3.2 Multi-Channel Recording & How to Play Channels

Blueprint topics 10401 and 10402 ask you to define multi-channel recording and describe how to play channels properly. This is the single biggest technical difference between transcribing a digital court recording and transcribing an ordinary audio file.

What multi-channel recording is

In a single-channel (mono) recording, every voice in the room is mixed into one track. When two people talk at once, their voices are fused and often impossible to separate.

In a multi-channel recording, each microphone, or a group of nearby microphones, is recorded on its own channel (track). The files stay synchronized in time, and the playback software lets you listen to all channels together, one channel alone, or any mix in between.

AAERT's CER and CDR programs train reporters to set up these systems. A CET receives the result: a multi-channel audio file, the reporter's log notes (annotations) and the case information. The CET practical exam uses a four-channel recording played in TheRecordXchange player, where "volume can be adjusted for each channel, as desired" (AAERT exam instructions).

How channels are typically assigned

There is no single national channel map. The reporter assigns channels to fit the room, and the log notes tell you the assignment. AAERT's Scalini practice log is a good example:

In jury trials, a common layout puts the judge, the witness stand and each counsel table on separate channels. AAERT has noted that its Best Practices setup for jury trials calls for at least four channels, sharing channels between locations such as the witness stand, clerk desk and jury box. Miking each location on its own would take eight or nine channels. Deposition setups usually give each speaking participant a microphone, plus a table microphone as backup.

Always read the channel map before you start. If it is missing, work it out in the first minutes by soloing each channel and noting whose voice is loudest.

How to play channels properly

1. Start with all channels mixed. Draft with every channel on so you hear the natural flow of the proceeding, including anyone speaking away from a microphone.

2. Balance the levels. Quiet speakers are usually quiet on their own channel too. Raise that channel's volume rather than turning up the master volume. A loud channel, often the judge's, can be lowered so it does not mask others.

3. Solo a channel to resolve overlap. When a witness and an attorney talk at once, mute everything except the witness channel and replay; then solo the attorney's channel. Transcribe each speaker's words in order, using double dashes for interruptions (Chapter 12).

4. Pan channels for spatial separation. Some players let you send channels to the left or right ear. Hearing counsel in one ear and the witness in the other makes overlapping speech easier to follow.

5. Use channel strength to identify speakers. The channel where a voice is loudest usually tells you who is speaking. Combine that with the log notes and context before assigning a speaker ID.

6. Remember that channels bleed. Every microphone picks up other voices at a lower level. A voice on the "witness" channel is not necessarily the witness. Check which channel carries the voice most strongly.

7. Do not transcribe private conversations just because a microphone caught them. Counsel-table microphones can capture whispered attorney-client conversations. Private communications and off-the-record conversations that are inadvertently recorded are not part of the transcript (Chapter 10).

A worked example

At 10:41:12 the log shows "Obj - Ms. Lee." On the mixed audio, the witness's answer and the objection overlap. You:

1. solo Channel 2 (witness) and hear: "I saw him take the -- the bag and put it";
2. solo Channel 3 (Ms. Lee) and hear: "Objection, Your Honor; nonresponsive";
3. check the mix to confirm who stopped first. The witness stops at "put it" when the objection starts.

A.   I saw him take the -- the bag and put it --
          MS. LEE:  Objection, Your Honor; nonresponsive.

Without multi-channel playback, that passage might have become "(indiscernible)."

Channel problems to report

• A dead channel. One channel is silent for the whole file when the log shows a speaker there. Report it; do not guess.
• A channel out of sync. Rare, but echoes or doubled words between channels signal a problem with the file.
• Missing time. Gaps in the timeline, or log entries with no audio.

These are equipment problems, not transcription problems. Section 3.3 covers how to troubleshoot and escalate them.