719 - DAVID IV FM/HD Radio Broadcast Processor

The DAVID IV is the fourth generation processor in our DAVID (vs. Goliath) series of FM and HD Radio air-chain processors. Our streamlined, 100% DSP-based audio engine gives you total leverage over the most important sonic ‘signature’ parameters, while smart controls allow you to enhance program material quickly and effectively. Processing includes 5 bands of dynamics compression with equalization, intelligent gain-riding AGC (Automatic Gain Control), Bass and Stereo Field Enhancements, and our proprietary PIPP™ (Polarity Independent Peak Processing) limiter. The DAVID IV combines a remarkably clean sound with a premium FM Stereo Generator that also includes internal metering with combining for the RDS(RadioData System) subcarrier. Setup is quick, and operation is intuitive via the multi menu front-panel interface or IP based remote control software, so you can make adjustments from the comfort of your favorite listening environment.

Presets are provided for popular world formats*, and user settings can easily be saved/backed up and shared over station networks. TCP/IP connectivity is virtually automatic and allows full remote control and access from anywhere in the world. Processing and stereo generator aside, the DAVID IV features a rugged closed box design (no fans or heat-sinks needed), with ultra low latency hardware allowing for direct off-air monitoring, and power to live audio in less than 1 second. But how does it sound? When it comes to audio performance, the DAVID IV really delivers. With tight lows, open mids, crisp but controlled highs, and the dynamic flexibility to really stand out, the DAVID IV’s sound promises results on par with products more than double or triple it’s price class. It has never been easier (or more affordable) to achieve maximum audio performance without breaking the budget. But don’t take our word for it, get one and demo it yourself-30 days risk free! *see Features section for a full list of included presets.

Features


  • Ultra low latency, all-digital DSP based design.

  • 5 bands of adjustable dynamic range compression and 'graphic-EQ'

  • "Windowed" gain-riding AGC with "intelligent" gating

  • Low-bass enhancements with independent 'Rumble' and 'Punch' adjustments

  • Stereo field processing to adjust the listening sound stage

  • Programmable high-pass function eliminates modulation-robbing sub-bass frequencies

  • Inovonics' proprietary PIPP™ (Polarity Independent Peak Processing) limiter ensures maximum carrier density.

  • AES3 digital input and outputs(XLR), accepting sampling rates of 32kHz, 44.1kHz, 48kHz, 96kHz.

  • Left/Right analog inputs and outputs (XLR) and multiple independent Composite MPX outputs

  • Built in Tone Oscillator

  • 'Adaptive pre-emphasis' high-frequency limiting for FM

  • Easy setup and control via the front panel, and remote access control via TCIP/IP

  • Built in Stereocoder (Stereo-Gen) with internal RDS metering and combining

  • English, Spanish, and Portuguese Language Hardware/Software menus

  • 25 factory presets optimized for popular radio formats included, and 20 customizable user presets that can be downloaded or shared as small files

  • Included Factory Presets: Adult Contemporary, Alternative, Bollywood, Contemporary Christian, Classic Hits, Classic Rock, Classical, Country, Easy Listening, Electronic / Dance, Exitos, Hip Hop / Rap, Flat, Jazz, Latin/Salsa, New Age, Oldies, Pop, Reggae / Island, Rock, Samba / Brazilian, Talk, Top 40, Urban, Variety,

Reviews

Checking it Out - Inovonics’ DAVID IV Audio Processor

- Dana Puopolo - Broadcasters' Desktop Resource Checking it Out - Inovonics’ DAVID IV Audio Processor

Inovonics DAVID IV Field Report

- Jeff Smith, CRBE DAVID IV Field Report - Radio Magazine July 2012

Specifications


PERFORMANCE SPECIFICATIONS

Frequency Response

  • Composite/MPX Output: ±0.25dB, 20Hz–15kHz assuming the use of a lab-quality FM-multiplex decoder with the appropriate de-emphasis characteristic

  • L/R Line Outputs: ±0.25dB, 20Hz–15kHz through an appropriate de-emphasis network in the FM mode; ±0.25dB, 20Hz–20kHz in the Flat mode

  • AES Digital Output (Digital Input): ±0.25dB, 20Hz –15kHz through an appropriate de-emphasis network in the FM mode; ±0.1dB, 20Hz–20kHz in the Flat mode

Noise (unweighted)

  • Composite/MPX Output: SNR >85dB with carrier modulation at maximum output level through an appropriate de-emphasis network

  • L/R Analog Line Outputs: Residual Noise better than 100dB below the output clipping point(through an appropriate de-emphasis network in the FM mode)

  • AES digital Output (Digital Input): Residual noise better than 130dB below 0dBFS (through an appropriate de-emphasis network when indicated

Distortion

  • Composite/MPX Output: <0.01% THD using an appropriate de-emphasis network

  • Line Outputs: <0.06% THD in digital and analog Line Outputs using an appropriate de-emphasis network when indicated

Stereo Separation

  • Composite/MPX Output: >65dB, 20Hz-15kHz assuming the use of a lab-quality FM-multiplex decoder with the appropriate de-emphasis characteristic. Linear Crosstalk (main/sub or sub/main):.78dB

  • L/R Analog Line Outputs: At 1dB below the output clipping level, >100dB through an appropriate de-emphasis network in the FM mode; unweighted in the Flat mode

  • AES Digital Output:At 0dBFS, >130dB through an appropriate de-emphasis network in the FM mode; unweighted in the Flat mode (using the Digital Line Input)

Program Signal Latency

≤4.2 milliseconds, any input to any output in any operating mode

19kHz Stereo Pilot Protection

65dB with reference to 9% pilot injection

38kHz Suppression

80dB with reference to 100% carrier modulation

57kHz RDS Subcarrier Protection

65dB with refernce to 5% RDS sub-carrier injection

REAR PANEL APPOINTMENTS

Digital Line Input

The AES3 stereo input (XLR) accepts program sources at sampling rates of 32kHz, 44.1kHz, 48kHz and 96kHz; 16/24-bit. Input gain is adjustable for average program levels between -5dB and -35dB, re: -20dBFS.

Analog Line Inputs

L/R active balanced/bridging (XLR) inputs accept average program line levels between -15dBu and +15dBu; +26dBu max peak level.

Line Outputs

The Digital and Analog Line Outputs may each be configured independently for 20kHz flat response, or for 15kHz ‘FM’ characteristics, either with pre-emphasis or normalized to flat.

Digital Line Output

The AES3 (XLR) stereo output may be adjusted between -20dBFS and 0dBFS, corresponding to 100% (peak) carrier modulation. The output sampling rate may be set to follow the Digital Line Input or forced to 32kHz, 44.1 kHz, 48kHz or 96kHz. Sampling resolution is 24 bits.

Analog Line Outputs

Active balanced (XLR) outputs are adjustable between -10dBu and +24dBu (+21.5dBm), corresponding to 100% carrier modulation; source impedance is 200 ohms.

Composite/MPX Output

Two unbalanced (BNC) outputs are independently adjustable between 0.8V p-p and 8V p-p (+11dBu), corresponding to 100% carrier modulation; source impedance is 75 ohms. Pre-emphasis may be set to 75μs, 50μs or OFF.

RDS Input

Unbalanced/bridging (BNC) input accepts a 57kHz RDS subcarrier at any level between 0.5V p-p and 5.0V p-p for a typical injection level of 5% of total carrier modulation.

19kHz RDS Sync

When RDS is enabled, the Sync Output (BNC) delivers a 5V p-p TTL-compatible square wave at the 19kHz pilot frequency; 75-ohm source.

Network Port

A RJ45 jack accepts TCP/IP network connections for remote setup and operation of the DAVID IV.

Headphone Jack (Front Panel)

A quarter-inch (TRS) headphone jack allows the user to monitor the processed program audio. A volume control next to the jack adjusts the listening level.

AUDIO PROCESSING FEATURES

Program High Pass

A user-programmable high-pass filter attenuates sub-audible noise that could compromise modulation efficiency. The filter is adjustable between 20Hz and 65Hz.

AGC

Unobtrusive, gated ʻgain-ridingʼ AGC is quasiaverage- responding with a capture/correction range of ±18dB. Positive AGC gain may be truncated to any value between +18dB and 0dB; the AGC correction rate is programmable.

Stereo Enhancement

This dual-action utility effectively broadens the soundstage for the stereo program and the centerchannel ʻsoloʼ component independently.

5-Band ʻMultipressorʼ

Program audio is split into five frequency bands. Each band imparts both dynamic compression and adjustable static gain to afford fixed equalization and other ʻsignatureʼ control of the program audio.

Bass Augmentation

Sub-bass program frequencies undergo independent dynamic compression, expansion, selective clipping and filtering for control over both static ʻRumbleʼ and dynamic ʻPunchʼ of bottom-end components.

PIPP™ Peak Limiter

Inovonicsʼ exclusive Polarity-Independent Peak Processing assures optimum modulation of the FM carrier or other delivery channel.

ITU Multiplex Power Control

The Peak Limiter section may optionally be configured to control the r.m.s. power of the composite multiplex signal to meet the European Standard ITU-R BS.412.9.

Adaptive Pre-Emphasis

Fast HF limiting and distortion-cancelled clipping are each utilized to best advantage in providing independent amplitude control of program frequencies subjected to the FM pre-emphasis curve. This helps preserve program brightness and clarity despite power bandwidth constraints native to FM broadcasting.

Composite Clipping

At the userʼs discretion, up to 3dB of clipping may be applied to the composite/baseband signal. Clipping is performed before the injection of the stereo pilot and RDS subcarrier.

HD Radio Delay

The composite/MPX output of the DAVID IV may be delayed between 1ms and 9.999 seconds in 1ms increments, relative to the analog and digital program line outputs when they are set to the 20kHz (Flat) output mode. When set to the FM mode(s), the line outputs are subjected to the programmed delay as well.

Software Control

The IP network port and supplied software allow remote setup and operation of the DAVID IV over a local network or the Internet using any Windows® PC (XP or later).

THE USER INTERFACE

Front-Panel

A front-panel graphic display and jog wheel allow easy, menu-guided in-situ setup and operation of the DAVID IV. LED-bar displays indicate in/out levels and audio processing action.

Software Control

The IP network port and supplied software allow remote setup and operation of the DAVID IV over a local network or the Internet using Windows® PC (XP or later).

Processing Presets

25 factory presets are provided and optimized for popular world formats, and an additional 20 custom user settings can easily be saved and shared across station networks.

MISCELLANEOUS

AC Mains Requirements

105–130VAC or 210–255VAC, 50/60Hz; 8 watts

Size and Weight

1¾”H x 19”W x 13”D (1U); 9 lbs. (net) / 12 lbs. (shipping)