Mackie SR24-4 Mixer
Features of the channel strip
Mixer Tecnology
The equalization section of this mixing board is used to help shape the tone of the sound going into the imput . The high frequency range is 12k it is used for treble cut or boost the mid range of the sound.There is also a section called frequency which is the sweepable mid range. This knob is used to set the frequency range of the mid eq.The low eq is a fine bass control with the same range as the low eq in the mackie 8 bus console,the low cut is a switch that inserts a 18db octave low cut filter with a cut off frequency of 75hz into the signal path.
There is also a knob called the pan, this is used to control which speaker the output is coming from. The pan can be set to the left, right, or to the middle.Panning to the middle sends the output though both speakers.
The mute button is used to stop all sounds coming out of the output. This is used for a simple stop of all sounds coming from a particular channel.
The L/R assign switch can assign the submix audio to the main left or right buses.This allows you to submix several channel strips to one fader for eaiser control, and then reassign that bus into your final mix.
The solo button solos the submix in the same manner as the channel solo switch. The subsolo LED flashes when this solo is used.
The main mix fader is used to control the output level of the imput. This goes up to a 10db boost in your signal.
Upper EQ/ Aux. Sends
Aux 1 and 2 are pre fader with the channel signal tapped off after the input amp, insert jack and mute switch, but before the EQ and the fader.Aux 5 and 6 are post faders with the signal coming from a point in the circuit just after the channel fader. Aux 3 and 4 are normally post fader ( much like sends 5 and 6), but can be switched as a pair to pre fader by depressing the pre switch in the aux section of the channel switch.Pre fader sends are generally more useful as monitor or headphones sends, while post fader sends are usually routed to reverb, or other effects.
Mix and Submix Bus
In conjuction with the pan pot, the bus assignment switches next to the fader route the signal out of the channel switch.
With no assignment switches depressed, it doesn't make any difference which way you have the signal panned. It does not go anywhere. Sometimes this is a good thing, if you are using the insert jack as a direct output and want to keep the signal out of the main mix.
But most of the time, you will want the signal to go to either the main mix or one of the submix buses. For stereo, you will want to depress the assignment switch on the subgroups you want and then pan the signal to it's rightful place on the soundstage.
You may want to operate the four submixes as four mono buses. In that case, use the assign switches with the pan pot panned completely to the L or R mark. This will allow you to select submix buses 1,2,3 or 4 independently.
Glossary
Amplitude: The level of a varying signal. All elsebeing equal, a signal with a higher amplitude will Sound louder than one with a lower amplitude. When a signal's amplitude becomes too large for a circuit to pass it, distortion is the result.
Attenuation: When an electronic circuit passes a signal and decreases its amplitude, the resulting signal is said to have been attenuated. The difference in level beween the original signal and the softer one can be exprissed in decibels, a logorithmic scale used to describe the difference in level between signals.
Audio Signals: Sound is carried by the air. But mixers work with electricity, not changing air pressure. Sound can be transformed into electrical signals by microphones. We call electrical signals Audio signal.
Bus: In a mixer, there is a point where individuals input signals come together and are combined, or mixed. This point is called a mixed bus.
Channel: The controls associated with one mixer input is called the channel. A channels controls are grouped in vertical columns, separate from the mixer output section.
Direct Box: A piece of equipment (usually a small metal box) designed to convert a 1/4" unbalanced signal into an XLR signal suitable for connecting to a microphone input.
Direct Out: An output from a single channel that is extracted from your mixer at an insert point, but doesn't get connected back to the mixer.
Distortion: a result of clipping…when an audio device tries to reproduce a sound that is too loud for it to handle.
Equalization: This is the type of mixer control that can change the amplitude of particular parts of a sound frequiency components, or harmonics. For example, a control that affects only the low frequencies of a sound can make the overall sound fuller, by boosting the level of the low frequencies, or thinner by cutting them.
Fader: On mixers and other electronic control panels, a fader is a control that changes the level, or amplitude, of a signal. Typically, a fader is assumed to be a control that travels is a straight line, like the white capped sliders on the 1604. In audio-circles, a fader is assumed to control the volume, or amplitude of an audio signal. Technically, faders can be rotating knobs as well.
Feedback: A condition where an output is connected back to its input (feeding back) can result in a runaway situation if the signal is amplified during a each successive round-trip. A microphone turned up and placed near the loudspeaker that is reproducing that mic's signal is likely to begin feeding back.
Gain: When an electronic circuit increases the amplitude of a signal, it is said to have gain. The amount of gain is measured in decibels, a logarithrithmic scale used to describe the difference in level between signals. Circiuts which reduce the amplitude of a passing signal are called attenuators. The special case when a signal is passed whithout changing levels is called unity gain.
Insert: A connector (also called channel access or insert Point) on a mixer channel that allows the channel's signal to be extracted, passed through an external signal processor and then returned back to the input channel.
Level: See amplitude
Oscillation: In the phisical world and the domain of electronic circuits, oscillation is something engaged in a regular back and forth motion. In the real world, oscillation bodies create sound by pushing against the air.
Output Section: The portion of a mixer that controls the main stereo output volume and other mixer functoins that apply to signals coming from individual mixer channels is called the output section.
Phantom Power: High-quality "Condenser" microphones need external power to operate. Phantom power is a voltage supplied to the mics through pins 2 and 3 of the XLR mic cable itself. Turning on the phantom swith causes 48 volts of DC (direct current) to appear at all Mackie Mic inputs.
Reverb: When a sound wave encounters a solid object, it may be partially absorbed or reflected away from it, depending on the nature of the surface. Within a confined space, reflected sound can bounce back and forth repeatedly until the sound slowly dies away. These reflecections are called reverbaration. Clap your hands in most large buildings for a demostration.
Signal Flow: The path an audio signal takes beween the input and output of a piece of audio equipment. Understanding this path makes it possible to understand and correctly predict how your sound system will work in different configurations.
Signal Processor: In general terms any electronic circuit that lakes an input signal and modifies it in some way. Typically, the term is used to refer to specialized equipment separate from your mixer, like reverb or echo devices as well as equalizers, compressors and others.
TRS: An abbreviation for Tip-Ring-Sleve, this audio connector is a three conductor version of the common "guitar cord" connector, the 1/4 phone plug. Sometimes called "RTS".
Waveform: A waveform is a visual representation of a sound wave, tracing its frequency and amplitude.
Connecting and Recording
In general, recording connections follow this pattern: