Echo is normally experienced where the user hears his/her own voice in headset / speaker later than what the user is accustomed to when naturally talking (natural echo = speed of sound from mouth to ears).

Echo can have various causes.

• Acoustical leakage from speakers to microphones of the same or different user stations

• Electrical leakage from cable induced crosstalk due to lack of shielding

• Audio routing issues in the intercom system and/or its connected peripherals

In pure analog systems, echo is rarely perceived by users as a nuisance. In digital systems, whose size can go from local to spanning continents or even go into orbit, echo can quickly become a nuisance. In these systems the best way to troubleshoot is by systematically isolating different system components to track down the source of the echo.

When experiencing echo on Station-IC please follow the following steps.

Step 1: Enable the Station-IC Echo Canceller

Station-IC is equipped with and echo canceller which can be enabled in the Settings dialog of Station-IC. Echo Canceller is an actively adaptive audio processing algorithm that continuously filters for the Station-IC’s unwanted return audio. Enabling the Echo canceller adds ~10ms of latency is in each direction.

Step 2: Enable Audio Enhancements if supported by the audio device.

Some audio devices may include additional processing elements that can enhance resilience to echo.
These often have the benefit of being designed and calibrated specifically for the audio device being used.
Try enabling these and evaluate for performance.

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Step 3: Audio/Intercom Echo basics

This is a large topic and will not be comprehensively covered in this article.

Basic principle #1; Isolate the signal paths until you find the problem!
Basic principle #2; Talker's voice should never be heard by the talker!

• Audio / Routing issues.
  Try talking on different keys, one at a time, to see if the echo changes.
  If echo changes you likely have an audio routing / configuration or nulling issue in your system.
  Isolate system components and users from keys/channels that have echo issues until you find the issue.
  Example of issues; bad headset, latched on headset, 2-wire with bad null, 4-wire without mix-minus.

• Electrical issues.
  Normally mis-wiring or headset cables with inadequate shielding between mic and speaker wires.
  May not be heard by the user of the troublesome device, other users may experience only when troublesome headset talk is in use.

• Acoustical issues.
  Live microphone picks up local sources dues to reverberation and proximity to intercom loudspeakers or headsets.