eSSB Hi-Fi Audio

During the 2020 Covid-19 lockdown I started to read about amateur radio stations utilizing professional audio equipment to enhance their transmitted SSB audio. The aim of extended single sideband (eSSB) is to support relative high fidelity, full range clean and articulate vocal audio.

eSSB Hi-Fi has many benefits, the most noticeable being a very pleasing and highly defined sound not inherent with traditional SSB audio. Also, it only occupies 1/2 of the bandwidth required by AM for the same audio quality, since SSB is a Single Sideband Suppressed Carrier mode vs. AM, which is a Double Sideband with Carrier mode and is therefor a more efficient signal and less subjected to the phasing and selected fading problems inherent with its AM counterpart.

Having spent time reading and looking at other amateurs eSSB setups I decided that the best option for my station was to create an audio rack containing the different components required. Below I list the components of the audio rack and the wiring of the audio chain from microphone to transmitter. I would like to thank the many amateurs who shared their setup on the web.

In 2023, during a reorganisation of the shack I decided to replace the rack equipment with a single Behringer XR16 digital mixer and to interface the unit a W2IHY iPlus audio switch.

Digital Mixer Unit

Behringer XR16 digital mixer

• 16 input channels
• 1 stereo USB return channel
• 4 stereo FX return channels
• 6 aux buses
• Main LR
• 40-bit floating point signal processing
• 8 XLR/TRS combo jacks, balanced
•  2.4 GHz WLAN onboard

Microphone /Radio Switch

W2IHY iPlus Audio Swich

• RCA linear keying inputs from 3 radios
• RCA stereo audio inputs
• Combination XLR / ¼” TRS audio input or 5-pin DIN audio input
• Audio Phase Reversal for proper AM audio asymmetry
• Individual output level control for the radio selected
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Microphone Preamplifier

Behringer Ultragain Pro MIC2200

• Audiophile Vacuum Tube Microphone/Line Preamplifier
• 2-channel
• Wide bandwidth from 10 Hz to 200 kHz for "open" sound
• Switchable 48V phantom power
• Integrated fully parametric EQs with dedicated center frequency, bandwidth and level controls
• Switchable HP & LP filters, phase reverse, output level control, VU meters, balanced XLR/jack

Noise Gate / Compressor / Expander/Limiter



Behringer Composer Pro-XL MDX2600

• 2-Channel
• Expander / gate controllable: Threshold, release, ratio
• Tube simulator
• De-esser: male / female voice
• Side chain
• Automatic mode for compressor and limiter: Attack / release
• Stereo link
• Gain Reduction and in / out-level metering via LED chains
• Peak Limiter adjustable (threshold)
• -10 dBV / +4 dBu switchable
• Balanced XLR and jack inputs and outputs

Spectral Enhancer



Behringer Ultrafex Pro EX3200

• Multiband processing for simultaneous low- and high-frequency enhancement
• "Natural Sonic"processor for extremely musical sound enhancement
• VSP (Variable Sound Processing) circuitry for simultaneous enhancer and exciter processing
• "Dual Mode" ultra-bass enhancer for awesome soft and tight bass sounds
• Shift function allows you to control the frequency range of added bass punch
• Surround processor for spatial enhancement and improved stereo imaging
• Built-in noise reduction system



Equaliser



Behringer Feedback Destroyer DSP1124P

• Digital 2-channel feedback suppressor/parametric EQ based on a high-power 24-bit DSP
• 20-bit A/D and D/A converters with 64/128 times oversampling
• Automatically searches and suppresses feedback frequencies
• 24 programmable, fully parametric filters, adjustable manually or via MIDI
• Single-Shot, Auto and Manual mode selectable for each filter
• 24-bit internal processing, professional 46-kHz sampling rate
• Servo-balanced inputs and outputs with XLR and 1/4 in. TRS connectors

Audio Mixer



Behringer XENYX 802

• 10 inputs (2 x XLR, 8 1/4 in. TRS connectors)
• 2 state-of-the-art XENYX Mic channels
  Neo-classic "British" 3-band EQs
• 1 post fader FX send per channel for external FX devices
• 1 stereo aux return for FX applications or as separate stereo input
• Main mix outputs plus separate control room, phones and stereo CD/tape outputs
• Built in Mic Preamp (Not used on this system)