Orban Optimod-FM 5500i Audio Processor

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OPTIMOD-FM 5500i puts coveted five-band and two-band OPTIMOD processing into a single rack unit package and brings it to you at the most affordable price ever. The 5500i replaces OPTIMOD-FM 5300 and 2300, offering the functionality of both processors in a new, cool-running package.

Quality sound is what 5500i is all about – sound that attracts audiences by providing a polished, professional presentation regardless of format and source material. Exceptional versatility allows you to adjust the processor’s audio texture to brand your audio, knowing that the resulting signature sound will remain consistent, cut-to-cut and source-to-source. Branding builds businesses and no other processors have the consistency to brand your sound like OPTIMODs.


The 5500i can also be used as a superb stand-alone stereo encoder with latency as low as 2 ms and full overshoot limiting in both the left/right and composite baseband domains. When used in this mode, the 5500i must be driven (usually via an STL) by a full-featured FM audio processor (like Orban’s 8600) that incorporates preemphasis-aware HF limiting and peak control. In both modes, the 5500i’s stereo encoder helps deliver a transmitted signal that’s always immaculately clean and perfectly peak limited, with full spectral protection of subcarriers and RDS/RBDS regardless of the amount of composite limiting.

The 5500i is the ideal choice for network broadcasters who process with Orban’s flagship OPTIMOD-FM 8600 at the network origination point and who need a processor at every transmitter to eliminate STL overshoots (using the 5500i’s stand-alone stereo encoder mode) and/or to process local insertions while also eliminating network STL overshoots (using the 5500i’s audio processor / stereo encoder mode). Moreover, the 5500i’s two modes make it easy for large government and network broadcasters to manage its inventory of spares because any 5500i can be used as a stereo encoder with or without audio processing.

Available in both modes, the built-in, defeatable ITU BS412 multiplex power controller allows the 5500i’s output to meet even the most stringent European government regulations.

New in 5500i is a 10 MHz frequency reference input allows the stereo pilot tone frequency to be locked to GPS or another high-accuracy frequency standard. This improves the performance of single-frequency networks in areas where coverage of the transmitters overlaps. Also new is a cool-running, energy-efficient switching power supply and use of the latest dual-core DSP chip technology from Freescale Semiconductor.

With the 5500i, your signature sound is just a preset away. An easy, one-knob Less/More adjustment allows you to customize any factory preset, trading cleanliness against processing artifacts according to the requirements of your market and competitive environment. Full Control gives you the versatility to customize your audio further. And, if you’re a hard-core processing expert, you can explore Advanced Control to tweak presets at the same level as Orban’s factory programmers. This versatility makes the 5500i a superb choice for any format. Its five-band processing is ideal for any pop music format (even the most competitive and aggressive CHR), while phase-linear two-band processing yields ultra-transparent sound for classical, classic jazz, and fine arts formats. Regardless of your choice, 5500i’s optimized technology ensures unusually high average modulation and coverage for a given level of subjective quality. Unlike many lesser processors, the 5500i handles speech particularly well – it’s always clean, even when you process for loudness.

Versatility doesn’t stop with sound. The 5500i’s built-in stereo encoder, AES/EBU digital inputs and outputs, and analog I/O permit hassle-free interfacing to any broadcast plant, whether the 5500i is located at the studio or the transmitter. Tight band limiting to 15 kHz means you can use any uncompressed digital STL to pass 5500i-processed audio from studio to transmitter without compromising on-air loudness – there’s no need to use STLs having 44.1 or 48 kHz samplerates. If you want to locate the 5500i away from the studio, you’ll be pleased by its three separate remote control ports – GPI contact closures, RS232 serial, and built-in Ethernet for TCP/IP networks. The serial and Ethernet ports are supported by the supplied 5500i PC Remote Control application. This Windows® 2000/XP/Vista/7 application allows you to do even more with the 5500i than you can do through its front panel, making remote control a pleasure.

Built-in clock-based automation lets you automatically daypart the processing. You can control many other 5500i operating parameters too; the 5500i’s feature set fully exploits the processor’s DSP and computer-based control architecture. To ensure absolute accuracy, you can automatically synchronize the clock to an Internet timeserver.

If you’re concerned about latency because you need to feed live talent headphones off air, be assured that the 5500i’s ultra-low-latency (5 ms delay) processing will keep the most finicky talent happy. Or use optimum latency (15 ms delay) processing for the most competitive sound with delay that’s still low enough to satisfy most any talent.

Technical Specification

System Frequency Response(Bypass Mode)
Follows standard 50 µs or 75 µs pre-emphasis curve ±0.10 dB, 2.0 Hz – 15 kHz. Analog left/right output and digital output can be user-configured for flat or pre-emphasized output.

Output noise floor will depend upon how much gain the processor is set for (Limit Drive, AGC Drive, Two-Band Drive, and/or Multi-Band 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.

Total System Distortion
(de-emphasized, 100% modulation) <0.01% THD, 20 Hz – 1 kHz, rising to <0.05% at 15 kHz. <0.02% SMPTE IM Distortion. Total System L/R Channel Separation >57 dB, 20 Hz – 15 kHz; 60 dB typical.

(Two-Band and Bypass Modes): Absolute polarity maintained. Positive-going signal on input will result in positive-going signal on output.

Processing Samplerate
The 5500i is a “multirate” system, using internal rates from 32 kHz to 512 kHz as appropriate for the processing being performed. Audio clippers operate at 256 kHz (and are anti-aliased), while the composite limiter operates at 512 kHz.

In stand-alone stereo encoder mode, minimum samplerate is 64 kHz.

Processing Resolution
Internal processing has 24 bit (fixed point) or higher resolution.

Analog Audio Input

Configuration Stereo.
>10 k ohm load impedance, electronically balanced.

Nominal Input Level
Software adjustable from -9 to +13 dBu (VU).

Maximum Input Level
+27 dBu.

Two XLR-type, female, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.

A/D Conversion
24 bit 128x oversampled delta sigma converter with linear-phase anti-aliasing filter. Converter outputs 64 kHz samplerate, which the 5500i then decimates to 32 kHz in DSP using an ultra-high-quality image-free synchronous samplerate converter. In strand-alone stereo encoder mode, 64 kHz output of converter is not downsampled.

RFI filtered.

Analog Audio Output

Stereo. Flat or pre-emphasized (at 50 µs or 75 µs), software-selectable.

Source Impedance
50 ohm, electronically balanced and floating.

Load Impedance
600 ohm or greater, balanced or unbalanced. Termination not required or recommended.

Output Level
(100% peak modulation): Adjustable from -6 dBu to +24 dBu peak, into 600 ohm or greater load, software-adjustable.

=90 dB unweighted (Bypass mode, de-emphasized, 20 Hz – 15 kHz bandwidth, referenced to 100% modulation).

L/R Crosstalk
= -70 dB, 20 Hz – 15 kHz.

=0.01% THD (Bypass mode, de-emphasized) 20 Hz – 15 kHz bandwidth.

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, with high-pass filter at 0.15 Hz (-3 dB).

RFI filtered.

Digital Audio Input

Stereo per AES3 standard. Output configured in software as flat or pre-emphasized to the chosen processing pre-emphasis (50 µs or 75 µs), with or without J.17 pre-emphasis.

32, 44.1, 48, 88.2 or 96 kHz, automatically selected.

XLR-type, female, EMI-suppressed. Pin 1 chassis ground, pins 2 and 3 transformer balanced and floating, 110 O impedance.

Input Reference Level
Variable within the range of -30 dBFS to -10 dBFS.

J.17 De-emphasis

RFI filtered.

Digital Audio Output

Stereo per AES3 standard. Output configured in software as flat or pre-emphasized to the chosen processing pre-emphasis (50 µs or 75 µs), with or without J.17 pre-emphasis.

Internal free running at 32, 44.1, 48, 88.2 or 96 kHz, selected in software. Can also be synced to the AES3 digital input at 32, 44.1, 48, 88.2 or 96 kHz, as configured in software.

Word Length
Software selected for 24, 20, 18, 16 or 14-bit resolution. First-order high-pass noise-shaped dither can be optionally added, dither level automatically adjusted appropriately for the word length.

XLR-type, male, EMI-suppressed. Pin 1 chassis ground, pins 2 and 3 transformer balanced and floating, 110 O impedance.

Output Level
(100% peak modulation): -20.0 to 0.0 dBFS software controlled.

RFI filtered.

Composite Baseband Output

Two outputs, each with an independent software-controlled output level control, output amplifier and connector.

Source Impedance
0 ohm  voltage source or 75 ohm, jumper-selectable.

Load Impedance
37 ohm  or greater. Termination not required or recommended.

Maximum Output Level
+16 dBu (8.72 Vp-p).

Pilot Level
Adjustable from 6.0% to 12.0%, software controlled.

Pilot Stability
19 kHz, ±0.5 Hz (10 to 40 °C).

D/A Conversion

Signal-to-Noise Ratio
= 85 dB (Bypass mode, de-emphasized, 20 Hz – 15 kHz bandwidth, referenced to 100% modulation, unweighted).

= 0.02% THD (Bypass mode, de-emphasized, 20 Hz – 15 kHz bandwidth, referenced to 100% modulation, unweighted).

Stereo Separation
At 100% modulation = 3.5Vp-p, > 57 dB, 30 Hz – 15 kHz.

= -80 dB, main channel to sub-channel or sub-channel to main channel (referenced to 100% modulation).

= -80 dB, main channel to sub-channel or sub-channel to main channel (referenced to 100% modulation).

38 kHz Suppression
= 70 dB (referenced to 100% modulation).

76 kHz & Sideband Suppression
= 80 dB (referenced to 100% modulation).

Pilot Protection
60 dB relative to 9% pilot injection, ±250 Hz (up to 2 dB composite processing drive).

Subcarrier Protection
(60-100 kHz)
= 70 dB (referenced to 100% modulation; with up to 2 dB composite limiting drive; measured with 800 line FFT analyzer using “maximum peak hold” display).

57 kHz (RDS/RBDS)

50 dB relative to 4% subcarrier injection, ±2.0 kHz
(up to 2 dB composite processing drive).

Two BNC, floating over chassis ground, EMI suppressed.

Maximum Load Capacitance
0.047 µF (0 O source impedance). Maximum cable length of 100 ft / 30 m RG-58A/U.

RFI filtered.

Subcarrier (SCA) Inputs

Subcarrier inputs sum into composite baseband outputs before digitally controlled composite attenuator.

> 600 ohm.

SCA Sensitivity
Variable from 220 mV p-p to >10 V p-p to produce 10% injection. Sensitivity is adjustable by an internal PC-board-mounted trim pot.

Two BNC, unbalanced and floating over chassis ground, EMI suppressed.

19 kHz Pilot Reference

SCA2 input can be re-jumpered to provide a 19 kHz pilot reference output.

Remote Computer Interface

Supported Computer and Operating System

IBM-compatible PC running Microsoft Windows® 2000/XP/Vista/7.


TCP/IP protocol via direct cable connect, modem, or Ethernet interface. Suitable null modem cable for direct connect is supplied. Modem and other external equipment is not supplied.

Serial Connector

RS232 on DB-9 male connector, EMI-suppressed. Uses PPP to provide for direct or modem connection to the 8500 PC Remote application.

Ethernet Connector
Female RJ45 connector for 10 – 100 Mbps networks using CAT5 cabling. Native rate is 100 Mbps. Provides for connection to the 8500 PC Remote application through either a network, or, using a crossover Ethernet cable, directly to a computer.

Ethernet Networking Standard

Remote Control (GPI) Interface

Eight (8) inputs, opto-isolated and floating.

6 – 15V AC or DC, momentary or continuous.
9 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.

RFI Filtering.

Tally Outputs

Circuit Configuration

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, including Input: Analog, Input: Digital, Analog Input Silent, AES Input Silent and AES Input Error.


85 – 264 VAC, 50 – 60 Hz, 30 VA.

IEC, EMI-suppressed. Detachable 3-wire power cord supplied.

2.5A, 20mm Quick Acting HBC, mounted on the power supply circuit board.

In order to meet EMI standards, circuit ground is hard-wired to chassis ground.

Safety Standards
ETL listed to UL standards, CE marked.


Operating Temperature
32 to 122 °F / 0 to 50 °C for all operating voltage ranges.

0 – 5% RH, non-condensing.

Dimensions (W x H x D)
19″ x 1.875″ x 14.25″ / 48.3 cm x 4.8 cm x 36.2 cm. One rack unit high.

Tested according to Cenelec procedures. FCC Part 15 Class A device.

Shipping Weight
21 lbs. / 9.5 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.

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