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MG12/4FX

8

Making the Most Of Your Mixer

A balanced cable has three conductors:

1)

A ground conductor which carries no signal, just the “ground” or “0” reference against which the signal in the other
conductors fluctuates.

2)

A “hot” or “+” conductor which carries the normal-phase audio signal.

3)

A “cold” or “–” conductor which carries the reverse-phase audio signal.

While the desired audio signals in the hot and cold conductors are out of phase, any noise induced in the line will be exactly the
same in both conductors, and thus in phase. The trick is that the phase of one signal is reversed at the receiving end of the line so
that the desired audio signals become in-phase, and the induced noise suddenly finds itself out of phase. The out-of-phase noise
signal is effectively canceled while the audio signal is left intact. Clever, eh?

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 nominal (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 sensitivity to the signal. More on this later.

Normal-phase signal

+ normal-phase noise.

Normal-phase signal

+ reverse-phase noise.

Desired signal 

with no noise.

Summary of Contents for 4FX

Page 1: ...MIXING CONSOLE MIXING CONSOLE Owner s Manual Owner s Manual Making the Most Of Your Mixer Pages 6 to 16 EN ...

Page 2: ...e precautions include but are not limited to the following Remove the electric plug from the outlet when the device is not to be used for extended periods of time or during electrical storms When removing the electric plug from the device or an outlet always hold the plug itself and not the cord Pulling by the cord can damage it To avoid generating unwanted noise make sure there is 50 cm or more b...

Page 3: ...RMATION U S A 1 IMPORTANT NOTICE DO NOT MODIFY THIS UNIT This product when installed as indicated in the instructions contained in this manual meets FCC requirements Modifica tions not expressly approved by Yamaha may void your author ity granted by the FCC to use the product 2 IMPORTANT When connecting this product to accessories and or another product use only high quality shielded cables Cable ...

Page 4: ...26 Specifications 26 Dimensional Diagrams 28 Block Diagram and Level Diagram 29 Features Input Channels page 21 With up to six mic line inputs or up to four stereo inputs the MG12 4FX can simultaneously connect to a wide range of devices microphones line level devices stereo synthesizers and more For exam ple you can connect four microphones and four ste reo devices or six microphones and two ster...

Page 5: ...a standard household power outlet Be sure to unplug the adaptor from the outlet when not using the mixer or when there are light ning storms in the area To avoid generating unwanted noise make sure there is 50 cm or more between the power adaptor and the mixer Turning the Power On Press the mixer s power switch to the ON position When you are ready to turn the power off press the power switch to t...

Page 6: ... isn t used much these days besides it s too easily confusable with phone jacks below RCA pin jacks are always unbalanced and generally carry a line level signal at 10 dB nominal You re most likely to use this type of connector when connecting a CD player or other home audio type source to your mixer or when connecting the output of your mixer to a cassette recorder or similar gear The Versatile P...

Page 7: ...basically confined to your desktop and all connections are no more than a meter or two in length then unbalanced lines are fine unless you re surrounded by extremely high levels of electromagnetic noise Another place balanced lines are almost always used is in microphone cables The reason for this is that the output signal from most microphones is very small so even a tiny amount of noise will be ...

Page 8: ...oustic 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 nominal average level of 10 dB Professional audio gear usually has line i...

Page 9: ... or a full blown 4 band parametric EQ When boost is applied the EQ stage also has gain You can actually overload the input channel by applying too much EQ boost It s usually better to cut than boost 3 Channel Peak LED Fader The channel peak LED is your most valuable tool for setting the input gain control for optimum performance Note that it is located after the head amp and EQ stage Master Sectio...

Page 10: ...at the amount of noise added by each stage is usually not dependent to any significant degree on the level of the audio signal passing through the circuit This means that the bigger the desired signal the smaller the added noise will be in relation to it In tech speak this gives us a better signal to noise ratio often abbreviated as S N ratio All of this leads to the following basic rule In our mi...

Page 11: ...l to each channel one at a time have singers sing players play and playback devices play back at the loudest expected level Gradually turn up the input gain control while the signal is being applied to the corresponding channel until the peak indicator begins to flash then back off a little so that the peak indicator flashes only occasionally Repeat for each active channel Raise your master fader ...

Page 12: ...s Monitor Mixes and Groups pre post A pre fader signal is taken from a point before the channel fader so the send level is affected only by the AUX send level control and not by the channel fader Pre fader sends are most commonly used to provide monitor mixes A post fader signal is taken from a point after the channel fader so its level will be affected by both the AUX send level control and the c...

Page 13: ...faders simultaneously Group buses usually also have their own outputs so you can send the group signal to a different external destination from the main mix Channel faders Assigned to Group Controlled As a Group Stereo Master Fader Group Fader Channel faders Assigned to Stereo Controlled Individually A group of channels whose levels need to main tain the same relationship a drum mix for example ca...

Page 14: ...ter to a specific channel although they can be used with just about any type of in out processor Channel insert jacks must be used with a special insert cable that has a TRS phone jack on one end and mono phone jacks on the split Y end One of the mono phone jacks carries the send signal to be fed to the input of the external processor and the other carries the return signal from the output of the ...

Page 15: ... the bass and drums to support the overall sound Example2 Funky R B Groove The approach will be totally different if you re mixing a funky R B number that centers on the groove In this case most engineers will start with the drums and then add the bass The relationship between the drums and bass is extremely important to achieve the drive or groove the music rides on Pay particular attention to ho...

Page 16: ... boost is that it adds gain to the signal increasing noise and potentially over loading the subsequent circuitry 5 4 Ambience Judicious application of reverb and or delay via the mixer s AUX busses can really polish a mix but too much can wash out the mix and reduce overall clarity The way you set up your reverb sound can make a huge difference in the way it meshes with the mix Reverb Delay Time D...

Page 17: ...h set ting the mixer does not apply this HPF to the line inputs of stereo input channels 4 Equalizer HIGH MID and LOW This three band equalizer adjusts the channel s high mid and low frequency bands Setting the knob to the position produces a flat frequency response Turning the knob to the right boosts the corresponding frequency band while turning to the left attenuates the band The following tab...

Page 18: ...ven channel feed to the Group 2 bus or the Stereo R bus On channels where this knob provides both PAN and BAL controls 5 6 and 7 8 the knob operates as a PAN control if you are inputting through the MIC jack or into the L MONO input only and operates as a BAL control if you are inputting into both L and R inputs 9 ST Switch This switch assigns the channel s signal to the Stereo L and R buses To se...

Page 19: ... identical signal to both the L and R Stereo buses 6 2TR IN Control Adjusts the level of the signal sent from the 2TR IN jack to the Stereo bus 7 PHANTOM 48 V Switch This switch toggles phantom power on and off If you set the switch on the mixer supplies power to all channels that provide XLR mic input jacks CHs 1 4 5 6 7 8 Set this switch on when using one or more condenser microphones When this ...

Page 20: ...ect to be applied You can select from 16 effects as shown in the table PARAMETER Control Adjusts the parameter depth speed etc for the selected effect The mixer saves the last value used with each effect type When you change to a different effect type the mixer automatically restores the value that was previously used with the newly selected effect regardless of the current position of the PARAM E...

Page 21: ...sible phase conflicts with other signals 3 Channel Input Jacks These are unbalanced stereo line input jacks Two jack types are provided phone type CHs 5 6 to 11 12 and RCA pin type CHs 9 10 11 12 Where a channel provides both a phone jack and an RCA pin jack you may use either one of these jacks but you may not use both at the same time Please connect to only of these jacks on each chan nel 4 GROU...

Page 22: ...ording device side 0 2TR IN Jacks These RCA pin jacks input a stereo sound source Use these jacks when you want to connect a CD or DAT directly to the mixer for monitoring You can adjust the signal level using the 2TR IN control in the Master Control section A FOOT SWITCH Jack This phone input jack can connect to the separately sold YAMAHA FC5 foot switch With the foot switch connected you can use...

Page 23: ...k you may use either one of these jacks but you may not use both at the same time Please connect to only one of these jacks on each channel To avoid causing damage to speakers power up the devices in the following order Peripheral devices mixer power amps or powered speakers When shutting the system down turn off the power in the opposite order Power amps powered speak ers mixer peripheral devices...

Page 24: ...DI Microphones Monitor Speakers Internal Power Amp CD Cassette or DAT Recorder Synthesizer Effector Bass CD Player Microphones Headphones Main Speakers External Example of Speaker Arrangement Audience External Stage Internal Drums Effector Foot Switch YAMAHA FC5 Guitar Power Amp ...

Page 25: ...orts are screwed onto the unit Use a screwdriver to remove these supports Turn the supports over and fasten them into place again using the same screws Mount the unit into the rack and fasten it into place Do not install the mixer near power amps or other heat generating devices 1 2 3 ...

Page 26: ...CH to ST 62 2 dB CH MIC INPUT to AUX SEND PRE 76 dB CH MIC INPUT to AUX SEND POST EFFECT SEND 86 dB CH LINE INPUT to GROUP OUT ST OUT CH to ST 58 dB ST CH MIC INPUT to GROUP OUT ST OUT CH to ST 84 dB ST CH LINE INPUT to GROUP OUT ST OUT ST CH to ST 58 dB ST CH LINE INPUT to AUX SEND PRE 47 dB ST CH LINE INPUT to AUX SEND POST EFFECT SEND 57 dB ST CH INPUT to GROUP OUT ST OUT ST CH to ST 34 dB RETU...

Page 27: ...mV 60 dBu 0 775 mV 40 dBu 7 75 mV XLR 3 31 type balanced 16 36 dBu 12 3 mV 16 dBu 123 mV 10 dBu 245 mV ST CH LINE INPUT CH5 L CH6 R CH7 L CH8 R 34 10 kΩ 600 Ω line 54 dBu 1 55 mV 34 dBu 15 5 mV 14 dBu 155 mV Phone jack unbalanced 10 10 dBu 245 mV 10 dBu 2 45 V 30 dBu 24 5 V ST CH INPUT CH9 L CH10 R CH11 L CH12 R 10 kΩ 600 Ω line 30 dBu 24 5 mV 10 dBu 245 mV 10 dBu 2 45 V Phone jack unbalanced RCA ...

Page 28: ...Appendix MG12 4FX 28 Dimensional Diagrams 317 4 416 6 325 6 102 6 2 108 322 480 322 When mounted on rack Unit mm ...

Page 29: ...Appendix MG12 4FX 29 Block Diagram and Level Diagram ...

Page 30: ...MG12 4FX 30 MEMO ...

Page 31: ...lano Italy Tel 02 935 771 SPAIN PORTUGAL Yamaha Hazen Música S A Ctra de la Coruna km 17 200 28230 Las Rozas Madrid Spain Tel 91 639 8888 SWEDEN Yamaha Scandinavia AB J A Wettergrens Gata 1 Box 30053 S 400 43 Göteborg Sweden Tel 031 89 34 00 DENMARK YS Copenhagen Liaison Office Generatorvej 6A DK 2730 Herlev Denmark Tel 44 92 49 00 NORWAY Norsk filial av Yamaha Scandinavia AB Grini Næringspark 1 N...

Page 32: ...ical Instrument Division Yamaha Corporation 2004 Yamaha Corporation WC71270 408CRAP8 3 01A0 Printed in China Yamaha Pro Audio global web site http www yamahaproaudio com Yamaha Manual Library http www2 yamaha co jp manual english ...

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