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I have been watching the 2022 FIFA World Cup.

Even with all the noise coming from crowds and commentators, you still can hear the sound of the ball being kicked loud and clear.

Even if the ball lands on a player's chest, it's still audible.

We can hardly hear players shouting, but the ball is very clear.

The microphones on the field should pick up all sounds, but they aren't, they only pick up the ball sounds. Why is that?

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  • Mic settings most likely. The mics around the pitch are the same.
    – dly
    Commented Nov 26, 2022 at 20:42
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    I don't think this is exclusive to the 2022 FIFA World Cup. I think this has been the case for years.
    – F1Krazy
    Commented Nov 26, 2022 at 21:12
  • @F1Krazy so why is this happening ?
    – asmgx
    Commented Nov 27, 2022 at 7:23
  • Most likely what dly said - microphone settings - but I'm reluctant to make that an answer because I have no proof.
    – F1Krazy
    Commented Nov 27, 2022 at 10:46
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    They do pick up the sounds of players and managers shouting, occasionally you will hear them shouting, but there is the literal noise of everyone else in the stadium that makes it harder to pick out. Whereas there should only be one ball being kicked so its easier to pick out. You can also hear the refs whistle quite easily until everyone is whistling at the end of the match. Commented Nov 28, 2022 at 11:36

1 Answer 1

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tl;dr summary: A lot of highly-directional microphones specifically for picking up the sound of the ball, mixed automatically based on live ball tracking data.

The microphones on the field should pick up all sounds, but they aren't, they only pick up the ball sounds. Why is that?

There are a number of microphones whose sole job it is to pick up the sound of the ball, nothing more. These microphones are typically highly directional "shotgun" type microphones that are designed to pick up sound mostly coming from directly in front of them and reject sound coming from the sides or behind:

Example of a shotgun microphone

[Example of a shotgun microphone. (Audio-Technica AT815a shotgun microphone from the 1990s.)—Source: Wikimedia Commons.]

Popular ones are the Neumann KMR-82i or the Schoeps CMIT series.

FIFA matches use at least 12 microphones solely for close ball mixing.

These microphones are mounted in regular intervals around the pitch, facing inwards. There are also microphones mounted on the sideline cameras and goal cameras, under the assumption that those cameras will mostly be pointed towards the ball. They might also be mounted on robotic rotating stands, although that is uncommon.

The "simple" problem now is to mute all the microphones except the one that is pointing the most closely and the most directly at the ball, and to constantly adjust the levels of the microphones as the ball is moving.

Traditionally, it was the job of the audio engineer (or an assistant) to always follow the ball.

Nowadays, there are automated systems for close ball mixing which can support the audio engineer.

These systems know where the microphones are placed, what kind of microphones they are (e.g. directivity, polar pattern, etc.), and where they are pointed. These parameters are configured before the beginning of the match (or, for the camera-mounted microphones, the system just assumes that the camera is pointing towards the ball or it can even get more accurate information from sensors on the camera). The system could even point the microphones itself by using robotic rotating mounts.

In a lot of cases, no configuration is necessary because the exact placement, configuration, and sometimes even brand and type of the microphones are standardized and enforced by the promoter of the match (e.g. FIFA, UEFA, DFL). For example, the German Football League's subsidiary Sportcast, which acts as Host Broadcaster for Bundesliga, Bundesliga2, and DFL-Supercup not only specifies the exact number and placement of microphones, but also mandates the use of a particular brand of close ball mixing system.

During the match, the system constantly receives a stream of tracking data from a tracking system, i.e. the same system that is used to, e.g., display stats about how many kilometers each player has traveled, possession percentage, etc. Through this tracking data, the system always knows exactly where the ball is.

Here you can see an example of such a system in action, using 12 static, non-moving microphones. The yellow points are the referees, the red ones the players, and the white point is the ball. The white arrow indicates the velocity vector of the ball. The 12 circles are the microphones, the "fill" of the circles indicates the level of this particular microphone at any point in time. The level is also indicated by the number inside the circle.

Lawo Kick

Here is a marketing-focused high-level explanation and demonstration of such a system, given at the introduction of the product. Here you see an example of rotating microphones:

And here is an example of a close ball mixing system controlling robotic rotating microphone mounts:

Note that to my knowledge, such robotic mounts are not actually in use.

There are certain Quality Control parameters that these systems are optimized for. For example, the avoidance of a double event, i.e. when different microphones at different distances pick up the sound at different times, which leads to the audience hearing the kick twice. This is practically unavoidable when controlling the levels by a human, because a human typically cannot react quickly enough. However, with an automated system, you can ensure that either only one microphone is active, or only microphones which are the same distance from the ball are active. You can also automatically add a bit of delay to the closer microphones, so the sound still arrives at the same time.

What we mentioned up until now, is only how to isolate the sound of the ball. But there is also an aspect of sound design, i.e. how the ball sounds. For the sound design, traditional techniques are used, such as equalization and audio effects.

In particular, there are two main components to the sound of the ball being kicked: a high-frequency "klicking" sound that gives the listener precise timing information as to when, exactly, the boot / head / chest / goalpost and the ball make contact, and a low-frequency "thud" that gives the sound its "fatness" and indicates how hard and how precise the ball was hit. By emphasizing the specific frequencies for those two components and reducing other frequencies, the sound of the ball can be "shaped" to be "larger than life" and at the same time even further reduce other noise that might be captured by the close ball microphones. An audio engineer might even use a so-called sub-harmonic synthesizer (such as reFuse Software's Lowender, or Waves' LoAir or Submarine) which synthesizes additional bass frequencies that are not actually present in the signal itself.


Disclaimer: I happen to be employed by Lawo, the manufacturer of the afore-mentioned KICK close ball mixing system. However, I only work with the video products, have nothing to do with KICK, and only joined after KICK had already been introduced into the market.

Also, I am a semi-professional live sound engineer, although I have nothing to do with broadcast or sports.

All of the information used in this answer is from public sources.

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