Stereo call recording explained: agent left, customer right

A normal VICIdial recording is mono: both voices are mixed into a single track. Stereo recording keeps them apart. The agent sits on the left channel and the customer sits on the right channel, so when you open the file in any audio editor you see two waveforms instead of one. That separation is the whole point, and it changes what you can do with the file after the call ends.

What stereo recording actually produces

When you turn on Stereo recording for a campaign, the system writes an additional recording on top of whatever your standard recording is doing. This extra file is two-channel: agent audio on the left, customer audio on the right. It does not replace the normal Call recording that your campaign already makes; it runs alongside it with its own filename, so you end up with both the mixed mono file and the split stereo file for the same conversation.

Because the two voices never overlap on the same track, you can mute one side without touching the other. Want to hear only what the customer said during a billing dispute? Pan to the right. Want to review only the agent's pitch? Pan to the left. With a mono file you cannot do that cleanly because the voices are already glued together.

How the channels are assigned

flowchart LR
  A[Agent audio] --> L[Left channel]
  C[Customer audio] --> R[Right channel]
  L --> F[Stereo recording file]
  R --> F
  F --> P[Playback split by side]

The assignment is fixed and predictable: agent left, customer right, every time. That matters when you feed recordings into a transcription or analytics tool, because the tool can label speakers by channel instead of guessing who is talking. A stereo file removes the speaker-separation problem before the audio ever leaves your server, which is why teams that run downstream scoring or Voice analytics almost always prefer it.

Stereo recording is a separate switch from your main recording mode, so you can run standard mono for general archiving and turn stereo on only for the campaigns where the split is worth the extra disk. For the bigger picture of how recording fits into a campaign, the call recording overview is the place to start.

When stereo earns its keep

The clearest win is quality work. A reviewer can isolate the agent to score tone and script adherence, then isolate the customer to confirm what was actually agreed. It also helps with disputed calls, where being able to hear one party alone settles arguments that a mixed track leaves muddy. If two people talk over each other, mono turns it into noise; stereo keeps each voice readable on its own side.

There are trade-offs. A two-channel file is larger than a mono one, so plan your Recording retention and disk budget accordingly before you flip it on across every campaign. You also need a dedicated stereo filename so the new files do not collide with your existing recordings, which is the first thing the system checks before it will write anything. If you want a deeper read on why the split matters for review work specifically, see why recording each party separately helps QA.

Stereo recording is included with every VICIfast plan, so there is no add-on to buy before you can test it on a campaign. Have a look at our pricing to see what a hosted dialer with stereo built in costs.