.SD File Extension
ESPS Sampled Data
| Developer | Entropic Research Laboratories |
| Popularity |
3.4 | 42 Votes |
What is an SD file?
An SD file is an audio file used by the WAVES+ display program, ESPS signal processing library, and the Hidden Markov Model Toolkit. It is saved in a proprietary format created by Entropic Research Laboratories. SD files may also be referred to as .ESPS files.
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Entropic Research Laboratories was a software company that specialized in creating software used to analyze and manipulate human speech signals. These programs included WAVES+, ESPS, and the Hidden Markov Model Toolkit (HTK).
All the above programs used audio files saved in proprietary file formats developed by Entropic Research Laboratories. SD files contain samples of human speech saved in the ESPS (Entropic Signal Processing System) format. This format was later replaced by Entropic's Esignal format.
NOTE: Microsoft purchased Entropic in 1999. As a result, Waves+ and ESPS were discontinued. However, Cambridge University continues to maintain and distribute the Hidden Markov Model Toolkit.
How to open an SD file
You can use the Hidden Markov Model Toolkit (multiplatform), FMJ-Software Awave Studio (Windows), or Festival (Linux) to play the speech an SD file contains.
Programs that open SD files
Sound Designer Audio File
| Developer | Digidesign |
| Popularity |
2.8 | 13 Votes |
An SD file may also be an audio file used by Digidesign Sound Designer, a discontinued audio-editing program for the Macintosh computer. It contains digital audio data in the proprietary, uncompressed Sound Designer (SD) format. SD files were replaced by .SD2 files when Sound Designer II was released.
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Sound Designer was an influential digital audio editing program in the late 1980s and early 1990s, particularly among Macintosh users in the music production and sound design industries. The program was one of the first applications that allowed users to work with digital audio in a user-friendly way, offering tools for sampling, editing, and processing audio files.
In the mid-1990s, Digidesign shifted its focus to developing Pro Tools, a much more sophisticated and powerful audio editing platform. As Pro Tools gained traction in both professional and consumer markets, Sound Designer’s usage decreased, leading to Digidesign discontinuing it in favor of Pro Tools and the SD format becoming obsolete.
How to open an SD file
You can open SD files with FMJ-Software Awave Studio. To open an SD file with Awave Studio, select File → Open.