What is the difference between Mono and Stereo?
Let’s take a look at Mono first:
Mono basically means that exactly the same signal is sent to every speaker. This means that no matter where you are in any given space you will hear the same sound- not considering room reflections and frequency build up which is the subject for a different blog- as everyone else in that space.
Most systems in bars, restaurants, conferences and live sound use this system as it is simple and effective.
The down side to Mono is the actual Sonic space available to mix and balance the separate instruments into a good sounding rendering of the performance.
While true that most people will not perceive anything is missing it does have an impact to the rendering- taking the separate instruments and mixing them into a well balanced pie.
The reason I used the word Pie allows me to make the following example:
There is a pie on the counter. You are the only one in the room so you get the whole pie. All of a sudden 10 people walk into the room and want a piece. Now you just went from a whole pie to a slice equal to 1/11 of the pie.
The same applies to a performance. Say you have 1 lead vocalist, 1 backing vocalist, a guitar player, a bass player and a drummer with a modest drum kit.
Remember that there is still only one pie-Mono.
So let’s start dividing up the pie. The lead vocalist gets a bigger slice than everyone else- let’s say 1/4 of the pie.
That leaves 3/4 of the pie divided into 8 slices for everyone else. Why 8 slices? Because the drummer gets 5 to handle all his different instruments.
Here comes the tricky part. Everyone is competing for room in the frequency spectrum available and there is a finite amount of total frequency available. So who gets what? (I’ll deliver into this more in another blog)
In order to help everyone get along we can use depth (the illusion of how close or how far away we perceive them to be ( more in another blog). This gives everyone a little more elbow room in the mix.
Upside: every customer hears mostly the same thing.
Downside: Cramped space in the mix for each instrument – vocals are an instrument too.
Now let’s take a look at Stereo.
Somewhere along the line- some think it’s when vinyl records became popular as vinyl needs two signals- things changed.
Instead of ending up with one signal to be sent to a speaker two signals of the main mix were needed. Still just two signals of the same thing.
Some really smart sound engineer came up with the idea of sending the guitar to one of those signals while sending the piano to the other signal and Stereo was born!!
As usual, us sound guys being very clever folks, we realized that we now had 3 pies instead of one!! That’s right 3 pies. How can that be? The simple answer is how we hear and use our hearing to determine where a sound is coming from- that’s why we have two ears. ( more on how we hear in another blog).
Now we have a Left pie, a Right pie and a Center pie.
The signals or sounds that are unique to the Left speaker we perceive as coming from the left. The signals or sounds that are unique to the Right speaker we perceive as coming from the Right. The signals or sounds that equally come from the Left and Right speaker we perceive as coming from the center. In reality this is not perfect so a Good Stereo signal shows up on a gionmeter- the tool that visualizes the stereo signal- as a writhing, pulsating ball of goodness.
So now we have 3 pies for the band to share!! Remember we mentioned depth in Mono? This adds Width( yes another blog) to the equation.
Upside: Three pies and a writhing ball of goodness!!
Downside: the only customers who get to hear this goodness are those located at the top of an equal lateral triangle with the distance between the speakers themselves establishing the length of the sides. Everyone else hears something different- if the guitar is panned- the tool that controls where a signal is sent to- to the left and you are standing on the left you hear more guitar.
In mixing: we take advantage of the benefits of Stereo but always check to be sure it sounds good when collapsed to Mono.
In Live Sound: every good sound engineer had developed a hybrid system that grabs as much of those two extra pies available in Stereo while allowing most customers to hear a very similar sound.
That’s part of what we do in our live sound enhancement offering.
That’s it for this blog- thank you God.
As they used to say in Austin:
ONWARD THRU THE FOG!!