Orban Optimod-AM 9300 Audio Processor

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Orban’s all-digital 9300 Optimod-AM audio processor can help you achieve the highest possible audio quality in monophonic AM shortwave, medium wave and long wave broadcasts. Optimod-AM delivers louder, cleaner, brighter, FM-like audio with an open, fatigue-free quality that attracts listeners and holds them. Because all processing is performed by high-speed mathematical calculations within Motorola DSP56367 digital signal processing chips, the processing has cleanliness, quality and stability over time and temperature that is unmatched by analog processors.

Optimod 9300 is descended from the industry-standard 9100 and 9200 Optimod-AM audio processors. Thousands of these processors are on the air all over the world. They have proven that the ¡°Optimod sound¡± attracts and keeps an audience even in the most competitive commercial environment.


The 9300 is very user-friendly. Its Quick Setup wizard walks you through the setup process. One-knob LESS-MORE control lets you customize the 9300’s comprehensive factory presets easily. If you’re an audio processing expert, you’ll love the new Advanced Control parameters (accessible from 9300 PC Remote software) that allow you to customize the 9300’s sound to your exact requirements.

Technical Specification


Except as noted, specifications apply for measurements from the analog left/right input to the analog #1 and analog #2 output..

Frequency Response (Bypass Mode): +0.2 dB, 50 Hz – 9.5 kHz, or as determined by user-settable high-pass and low-pass filters.

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.

Total System Distortion (de-emphasized, 100% modulation): <0.01% THD, 20 Hz – 1 kHz, rising to <0.05% at 9.5 kHz. <0.02% SMPTE IM Distortion. Polarity The processing employs phase rotation to maximize loudness. Therefore, the polarity is frequency-dependent.

Processing Sample Rate: The 9300 is a “multirate” system, using internal rates from 32 kHz to 128 kHz as appropriate for the processing being performed. Audio clippers operate at 128 kHz.

Processing Resolution: Internal processing has 24 bit (fixed point) or higher resolution; uses Motorola DSP56367 DSP chips.

Low-Pass Filter: 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0 or 9.5 (NRSC) kHz as set by user. Unit can be set up to comply easily with ITU-R and NRSC spectrum masks. Lowpass filter shape is parametric and can be set to be -0.1, -3, or -6 dB down at the cutoff frequency. This allows you to trade off brightness against audible filter ringing.

High-Pass Filter: Constrained by user settable fifth-order “quasi-elliptical” highpass filter to 50, 60, 70, 80, 90, or 100 Hz. All filters have equal-ripple Chebychev-like) passbands and a 25 Hz notch for transmitter protection.

Channel Configuration: Processing is monophonic.

Analog Audio Input

Configuration: Stereo (Configurable to drive the processing with mono from left, mono from right, or mono from sum).

Impedance: >10 kΩ load impedance, electronically balanced. (No jumper selection available for 600. Through-hole pads are available on I/O module for user-installed 600Ω termination.)

Nominal Input Level: Software adjustable from -9.0 to +13.0 dBu (VU).

Maximum Input Level: +27 dBu.

Connectors: 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 sample rate, which the 9300 then decimates to 32 kHz in DSP using an ultra-high-quality image-free synchronous sample rate converter.

Filtering: RFI filtered, with high-pass filter at 0.15 Hz (-3 dB).

Analog Audio Output

Configuration: Two monophonic outputs, capable to driving two transmitters. The two outputs have independent level controls.

Source Impedance: 351 Ω (includes the third-order output EMI suppression network), electronically balanced and floating. The user can specify the output load in software to calibrate the output level accurately into a bridging or 600 Ω load.

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

Output Level: (100% peak modulation)

Adjustable from -6 dBu to +20 dBu peak, into 600 Ω or greater load, software-adjustable.

Signal-to-Noise: ≥ 90 dB unweighted (Bypass mode, de-emphasized, 20 Hz – 9.5 kHz bandwidth, referenced to 100% modulation).

Distortion: ≤ 0.01% THD (Bypass mode, de-emphasized) 20 Hz – 9.5 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.

Digital Audio Input

Configuration: Stereo per AES3 standard, 24 bit resolution, software processing selection of mono from left, mono from mono from sum.

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

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

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

J.17 De-emphasis: Software-selectable.

Filtering: RFI filtered.

Digital Audio Output

Configuration: Dual-channel per AES3 standard. Each channel carries an identical monophonic signal.

Sample Rate: Internal free running at 32, 44.1, 48, 88.2 or 96 kHz, selected in software. Can also be synced to the AES3 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 highpass noise-shaped dither can be added. Dither level automatically adjusted appropriately for the word length.

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

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

Filtering: RFI filtered.

Remote Computer Interface

Configuration: TCP/IP protocol via direct cable connect, modem, or Ethernet interface. Modem is not supplied.

Serial Port: 115 kbps RS-232 port DB-9 male, EMI-suppressed.

Ethernet Port: 10 or 100 Mbit/sec on RJ45 female connector.

Remote Control (GPI) Interface

Configuration: Four (4) inputs, opto-isolated and floating.

Voltage: 6 – 15 V 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 four of user presets, factory presets, bypass, test tone, mono L mode, mono R mode, mono sum mode, analog input, digital input.

Filtering: RFI filtered.


Voltage: Universal switching power supply, 85 – 264 VAC, 50 – 60 Hz, 15 VA.

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

Grounding: 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.

Humidity: 0 – 95% RH, non-condensing.

Dimensions (W x H x D) 19″ x 1.75″ x 14.25″ / 48.3 cm x 4.5 cm x 36.2 cm. One rack unit high. RFI / EMI Tested according to Cenelec procedures. FCC Part 15 Class A device.

Shipping Weight: 19 lbs / 8.7 kg

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