XDR (audio)

In this way, the dynamic range of audio recorded on an XDR-duplicated cassette can be up to 13 decibels greater.

[1] XDR (Expanded Dynamic Range) was originally developed by Capitol Records in LA in their R&D facility.

Capitol Records Canada was able to do this for the following reasons: The XDR/SDR process involves many steps, the most prominent being: As well as with EMI & Capitol Records, PolyGram and other labels also offered cassette releases duplicated with the XDR process.

Some XDR cassettes include a series of DTMF-like dual-tones after the second toneburst at the end of the tape which uniquely identifies the album.

XDR's dual-tones are a modified form of DTMF where each of the two frequencies is one-half the usual specification.

The XDR logo, on the label and case insert of cassettes duplicated with the XDR process
Spectrogram of SDR Soundburst from cassette of David Bowie's "Let's Dance"
Listen to an example of XDR's dual tones
Spectrogram showing XDR soundburst and dual-tone data.
Note the dual tone data following the XDR soundburst.