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DAS - Digital Archive System
Features | Specifications
Manufacture to order
The Otari DAS (Digital Archite System) Series is a set of equipment used to digitize analog audio signals on magnetic tapes at high speed. The system consists of three units - analog tape player (open reel or cassette), analog-to-digital conversion unit, noise reduction/level normalization unit (PC software). Numerous analog tapes (such as talking books) which have been stored in information fascililites such as libraries, broadcast stations, etc.) can be digitized efficiently.
  • High-speed digitizing at 2 or 4 times normal playback speed.
  • Various track formats supported - monaural 2 tracks to stereo 4 tracks.
  • All tracks are reproduced simultaneously. The signals of the reverse direction channels can be automatically flipped during digitizing.
  • Three sampling frequencies supported - 48 kHz, 44.1 kHz, 22.05 kHz (48 kHz & 44.1 kHz : only with 2x speed).
  • The digitized audio data is stored as WAVE format files.
  • Removable type hard disk drives are used for storing digital audio.
  • The analog tape players are controlled from the A/D conversion unit.
  • A PC keyboard connector is supplied on the A/D conversion unit.
  • Noise reduction and level normalization can be performed on the digitized audio.
  • DAISY system supported - It is possible to generate phrase index data for the DAISY system.
  • The index data can be generated using cue signals recorded on the analog tapes (special order).
  • Digitized programs can be used as master programs for the Otari duplication systems.

  • MTR-15DAS2/4: This high-speed analog tape player is for reel-to-reel (open reel) type analog audio tape and it plays tape at 4x or 2x normal play speed. The machine has a playback frequency range of 40 Hz to 40 kHz (4x 10 Hz to 10 kHz or 2x 20 Hz to 20 kHz), and has both 1/4" 2-track and 1/4" 4-track playback heads. To support major 1/4" tape track formats, the 2-channel model MTR-15DAS2 and the 4-channel mode MTR-15DAS4 are available.
    • Tape Deck Functions: In Off-line mode (i.e., Local mode), operators can use the machine as a usual tape player; it provides usual tape deck modes of Play, Stop, Rewind, and Fast Forward. By pressing the PLAY button simultaneously with the 2nd FUNC button, the machine enters Reverse Play mode to monitor the sound of tracks which are played in the reverse direction in normal forward playback. Pressing the RWD or F.FWD button simultaneously with the 2nd FUNC button places the machine in Reverse or Forward Library Wind mode in which tape is wound at half the speed of normal fast winding to provide smoother tape pack for storage. In On-line mode (see below), local tape deck operations are disabled.
    • Playback Head Selection: The machine has 1/4" 2-track and 1/4" 4-track playback heads which can be selected by a switch on the control panel.
    • Original Tape Speed Selection: Tape speed at which the tape was originally recorded can be selected from: 38 cm/s (15 ips), 19 cm/s (7.5 ips), and 9.5 cm/s (3.75 ips) on the control panel.
    • Copy Rate Selection: Conversion speed can be selected from 4x and 2x. Playback speed in On Line mode is obtained by multiplying original tape speed by copy rate. Since the playback speed for copy operation is 76 cm/s (30 ips), 38 cm/s (15 ips), or 19 cm/s (7.5 ips), if the original speed is 38 cm/s (15 ips), selection of 4x mode is invalid: when the copy rate selection is incorrect, it is impossible to put the machine in On Line mode (see below).
    • On-Line Mode: When this mode is selected by the ON LINE switch on the meterbridge, the copy operation will start by receiving the start command from the ADC unit. During this mode, local deck operations on this player (e.g. Play, etc.) are disabled.
    • Reel Servo: The proven studio master recorder MTR-15's reel servo system optimizes the tension applied to the tape, enabling gentle handling of old and valuable original master tapes.
    • Output Level Adjustment: The SRL button and level trim control are provided for the adjustment of output (playback) level. By turning on the SRL button (LED on), the playback amplifier gain set to a predetermined level, allowing a tape recorded at the reference level to be played at the reference level. By disengaging the SRL button (LED off), the output level trim control is enabled, allowing the output level to be set to an arbitrary level.
  • DAS-2/4C: This high-speed analog tape player is for compact cassette type analog audio tape and has two cassette tape decks each of which can play bi-directional stereo or dual bi-directional monaural compact cassettes at 4x or 2x normal play speed. To support major compact cassette tape track formats, the 2-channel model DAS-2C and the 4-channel model DAS-4C are available.
    • Tape Deck Functions: In Off-line mode, Play, Stop, and Rewind modes are possible. (Playback monitoring is impossible because the playback is done at the copy speed.) In On-line mode, deck operations are disabled.
    • On-Line Mode (Ready Status): In this mode, the 4x (or 2x) copy operation is started by receiving the start command from the ADC Unit. During this mode, Play, Stop, and Rewind at each cassette deck are disabled. In Off-line mode, commands from the ADC Unit are ignored.
    • Playback Level Indication: Playback signal level of each track of each deck is displayed. The output signal level can be adjusted by the trim controls.
    • Copy Rate Selection: Playback EQ for 4x and 2x normal speed cassette can be selected. The player automatically detects the original EQ of the cassette tape.
  • DAS-ADC Unit: This system performs analog-to-digital conversion (digitizing) at 4x, 2x, or 1x basic sampling frequency on supplied analog audio signals played at 4x, 2x, or 1x normal play speed and records the converted digital audio signals on removable hard disks or magneto-optical disks in the WAVE file format which is the most popular audio file format for personal computers.
    • Analog Audio Inputs: This system has two sets (A & B) of 4-channel analog audio signal inputs having a 40 Hz to 40 kHz bandwidth. The A or B 4-channel input set is selected by a front panel switch. By selecting Auto mode (see below), the system automatically selects the input receiving the signal.The analog input signal levels can be individually adjusted by the eight input level trims on the front panel. Trimmed signal levels of the selected four channels of the analog inputs are shown by the front panel bargraph LED level meters. These indicated levels are also the levels for digitizing.
    • Copy Rate (Conversion Speed) Selection: Digitizing speed can be selected from 4x, 2x, or 1x by a front panel switch. Incoming analog input signals must be played at the same playback rate as the copy rate selected by this selection.
    • Sample Rate Selection: By using a front panel switch, sampling frequency for digitizing can be selected from 48 kHz, 44.1 kHz, and 22.05 kHz. The A/D converter's actual sampling frequency is a value obtained by multiplying the selected sample rate by the copy rate. For 48 kHz and 44.1 kHz, selection of 4x is defeated.
    • Track Format Selection: According to the analog tape track format to be played back, the operator needs to select the input signal's track format with a front panel switch. When the track format is selected, the channels to be used are automatically selected. The following formats are available:
      - Mono 2-trk (CH 1 fwd and CH 2 rev)
      - Stereo 2-trk (CH 1 fwd Left and CH 2 fwd Right)
      - Mono 4-trk (CH 1 fwd, CH 2 fwd, CH 3 rev, and CH 4 rev)
      - Stereo 4-trk (CH 1 fwd Left, CH 2 fwd Right, CH 3 rev Right, and CH 4 rev Left)
      (When mono 2-trk, mono 4-trk or stereo 4-trk format is selecetd, the tracks for side A and side B are played back simultaneously and the side B tracks are reproduced in the reverse direction. However, the system automatically flips the reversed audio signal in time during the digitizing process and stores the data on the storage media.)
    • Storage of Converted Data: Two front panel SCSI device bays can accept two removable hard disk drives for storage of converted data. The drive to be used is selected by a front panel switch. Remaining capacity of the hard disk is shown by the front panel bargraph LED. Two 3.5-inch MO disk drives connected to the rear panel SCSI connectors can also be used for storage.
    • Copy (Convert) Operation: Playback of connected tape players is controlled by pressing the START and CANCEL buttons on the ADC unit. When the system detects that the input signal level reaches a predetermined threshold, it automatically starts writing digitized audio data to the storage media. This eliminates cue-up operation of tape and simplifies conversion operation. When the input signal level is held lower than the threshold for a predetermined period of time, the operation automatically stops. Therefore, the operator does not have to watch for the tape to end to complete the operation. If Auto mode is selected, at the end of one tape, the system automatically starts playback of another tape to continue digitizing.
    • Auto Mode: This mode provides automation of conversion operation. Auto mode is selected by a front panel switch. When the system is put into Auto mode, the set A inputs are selected. The operator sets the first reel of tape to be digitized onto the player A. By pressing the START button on the ADC unit, the player A starts automatically. If the operator sets the second reel of tape on the player B before the first reel ends, the second reel of tape automatically starts at the end of the first reel and digitizing is continued. If the operator sets following tape reels alternately on the players A and B, the system continues digitizing until the limit of the storage media is reached.
    • Filenames and Keyboard Input: The operator can name digitized data files via a QWERTY keyboard connected to the keyboard connector on the front panel. If the operator does not name a digitized data file, it is automatically labeled with a default filename.
    • Peak Level Information Recording: The maximum input level detected during digital conversion is memorized and it is written on the storage media as another file at the completion of digitizing. This information can be used for automatic normalization of recording level in later post processing steps.
    • DAISY Format Support: The digitized data file is a standard WAVE format file and it can be acquired into a DAISY system by using its WAVE import feature. During digitizing, the ADC unit can generate the phrase index information which can be acquired directly by the DAISY system. If an analog signal includes a low frequency tone signal, the ADC unit can detect it and generate the index information. Implementation of this feature requires further discussion with each customer because tone signal application, frequency, etc. may differ between customers.
  • Noise Reduction/Level Normalization Unit: A PC in which a special edition of Cool Edit Pro (Syntrillium Software Corporation []) is installed (customers can purchase this DAS special edition software from us to install into their existing PCs). This unit is used to correct level differences between programs and remove analog tape inherited noises such as tape hiss at a higher speed to improve program sound quality, and store, duplicate, and publish the completed programs.
Cool Edit Pro is a trademark of Syntrillium Software Corporation. All other trademarks are property of their respective owners.