Video Transcript
Input Processing
6m 9s
00:07
We’re ready to start making actual adjustments to the audio in our system.
00:11
We’ll start with Adjusting the Input Settings, then move on to the Output settings.
00:15
These Setup Wizard shortcuts will take you to the Master Inputs and Output screens,
00:20
and now we’ll explore all these other pages for each input and output channel.
00:25
We’ll show you where to find your PEQ, Dynamics and Gate controls,
00:29
so you know how to make adjustments when you want to make them.
00:32
If you’e interested in the finer details of these adjustments,
00:35
we’ll have deeper dive videos for that.
00:37
Let’s start with properly gain-staging your signal.
00:40
The objective of gain-staging is simple –
00:43
– you’re matching the input sensitivity of the mixer to the output level of the source.
00:48
Start by playing one of your source devices—or if you’re using a microphone, talk into it.
00:53
Whichever one you do,
00:55
make sure the signal level from the source gets as loud as it is ever likely to be in use.
01:00
On the setup screen, you’ll want to adjust the Input trim
01:04
until the loudest peaks are into the yellow range but nothing is clipping into red.
01:09
We highly recommend using the MP-M Cue function to aid in this.
01:13
Just like a professional mixing console,
01:15
the MP-M Cue function lets you plug in headphones or earbuds
01:20
and listen to input and output signals without effecting the sound in the zones at all.
01:25
You can do this in the equipment room, far away from the active zones—
01:29
—just engage the Cue button for each source and use the Cue Level button to adjust your headphone volume.
01:36
Once it’s done, remove that input from your Cue and move on to the next input.
01:41
If your system includes video sources,
01:44
you might also be using a video switch that introduces a little bit of latency to your video signal.
01:49
When this happens,
01:50
the lip movements of the announcers on screen appear to be out of time with the audio you’re hearing.
01:55
This is sometimes called “lip flap”.
01:58
The solution is to delay the audio signal using the Video Sync Delay.
02:03
Typically the delay created by a video switch is only a frame or two:
02:07
so if your video is 24 frames per second then each frame is 41.6 milliseconds,
02:14
so you may want to start in the 40 millisecond range when adding Video Sync Delay.
02:19
Start there to see if you can get the lips and the sound to match.
02:23
If your video is 30 frames per second each frame is 33.3 milliseconds
02:28
so you should try around 30 milliseconds to correct this.
02:31
Don’t forget to enable this delay if you’re using it.
02:35
Now that we’ve truly finished with the Setup page, let’s look at the other configuration pages.
02:40
The PEQ gives us access to a 4-band parametric equalizer,
02:45
and you can select the gain, frequency, and width—or Q—of each adjustment.
02:50
You can also move the handles directly on the graph.
02:54
If you don’t have as much experience with this,
02:56
you may wish to engage Simple mode, which will limit your control to the gain knob only.
03:01
If you’ve already made some adjustments before you engage Simple—
03:04
—don’t worry, it keeps your previous settings exactly where they were.
03:08
On the Dynamics page,
03:10
you’ll see options for engaging either a Compressor or an Automatic Gain Control (or AGC) on this channel.
03:16
In order to activate either one you’ll need to toggle the “In” switch,
03:20
and you’ll notice that any channel with its Dynamics engaged
03:23
will have an indicator illuminate next to its fader on the channel strip.
03:27
This also illuminates the graph on screen, to help you know when the processing is active.
03:33
For a Compressor,
03:34
you can once again engage Simple Mode if you’d like to simplify the control here to a single knob,
03:39
or you can fine-tune the threshold, attack and release time, ratio and gain of the compression.
03:46
For the Automatic Gain Control,
03:48
this would often be applied to music tracks that might vary in average volume.
03:52
You want to turn down the songs that were recorded a little louder,
03:56
or turn up the songs that were recorded a little quieter.
03:59
Some good values to start with would be to set the Max Target to -3dB,
04:05
and the Min Target to -15dB giving you a 12 dB window.
04:10
The way the AGC works is that it applies gain or gain reduction
04:15
to try and get the RMS (average) signal level inside the window.
04:19
If the RMS value is above, the AGC will reduce gain,
04:24
and if the signal is below, it will add gain up to the Max gain value that you set.
04:29
If you reduce this window size,
04:31
you make the AGC circuit work harder trying to keep the signal in the target window
04:36
and those changes might be too noticeable.
04:39
The Max gain is the most gain that will be applied while trying to push a low level signal into the window.
04:45
The Threshold is the point at which the circuit no longer looks at the RMS –
04:50
– this means that for long fades or gaps in songs
04:52
it will no longer push the gain up to try and get the song louder (and bring up the noise floor).
04:58
The Release is how long the circuit waits before it stops applying gain or gain reduction –
05:03
– the longer the number the slower the circuit
05:05
and with an AGC you generally want it to be slow so you don’t hear the gain changing.
05:12
Finally, the Gate.
05:13
Similar to the Dynamics,
05:15
you’ll notice that engaging the Gate will illuminate an indicator by the channel strip.
05:19
You can fine-tune all the settings of how you’d like this channel to be gated open or closed,
05:24
or you can engage Simple mode to just make one general gating adjustment.
05:30
You might also notice that you can assign channels to be controlled by our Auto-Mixer,
05:35
which can regulate the levels and share the gain of multiple microphones.
05:39
This feature works great for panel discussions where multiple talkers have open microphones
05:44
and you don’t necessarily want to be riding their faders.
05:47
We’ll discuss this in greater detail in our video that covers the Mixer section,
05:52
so let’s ignore this for our initial setup.
05:55
Once we’re happy with our Input settings,
05:57
we can check that task off of our Setup Wizard, and move on to the Outputs.
06:00
In the next video we’ll look at our Output settings.
06:04
Move on whenever you’re ready.
Lesson Description
Input Processing
6m 9s
Walkthrough of all processing features available for input channels on the MP-M Mixer.