Video Transcript
RTAs
5m 46s
0:07
In this video, we’re going to tell you about the TouchMix-30 Pro’s Real Time Analyzers, how they work and what you can do with them.
0:14
Let’s start by talking about what a Real Time Analyzer – or RTA – is.
0:20
An audio Real Time Analyzer breaks the audio spectrum into frequency bands – 1/3 octave bands are most typical and that’s what you’ll find on the TouchMix-30 Pro.
0:29
The RTA displays the amplitude of the signal in each frequency band so you can see, in real time, what the distribution of energy looks like.
0:37
And, of course, having an RTA display looks really cool at the mix position.
0:43
The TouchMix-30 Pro has two on-board Real-Time Analyzers.
0:46
One of these RTAs is available on any input or output EQ screen.
0:51
Simply navigate to a channel’s “EQ” tab, and touch the “RTA On” button.
0:56
When you do, you will see a display of the selected channel’s audio spectrum.
1:00
The second RTA can be displayed by pushing the RTA button to the right of the touchscreen.
1:06
This RTA offers options for source selection.
1:10
You can select the Main Left/Right signal, the signal from any Auxiliary mix
1:15
the Follow Cue (which will display whatever you have selected for the Cue buss), or the Talkback microphone input.
1:23
By selecting the Talkback input for the source, you can actually look at an RTA display of the sound in the room
1:29
using a microphone that’s plugged into the mixer’s Talkback input.
1:33
You could view both RTAs at the same time by connecting a tablet device to your TouchMix.
1:39
You could have this second screen available at the mixer, or you could take it with you as you ring out the system.
1:45
So how can you use the RTA? First, use the RTA and your ears together.
1:51
Don’t rely entirely on the RTA display. There is no “right” way that an RTA display should look.
1:57
The RTA can help you identify where a tonal imbalance or feedback ring is located on the frequency spectrum,
2:04
but it’s not a substitute for ears and good audio judgment. That said, here are some examples of how to use the RTA.
2:12
The input channel RTA is useful for working on the tone for a single source.
2:17
Let’s say you’re doing a sound check and an input – for example the bass guitar – isn’t sounding quite right.
2:24
It’s kind of “boxy” sounding but you’re not sure what to do about it.
2:27
So you watch the RTA while the bass is playing and you see that the 250 Hz band is sticking out above the other bands.
2:35
If it sticks out the most when you are also hearing the offending sounds the most, that tells you the problem is likely somewhere around 250 Hz.
2:43
Now you know where to start pulling the channel EQ.
2:47
Here’s another way to use the TouchMix-30 Pro’s RTA’s.
2:50
Let’s say that you’ve set up your system and it sounded great when you played a reference tracks.
2:54
Even the individual inputs sounded fine during sound check. But when you pull up all the faders and listen to the mix – not so much.
3:02
There’s just too much of some frequencies in the mix.
3:06
What’s happened is that multiple channels are adding together in an undesirable manner. The RTA’s can help you find and fix the problem.
3:13
Start by using the output RTA to identify where this tonal imbalance is.
3:19
Once you’ve done that, you could just adjust the output graphic EQ to get the balance you want.
3:25
But a better choice might be to find the individual channels that are contributing to this imbalance.
3:30
Let’s say that the mix sounds a bit “tubby” and the output RTA is indicating too much energy on the low end.
3:36
Note the frequencies that are over-balanced. Now go to the inputs and look for sources with a bit too much of these frequencies.
3:45
Maybe all you need to do is roll a bit of low-end off the bass and guitar channels to clean up the whole mix.
3:51
Just remember – an instrument that sounds great on its own may not blend well with other instruments.
3:58
A skilled engineer knows how to make all the instruments “sit in the mix”.
4:02
Your RTA can help you find frequency overlap problems and get your mix dialed in.
4:08
Once you’ve got your instruments balanced, you could still use the RTA to identify any tonal imbalances in the aux mixes.
4:14
Let’s say that one of the performers is complaining about a “tubby” sounding stage monitor.
4:19
Just select the performer’s output and look at what you’re sending to his wedge.
4:24
Looking at his signal you see that, yes, there’s ample low-end there and you can take some out without making the mix too thin.
4:31
Or – maybe the RTA display indicates that this monitor mix is fairly well balanced.
4:36
That could be a hint there’s something wrong with the stage monitor itself – like a blown high-frequency driver or an improperly adjusted processor.
4:44
So the RTA also can serve as a trouble-shooting tool as well.
4:47
The TouchMix-30 Pro has a powerful anti-feedback system which we cover in another video.
4:53
But, if you would prefer to handle feedback using the mixer’s 1/3 octave EQ, the RTA can help identify which EQ bands to cut.
5:01
Now, you might find yourself tempted to try balancing the system with just a noise generator, microphone and the RTA.
5:09
This isn’t recommended, because if all you do is adjust the output GEQ sliders until the RTA shows a flat response
5:17
the results with actual instruments will probably not be what you had in mind. It may look right on the screen now, but remember
5:24
your goal is to achieve a tonal balance with the real signal and ultimately, your ears will still be your guide on the mix.
5:32
The Real-Time Analyzers. Just one more way the QSC TouchMix-30 Pro goes beyond mixing to help you get great results – fast.
Lesson Description
RTAs
5m 46s
The TouchMix-30 has two on-board Real-Time Analyzers - see how RTAs work and what you can do with them
Downloads and Links
RTAs
5m 46s