Behind The Mixer

Learn Church Audio Artistry | Church Sound

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Resolving line check problems can be quick and easy when you use this three-step approach. It’s simple, it follows a logical flow, and it can be done in a very short period of time.

A line check is the process of checking that all instruments and microphones on the stage are sending signals to the sound board. This process happens before a sound check or might be considered part of the sound check. During a line check, you are apt to discover problems like bad cables, bad connections, dead batteries, and (gasp!) dead mixer channels.

I think of a line check as more than just getting the signal but also getting a clear signal as well. In some cases of line check problems, you will neither get volume nor a signal light on the channel. While the lack of the signal light can determine what you check, using the below process list, you’ll find out everything that should be checked when either case arises.

Resolving a simple issue with a vocal microphone

Let’s say the singer is singing into the microphone and you don’t hear anything coming through the main speakers.

Step One: Check for the obvious

These are all things you can do from the sound booth and/or have the person on stage easily check for you.

  1. Channel fader. Make sure it’s at the 0 position as a good starting point.
  2. Channel gain. Check the channel gain is turned up. If you aren’t seeing the signal light on the channel glowing on and off, then increase the gain to see if that’s the source of the problem.
  3. Channel padding. Make sure you haven’t engaged the signal padding where it’s not needed. That could cut your signal so low you don’t hear anything.
  4. Sound board volume. Make sure you have the master volume turned up on your sound board. Hey, I wouldn’t mention it if I hadn’t done it myself.
  5. Subgroup usage. Make sure the channel isn’t routed to a subgroup. If it is, take it out of the subgroup and listen for the sound.
  6. Wireless microphones – receiver power and signal. Make sure the receiver is turned on and the receiver shows a wireless signal. If you don’t see a wireless signal, ask the person on stage to make sure the wireless pack (or wireless handheld) is on. If it’s on but the pack/handheld doesn’t show any associated power light, it might be as simple as battery replacement. See your wireless microphone manual for how it displays a battery-strength light indicator.
  7. Wired Microphones. Make sure that if it has an on/off switch that it’s turned on. Ask the person on stage.
  8. Channel / Stage jack pairing. Sometimes, a problem can be as simple as the cable being plugged into the wrong stage jack or you have it marked as the wrong channel. Ask the person on stage to check the jack number.

Step Two: Follow the signal flow

  1. Connection into microphone. Re-seat the cable into the microphone. Make sure the channel is off / muted when you do this.
  2. Connection at stage jack. Re-seat the cable into the stage jack. Make sure the channel is off / muted when you do this.
  3. Connection at mixer. It’s unlikely but it’s *possible* that the connection into the mixer was pulled out for that channel. Make sure it’s properly connected.

Step Three: Time to swap

  1. Swap microphones. Swap the microphone for known good one and try again. You might have a microphone that’s gone bad.
  2. Swap cables. Swap the microphone cable with a cable that’s known to work.
  3. Swap stage jacks. Still not getting a signal to the sound booth? Might be something from the stage jack to the mixer itself. Connect to a different jack/channel and see if the mixer gets that signal. If that does get a signal, also try swapping cables on the back of the mixer from the good channel to the channel that wasn’t receiving the signal. If you still don’t have a signal, you have a bad channel on your board.

Summary

Follow this three-step approach to resolving line check problems with vocal microphones and you’ll be moving onto your sound check faster than a vocalist can say “testing 1, 2, 3.“

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Comments

  1. what would you do if the church you are renting only gives you 30 min before y0ur service starts at 11:00 and you have to clear the stage setup curtain/sound/musicians/monitors then it’s 11:05 and no time to sound check/dial in gains, etc. never have good monitor mix?

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  2. Thanks for the write-ups. I’ll be referring our techs this way.

    I think another “Check for the Obvious” falls right in between checking channel gain and pad – phantom power. Its the most common issue I’ve seen when condensers are involved. So much so, that its become a knee jerk reaction for me to glance at the mic model and shout “phantom power” anytime I see a tech struggling with no mic signal on a condenser.

    Chris C

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  3. What I do as a general rule of thumb, once I’ve checked the immediately obvious, is to halve the signal path and check it there.
    For example, if it’s a radio mic for PA – check the receiver. If there’s nothing there it’s probably between the receiver or mic, if there IS something then it’s probably between the receiver and the desk.
    Or, if it’s a dead channel on a multitrack recording from a live gig, check the split at the PA desk.

    If it’s a long signal path, then halve it again!

    It’s the quickest way :)

    Reply

    • I never thought I’d bring up philosophy on this site as it relates to your comment, but one philosopher said we can never go anywhere. The reason is we first must go half that distance. But to go half that distance, we first must go half THAT distance. Ultimately, we would have to go an infinite amount of “halves” which of course would make it impossible to go anywhere. To his credit, he was showing the ridiculousness of some philosophical statements. That was taught as the last subject of the day in my college philo class. Dr. Chandler said “class is dismissed, you are free to go.” And being the wise-guy that I was, I said “I’d like to leave, however…”

      On a more serious note, I’d never thought of doing it with halves. For someone who is used to working in audio and fully understands signal flow, I say that sounds like a great idea. For anyone new or simply uncomfortable with tracking such issues, I say stick with the signal flow order.

      Thanks for the post. I’ve learned something new today!

      Reply

      • working through the signal flow absolutely is the way to do it if you’re new. It solidifies exactly where the audio is going, and you learn very quickly what is likely to have gone wrong, so with experience you know where to look first. And it stands you in good stead when you just can’t find the problem – start from the beginning and check it every stage of the way through!
        A very good point, and a great discipline to learn. Highly recommended!

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  4. Chris,
    Good post. Lots of solid guidelines here. Two thoughts: One more thing can can get you on a line check is a gate. I typically gate most of my drum mics and often during line check, a soft tap on the mic or drum is not enough to open the gates, and it can appear as though there is no signal. So I often lift the gates during line check.

    Second, as sound guys, we shouldn’t ever “Check 1, 2, 3” because on 3, you lift. That’s what roadies are for. ‘;-).

    mike

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