Engineering · 4 min read
Stereo recording (lead on left, agent on right) sounds like a detail. It changes what your analyzer can do.
Most AI calling tools record calls as mono — a single audio stream mixing the lead and the agent. It works, but it loses the channel separation. Talk-to-listen ratio becomes a heuristic. Diarisation (who said what) becomes a model-call. Sentiment per speaker becomes guesswork.
Stereo recording — channel 0 = lead, channel 1 = agent — solves all of it for free. Talk-to-listen is a direct calculation. Diarisation is the channel. Per-speaker sentiment is a clean signal. The downstream analyzer doesn’t have to guess; it has the structure handed to it.
Stereo audio is ~2× the disk space of mono. For a 90-day retention window, that’s genuinely a few extra GBs per customer. We made the choice anyway because the analytics quality lift is huge and disk is cheap. Most vendors don’t make this choice; their analytics suffers.
If you’re evaluating an AI calling vendor, ask whether they record in stereo. The answer tells you whether they’ve thought about the analytics layer or just the call layer.
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