Optimod 8685 Surround ~ Overview
Orban Television Audio Processing — Sound That Keeps Audiences Listening
The 8685 is Orban's second-generation surround/2.0 processor. In addition to the effective automatic loudness control of its predecessor, the 8685 offers new input/output capabilities that include support for SDI and HD-SDI and for Dolby E. Dual redundant power supplies help ensure maximum uptime. In addition to surround processing, the 8685 can simultaneously provide up to three channels of 2.0 processing, allowing it to provide all the audio processing necessary for a typical ATSC broadcast with multiple subchannels. Like the 8585, the 8685 is dialnorm-aware. Loudness control is excellent when measured by the ITU BS.1770-2 and EBU R-128 standards or by the 8685's built-in CBS Loudness Meters, allowing stations to comply effortlessly with the requirements of the CALM act.
Experience has shown that the mass television audience wants two things from television audio: dialog should be comfortably intelligible and commercials should not be irritatingly loud compared to program material. Home theater owners may want the opportunity to watch feature films while hearing a wide dynamic range signal. However, even these viewers usually consume television in a much more passive way when viewing garden-variety programs. To be an acceptable part of the domestic environment, television sound cannot overwhelm household members not interested in viewing (not to mention neighbors, particularly in multi-family dwellings). For a variety of reasons, the dynamic range of sound essential to the intelligibility of the program should not exceed 15 dB in a domestic listening environment. Underscoring and ambient sound effects will, of course, be lower than this.
The issue of loud commercials is particularly important. In the U.S., it is against Federal Communications Commission rules to broadcast irritatingly loud commercials. As a result of viewer complaints, the FCC has twice investigated the problem.
Orban understands such issues well. Since 1980, we have provided analogue television broadcasters with industry-standard dynamics processors: Optimod-TV 8180, 8182, 8282, and 8382. In 1998, we introduced Optimod-DAB 6200 — two-channel processing specifically tailored for digital channels using lossy compression like Dolbys AC-3, which is used for ATSC transmissions. Our 6300, introduced in 2006, is a second-generation two-channel processor for digital channels, including DTV, DAB, and netcasting.
In typical analogue television practice, all audio is applied to a single transmission audio processor that automatically controls the average modulation and the peak-to-average ratio while smoothing out transitions between program elements. Simple compression and peak limiting cannot do this effectively. Starting with the 8182, all Optimod-TV processors have incorporated the CBS Loudness Controller™.
Developed after 15 years of psychoacoustic research at CBS Laboratories, the CBS LC accurately estimates the amount of perceived loudness in a given piece of program material. If the loudness exceeds a preset threshold, the controller automatically reduces it to that threshold. The CBS algorithm has proven its effectiveness by processing millions of hours of on-air programming and greatly reducing viewer complaints.
In ITU parlance, the CBS LC relies on a "short-term" loudness measurement that takes into account the human ear's loudness integration time — approximately 200 milliseconds. The CBS algorithms attack time is fast enough to prevent audible and irritating loudness overshoots — blasts of sound that have viewers scrambling for their remote controls. Loudness control is always smooth and unobtrusive. Unlike "long-term" loudness measurement and control technologies, the CBS LC recognizes that a piece of program material whose average loudness seems acceptable according to a long-term loudness measurement may nevertheless have short sections whose loudness should be reduced because it is extremely annoying. While main purpose of this processing is to control the loudness of commercials, other exuberantly mixed elements can also benefit.
(A good example is applause with whistling.)
Effective Automatic Loudness Control for Up to 7.1 Channels
For many years our television customers have been asking for Optimod-quality surround sound processing along with the ability to process the local insertion of news, weather and sports independently. Our customers know that there is no substitute for the smooth, natural-sounding control that only Optimod provides, particularly with speech material.
Orban's response is the 8685. This next generation Optimod provides the function and control necessary for up to eight channels simultaneously. It can help you achieve the highest audience satisfaction in digital audio broadcasting, digital television, and netcasting.
The 8685 features Optimod-quality two-band and five-band audio processing for surround sound broadcasting and netcasting. Thanks to versatile compression ratio controls and a mastering-quality look-ahead peak limiter, the 8685 is also ideal for mastering audio in broadcast productions as well as productions intended for media such as DVD and Blu-ray.
The 8685 starts with the technology of Orban's popular Optimod 6300 and takes it to the next level with surround processing that reflects the latest psychoacoustic research into loudness perception. The 8685's CBS Loudness Controller works in both two-band and five-band modes. Third generation improvements reduce annoyance better than simple loudness control alone, doing so without audible gain pumping.
In July 2011, the ATSC revised its Recommended Practice entitled Techniques for Establishing and Maintaining Audio Loudness for Digital Television (A/85:2011), which recommends use of the ITU-R BS.1770-2 long-term loudness meter algorithm to measure loudness. We have verified that the CBS Loudness Controller as implemented in the 8685 (as well as in Orban's two-channel 6300 and 1101 processors) effectively controls long-term loudness as measured by the BS.1770-2 and thus allows U.S. broadcasters to comply with the CALM Act. (BS.1770-2 is based on BS.1770 but adds gating to prevent it from reading too low during material having pauses or silence.) The 8685 now offers a built-in ITU-R BS.1770-2 loudness meter so that users can verify the effectiveness of its loudness control.
The 8685 is two processors in one, offering surround processing for either 7.1 channels or 5.1 channels plus an independent 2.0 channel processor (equivalent to Optimod 6300 processing) that can operate stand-alone with its own CBS Loudness Controller. Additionally, the 2.0 processor's output can be mixed into the left and right front channels of the surround processing so that the surround processing's Loudness Controller and look-ahead limiters control the loudness and peak level of the mix. Built-in CBS Loudness Meters indicate the subjective loudness of the surround and 2.0 channel processing.
The multichannel and 2.0 processors can operate with separate audio processing parameters like release times. For example, the 2.0 processing could be set up for relatively heavy processing to make a newsroom feed more consistent, while the main processing could be set up more conservatively to correct network material and commercials unobtrusively.
Because the 2.0 processing has its own loudness controller and peak limiters, another important application is processing subchannels in digital television. The 2.0 processing can operate in dual-mono mode, so it can process one subchannel in stereo or two subchannels in mono.
The 8685 is built on Orban's flagship hardware platform. This features a GUI displayed on a quarter-VGA active matrix color LCD, making it easy to do all setup and adjustment from the 8685's front panel. To minimize latency and to achieve highest reliability, the 8685 uses a dual hardware architecture. Freescale 24-bit DSP chips do all audio processing while a separate microcontroller supports the GUI and control functions. Even if this controller malfunctions, the 8685 will continue to process audio normally. Minimum latency of the fully processed signal is 21 milliseconds, which can be padded to exactly one frame of delay for any video standard. The low latency headphone feed (containing all processing except for peak limiting) has a latency of approximately 6 milliseconds.
Optimod Surround Features
- Up to four full-featured 2.0 processors that can run simultaneously with the surround (up to 7.1-channel) processing. (The 8585 offers one such 2.0 processor.) Each 2.0 processor has a loudness controller and loudness meter. A single 8685 can provide processing and loudness control for up to three stereo ATSC SD subchannels with stereo audio and one surround ATSC HD subchannel. (The number of usable 2.0 processors depends on the I/O configuration; only the optional HD-SDI I/O can accommodate the number of inputs and outputs necessary to feed the four 2.0 processors and the surround processor simultaneously.)
- Optional SDI input and output interface that supports SD-SDI (per SMPTE 259M); 1.5 Gbit/s HD-SDI (per SMPTE 292M; up to 720p and 1080i) and 3.0 Gbit/s single-wire HD-SDI (per SMPTE 424M; 1080p). A relay provides hard-wire safety bypass from the SDI input to the SDI output in case of hardware failure. The SDI I/O includes three AES3id inputs and three AES3id outputs, which can be used as a loop-through for Orban's Penteo® 2.0->5.1 upmixer or to provide I/O for up to three channels of 2.0 processing. The SDI I/O option provides up to 11 frames of video delay to match the delay of the 8685's loudness processing, optional Penteo 2.0->5.1 upmixer, and optional Dolby-E encode and decode. Dolby E encode and decode requires the optional SDI I/O interface.
- An expanded routing switcher that offers versatile, programmable, remote-controllable routing of the various inputs and outputs added by the SDI interface.
- Dual-redundant, automatically switched, high-efficiency power supplies with separate AC line inputs.
Absolute Control of Loudness and Peak Modulation
The 8685 includes third-generation CBS Loudness Controllers™ for DTV applications.
Separate loudness controllers are available in the multichannel and 2.0 processing chains and work with the both Two-Band and Five-Band structures. The third-generation improvements reduce annoyance more than simple loudness control alone, doing so without audible gain pumping. Attack time is fast enough to prevent audible loudness overshoots, so the control is smooth and unobtrusive. Loudness control is excellent when measured by the ITU BS.1770 or EBU R-128 standards or by the 8685's built-in CBS Loudness Meters, allowing stations to comply effortlessly with the requirements of the CALM act.
Using the ITU BS.1770 and CBS Loudness Meters To Measure Loudness Controller Performance
Precise control of peak levels
The 8685 precisely controls peak levels to prevent digital clipping. The maximum level of the digital samples is controlled to better than 2%..
Pre-emphasis limiting for the two standard pre-emphasis curves of 50 µs & 75 µs
While primarily oriented toward "flat" media, the 8685's 2.0 channel processor can also provide pre-emphasis limiting for the two standard pre-emphasis curves of 50 µs and 75 µs. This allows it to protect pre-emphasized microwave links, satellite uplinks and similar channels where protection limiting or light processing is required.
Note that the 8685's 2.0 channel processing cannot provide simultaneous, independent audio processing for flat and preemphasized channels. Even though one output may be pre-emphasized while other is flat, the only difference between the outputs is that the "flat" output has de-emphasis applied to it after the processing while the preemphasized output does not.
Colour LCD and large rotary knob
A large (quarter-VGA) colour liquid crystal display (LCD) makes setup, adjustment and programming of the 8500 easy. Navigation is by a miniature joystick, two dedicated buttons, and a large rotary knob. The LCD shows all metering functions of the processing structure in use.
Use the Locate joystick to navigate through a menu that lets you recall a preset, modify processing (at three levels of expertise), or to access the system's setup controls.
Five processors in one
A gain-coupled multichannel processor for up to 7.1 channels, plus four additional, independent 2.0 channel processors (whose performance is equivalent to an OPTIMOD 6300) that can be used for many tasks such as processing the audio for a second language and up to three ATSC subchannels. Because its output can be mixed into the LF and RF outputs of the multichannel processing, the primary 2.0 channel processor can also be used to process an independent feed (like the output of a sports truck, news truck, or newsroom) before it is mixed with the station's main multichannel audio path. The audio processing parameters can be set independently for the surround and 2.0 processors. (All 2.0 processors have the same processing parameters.)
AES3id Inputs & Outputs
The base 8685 configuration includes five AESid digital inputs and six AES3id outputs, all transformer-coupled. These inputs and outputs appear on BNC connectors and have 75 Ω impedance. The digital inputs and digital outputs have samplerate converters and can operate at 32, 44.1, 48, 88.2 and 96 kHz samplerates. The optional HD-SDI I/O board instead offers HD-SDI I/O, three AES3id inputs, three AESid outputs and one (+ loop) video sync reference input.
Configurations via remote-controllable internal routing switchers
OPTIMOD 8685's inputs and outputs are highly configurable via remote-controllable internal routing switchers. Additionally, the outputs of the multichannel and 2.0 processing chains can be independently configured to emit the output of the AGC or the output of the multiband compressor/limiter, all configurable to use or bypass look-ahead limiting.
Use 8685 as an AES splitter
Via the internal output routing switcher, a given output signal can be applied to more than one hardware output. This allows using the 8685 as an AES splitter.
Stereo analogue monitor output
For both the base I/O configuration and the optional HD-SDI module, a stereo analog monitor output appears on XLR connectors on the rear panel. It can be configured to emit any 8685 output signal, including a downmix of the multichannel audio. The analog outputs are transformerless, balanced, and floating (with 50 Ω impedance) to ensure highest transparency and accurate pulse response. They can be used to drive a transmitter, although their normal function is monitoring.
Stereo headphone jack
A stereo headphone jack is available on the front panel. It can be configured to emit any 8685 output signal and is independent of the stereo analog monitor output.
RS485 ports for Dolby Digital Metadata I/O
Two RS485 serial ports allow the 8685 to accept and emit Dolby Digital metadata. If the optional HD-SDI module is installed, metadata can also be de-embedded and re-embedded in the HD-SDI V-AUX area and, if the Dolby E modules are installed, de-embedded from and re-embedded into Dolby E data that is conveyed either through the HD-SDI connection or the AES3id connections.
The 8685's 2.0 processing offers a dual-mono mode that allows two entirely separate mono programs to be processed, facilitating multiple-language operation.
In this mode, both processing channels operate using the same processing parameters (like release time); you cannot adjust the two channels to provide different processing textures.
An audio sync input is configurable to accept AES11id or wordclock sync. You can synchronize the output samplerate of all AES3id outputs to this input. You can also synchronize the outputs to the AES3 digital input #1 or to the 8685's internal clock.
The sync source of each AES3 output is independently selectable.
Dual power supplies with independent AC line inputs provide redundant operation.
All connections are rigorously RFI-suppressed
All input, output, and power connections are rigorously RFI-suppressed to Orban's traditional exacting standards, ensuring trouble-free installation.
The 8685 is designed and certified to meet all applicable international safety and emissions standards.
Adaptability through Multiple Audio Processing Structures
Complete audio processing system
A processing structure is a program that operates as a complete audio processing system. Only one processing structure can be on-air at a time. OPTIMOD 8685 realizes its processing structures as a series of high-speed mathematical computations made by Digital Signal Processing (DSP) chips.
Two processing structures
The 8685 features two processing structures: Five-Band for a spectrally consistent sound and Two-Band for a more transparent sound that preserves the frequency balance of the original program material.
A special Two-Band preset creates a no-compromise "Protect" function that is functionally similar to the "Protect" structures in earlier Orban digital processors.
Rides gain over an adjustable range of up to 25 dB
The 8685's AGC rides gain over an adjustable range of up to 25dB, compressing dynamic range and compensating for both operator gain-riding errors and gain inconsistencies in automated systems.
The AGC output is available to drive STLs, so the 8685 can be used as a studio AGC.
Switching between processing structures
The Five-Band and the Two-Band structures can be switched via a mute-free crossfade.
Phase-linear processing structures
The 8685's processing structures are all phase-linear to maximize audible transparency.
Mastering-quality noise and distortion performance
The 8685's equalizers and crossovers use 48-bit arithmetic to ensure mastering-quality noise and distortion performance.
Orban's PreCode™ technology
Orban's PreCode™ technology manipulates several aspects of the audio to minimize artifacts caused by low bitrate codecs, ensuring consistent loudness and texture from one source to the next. It is particularly useful when processing for netcasts or mastering for any low bitrate channel.
PreCode includes special audio band detection algorithms that are energy and spectrum aware. This can improve codec performance on some codecs by reducing audio processing induced codec artifacts, even with program material that has been preprocessed or mastered by processing other than OPTIMOD. There are several factory presets tuned specifically for low bitrate codecs.
Eight programmable, optically isolated GPI ports
The 8685 can be remote-controlled by 5-12 V pulses applied to eight programmable, optically isolated "general-purpose interface" (GPI) ports.
8685 PC Remote software
8685 PC Remote software is a smooth, responsive graphical application that runs under Windows XP, Vista and 7. It communicates with a given 8685 via TCP/IP over modem, direct serial and Ethernet connections. You can configure PC Remote to switch between many 8685s via a convenient organizer that supports giving any 8685 an alias and supports grouping multiple 8685s into folders. Clicking an 8685's icon causes PC Remote to connect to that 8685 through an Ethernet network or initiates a Windows Dial-Up or Direct Cable Connection if appropriate. The PC Remote software allows the user to access all 8685 features and allows the user to archive and restore presets, automation lists, and system setups (containing I/O levels, digital word lengths, GPI functional assignments, etc.).
Remote administration over TCP/IP
An API provides remote administration over TCP/IP via the RS232 serial or Ethernet ports. The 8685 hosts a TCP/IP terminal server to allow external control of the 8685 from either a Telnet/SSH client or a custom third party application. All commands are simple text strings. You can recall presets, operate the input and output routing switchers and more. Password security is provided.
Versatile real-time clock
The 8685 contains a versatile real-time clock, which allows automation of various events (including recalling presets) at pre-programmed times. To ensure accuracy, the clock can be synchronized to an Internet timeserver.
Silence Alarm & Tally Outputs
Silence alarm and digital audio fault tally outputs are available.
Bypass Test Mode
A Bypass Test Mode can be invoked locally, by remote control (from either the 8685's GPI port or the 8685 PC Remote application), or by automation to permit broadcast system test and alignment or "proof of performance" tests.
Built-in line-up tone generator
The 8685 contains a built-in line-up tone generator, facilitating quick and accurate level setting in any system.
The 8685's software can be upgraded by running Orban-supplied downloadable upgrade software on a PC. The upgrade can occur remotely through the 8685's Ethernet port or serial port (connected to an external modem) or locally (by connecting a Windows® computer to the 8685's serial port through the supplied null modem cable).
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.
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 analogue studio/transmitter links.)
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.
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.
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.
Internal processing has 24 bit (fixed point) or higher resolution; uses Freescale (formerly Motorola) 250 MHz dual-core DSP chips.
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.)
Digital Audio Inputs (x5)
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.
Unit can pass AES3id User Bits from Input #1 to Output #1.
32, 44.1, 48, 88.2 or 96 kHz, automatically selected.
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.
Digital Audio Output
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.
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.)
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.
BNC, female, shell bypassed to chassis via 1000 pF capacitor, EMI-suppressed. 75 ? impedance, terminated.
(100% peak modulation): -20.0 to 0.0 dBfs software controlled.
OPTIONAL HD-SDI INPUT/OUTPUT INTERFACE MODULE
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 analogue 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.
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.
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.
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
Analogue Audio Outputs
600 Ω or greater, balanced or unbalanced. Termination not required or recommended.
Adjustable from -6 dBu to +24 dBu peak, into 600 Ω or greater load, software-adjustable.
(100% Peak Modulation)
≥ 100 dB unweighted (Bypass mode, 20 Hz - 20 kHz bandwidth, referenced to 100% modulation).
≤ 0.01% THD (Bypass mode, de-emphasized) 20 Hz - 20 kHz bandwidth.
Two XLR-type, male, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
24 bit 128x oversampled.
Can accept wordclock or AES11id (75 Ω) sync, automatically selected.
Female BNC, shell grounded to chassis.
Unterminated. Use an external 75 Ω terminator if the 8685 is the last item in the chain.
Remote Computer Interface
TCP/IP protocol via direct cable connect, modem or Ethernet interface. Modem is not supplied.
115 kbps RS232 port DB-9 male, EMI-suppressed.
100 Mbit/s on RJ45 female connector.
RS485 Serial Interface (x2)
115 kbps RS485 port DB-9 male, EMI-suppressed.
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
Eight (8) inputs, opto-isolated and floating.
6 - 15V AC or DC, momentary or continuous.
12 VDC provided to facilitate use with contact closure.
DB-25 male, EMI-suppressed.
User-programmable for any eight of user presets, factory presets, bypass, test tone, stereo or mono modes, analog input, digital input.
Two NPN open-collector outputs.
+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.
30 mA maximum.
Tally outputs can be programmed to indicate a number of different operational and fault conditions.
100 - 264 VAC, automatically selected, 50 - 60 Hz, 75 VA.
IEC, EMI-suppressed. Detachable 3-wire power cord supplied.
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.
ETL listed to UL standards, CE marked.
32 to 122 °F / 0 to 50 °C for all operating voltage ranges.
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.
28 lbs. / 12.7 kg
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.
Optimod 8685 ~ Penteo® Surround Synthesis from Stereo
When the 8685 was first introduced, we chose not to include 2.0 to 5.1 surround synthesis. There were several technical reasons (including stereo and mono downmix compatibility), but our dominant concern was the subjective quality of the algorithms, none of which sounded fully convincing and some of which sounded downright ridiculous.
Since then, we have evaluated and licensed the Penteo® Surround "panorama slicing"™ algorithm (http://www.penteosurround.co.uk/
). For the first time, we heard an upmix that sounds like discrete five-channel while preserving the balance of the stereo source without coloration. We were particularly impressed by Penteo's ability to place dialog firmly in the center channel even when the mix includes other elements placed around the stereo soundstage. Moreover, Penteo surround material downmixes back to the original stereo, absolutely respecting the vision of the original mixing engineers.
"The Penteo system is based on entirely new stereo analysis," says John Wheeler, Penteo, LLC founder and inventor of the new technology. "We believe it's the first truly significant breakthrough in the art of converting stereo into 5.1 surround sound in the last 15 years."
Orban's Penteo upmixer for the 8685 resides in a stand-alone 1 rack unit chassis that is controlled by the 8685 via an Ethernet connection The Penteo unit will only upmix if it detects a controlling 8685 on the same subnet; otherwise it will remain in "pass-through" mode.
The Penteo upmixer has three AES3 inputs and three AES3 outputs. In an 8685 without the optional HD-SDI I/O card, the Penteo upmixer is placed immediately before the 8685's inputs in the signal chain. In 8685s with the HD-SDI card, the card's three AES3 inputs and outputs allow the Penteo upmixer's I/O to be wired in a loopthrough configuration that allows audio originally embedded in the HD-SDI bitstream to be sent to the Penteo upmixer and then to the 8685 for loudness processing.
The Penteo upmixer expects stereo material to be applied to its Lf/Rf input. Program-adaptive automatic mode switching is available, where the Penteo detects whether its input is receiving stereo or 5.1 material and automatically activates upmixing if it detects stereo. If 5.1 material is detected, it is passed through to the Penteo's output with the same delay as the upmixed material, preserving lip-sync. One can also control the Penteo's modes from the 8685 by using its GPI, clock-based automation, terminal mode via RS232 or Ethernet, or PC Remote via RS232 or Ethernet.
The combined delay of the Penteo and 8685 processing is a minimum of about 166 ms and can be padded to exactly 5 frames of 30 or 25 fps video. The 8685's optional HD-SDI card automatically delays the video to maintain lip-sync. In installations without the HD-SDI card, the video delay must be implemented elsewhere.