Have you ever tried figuring out how the different audio inputs from various instruments and mics onstage come out of the loudspeakers balanced and pleasant to listen to? If you have, you’re not alone, for when I was a bit younger, I also had been perplexed by it, and now that I am old, I entirely understand that it is because of the mixer that makes possible all these balanced sounds from the loudspeakers.
If sound balancing is a war, the mixer is the headquarter where all the potential actions are coordinated. It is the hub where all the inputs from instruments, mics, FX, and many others are processed, controlled, and then rerouted to the specific channels or outputs.
Mixing consoles vary from each other. You can find high-end mixers with complicated and innovative features. You can also find low-end mixers that let you do the very basics of mixing. Nevertheless, they all perform the same essential functions.
How Does Audio Mixer work In Live Sound?
Mixing consoles are essential to sound reproduction and recording. It is the device that you would use to combine sounds coming from different devices. The audio inputs that go into the mixing console include audio inputs from singers’ microphones, acoustic instruments, electronic and electric instruments, or recorded audio inputs.
Mixers can also control digital or analog signals, depending on the mixing console type. These signals are then modified by the mixers and summed up to come up with mixed output signals.
The mixing process is an essential process when you perform live or record music. It makes sure that no individual signal input becomes overpowering than the others.
If it is your first time using or seeing a mixer, you will be taken aback by the myriads of channels in a mixing console. Yet, once you start tinkering with its channels and knobs, you will quickly get the hang of its use.
Once you’ve connected the instruments and mics, you can begin adjusting each input volume until you get the right mix.
The typical consoles come with 8 to 32 channels, stereo “main outputs, multiple aux outputs for outboard effects and stage monitors, and a few subgroups. Once you’ve processed the signals, you can then route all channels to the main stereo outputs. From there, you can send the outputs to the PA system so that the audience can enjoy the mixed signals.
Techniques for Setting Up the Live Sound Inputs and Sound Outputs
The work of setting up the mixer for live sound is not for the newbies who have not yet tried such a setup. But if you want to know and learn the process, you can check out the following techniques:
If you are just beginning to tinker with the mixing console, you will discover that the typical mixing console has 16 channels with microphone options, aux sends, and inserts. If you want to mix the sound inputs from a 4-piece band like the Queen, for example, you will be working with two guitars, one bass, drums, and four vocals, because each of them will be singing.
The typical monitors’ setup includes four stage monitors: the center stage, stage right, stage left, and upstage near the drummer. Furthermore, you can connect these monitors to Auxes one to four.
You will also have two FX processors, one for the delay and one for reverb. Moreover, you can connect the delay to Aux 6 and the reverb to Aux 5. Besides, you can use this setup as your guide, at the onset, for your first mixing gig.
The endpoints of your signal chain are the speakers. They are the ones that broadcast the mixed sounds. Speakers can either be passive or active. Active speakers, of course, are powered speakers. They come with a built-in power amp. Thus, you need to plug in the IEC cable to the power outlet to make them work.
You will often find these speakers in portable systems. Moreover, you can connect the active speakers to your mixing console using a TRS or XLR cable. Connect one cable end to the mixing console main outputs and one end to the speakers.
Passive speakers, on the other hand, are not powered. Thus, you must connect them to an external power amp to make them work. You will often find these speakers in permanently installed sound systems.
You can connect the passive speakers to your mixing console by running an XLR cable from the main outputs to the power amps. Then, connect the power amps’ outputs to the speakers’ inputs using Speakon cables or TS cables. It will be useful to note that you need to pair each speaker with a GEQ along with a matching power amp.
Your system will undoubtedly include many subwoofers for enforcing the low end. Nevertheless, if you are using two active subwoofers, you can route your mixing console outputs to the subwoofers’ inputs. Afterward, you can utilize the “thru” outputs for connecting the subwoofers using XLRs to the active “tops.”
Active subwoofers come with built-in “crossovers“. These components split the signal into two: the low frequencies going to subwoofers and other signals going to the mains. You need to avail of an outboard crossover if you are using passive speakers.
Sometimes, you will need more subwoofers for a show or gig. In such a case, you must utilize a speaker management system that comes with many digital signal processors like compression, EQ, and stereo imaging. These DSPs let you separate a stereo signal into eight outputs or more. In doing so, you get ample elbow room to come up with multiple subs.
A mixing console setup for live sound will never be complete without the needed monitors. The band members, for example, need to hear themselves to ensure that they are playing in synchrony. You can connect the stage monitors in a similar fashion that you have connected the mains. Nevertheless, instead of using the main outputs, you will need to utilize the aux outputs.
Each stage monitor necessitates an aux send and graphic EQ. To connect each stage monitor, you can begin at the console. Hook the aux outputs to that of the GEQs. Use either a TRS or an XLR cable to connect them. Afterward, hook the GEQs using a TRS or XLRs to those of the power amps. Lastly, you can connect the monitors to the power amps using Speakon or TS cables.
Setting Up the Microphones
The show will not start without the microphones. So, you need to set up the microphones with stands for each band member. If you are setting up for a band like Queen, you need to set up four mics. You need to set up mic stands for each guitarist. For drums, you need to set up the stands and mics for the snare, kick, hi-hat, overhead, and toms.
Figuring Out the EQ Settings
Once you’ve set the mics, you can then tinker with the EQs. Using an analog console, you will see that it comes with 4 band semiparametric EQ. The looks of it may intimidate you, but they are not what they appear to be.
You will have a fixed high band and low band while adjusting the frequencies and gain. You will also see a bell-shaped high-mid and low-mid band that comes with adjustable frequency, gain, and Q parameters. Lastly, you will see a high-pass filter switch that you would set to a particular frequency and slope.
Utilizing the Aux Sends
Your signal would pass through the Aux Sends. The typical analog console comes with four or more aux sends. You can utilize the aux sends to duplicate signals. You can then channel the signals to one or two endpoints: the FX processors or the stage monitors. You can look for the desired channel at the Aux Send section. Then, turn up that specific send relative to the Aux.
Nevertheless, you need to check the board’s back if the Aux Outputs are connected to the right FX processors or stage monitors. When utilizing the FX processors, you may route from the Aux Sends a signal. Yet, you can never hear it. If you want to listen to it, then you must return the signal to you as well. Many consoles come with a Stereo Aux Returns for FX.
You can also find the Aux Master section at the console’s center portion. It has the master volume control for every Aux Send. You can use it if you have the right balance but want less overall volume. Turn it up to ensure that you can send signals.
Tinkering with the Fader, Pan Knob, and Routing Buttons
Most signals during a live mix are panned towards the center. You may occasionally pan the tom a bit to the right or left or move one signal over there to unclog the busy mix. Nevertheless, panning signals in the center is the best thing to do for live sound. It is reasonable, of course, to pan signals if your crowd are all wearing headphones. Yet, it doesn’t make sense to overdo the panning during the live mix. Moreover, more issues would emerge when you pan a lot during live performance.
With regards to the fader, you can get the hang of the fader by feeling it. If you are using an analog console, you will see some buttons like the M1=2, 3=4, next to every fader. These buttons let you send a signal to the subgroups or the mains.
You can process individual signals using the channel strips. Then, use the subgroups for balancing the mix. In doing so, you are in a better position to balance the levels by way of controlling many mics at the same time. This leaves your free hand for mixing and running lights and effects.
Volume and Panning Adjustment
Once you’ve set each channel correctly, you can have a warmup jamming for the musicians. Let them play one of their songs. Then, take that time to adjust the volume through the faders to achieve a well-balanced output. It will be useful to remember that you need to make the less sounding inputs audible to the listeners.
Be mindful of the balance between the instruments and vocals. Make sure the instruments do not overpower the vocals. You can likewise adjust the left-right balance of sounds. You can use the PAN controls for this purpose.
It will be useful to pan the bass guitars and kick drums to the center. In doing so, you balance the music. Moreover, it will also help to pan the vocals to the center for a more balanced mix. You will get the hang of panning as you often practice mixing live sounds.
As an aspiring sound engineer, you need to have a solid understanding of how signals flow. Without such knowledge, you will never thrive as a sound engineer. You need to figure out where you will channel signals and where these signals must go. To achieve such skills, you need to know the different PA system components and how each piece works.
As mentioned above, the mixing console is your hub from where you can control all the inputs and process and route the right outputs. Thus, it behooves you to understand the mixing console and master how to use it for live sound mixing. With the mastery of the mixing console, you can claim that you are indeed an able sound engineer.