You are about to experience something new.  You are about to mix stereo sound while watching one meter.  
Just One.  It will display everything you need to know:

1) How loud the left channel is.
2) How loud the right channel is.
3) How much separation there is between them.
4) If your stereo audio is compatible with mono listeners.
5) If your broadcast signal is as loud as it can be.

Wait, I can hear you saying.... “I have a pair of meters that tell me that”!
And -- you're (almost) correct - you do have a pair of meters to tell you that.
You've had them for a long time, and you've been switching your eyes back and forth between them for a long time.  Isn't it fun remembering what the left meter said so you can compare it with the right meter?

When your eyes focus on the right meter, are you SURE you remember what the left meter was reading?
Are you tired of constantly jumping back and forth between left and right meters?

There is finally an easier way.  It’s much easier, much simpler, and it makes a world of difference.  
It’s SAM: which uses the Single Stereo Display (patent pending).

A meter with a row of LEDs can display a left channel, and another row can do the right.  You can use two LED meters to take the place of the old analog pointer-type meters, but simply changing to LEDs isn't really an advantage.

How about if we use one color LED for the left channel, and a different color for the right?
And we put these two different colors into one row of LEDs?  That’s the Single Stereo Display.

For example, let’s use Green for the Left channel. That means that audio in the left channel will light up just the green segments.  And let's use Red for the right channel so right audio will turn on the red segments.

And… here's the clincher -- audio from both the left and the right channels will turn on BOTH colors.  Red and Green.  But when they're both turned on, we don't see the green and red colors individually.  We see a mix of the two, and it creates Yellow. So Yellow shows us when both channels are on.

When we have a song or program that has evenly balanced channels, we'll see a yellow arc starting at the bottom and going upward, just like a conventional LED meter.

If the Left channel is louder than the right, the Green segments go up farther than the yellow ones, so we see yellow bars with some extra green ones at the top.   How many green segments there are shows how much louder the left channel is.

If the Right channel is louder, then the yellow segments will have red at the top.  

It’s simple, intuitive, and so convenient! One quick glance instantly shows what the two meters tried to show:
the Left level, the Right level, and the Balance between them. But the Single Stereo Display is faster, easier,
and more productive. And your eyeballs don’t need to jump back-and-forth between two meters!

It makes sense.  But if you've been using two different Left and Right meters for a long time, you've learned some 'bad' habits.  Not really -- it's just like learning the old way to do something and being comfy with it.  It's worked well enough all these years, etc., etc. So why take the time to learn something new?   Well, there was a time when people who were using typewriters became aware of a new invention called the “word processor”.  It was complicated, and had more things to learn than you could imagine.  Many professional typists said “Yeech! Who needs that?”  But once typists got down and dirty with the new stuff, the typewriter ended up making labels and typing envelopes. That was all anyone wanted it for.  

The Single Stereo Display is similar.  Once you take the time and learn this new way to visualize audio levels, the old Left and Right meters will become obsolete.  They did what we needed, as best they could, for a long time.  Like typewriters, horse-drawn buggies and butter churns.