Design & Best Practices: Part 1

Today we're going to make you aware of some basic design guidelines and best practices when working  

with QSC cinema products. That goes for both commercial cinemas and systems installations  

that call for cinema-like experiences. Let's do it!

This training is for systems integrators and technicians with an interest in projects that require a basic level of cinema knowledge,

and also for cinema dealers who want a refresher. We'll go over room design and acoustics,

loudspeaker installation, aiming and wiring, room tuning and equalization, and then we'll break  

down the Best Practices of a 7.1 audio system design that uses Q-SYS as the audio processor.

The principles we'll cover today are not just for commercial, DCI-compliant, movie theaters.

They can also help optimize the sonic experience whenever it's used to support a visual experience,

from a university auditorium, a museum exhibit, or actually any multi-purpose venue where you want  

to create a cinema-like experience that has a produced, multi-channel sound source.

Throughout this course we're going to reference documents and charts that we might not cover in depth here but we've  

added them to the Links and Downloads section for your convenience. So whenever you see this icon  

just think of it as a special little surprise waiting for you to open and enjoy.

The primary difference between true Cinema applications and  almost any other type of project in the pro audio  

or AV world is the idea of translation. Translation of the artistic intent of the content creator.

With normal music recording, no consumer will ever hear the music the same way that it sounded  

when the recording was produced. The creator can't control where it will be listened to, what kind of  

equipment or settings they will use - there's just too many variables. But that's not the case with  

movie theaters. The function of a movie theater is to recreate what was heard on the dubbing stage  

when the film was mixed. We call this "translation". To assist with this process cinema standards have  

been developed over the course of the last 100 years or so by organizations like these,

that govern areas like loudspeaker selection and placement, installation practices,

sound pressure level targets, a very specific sound measurement process, and a well-defined acoustic environment designed to take the "room" out of the mix.

These same standards are also used to design the dub stages where films are mixed. The extent to which these standards are followed determines how close

the translation is. So what exactly is good cinema sound? And why is it so important?

Well, we've already covered "Translation". Next is the removal of coloration of the sound source. The audio system should be neutral, and the room should have as little

impact on what we hear in the audience as possible. Dialogue is king - if the actor's voice is not crystal clear, you've missed the mark.

Even and balanced coverage is critical. Everyone pays the same price so everyone should get  

the same experience right? And finally never ever distract the audience's attention from the screen.

This means that the sound should be localized to the image on the screen, and there should be no  

audible echoes, or rattles and noises in the room. The whole point is to not break from the illusion.  

So how do we get "the best sound system" for an application? We start with the room itself,

the sound system design and the components of the system, and the system installation.

Getting any of these wrong can make the best gear in the world sound bad. But getting them all right will  

get you the best sounding audio system possible for a cinematic experience. First let's focus on  

the room. Good sound (and image for that matter) in any space starts with the Room. The size and shape  

of the room, and its acoustics are two of the most fundamental issues, and they're highly interrelated.

The length to width proportion has an effect on how reflected sound will sum or cancel in the room.

A room with equal proportions is probably the worst shape, followed closely by long, narrow rooms.  

For both acoustics and image, the best room proportions are between 1.2 to 1 up to 1.5  

to 1 length to width. For example, a minimum length for a room that's 30 feet wide would be 36 feet  

using the 1.2 to 1 ratio. The optimal ceiling height is defined by the length to width ratio,

according to this diagram. Based on this chart a room that has a ceiling height of around 19 and  

a half feet and is 30 feet wide would be in the ideal range. Of course sometimes you might not  

have any control over these dimensions, but if you understand that if the room doesn't fall within  

the sweet spot of this chart, you can at least have an informed conversation with your client.

All right let's take a break there, and come back when you're ready!