Set a clean audio level for live translation.

Set a clean audio level in six steps

Do it once with the room empty, then confirm with a real sentence.

1. 1

   Find the earliest place you can change the level

   The desk app has no level control of its own. It shows you what Windows gives it, so the level is changed upstream, at the stage that needs it:

   1. On the sound desk, if the feed comes from one. First check that each speech microphone channel is clean, with its own gain not clipping. Then set the dedicated translation send, the one only SpanVoice listens to, to a suitable level. Adjust that feed, not the main room volume.
   2. On the audio interface, if there is one: its input gain, or whatever level control that model has.
   3. In Windows sound settings, for the recording level of the device. This is the place for the computer’s own microphone, or a USB microphone with no knob.

   If something clips, correct the level at or before the stage where it clips. Turning a distorted signal down further along does not repair it: lowering a send does not help if the microphone preamp is already clipping, and lowering the interface gain is the right fix if that is where it clips. A mixer’s USB feed may be taken before its output control, so check its manual before relying on that knob to change the USB level.

   Speaker the loudest you expect

   sound

   Translation send mic channels clean first

   line

   Interface gain, if it has one

   USB

   Desk app the meter shows the result

2. 2

   Set it with the loudest speaker, in their real position

   Open the desk app and choose the input. The meter runs as soon as a device is chosen, before you start streaming, so nothing is sent while you do this. Have the person who will speak loudest stand where they will actually speak, with the microphone they will actually use, and talk the way they will on the day.

   Adjust until the meter moves clearly into the green on every sentence and the two red segments at the top stay dark, with room to spare for a louder moment. That room is headroom: the space between normal speech peaks and the level where the signal overloads. It does not need to be loud; steady and clean matters more than high.

   The meter shows the average level of the sound arriving from the input, measured in short slices, on a scale from about -60 dB at the bottom to 0 dB, the loudest the input can carry, at the top. Each segment is roughly 4 dB. The two red segments light only when that average is within about 6 dB of the top, which for speech usually means its loudest moments have already hit the ceiling. Treat red as a sign to check for clipping. Check the desk and the interface for clipping as well: a healthy-looking meter in the app does not prove the signal was clean earlier in the chain.

   A quiet speaker who arrives later will sit lower, and that is fine. A loud one who pushes the meter into the red is the one you are guarding against.

3. 3

   Stop talking and check what the meter does

   Ask them to stop. The meter should fall almost to nothing. If it keeps moving or sits part way up, something other than the speaker is in the feed. Work out what by taking things away one at a time:

   • Other microphones that are open but unused. Mute them on the desk.
   • Music, playback or effects that have reached the send. Take them out of it.
   • Room noise such as air conditioning, a projector fan or an audience before the start. Bring the microphone closer to the speaker rather than raising the level.
   • Hum or buzz from the cable path. See the mixer guide for the cable and ground checks.
   • The input’s own noise, when the gain is turned a long way up to make up for a quiet source. Raise the level at the source instead.

   Mute the translation send for a moment. If that mute controls the output SpanVoice is taking, a drop in the meter helps locate the noise upstream, in the mix; if it does not drop, check the interface and the Windows input.

4. 4

   Cover the other voices in the room

   The loudest speaker sets the ceiling. Then check the rest, because one setting has to work for all of them:

   • Someone who speaks softly or turns away from the microphone. If they are too low, ask them to speak closer or use a microphone that stays near them; raising the level for them can push the next loud speaker into the red.
   • A handheld microphone that moves between the mouth and the chest. Ask the speaker to hold it steadily.
   • Guest speakers and new microphones. Each has to be in the feed, at a similar level to the others. A microphone that was added to the room mix but not to the SpanVoice send is never heard.

   Where one microphone is much louder or quieter than the rest, balance it on the desk rather than changing the whole feed.

5. 5

   Check the words, not only the meter

   A good meter is necessary, not proof. Press Start streaming, say a sentence with a name and a number in it, and read the words on your own phone from the audience link. In the desk app, open Transcript: the Heard in the room column shows what is being recognised. If words are missing or garbled while the meter looks right, check the speaker’s position and the microphone, and check the desk and interface for clipping, before changing the level again.

   With nobody to speak, switch the Input panel to Test file and play a recording. That checks the app and the streaming path, not the desk, so it tells you nothing about the level on the day; do the live check as well.

   If the speech is clear but a name is repeatedly recognised incorrectly, check the spoken-language setting and add the name to the Glossary, then test again.

6. 6

   Leave it alone, and keep an eye on it

   Once it is right, leave it and save the working setup as your starting point, including the desk scene with the translation send in it. A recalled scene or a new microphone is the usual reason it changes. Before each event, check the actual microphones and speakers, and confirm that the feed remains clean.

   During the event, glance at the meter now and then. The meter keeps running when you press Pause audio, so it still shows what is arriving. If someone is speaking and the meter stays still, check the selected input and the audio path. If it has climbed into the red since you set it, someone may have raised a level upstream. Look before you change anything in the app.