Important Concepts To Understand; Understanding The Mixer - Roland VS-880EX Application Manual

Important Concepts to Understand

Understanding The Mixer

In order to make best use of your VS-880EX, an understanding of the built-in digital mixer is required. This
will save you valuable hours later when you are trying to figure out why you can't hear the reverb, why
there is EQ on the bass drum, and why you cannot hear anything in your headphones.
The term 'MIXER' is normally applied to any electronic device that 'mixes' one or more audio sources and
routes them to one or more destinations.
Signal Flow
What is signal flow and why do you need to know anything about it? Signal flow describes how your
music (the signal) flows through the VS-880EX.
There are six important signal flow concepts to understand:
DIRECTION – In order to understand the signal flow of your VS-880EX or any audio device, you
should first understand that the audio signal (your music) is always traveling in one
direction. It might travel from point A to point B to point C to point B to Point D to Point A,
etc.; however, it is always travelling FROM one place TO a different place. It may even
travel to one or more destinations at the same time, but it is always travelling FROM > TO.
INPUT – Where your music travels 'TO' is called an INPUT. Every audio amplifying, processing, or
mixing device has one or more inputs. You "put a signal IN" to an INPUT. Many terms are
used to describe an audio signal going IN to an INPUT. e.g. You 'feed' the guitar into the
guitar amp. You 'send' the signal to a reverb device. You 'buss' the piano track to an
equalizer. Whatever term you use, you will notice that your music is always traveling
towards an INPUT. Even when the music is played through a speaker, it is traveling to your
ear - an INPUT. Some devices have multiple inputs, some have analog and digital inputs,
and some have different 'level' inputs (discussed later).
OUTPUT – Where your music travels 'FROM' is called an OUTPUT. You receive an audio signal
from an OUTPUT. For example, the speaker terminals on the back of your Hi-Fi amplifier
are the OUTPUTS of the amplifier, the phone jack on your guitar is the OUTPUT of your
guitar, etc.
SIGNAL PATH – The signal path is the wire (conduit, pipe, conductor, etc.) that carries your audio
signal (the music) from an OUTPUT to the next INPUT. For example, the wire between your
Hi Fi amplifier and your speaker is a SIGNAL PATH. This wire carries the music from the
amplifier to the speaker. Your guitar cord is a signal path. It carries the OUTPUT of the
guitar to the INPUT of your guitar amp or VS-880EX.
BUS – A BUS is a special type of signal path to which a number of inputs may be connected for feed
to one or more outputs. In a mixing console a BUS is usually a long piece of wire to which
any input channel may be connected by means of a switch or push button. The end of the
wire (bus) goes into a combining amplifier or summing amplifier to combine all the INPUTS
together. The combining amplifier then feeds one of the console outputs.
LEVEL – The last item to consider about signal flow is the level or volume of the signal.
Audio signals can be very low level (the output of a dynamic microphone if you whisper into it) or
extremely high level (the output of your 400 watt power amplifier).
There are two basic audio levels of interest when using your VS-880EX – Microphone Level and Line
Level. The term of measurement for level is the decibel (dB). This is not the place for a complete
description of the decibel, however, a few numbers are handy to remember.
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VS-880EX Application Guide