Media preservation survey: A report (pp. 1-132, Rep.) (A. Burdette, Ed.). Bloomington, IN: Indiana University Bloomington.
Best Practices for storage and handling:
- Wash hands
- Keep materials stored in a clean place
- Don’t touch playing surfaces
- Keep playback equipment clean
- Allow time for acclimation between storage rooms
- Handle discs by the edge
- Handle optical discs by the hole
- Store discs upright and on edge
- Do not store discs with different diameters together
- Store in polyethylene sleeve
- Store on unslotted hubs
- Handle by the edge of reel or by the center
- Handle by outer shell
- Don’t touch spools
- Store played tapes without rewinding just rewind them right before you play
- Keep in a cool dry room, 65-70 F and 35-50% relative humidity
- Keep materials away from light, magnets and sources of vibration
Library of Congress. (n.d.). Care, Handling, and Storage of Audio Visual Materials. Retrieved May 02, 2016, from http://www.loc.gov/preservation/care/record.html
Resources and Links:
- Digitization and Preservation Standards
- TAPE (Training for Audiovisual Preservation in Europe). European Commission on Preservation and Access.
- Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Tranferring Analog Discs and Tapes. (2006) Council on Library and Information Resources and Library of Congress.
- Sound Directions - project website, maintained by Indiana University Digital Library Program.
- Sound Directions: Best Practices for Audio Preservation. (2007) Casey, Mike & Bruce Gordon.
- Grammy foundation® Basic Methodology for Preservation, Conversion and Archiving Recorded Media. (revised 2008) Grammy Foundation, Santa Monica, CA.
- File Formats - from LOC Digital Preservation/Digital Formats site
- Audio Decision List
- Condition Assessment of Audio Formats