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5 Steps to Perfect Live Sound

Working in a studio gives audio engineers countless possibilities for optimising the sound. If all else fails, you can start over and take a new approach. A live mix, however, is a real-time performance, and you only have one take per song. In this blog post, we’ll show you the five most important steps to achieving perfect live sound.

Step 1 – preparation

A good live sound starts with thorough preparation and careful planning. At the event, you should be able to focus entirely on the sound without getting into needless hassle. To ensure that the job runs smoothly, it is essential to obtain information about the event, the venue and the featured artists in advance. A band’s so-called stage rider, which contains details of equipment and technical requirements, can be helpful. The equivalent of this is the venue rider, which lists all the technical conditions at the event location. This way, you can ensure in advance that the necessary equipment and the proper setup are available.

During events such as festivals, local stagehands are usually standing by to keep the changeover time as short as possible, for example, by helping with the wiring of the musicians. A detailed patch list is indispensable for this, both for their and your planning. It should provide all the relevant information about the signal flow at first glance. The following points should be included in such a spreadsheet:

  • Signal labelling (e.g. bass drum)
  • Input slot on the stage box
  • Source (which microphone or which DI box)
  • Special features such as 48 V phantom power
  • Output assignment for monitoring and front PA

This way, even a large band can be set up and ready for the soundcheck in just a few minutes.

It is also helpful to decide in advance how you want to organise the signals in the mixer, and which functions you can actually use – such as group summing and the number of FX sends. Many of the common live consoles are limited in their options. Having a plan how to assign the functions saves time during the event.

Channel setup example
Channel Instrument Signal Microphone Inserts
1 Kick In XLR Shure Beta 91a +48V
2 Kick Out XLR Sennheiser e602-II Gate
3 Snare Top XLR Sennheiser e904 Compressor
4 Snare Bottom XLR Shure SM 57 Phase 180°
5 Racktom High XLR Sennheiser e604 Gate
6 Floor Tom Low XLR Sennheiser e604 Gate
7 Overhead L XLR Sennheiser e914 +48V
8 Overhead R XLR Sennheiser e914 +48V
9 Hi-Hat XLR AKG C430 +48V
10 Bass XLR Direct Out Compressor
11 1st Guitar (Steffen) XLR Direct Out
12 2nd Guitar (Player) XLR Cymatic uTrack24
13 Backtrack Samples L XLR L Cymatic uTrack24
14 Backtrack Samples R XLR R Cymatic uTrack24
15 Vocals Jul (Lead) XLR SE Electronics V7 Compressor
16 Vocals Steffen (Clean) XLR Sennheiser e935 Compressor

On an analog console:
FX Return Drums
FX Return Vocals

If you are not yet familiar with a console, it is also advisable to learn the most important functions in advance. For example: Where is the patch matrix for the input and output routing? How can you customise the user interface (e.g. fader setup)? If you are familiar with the setup, you can configure the console on location in just a few minutes to ensure you are well prepared for the soundcheck and the mix.

Let’s summarise: you were hired by a band to mix their concert. You are familiar with the technical conditions of the location and know what to expect on the day of the event. You are also familiar with the band’s requests and have prepared a patch and mixing desk plan that takes all signals into account. In short: the event is ready to go, at least on your end.

Step 2 setting up the PA

After arriving at the venue and unloading the equipment, the first thing to set up is usually the PA (Public Address). The general aim is to provide an even and balanced sound across the full frequency spectrum in the entire audience area. For small to medium-sized events, this is usually a “stack” system in which the subwoofer and top are stacked on top of each other in a left/right configuration. When the audience numbers get higher, line array systems are more likely to be used – in such venues, the sound system is usually already installed and maintained by local technicians. Nevertheless, a profound understanding of speaker placement is valuable, even if you are not a dedicated FOH engineer. Many sound problems result from suboptimal positioning of the speakers and can usually be significantly improved by small adjustments.

While subwoofers reproduce low frequencies below about 80 to 100 Hz, the tops cover the higher frequencies. As such, they are essential for speech intelligibility and sound transparency. Our tip for aligning the tops: since high frequencies are absorbed more effectively by people and objects due to their shorter wavelengths, it is recommended that the tops be positioned at overhead height and angled slightly downwards. This results in a uniform distribution of high frequencies, and even the rear rows benefit from balanced sound without the sound level becoming uncomfortable for the front row listeners. Line array systems are designed to ensure even sound distribution in the room by angling the individual speakers.

The classic stack system is easy to set up and creates a balanced stereo sound. A disadvantage, however, is the bass propagation: there are “bass holes” in front of the stage where the low frequencies are attenuated. To achieve consistent bass reproduction, a mono bass setup is used: two or more subwoofers are positioned either in front of or below the stage and play the same signal. This results in an equally distributed bass throughout the venue, but often also in a significantly higher bass pressure level on stage. To find the right balance for the audience and the band, a cardioid bass configuration is recommended in larger installations, which specifically focuses the bass to the front. We cover these and many other array techniques in detail in our online course Live Sound Engineering.

In this online course, you’ll learn everything needed to successfully realise and supervise live events.
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Step 3 – calibrating the PA

Calibrating the system is the final step in setting up the system for optimal room acoustics, ensuring that the speakers are in phase and that the frequency response is as flat as possible – the basis for a balanced FOH mix. The calibration should be done before the sound check and the stage entrance of the artists.

Every room has its specific acoustics, and especially at concerts, the acoustics can have a significant effect on the sound. For smaller settings, this level of tweaking may not be necessary, but in larger venues or for professional productions, calibrating the PA will make the difference between a balanced and a diffuse sound. With the measuring systems available today, it is possible to precisely calibrate a PA without spending a lot of money. When it comes to the final result, you should of course trust primarily your ears, but measurements show flaws in the sound that you can’t identify as such by listening alone.

Let’s take as an example the timing differences between a subwoofer and a top speaker. If you use a combination of two different manufacturers or place the speakers physically apart, timing differences can degrade the sound quality. Measurement systems provide a way to determine the delay time, allowing the temporal offset between the speakers to be clearly shown in the impulse response.

Engineers used to rely on real-time analysers (RTAs) and third-octave equalisation to optimise frequency response, but these days, FFT (fast Fourier transformation) offers a more precise solution. FFT isolates the direct signal from the reflected sound and identifies room resonances with great precision. To calibrate the PA, pink noise is used as a test signal, which is adapted to the human hearing in its frequency response. The measurement software – which usually has an integrated signal generator – sends the pink noise to the PA, while a measurement microphone captures the signal in the room. The software compares the captured signal with the original and analyses the room resonances and the impulse response. This allows acoustic parameters such as the frequency diagram, waterfall diagrams and RT60 times to be visualised. The resulting data can now be used to precisely adjust the frequency response using a parametric equalizer.

Step 4 miking

Using microphones on stage is completely different from the way we use them in the studio. When miking instruments and singers on stage, it is not so much about the highest level of sound resolution, fidelity or colouring, but rather that an element is sufficiently audible and can stand its ground in the mix. The focus is on capturing the sounds as isolated as possible with the least amount of effort.

Before you start planning, you should determine which elements need to be miked. The size of the venue in particular has a major impact. A band in a small club automatically generates a considerable sound level due to the stage sound alone. This means that loud signals such as cymbals will probably be heard sufficiently loud throughout the venue and may not need to be picked up by separate microphones. For large events, miking is usually much more complex.

There are mainly two types of microphones used in the live sector: dynamic microphones and condenser microphones. Dynamic mics are particularly robust and resistant to high sound pressure levels, making them the first choice for loud sources such as guitar amps and drum kits. Condenser microphones, on the other hand, capture more detail and are ideal for recording quieter or more nuanced instruments such as acoustic guitar or strings.

Using the best-suited polar pattern helps enormously in isolating individual sounds as much as possible and capturing them without bleed. The more directional a microphone is, the less ambient sound is picked up, as background noise and lateral sound sources are damped. Supercardioid or hypercardioid mics, which have a narrower angle of incidence and attenuate ambient noise more effectively than normal cardioid microphones, are often more suitable. You have to keep in mind, though, that they are more sensitive to rearward sound as well, so avoid placing them with their backs facing monitors or drum sets. A good practical example is a snare drum: the Shure Beta 57A with a supercardioid polar pattern is often used for this both on stage and in the studio. If you do use this mic, you should avoid positioning it with the back facing the hi-hat.

Step 5 – soundcheck and mix

The soundcheck is often the most exciting part of a live production and can be quite challenging for sound engineers. This is ultimately the point at which it becomes clear whether all the previous steps have been carried out properly and all the planning will pay off.

Before you can start the actual mix, it is important to bring all signals to a suitable level. The so-called ‘gain staging’ lays the foundation for the entire mix. In this process, it is essential to leave some headroom for the signals, as the musicians’ enthusiasm during the show often results in louder levels. But it can also go the other way; if there are very quiet passages in the show, it may happen that the channel fader is no longer sufficient to bring the signal up to the desired level. If the console is only responsible for the FOH mix, you can ‘re-gain’ without affecting other stages in the chain (e.g. monitor mixes, broadcast feeds). That is, however, the exception rather than the rule; if possible, the gain and trim settings should therefore be left untouched after the soundcheck.

We recommend starting the soundcheck with the vocals – for two reasons: on the one hand, this establishes a line of communication between the stage and the FOH engineer. On the other hand, in most situations the vocal microphones pick up a lot of bleeding from other instruments (e.g. drums).

Once the vocals have been checked, the drums are usually the next step, followed by instruments such as bass, guitars and keyboards. When you have checked all signals, let the band play a typical song to set the basic levels and balance the frequencies in the mix. Are there still any clashes between instruments that need to be fixed with an EQ? Do instruments or vocals still have too much dynamics?

During the show, transparency is the most important quality of the mix. Make sure that each instrument can be heard clearly. The audience wants to hear all the sounds and make a connection between the visuals and the audio. It is less important that each instrument has an optimal frequency response or is provided with fancy effects.

Another key aspect is speech intelligibility. Make sure that the vocals are clearly audible. However, this does not mean that they have to dominate everything; often it is enough for them to blend harmoniously into the big picture without interfering with other signals. You can also add a few more high frequencies than you would use in a studio mix.

Power and energy make the concert an exciting experience for the audience. In many genres, the kick drum should be heard as well as felt – bass makes people dance, and a good, balanced mix creates a sense of well-being. Find the right balance between the different frequency ranges to achieve a strong mix. A powerful bass range also needs a counterpart: precise mid and high ranges.

Conclusion:

Perfect live sound is the result of good planning, technical expertise and a feel for musical nuances. From preparation to positioning and calibrating the PA to the final mix, each step makes a significant contribution to the overall quality of the sound.

In this short article we could not cover all the important aspects of a good live sound and have only scratched the surface. If you want to deepen your knowledge in the field of live mixing, our online course ‘Live Sound Engineering’ is perfect for you! In this course, you will learn everything you need to successfully handle live events – from technical know-how and the latest technologies to practical tips from experienced professionals. The course not only provides you with a great deal of theoretical knowledge, but also includes numerous exercises that you can put directly into practice.

And if you want to learn a lot more about audio engineering and music production in addition to live sound engineering, take a look at our AUDIO DIPLOMA online course programme.

Author

Simon Erzinger
Simon Erzinger
Music production and the associated sound technology fascinated Simon from an early age. He started teaching himself how to play different instruments as early as his childhood. In the meantime, he produces his own projects and those of others. Due to the sound technical support of numerous events at FoH, he can fall back on an extensive knowledge.

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