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Optimod 8685 Surround ~ Specifications

It is impossible to characterize the listening quality of even the simplest limiter or compressor based on specifications because such specifications cannot adequately describe the crucial dynamic processes that occur under program conditions. Therefore, the only way to evaluate the sound of an audio processor meaningfully is by subjective listening tests.

Certain specifications are presented here to assure the engineer that they are reasonable, to help plan the installation, and make certain comparisons with other processing equipment.

System

Frequency Response: Surround Processing: ±0.10 dB, 20 Hz - 20 kHz for 44.1 kHz or higher input/output samplerates. At 32 kHz input and/or output samplerate, the passband is reduced to approximately 14.7 kHz.

2.0 Processing: Depending on settings, is flat or follows standard 50 µs or 75 µs pre-emphasis curve ±0.10 dB, 20 Hz-20 kHz (except at 32 kHz; see above). Output can be user-configured to be flat or pre-emphasized. (Pre-emphasis limiting is offered to accommodate certain older analog studio/transmitter links.)
Noise: Output noise floor will depend upon how much gain the processor is set for (Limit Drive, AGC Drive, Two-Band Drive, and/or Multiband Drive), gating level, equalization, noise reduction, etc. The dynamic range of the A/D Converter, which has a specified overload-to-noise ratio of 110 dB, primarily governs it. The dynamic range of the digital signal processing is 144 dB.
Polarity (Bypass Mode): Operate Mode when processing chain is configured for linear phase): Absolute polarity maintained.

Positive-going signal on input will result in positive-going signal on output.
Internal: Processing Samplerate: 48 kHz. We believe this provides maximum audible transparency by minimizing numerical "noise" in the equalizers and filters while still preserving a pure, transparent sound. The double-precision equalizers and crossover filters used throughout the 8685 produce at least 6 dB lower noise and nonlinear distortion than they would at 96 kHz.
Processing Resolution: Internal processing has 24 bit (fixed point) or higher resolution; uses Freescale (formerly Motorola) 250 MHz dual-core DSP chips.
Delay: The minimum available input/output delay is approximately 20 ms with look-ahead limiting active and 6 ms with look-ahead limiting bypassed. This can be padded to exactly one frame of 24, 25, 29.97 or 30 frames / second video up to a maximum delay of 50 ms.
Surround Processing Stereo Coupling: All channels of the AGC and compressors are coupled using r.m.s. summation. The user can select whether or not the LFE channel contributes to the r.m.s. sum in the AGC and compressor control sidechains. Peak limiters in the multiband compressor limiter and look-ahead limiters all operate uncoupled to prevent transients in a given channel from causing audible loudness modulation in other channels.
2.0 Processing Stereo Coupling: Stereo or dual-mono. In dual-mono mode, both processing channels have the same subjective adjustments (as determined by the active preset) but are otherwise independent, making this mode appropriate for dual-language transmissions. In stereo mode, the user can set the maximum permitted gain difference between the channels in each band of the multiband compressor/limiter. 2.0 Stereo/Dual-Mono operating mode can be set via GPI, Ethernet and serial connections, internal clock-based automation, and AES3 Status Bits.
Loudness Level Meter (x5): One meter for the surround processor and one meter for each of the 2.0 processor, both meters realized in software. In a 2.0 processor's dual-mono mode, each mono channel has its own loudness meter. Meter can be displayed on the 8685's front-panel screen and on its PC Remote software. There are two meters, a short-term meter and long-term meter, which are displayed simultaneously. The long-term meter uses the ITU BS.1770 or EBU R-128.algorithms, user selectable. The short-term meter's display time constants are matched to the loudness integration time of the human ear, reaching steady-state level in approximately 200 ms and having a decay time constant of approximately 300 ms. The short-term meter uses the Jones & Torick algorithm developed at CBS Technology Center. (B. L. Jones & E. L. Torick: "A New Loudness Indicator for Use in Broadcasting," J. SMPTE, September 1981, pp 772-777.)

BASE CONFIGURATION

Digital Audio Inputs (x5)

Configuration: Each of five hardware inputs accepts two audio channels per AES3id standard, 24 bit resolution. Internal programmable routing switcher allows any of the 10 physical input channels to be routed to the LF, RF, C, LB1, RB1, LFE, LB2, RB2, STEREO L, or STEREO R inputs of the audio processing. For the 2.0 processing, unit can detect Stereo or Two-Channel status bits appearing at Input #1 and switch the 2.0 processor between stereo and dual-mono modes.
User Bits: Unit can pass AES3id User Bits from Input #1 to Output #1.
Sampling Rate: 32, 44.1, 48, 88.2 or 96 kHz, automatically selected.
Connector: BNC, female, shell bypassed to chassis via 1000 pF capacitor, EMI-suppressed. 75 ? impedance, terminated.
Input Reference Level: Variable from -30 dBfs to -10 dBfs.
Filtering: RFI filtered.

Digital Audio Output

Configuration: AES3id. Internal, remote-controllable routing switcher allows sending LF, RF, C, LB1, RB1, LFE, LB2, RB2, STEREO L, STEREO R, DOWNMIX L and DOWNMIX R to any hardware output channel.
Sampling Rate: Internal free running at 32, 44.1, 48, 88.1 or 96 kHz, selected in software. Can also be synced to the AES3id Input #1,or to the sync input (which supports AES11id and wordclock) at 32, 44.1, 48, 88.1 or 96 kHz, as configured in software. (Passband is limited to approximately 14.7 kHz when using 32 kHz input and/or output samplerate.)
Word Length: Software selected for 24, 20, 18, or 16-bit resolution. First-order highpass noise-shaped dither can be optionally added, Dither level is automatically adjusted to complement the word length.
Connector: BNC, female, shell bypassed to chassis via 1000 pF capacitor, EMI-suppressed. 75 ? impedance, terminated.
Output Level: (100% peak modulation): -20.0 to 0.0 dBfs software controlled.
Filtering: RFI filtered.

OPTIONAL HD-SDI INPUT/OUTPUT INTERFACE MODULE

Option #1

HD-SDI Input/Output Interface Module: Replaces the base I/O module, which offers only AES3id input/output.; Supports 1.5 Gbit/s HD-SDI (SMPTE 292M; up to 720p and 1080i) and 3.0 Gbit/s single-wire HD-SDI (SMPTE 424M; 1080p).; Includes three AES3id inputs, three AESid outputs, one (+ loop) video reference input, and a pair of analog outputs. In addition to the ability to receive and emit the program audio, the AES3id I/O can be configured as a loop-through to support Orban's external Penteo upmixer. The AES3id I/O offers the same performance as the AES3id I/O in the base configuration above.; Sockets exist to accept Dolby E encoder/decoder modules; unit is field-upgradeable to support Dolby E.
Includes up to 11 frames of video delay to preserve AV-sync.
Normal 8685 loudness control processing requires one frame of delay; the Penteo upmixer requires an additional four or five frame delay.; Includes a video reference input (per SMPTE 274M and SMPTE 296M) that can be used to correctly align Dolby E frames with video per Dolby's requirements (SMPTE RDD 6-2008 and Dolby Labs published specifications) in cases where HD-SDI is not in use. When HD-SDI is in use, frame sync is obtained from the HD-SDI input stream.

Option #2

HD-SDI Input/Output Interface Module with Dolby E Decoder: Base configuration (Option #1) with the addition of a Dolby E Decoder module.; Can accept a Dolby E bitstream from HD-SDI or AES3id inputs and decode it to PCM for 8685 audio processing or for direct AES3id and HD-SDI outputs.; Supports Dolby E metadata received through HD-SDI and RS485 interfaces.

Option #3

HD-SDI Input/Output Interface Module with Dolby E Encoder: Base configuration (Option #1) with the addition of a Dolby E Encoder module.; Can encode PCM outputs from the 8685 audio processor or PCM received from HD-SDI or AES3id inputs into the Dolby E bitstream.; Can emit Dolby E metadata from an RS485 serial port and through HD-SDI.

Option #4

HD-SDI Input/Output Interface Module with Dolby E Decoder and Encoder: Base configuration (Option #1) with the addition of Dolby E Decoder and Encoder modules.; Accepts and emits Dolby E bitstreams from the HD-SDI and AES3id I/O.; Supports Dolby E metadata through HD-SDI and RS485 serial ports.

OPTIONAL HD-SDI INPUT/OUTPUT INTERFACE MODULE

Conveying and Re-authoring Dolby Metadata

: The 8685 can, via an SMPTE Rdd06-2008-compliant RS-485 serial connection, via an HD-SDI connection (when the optional HD-SDI module is installed), or via embedded Dolby-E metadata (when the optional Dolby-E modules are installed in the HD-SDI module), automatically convey its active surround metadata value to a downstream Dolby Digital encoder like the Dolby DP-569, which must be set up according to its operating instructions to receive and act upon this input.

This greatly reduces the possibility that operator error will cause the wrong value of surround metadata to be transmitted to consumers.; To emit an Rdd06-2008-compliant signal, the 8685 must be receiving a valid input stream that is compliant with Rdd06-2008 — this is necessary to synchronize the output metadata to video frame boundaries per the Dolby specification.

When a valid input stream in present, the 8685 passes this stream unchanged to its output except for the following modifications:; • The ac3_dialnorm word in the output metadata stream is reauthored so it is the same as the 8685's active Dialnorm value.; • The ac3_dynrnge word in the output stream is set to 0, indicating that the downstream AC3 encoder must reauthor the line-mode DRC metadata, following the level compression profile found in the ac3_dynrng1 word in the input metadata.; • The ac3_compre word in the output stream is set to 0, indicating that the downstream AC3 encoder must reauthor the RF-mode DRC metadata, following the level compression profile found in the ac3_compr1 word in the input metadata.

BASE AND HD-SDI CONFIGURATIONS

Analog Audio Outputs




Load Impedance: 600 Ω or greater, balanced or unbalanced. Termination not required or recommended.
Output Level: Adjustable from -6 dBu to +24 dBu peak, into 600 Ω or greater load, software-adjustable.
(100% Peak Modulation) Signal-to-Noise: ≥ 100 dB unweighted (Bypass mode, 20 Hz - 20 kHz bandwidth, referenced to 100% modulation).
Distortion: ≤ 0.01% THD (Bypass mode, de-emphasized) 20 Hz - 20 kHz bandwidth.
Connectors: Two XLR-type, male, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
D/A Conversion: 24 bit 128x oversampled.
Filtering: RFI filtered.

Sync Input

Configuration: Can accept wordclock or AES11id (75 Ω) sync, automatically selected.
Connector: Female BNC, shell grounded to chassis.
Termination: Unterminated. Use an external 75 Ω terminator if the 8685 is the last item in the chain.

Remote Computer Interface

Configuration: TCP/IP protocol via direct cable connect, modem or Ethernet interface. Modem is not supplied.
Serial Port: 115 kbps RS232 port DB-9 male, EMI-suppressed.
Ethernet Port: 100 Mbit/s on RJ45 female connector.

RS485 Serial Interface (x2)

Hardware: 115 kbps RS485 port DB-9 male, EMI-suppressed.
Compatability: Designed to be hardware-compatible with Dolby Digital^® hardware that sends and receives Dolby Digital metadata. (Metadata I/O is not supported by 8685 V 1.0 software. We expect to support it in a future software release.)

Remote Control (GPI) Interface

Configuration: Eight (8) inputs, opto-isolated and floating.
Voltage: 6 - 15V AC or DC, momentary or continuous.
12 VDC provided to facilitate use with contact closure.
Connector: DB-25 male, EMI-suppressed.
Control: User-programmable for any eight of user presets, factory presets, bypass, test tone, stereo or mono modes, analog input, digital input.
Filtering: RFI filtered.

Tally Outputs

Circuit Configuration: Two NPN open-collector outputs.
Voltage: +15 Volts maximum. Do not apply negative voltage. When driving a relay or other inductive load, connect a diode in reverse polarity across the relay coil to protect the driver transistors from reverse voltage caused by inductive kickback.
Current: 30 mA maximum.
Indications: Tally outputs can be programmed to indicate a number of different operational and fault conditions.

Power

Voltage: 100 - 264 VAC, automatically selected, 50 - 60 Hz, 75 VA.
Connector: IEC, EMI-suppressed. Detachable 3-wire power cord supplied.
Configuration: Two independent power supplies with independent IEC input connectors.

Power supply health is monitored and the good supply is automatically connected to the load should one supply fail.
Safety Standards: ETL listed to UL standards, CE marked.

Environmental

Operating Temperature: 32 to 122 °F / 0 to 50 °C for all operating voltage ranges.
Humidity: 0 - 95% RH, non-condensing.
Dimensions (W x H x D): 19" x 5.25" x 15.5" / 48.3 cm x 13.34 cm x 39.4 cm. Depth shown indicates rack penetration; overall front-to-back depth is 17.75" / 45.1 cm. Three rack units high.
RFI / EMI: Tested according to Cenelec procedures. FCC Part 15 Class A device.
Shipping Weight: 28 lbs. / 12.7 kg

Warranty

Two Years, Parts and Service: Subject to the limitations set forth in Orban's Standard Warranty Agreement.

Because engineering improvements are ongoing, specifications are subject to change without notice.

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