+20dBm into 150 ohms was provided by the output-buffer amplifier with the signal then output at the XLR connector on the DTR's rear panel. The output signal path from DAC to output XLR connector was DC coupled. Honeywell Tape Drives Soundstream-modified Honeywell 5600e Instrumentation Tape Drives (HTD) used custom high-frequency 18-track record and playback heads. The two outer tracks were reserved for ancillary data - SMPTE time code and the like. The remaining sixteen tracks were used to record up to eight channels of digital audio - two redundant tracks for each audio channel. The two tracks in a redundant track pair were separated as widely as possible to minimize playback errors due to tape defects (dropouts) - audio channel one was recorded on tracks 1 and 9. At the front of the HTD, Soundstream installed track selector hardware. The left side selector allowed the operator to choose which audio channel pair (1,2; 3,4) was assigned to which tape track pair (1,2; 3,4; 5,6; or 7,8). The right-side selector controlled the application of record circuitry power for each of the eight tracks. The HTD initially used 1" Ampex 460 reel-to-reel tape at 35ips. Later, Soundstream switched to Ampex 466 tape which allowed for the slower tape speed of 30ips. Digital editing system Soundstream's digital editing system was the first instance of a computer used to edit commercial recordings. It consisted of a Digital Equipment PDP 11/60 computer running the DAP (Digital Audio Processor) editing software (written by Soundstream employee Robert Ingebretsen), Soundstream's interface (the Digital Audio Interface) to transfer data between its recorder and the computer's disks (a pair of Braegen 14" disk drives), digital-to-analog playback hardware, a text-based video display terminal for entering commands to operate and control the DAP software, and a storage oscilloscope to display the waveforms of the audio being edited or processed. For all intents and purposes, this system was the very first digital audio workstation. In addition to its own facility, Soundstream installed editing systems at Paramount Pictures (Hollywood), RCA (New York), and Bertelsmann (Germany). A system was delivered to the U.S. Department of Justice to aid the analysis of bootleg recordings. Editing could be performed at sample accuracy (i.e., 1/50,000 of a second); any mixing was performed digitally. The sound system in the editing room in the Salt Lake facility used a Threshold SL-10 preamp, a Sumo "The Power" amp, and Infinity RS4.5