Orban Optimod-FM 8700i Audio Processor


OPTIMOD-FM 8700i is Orban’s flagship processor. Featuring versatile five-band and two-band processing for both analog FM transmission and digital media, the 8700i provides the industry’s most consistent sound, track-to-track and source-to-source. This consistency allows you to create a sonic signature for your station with the assurance that your signature will stay locked in, uniquely branding your sound.

Newest Features of the OPTIMOD-FM 8700i

  • Xponential Loudness™ brings hyper-compressed music back to life, revealing detail and increasing impact while reducing listening fatigue and distortion.
  • Built-in streaming server allows you to monitor the 8700i-processed FM and HD audio wherever there is a LAN or Internet connection using free OPUS and MP3 codecs.
  • Exclusive “Multipath Mitigator” phase corrector reduces multipath distortion without compromising stereo separation.
  • Dante dual-redundant Audio-Over-IP now with AES67 support coming fall of 2017 via an easy software upgrade.
  • Subharmonic synthesizer adds modern-sounding bass punch to older recordings.
  • Dual redundant power supplies and safety bypass relays ensure 24/7 operation with no dead-air.

The 8700i builds on 8600 V4’s outstanding reliability and industry-leading sound quality. It adds Ravenna audio-over-IP connectivity (100% AES67 compliant) and a hot-swappable, dual-redundant power supply with automatic failover. A digital MPX output using a 192 kHz AES3 connection is now standard, as are two digitized SCA inputs. A new program-adaptive subharmonic synthesizer ensures punchy bass, even with older program material. An important feature is a phase skew corrector/multipath mitigator that ensures crisp reception when receivers blend to mono and minimizes energy in the stereo subchannel without compromising separation. The phase skew corrector uses a proprietary multidimensional processing algorithm that can simultaneously correct multiple phase problems, like a combination of analog tape gap skew and comb filtering caused by multiple-microphone pickup of a single instrument in the original recording session.

Orban’s exclusive MX peak limiter technology decreases distortion while increasing transient punch and high frequency power handling capacity. Compared to the 8500’s limiter, the MX limiter typically provides 2.5 to 3 dB more power at high frequencies, which minimizes audible HF loss caused by pre-emphasis limiting. Drums and percussion cut through the mix. Highs are airy. “Problem material” that used to cause audible distortion is handled cleanly.

The 8700i’s main goal is to make FM analog broadcasts more competitive with the cleanliness, punch, and open high frequencies of the digital media against which FM analog transmissions now battle. The FM loudness wars represent 20th-century thinking; in the 21st century, the new competition is digital media. Thanks to its crisp, punchy sound, the 8700i helps level the playing field between analog FM and its ever more aggressive digital-only competitors.


Dual Power Supplies
The 8700i’s dual power supplies with independent AC line inputs provide redundant operation to ensuring maximum uptime.

Safety Bypass Relays
Analog and AES3 digital inputs and outputs have hard-wire safety bypass relays in case of hardware or power failures.

Dante™ Audio-Over-IP Connectivity
Dante provides a dual-redundant Ethernet connection for two stereo audio inputs and two stereo outputs, each with a dedicated level control. Sample rate conversion is provided for both the inputs and the outputs. Full AES67 compatibility is coming Fall 2017 via an easy, free software upgrade.

Digital MPX
The 384/192 kHz AES3 digital composite output that is compatible and interoperable with the 192 kHz standard being implemented by several transmitter manufacturers.

10 MHz Reference Input
A 10 MHz reference input allows the stereo pilot tone frequency and digital composite output sample rate to be locked to a 10 MHz reference signal (like GPS), facilitating
single-frequency-network (SFN) and near-single-frequency-network (N-SFN) operation.

Low-Delay DJ Monitor Output
The MX limiter, Multipath Mitigator, and subharmonic synthesizer add delay that makes it impractical for talent to monitor all of the processing structures off-air with headphones. A new, dedicated headphone monitor chain (with about 5ms delay) provides a full 5-band FM processor that lets you dial in your preferred amount of “FM clipper sound.”

Streaming Monitor Output
Used with the 8700i’s remote control application, the streaming monitor facilitates checking or improving your station’s signature sound when you are unable to receive the 8700i processed FM signal off-air. The steaming feature allows you to monitor several points within 8700i. The MP3 and OPUS codecs and the Icecast2 and SHOUTcast2 streaming protocols are supported, allowing streaming directly to the client PC via your LAN or the Internet.

Subharmonic Synthesizer
The Subharmonic Synthesizer creates energy one octave below program energy in the range of 50-90 Hz when such energy is not present at the input and when music is detected. It adds punch and slam to older material while retaining musicality.

Xponential Loudness™ Algorithm
The Xponential Loudness™ algorithm reduces listening fatigue and actually improves listeners’ hearing using adaptive psychoacoustics. It revives music that has been “hypercompressed” in mastering and/or passed through lossy compression, like MP3. It’s like an audio magnifying glass that brings out hidden detail, clarifying audio and inspiring audiences to listen longer.

“Multipath Mitigator” Left/Right Phase Skew Correction
The phase skew corrector maximizes both FM and Digital Radio processing paths for the quality of a mono mixdown or blend that might occur in a receiver or player device.

ITU BS-412 Multiplex Power Control
An improved BS-412 Multiplex Power Controller provides a new user-adjustable, program-adaptive algorithm to make operation smoother and more subtle.



Technical Specifications

Frequency Response (Bypass Mode; Analog Processing Chain): 
Follows standard 50µs or 75µs 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.

Sample Rate: 
64 kHz to 512 kHz, depending on processing being performed.

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. It is primarily governed by the dynamic range of the A/D converter, which has a specified overload-to–noise ratio of 110 dB. 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 Separation: 
> 55 dB, 20 Hz – 15 kHz; 65 dB typical.

Polarity (Two-Band and Bypass Modes):
Absolute polarity maintained. Positive-going signal on input will result in positive-going signal on output when HD Polarity and FM polarity controls are set to POSITIVE.

Peak Control at HD Output: 
The peak limiter is oversampled at 256 kHz, yielding a worst- case overshoot of 0.5 dB at the analog output and for all output sample rates. (To achieve this performance at 32 kHz output sample rate, it is necessary to set the 8700i’s HD lowpass filter cutoff frequency to 15 kHz.)


Defeatable Analog FM Diversity delay: 
0.27 to 12.0 seconds, adjustable in one-sample increments at 64 kHz sample rate to allow the delays of the analog and digital paths in the HD Radio system to be matched at the receiver output. The relative delay between the HD and analog FM outputs stay constant regardless of the structure in operation. The delay can be changed via 8700i PC Remote software, via SNMP, and via Telnet-style (terminal control) commands through the serial and Ethernet ports. Several manufacturers make HD Radio monitors that can adjust the 8700i’s diversity delay via terminal control to compensate for changes in HD delay that might occur elsewhere in the transmission system. To avoid introducing artifacts in the analog FM path, its delay is held constant and HD delay is varied if the adjustment does not exceed ±1.3 seconds.

Minimum Processing Delay: 
Processing structure dependent. Typically 17 ms for normal latency Five-band, 13 ms for low-latency Five-band, 3.7 ms for ultra-low-latency Five- band, and 17 or 22 ms for 2-band, depending on crossover structure chosen. MX presets have approximately 270 ms delay. The multipath mitigator adds 146 ms of additional delay, and can be bypassed in situations like outside broadcasts where talent needs to monitor off-air. The defeatable subharmonic synthesizer adds 67.5 ms of delay when active.

Headphone Monitor Processor Delay: 
The low-delay, dedicated headphone monitor processor has 5 ms of delay and provides a complete FM processing chain, including 5-band compressor and distortion-cancelled FM clipper. The clipper drive is adjustable to allow dialing in the preferred amount of “FM clipper sound.”

Analog Audio Input


> 10kΩ load impedance, electronically balanced1.

Nominal Input Level: 
Software adjustable from –4.0 to +13.0 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.

RFI filtered, with high-pass filter at 0.15 Hz.

Analog Audio Output

Stereo. The analog output can emit the analog FM processed signal, the digital radio processed signal, or the low-delay monitor signal. The FM processed signal can be flat or pre-emphasized (at 50µs or 75µs), software-selectable.

Source Impedance: 
50Ω, electronically balanced and floating.

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

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

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

<= –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.

RFI filtered.

Hardwire Bypass:
Removing power from the Optimod will connect the left and right audio inputs to the left and right audio outputs via a relay.

Digital Audio Input

Stereo per AES3 standard, 24 bit resolution, software selection of stereo, mono from left, mono from right or mono from sum.

Sampling Rate: 
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz automatically selected.

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

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

J.17 De-emphasis: 

RFI filtered.

Hardwire Bypass:
Removing power from the Optimod will connect the Digital Audio Input to Digital Output #1 via a relay.

Digital Audio Outputs

Two outputs, each stereo per the AES3 standard. The outputs can be set independently to emit the analog FM processed signal, the digital radio processed signal, or the low-delay monitor signal. The FM processed signal can be configured in software as flat or pre-emphasized to the chosen processing pre-emphasis (50µs or 75µs). The HD processing chain receives the output of the multiband limiter and processes it through a look-ahead peak limiter that operates in parallel with the main FM peak limiting system. The HD and FM signals are always simultaneously available. Each output can apply J.17 pre-emphasis if desired.

Sample Rate: 
Internal free running at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, or 96 kHz, selected in software. (Use 44.1 kHz or higher for best peak control.) Can also be synced to the AES3 SYNC input or the AES3 digital input at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz, as configured in software.

Word Length: 
Software selected for 24, 20, 18, 16 or 14-bit resolution. First-order highpass 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, 110Ω impedance.

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

RFI filtered.

Frequency Response (Digital Audio Output driven by HD Processing Chain): 
For output sample rates of 44.1 kHz and above, the frequency response from input to HD-configured output is ±0.10 dB, 2.0 Hz – 20 kHz; flat or with J.17 pre-emphasis applied. The user may specify lowpass filtering to constrain the bandwidth to 15, 16, 17, 18, or 19 kHz.

Dante Audio-Over-IP I/O

Fully supports Dante networks. Will be AES67-compliant after field-installable firmware upgrade for the Audinate Ultimo chip, expected Fall 2017 from Audinate. (May require third-party software to facilitate device discovery in non-Dante networks.)

Two L/R stereo inputs and two L/R stereo outputs. The outputs have the same configuration options as the AES3 outputs (above) except for the sample rate.

Sample Rate: 
Inputs and outputs support 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz. Input locks automatically to the incoming sample rate; out sample rate is software-selectable.

2x RJ45, dedicated solely to the audio-over-IP connection. Supports redundant network operation.

Digital Sync Input

Used for synchronization of either or both AES3 signals to an external reference provided at this input.

Sampling Rate: 
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz, automatically selected.

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

RFI filtered.

Hardwire Bypass:
Removing power from the Optimod will connect the Digital Sync Input to Digital Output #2 via a relay.

Wordclock/10 MHz Sync Reference Input

Accepts 1x wordclock or 10 MHz reference signals, automatically selected. The DSP master clock can be phase-locked to these signals, which in turn phase-locks the 19 kHz pilot tone frequency, facilitating single-frequency network operation. The digital output sample frequency can also be locked to these signals.

Unit will lock to 1x wordclock and 10 MHz squarewaves and sinewaves having a peak value of 0.5 V to 5.0 V.

BNC female, grounded to chassis, non-terminating to allow reference signals to be looped through via an external BNC “tee” connector (not supplied).

Composite Baseband Outputs

Number of Outputs: 
2 x analog; 1 x AES3

Subcarrier Modulation Mode: 
Standard double sideband mode or compatible single sideband/vestigial sideband mode with SSB/VSB crossover at 150 Hz. SSB/VSB mode adds approximately 12 ms of delay to the composite output signal.

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

Source Impedance: 
0Ω voltage source or 75Ω, jumper-selectable. Single-ended, floating over chassis ground.

Load Impedance: 
37Ω or greater. Termination not required or recommended.

Maximum Output Level: 
+12.0 dBu (8.72 Vp-p).

Minimum Output Level: 
–12 dBu (0.55 Vp-p) for 0.5 dB adjustment resolution.

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

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

D/A Conversion: 

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

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

Stereo Separation (analog outputs): 
At 100% modulation = 3.5Vp-p, > 60 dB, 30 Hz – 15 kHz. At 100% modulation = 1.0 – 8.0 Vp-p, > 55 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) Protection: 
50 dB relative to 4% subcarrier injection, ±2.0 kHz (up to 2 dB composite processing drive)

Analog composite outputs.

Two BNC, floating over chassis ground, EMI suppressed.

Maximum Load Capacitance: 
0.047µF (0Ω source impedance). Maximum cable length of 100 feet / 30 meters RG–58A/U.

RFI filtered.

AES3 Composite Output

One XLR-type, appearing on breakout cable

Sample Frequency: 
192 kHz

Extension to Interim Industry Standard: 
The composite baseband is internally sampled at 384 kHz and alternate samples are placed on the left and right audio channels. With compatible receiving hardware, this allows the entire baseband frequency range (0 to 99 kHz) to be accommodated without aliasing. If the frequency range of the SCAs applied to the digital output is limited to less than 96 kHz, this is fully compatible and interoperable with the existing system adopted by the industry, which uses only the left channel at 192 kHz.

Subcarrier (SCA) Inputs

Non-Digitized Inputs

SCA Sensitivity (all inputs): 
Variable from 220 mV p-p to > 10 V p-p to produce 10% injection. Sensitivity of analog inputs is screwdriver-adjustable by trim pots that are accessible through holes in the rear panel. Sensitivity of digitizing inputs is adjustable in software.

2 x BNC, unbalanced and floating over chassis ground, EMI suppressed.

Hardwire Bypass:
The SCA1 input can be configured to accept the composite output of a backup audio processor or stereo encoder; removing power from the Optimod will connect this input to analog composite output #1 via a relay.

Digitized Inputs

SCA Sensitivity (all inputs): 
Variable from 220 mV p-p to > 10 V p-p to produce 10% injection. Sensitivity of analog inputs is screwdriver-adjustable by trim pots that are accessible through holes in the rear panel. Sensitivity of digitizing inputs is adjustable in software.

19 kHz Pilot Reference: 
Analog SCA2 input jack can be jumpered to provide a 19 kHz pilot reference output or to serve as a second analog SCA input. The phase of the reference signal can be set to 0°, 90°, 180°, or 270° with respect to the pilot tone appearing at the composite output. The default is 0°.

Remote Computer Interface

Supported Computer and Operating System: 
IBM-compatible PC running Microsoft Windows® Vista/7/8/8.1/10.

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

Serial Connectors: 
RS–232 port (3) DB–9 male, EMI-suppressed. Serial Connector 1 uses PPP to provide for direct or modem connection to the 8700i PC Remote application. Serial Connector 2 supports communication to a computer or remote control system via simple ASCII commands for administration and recalling presets. Serial Connector 3 is reserved for future developments.

Ethernet Connector: 
Female RJ45 connector for 10-1000 Mbps networks using CAT5 cabling. Native rate is 100 Mbps. Provides for connection to the 8700i 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. 9VDC 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 filtered.

Tally Outputs (x2)

NPN open-collector

Maximum Voltage: 
30 VDC positive. Protected against reverse polarity by a diode; do not exceed 50 mA through this protection diode.

Maximum Current: 
30 mA; current must be limited externally.


100–264 VAC, automatically selected, 50–60 Hz, 50 VA.

Two supplies are included with automatic failover.

IEC, EMI-suppressed x 2. Detachable 3-wire power cord supplied.

Safety Standards: 
ETL listed to UL standards, CE marked.


NPN open-collector

0–95% RH, non-condensing.

Dimensions (W x H x D): 
19” x 5.25” x 15.5” / 48.3 cm x 8.9 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.

0–95% RH, non-condensing.

Tested according to Cenelec procedures.

Shipping Weight & Dimensions: 
30 lbs / 13.6 kg – 25″ x 24″ x 9″


Five 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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