Unit 49 Brief 1 - Setting Up Sound Production Equipment

PA SYSTEMS

Equipment List:

·       Yamaha EMX 5016 CF

·       ASX 18 dB amp (Mixing Desk), t. amp A1400 (Main Speaker), t. amp A2400 (Bass Boxes)

·       dB Bass Boxes

·       dB Main Speakers

·       Support Pillars

·       XLR Cables

·       Speakon Cables

·       Jack Cables

·       Masking Tape

·       Power Leads

·       Shure SM58 Microphone

Risk Assessment

Risk	Hazard	Resolution
Lifting	Injuring yourself when lifting heavy equipment	Make sure when lifting that you bend your knees
Volume	Exceeding 120dB may burst your eardrums	Make sure that the volume is at a suitable level
Water	Spilling water on equipment making it faulty or even catch fire	Keep water/any liquid well away from the equipment
Equipment	Equipment falling on feet with a chance of injury	Make sure at least 2 people are handling a piece of any equipment at any given time
Wires	If wires aren’t correctly taped then someone could trip and injure themselves	Make sure that wires are correctly taped and out of the way
Electricity	If wires aren’t safe/pat tested then there could be a risk of electrocution	Make sure that all plugs are pat tested and connected correctly
Feedback	Feedback can damage a persons ears due to the increasing frequency	Make sure that levels on the mixing desk are all at an adequate level

How To Setup PA System

Firstly, you need to make sure that the equipment is all in the correct position. This entails the mixing desk being in the centre of the two bass boxes, these should be either side, this creates stereo sound. Stereo describes sound emanating from a speaker on the left and a speaker on the right. Make sure that when moving any item that two people are handling it at any given time.

When the bass boxes and the mixing desks are in the correct positions, connect the poles onto the top of the bass boxes, once they're connected, lift the smaller speakers onto the poles (they don't need to be fastened)

Moving onto the mixing desk, the first thing to do is remove the case by twisting the mechanisms on each side, after this, open the back of the desk, do the same with the bottom box, this will expose the amplifiers.

The setup obviously won't work without power so what you must do is connect a red speakon cable to the right speaker (p.o.v from behind the desk) and a blue speakon cable to the left speaker, do the same with the bass boxes. You also need to make sure that there is a quarter inch jack going from the amplifier to the mixing desk. Lastly what you must do is connect the microphone to the desk, to do this you need to connect an XLR cable from the bottom of the mic (female part) to the XLR slot in the desk (male part). Depending on which slot you've connected the cable to you need to turn on that row and from there you can contract the volume and the effects of the microphone as it comes through the speaker. Lastly you must make sure the desk is connected to the mains, using a kettle connector.

Microphones

How They Work

Dynamic Microphones

There are different types of microphone and they work in slightly varied ways, for example, there are dynamic microphones- in a dynamic microphone the diaphragm is attached to the coil, when the diaphragm vibrates due to the sound waves arriving, the coil moves back and forward past the magnet. This creates a current in the coil, which is transferred from the microphone along the wires.

This small section on the top of the microphone is called the capsule; the whole process of generating electric current is called electromagnetic induction.

     

A good example of a dynamic microphone is the Shure SM58

Condenser Microphones

The condenser microphone, otherwise known as the capacitor microphone works slightly differently to the dynamic microphone, for example- a capacitor has two plates with a voltage between them. In a condenser microphone, one of these plates is made of very light material and acts as the diaphragm. The diaphragm vibrates when struck by sound waves, changing the distance between the plates and in turn changing the capacitance. Specifically, when the plates are closer, capacitance will increase and a charge current is created. When the plates are further apart, capacitance decreases and a discharge current occurs. A voltage is required across the capacitor for this to work. This voltage is supplied either by a battery in the microphone or by external phantom power.

    

    Phantom power is generally considered convenient for condenser microphones, it is the power transmitted through the microphone cable.

 

 A good example of a condenser microphone would be the AKG C100S  

FREQUENCY
Frequency is how many waves occur per second.
Frequency is measured in Hertz (Hz) and Kilohertz (KHz)
The lowest frequency humans can hear is 20Hz and the highest is 17000-20000Hz depending on how old you are, taking into account depletion of hearing.

In music, frequency is controlled by an equalizer, this allows you to raise certain elements of sound, for example, the layout of an equaliser is- Low, Mid, Mid, High- altering the low will change the deeper noises, mainly bass. Altering the mid sections will change the mid frequency sounds, this is usually the main part of the music. Altering the high will change the higher frequency sounds, if the high is the only part turned on then the music will sound tinny.

There are different effects associated with music that manipulate the sound.

REVERB
Reverb is a good example of this as if increased it will cause the music to sound like it's in a hall, or any stage setting. This is because the sound bounces of the walls (reverberates) differently.

GATE
Gate is a more complex example because what gate does is block certain sounds out unless they are at a certain velocity threshold, for example, if you set the threshold to 3000Hz then it will block out anything under 3000Hz.

COMPRESSION
Another effect is Compression, compression narrows dynamic range, making louder sounds quieter and quieter sounds louder, levelling everything for smooth sound. This will make sure that if 3dB is inputted, then 3dB is outputted.

Setting Up A Recording Studio and Recording

• Firstly, you must set up the studio, there are a few steps you must do to achieve this.

-Log into the mac using username: 'teacher' and password: 'sicko'.
-Open Cubase 7 which can be found in applications.
-Click cancel on any popups.
-When loaded, got to file then new project.
-Select 'empty' from the 'more' tab.
-Check the desk is set up (all drivers are connected.)
-Go to project, add track.
-Change the input using the left bar which says mono in.
-Click the small speaker icon on the track to test audio.

• After this, connect the microphones to the wall box in the studio with XLR leads.
• Then, open the mixer in cubase so that you can monitor the levels
• Now, set the gain on the desk
• Optionally, the performer can use headphones to hear the backing track, plug them into the control box
• Finally, you're ready to record, this can be achieved by clicking the red button on the transport bar