Introduction to the Mixing Board

The sound mixing board is the most crucial piece of equipment in the Karaoke Host's toolbox. Sadly, it is also the least understood.

This article is designed to help you learn what the knobs and buttons of the sound board are for and offers a few tips on their operation.

A common configuration is pictured here. The information applies to all sound boards and can be easily transposed by those who do not use this style.

Sections of the Mixer:

In the photo, there are three main sections to the board. The left with all the white sliders is the set of input channel controls. Each slider represents the control for one of the input signals. The middle-right side with the gray sliders is the sub-mix and effects section and the right most with the red slider is the output control. We will go through these sections one by one.

Input Channels:

This section makes up the bulk of the soundboard's area. There may be as few as two channels up to as many as 52 or more depending on the size of the mixer. The average Karaoke Mixer has approximately 8-12 input channels.

The key to this section is the realization that each vertical section is the same as every other vertical section. All the controls effect only the input signal for that particular channel. We will show you what to do with the controls on one of them and this applies to each of them.

At the top of each channel are the input connectors. They are of types XLR, PHONE and RCA depending on the channel. XLR is the typical microphone cord input, PHONO is for instruments and some wireless microphones, and RCA is for your Karaoke Players. (NOTE: Some boards do not have stereo channels with RCA plugs. Just get cables which will patch into the PHONE jacks). Here are pictures of the types of jacks:

Location	XLR	PHONE	RCA
CORD END
MIXER INPUT JACK

Once you have your wires connected to the input jack of the board, you should turn your attention to the first knob on the channel called "GAIN". Think of GAIN as the volume of the raw signal coming into that channel. This is the first, and often most crucial, control you have over the signal as it passes down the vertical channel. Too little gain means that you don't have enough signal to work with through the rest of the channel. Too much means that your signal will be distorted before you get to do anything else with it. You should use GAIN to make all of your input signals clear without distortion. NOTE: Too much signal through the rest of the channel will negate the effectiveness of the rest of the controls to shape the sound. Most GAIN dials also have a red light nearby to indicate when the input is 'clipping' (too loud and distorting). Use PFL's to see an indication of the volume level of this channel on the main level display (Typically green/amber/red light bars for left and right)

The next part your signal travels through is the EQUALIZER for each channel. All boards will have a HIGH, MEDIUM and LOW dials. Some boards will have two MEDIUM dials for greater control - One for high-med and one for low-med. This is where your tonal control should be adjusted - NOT the output EQ. For your Karaoke Decks, I recommend you keep all of these controls on their middle setting. For vocals, you should adjust these depending on the tonal qualities of your singers' voices. There is no substitute for a good ear when setting these controls. Start at the mid-points for all tone controls and adjust as required from there.

Following the equalizer is the effects controls. This is where you set the volume of the signal going to and coming from the effects processors (Most boards like the one pictured will have effects built in. Some will require additional hardware.) If you plan to add reverb or echo to a singer's voice, this is where you select how much of the voice goes into the effect and then how much of the mixed voice and effect will go to the outputs.

There are two buttons on this board below the effects dials. Typically, one is called a PFL (Or Pre-Fader Level) control and the other typically dictates which sub-mix fader control to send this channel's input to. More on this later. It's best to keep the PFL button off. When you're setting your initial levels, use PFL to see an indication of the volume of the signal going into the main fader (or slider). This allows you to gauge the amount of gain you need for a clean signal and what additions to your input signal strength the eq and effects will have. You want to get your signal to the point where the highest volume at most will just barely light the lowest red on your level indicators. Most of your input should light up all the green and some of the amber on the louder parts. When you're done, turn the PFL off so that your level indicators show the entire mix volume level.

Below these two buttons is a PAN dial. This affects which speaker you want the sound from this channel to go to. All the way left means that the sound will only be in the left speaker, Middle means the sound will come equally from both speakers and all the way right means that the sound will come only from the right speaker. (Assuming you are running your speakers in STEREO)

Finally, on the input side, there is the fader or slider control. This adjusts the volume of this input channel in your final mix. All the way to the top means that you are sending the entire signal to the mix. It's best to set this into the indicated 'optimum' area. This is generally indicated on most mixers as being almost to the top, but not quite.

So, Now you have an idea of what each channel's controls do. You can get an input signal from a Mic, Set the initial level, affect the tonal quality with the channel's eq, add effects, test levels, set the speaker(s) you wish the sound to come from and adjust the channel's volume in the overall mix. These settings are absolutely crucial to getting a good final mix through the speakers. There is no substitute for a good ear when setting these controls. This is where the largest challenge of your mixing lies.

The Sub-Mix and Effects Controls:

Some mixers have a section which allow you to control certain portions of your mix together with one volume control. This is more often used when dividing a band's inputs into sections so that you have one fader to control all of the drums, another for guitars, and another for vocals, etc. They are not commonly used like this for Karaoke. One use I have seen them put to is all the Karaoke inputs (Decks and mics) are connected to one fader to turn down the entire mix volume and another channel for some background music while making announcements and changing discs while a third controls the announcements microphone. This is a somewhat more advanced usage and is not fully covered here. For most Hosts, set all of the inputs to the same sub-group. It'll make your life a little easier while you're learning the critical parts of the board.

The effects section on some boards allows you to add reverb, echo, delay or even chorus effects to your inputs. As a general rule of thumb, do not use effects on your Karaoke Decks. Let the music play through as recorded. Add effects as required to the singers' voices. Listen to your singers wishes here and use your ears to determine the type of effect and levels required.

There is also the possibility of having a graphic equalizer in this section too. The tendancy is to set these EQ's to odd shapes like a 'W' or 'M' type of pattern. The best thing to do with this EQ is to set it flat (All faders at the mid point) and use it to lower the ranges which may be contributing to feedback through the system. Use the controls on the input channels to shape the sound, use the Graphic EQ to remove feedback frequencies. This EQ should not be used to enhance sound as it changes ALL the sound through the board and removes much of your individual channels control that you've spent so much time to perfect.

The Output Controls:

Here you have a main amp volume knob to set the output volume of the built-in amp. You should also have the light bars indicating signal levels for the left and right outputs - this is also where you will read the PFL levels. The slider control here allows you to set the volume of the mixed inputs to the amplifier. Please note: You do not necessarily want this to be full volume. Consider the room size and the amount of people. You want to set the volume so that people who want to sing have a good area covered with clear sound and there should be parts of the room where people can still sit and have their conversations. Don't fill the entire room with full volume. That'll just send most of your patrons back out the door and make it very difficult for the servers to take the patrons' orders.

Conclusion:

For the most effective control with the sound board, remember these points:

• Set input gain to a clear level, but not so high that the channel controls are overpowered - This causes distortion and minimizes the available control of the signal while significantly contributing to the possibility for feedback.
• Adjust your tonal quality on the input channels and use the separate graphic EQ for feedback control.
• Most CD-G's are recorded well enough that you can keep the EQ on these channels flat (Mid-point on all tone controls)
• Easy on the effects and choose them wisely. A little reverb goes a long way. Do not run the Karaoke Decks through effects.
• Output volume does not have to be at the maximum available. Use your ears, and your clients' ears to gauge appropriate levels.
• Set the singers' microphones at a level slightly higher than the accompanying music. You want the voices to come through clearly and not be overpowered by the music tracks.

This concludes our quick introduction to the sound board. Most of the controls discussed here are found on the typical mixers used for Karaoke. Above all, Have fun and experiment a little with the boards when you can so that you can learn more about how the controls can affect the overall mix coming through the speakers. There is no substitute for a good ear - both in gauging the sound quality and in listening to your audience for their constructive criticisms.