Yamaha MG16XU Musical Toy Instrument User Manual


 
Making the Most Of Your Mixer
MG16/4, MG12/4
9
1-3. Signal Levels—Decibel Do’s and Don’ts
From the moment you start dealing with things audio, you’ll have to deal with the term “decibel” and its
abbreviation, “dB”. Things can get confusing because decibels are a very versatile unit of measure used
to describe acoustic sound pressure levels as well as electronic signal levels. To make matters worse there
are a number of variations: dBu, dBV, dBm. Fortunately, you don’t need to be an expert to make things
work. Here are a few basics you should keep in mind:
“Consumer” gear (such as home audio equipment) usually has line inputs and outputs with a nomi-
nal (average) level of –10 dB.
Professional audio gear usually has line inputs and outputs with a nominal level of +4 dB.
You should always feed –10 dB inputs with a –10 dB signal. If you feed a +4 dB signal into a –10 dB
input you are likely to overload the input.
You should always feed +4 dB inputs with a +4 dB signal. A –10 dB signal is too small for a +4 dB
input, and will result in less-than-optimum performance.
Many professional and semi-professional devices have level switches on the inputs and/or outputs
that let you select –10 or +4 dB. Be sure to set these switches to match the level of the connected
equipment.
Inputs that feature a “Gain” control—such as the mono-channel inputs on your Yamaha mixer—will
accept a very wide range of input levels because the control can be used to match the input’s sensi-
tivity to the signal. More on this later.
MG12-16_E.book Page 9 Monday, May 26, 2003 1:14 PM