Why is the number of people only a starting point?

The number of participants indicates how large the event is organizationally, but it does not describe the actual electroacoustic task. The most important factor is the space that needs to be covered with sound.

One hundred people can stand on an area of several dozen square meters or sit in a long hall, where the last row is significantly farther from the stage. Similarly, 1000 people can be gathered in a compact tribune or spread out over a large outdoor area.

Therefore the selection of sound reinforcement for the number of participants and the type of event should take into account at least:

• the area,
• the width and depth of the audience,
• the distance of the first and last listener,
• the nature of the program,
• the required SPL,
• the acoustics,
• outdoor or indoor.

The number of people is therefore useful at the stage of the initial conversation, but it should not lead directly to the selection of a specific number of speakers.

Sound reinforcement for about 100 people

 With around 100 participants, the system can often be relatively simple if the space is compact. However, a conference, event, and concert are still three different tasks.

Conference

At a conference for about 100 people, the priority is speech intelligibility.

Most often needed are:

• even coverage of all seats,
• microphones for speakers,
• appropriate gain before feedback,
• input for presentations and video materials.

If the room is small and not very reverberant, the system does not need to generate a very high SPL.

The position of the speakers relative to the microphones is very important. Too close a placement of the PA to the stage can limit the available level before feedback.

Event

A corporate event for about 100 people can be more challenging than a conference, as it often combines speeches, background music, videos, and later entertainment.

If there is a DJ or band after the presentations, the system should have adequate capacity for the musical part as well.

Therefore, it is not worth designing the PA solely for the first item on the agenda.

Concert

A concert for about 100 people may require more headroom, subwoofers, stage monitors, and significantly more input channels than a conference.

Even with a small audience, the following appear:

• microphones,
• DI boxes,
• monitoring,
• stagebox,
• FOH,
• possible IEM.

This shows that the number of people does not determine the complexity of the implementation.

Sound system for about 300 people

With about 300 participants, the actual geometry of the audience becomes increasingly important. The system can still be simple, but it is much more often necessary to analyze directionality and coverage.

Room

In a room for 300 people, acoustics are very important.

If the room is short and wide, good horizontal coverage may be primarily needed. In a long room, the difference in level between the front and back will become a bigger problem.

In some cases, a single pair of high-quality point source speakers is sufficient. In others, additional sources or a more controlled system must be used.

There is no rule that "300 people = a specific setup".

Outdoor

In an outdoor setting for 300 people, the typical room reverberation disappears, but a greater dependence on distance appears.

If the audience is close to the stage in a compact space, a simple system may be sufficient. If the area is wide or very deep, greater control of directionality may be needed.

With full-range music, the appropriate subwoofer section is also important.

Sound system for about 500 people

With around 500 participants, the range and uniformity of coverage become increasingly more important than the maximum SPL itself.

When does range start to matter?

Range matters when the difference between the distance of the closest and farthest listener from the system increases.

If the first person is a few meters from the PA, and the last is several dozen meters further, trying to equalize the level by simply boosting the system leads to a very high SPL at the front.

Then appropriate directionality, mounting height, or dividing the audience into several zones is needed.

The topic is discussed in more detail in the article how to plan sound reinforcement for a large space and avoid uneven sound coverage..

When are additional zones needed?

Additional sources appear when the main system does not cover the entire audience evenly.

It may be necessary:

• frontfill for the front rows,
• outfill for the side sections,
• delay for the further audience.

This does not mean that every event for 500 people requires additional zones. A compact room for 500 people may be simpler to sound than an event for 300 people in a very unusual area.

Sound system for about 1000 people

With around 1000 participants, the system often starts to require a more complete design. However, this does not automatically mean a line array, a larger number of subwoofers, or delay systems.

The importance of audience geometry

Geometry becomes crucial.

One thousand people set up in a wide square may require a large horizontal coverage. One thousand people in a narrow, deep audience may place significantly greater demands on range.

At large distances, it is worth preparing a prediction of the system before installation.

You can then assess:

• the distribution of SPL,
• coverage,
• the need for additional zones,
• the height of the system,
• directionality.

Main system, subwoofers, and fill

For a music event for about 1000 people, the full configuration may include:

• main PA,
• subwoofers,
• frontfill,
• possible outfills,
• in certain conditions delay.

The number and type of subwoofers do not result from the number of participants.The selection of subwoofers for a concert and outdoor eventdepends primarily on the program, the required level in the LF range, and geometry of their placement.

Therefore, it should not be assumed that a system for 1000 people must have a specific number of sets.

1000 people in the hall and 1000 people outdoors – why is this
not the same project?

The hall and the outdoors place completely different demands on the system.

In the hall, sound reflects off:

• walls,
• the ceiling,
• the stands,
• other large surfaces.

The problem may be long reverberation and decreased intelligibility. In such a venue, it is crucial to limit the energy sent outside the audience.

Outdoors, there is no typical reverberation field of a hall, but there are:

• greater distances,
• atmospheric conditions,
• the need for emission control outside the event area.

Therefore, the system for the same number of people may look completely different.

In the hall, a more directional PA may be needed primarily because of the acoustics. Outdoors, the same type of control may serve to maintain levels at a great distance.

This is explained in more detail in the material how the acoustics of the venue affect the choice of sound system.

Conference for 1000 people and concert for 1000 people

A conference for 1000 people and a concert for 1000 people do not have the same requirements.

At the conference, the priority is:

• high speech intelligibility,
• even coverage,
• appropriate gain before feedback,
• control of reverberation.

Usually, there is no need for such an extensive low-frequency section or such high headroom as in a concert.

A concert, on the other hand, requires:

• higher SPL,
• wider bandwidth,
• greater dynamic range,
• subwoofers,
• full stage setup and FOH.

The number of sources is also different.

A conference may use several or a dozen microphones. A band's concert may have an extensive input list, separate monitoring, and many independent mixes.

The number of participants is the same, but the technical system can differ drastically.

What should not be determined based solely on the number of
participants?

Based solely on the number of people, one should not determine:

• the number of speakers,
• the number of subwoofers,
• the power of amplifiers,
• the type of system,
• the necessity of using a line array,
• the need for a delay line,
• the required number of channels.

Power conversion factors are particularly misleading.

The statement "X watts per person is needed" does not take into account:

• the efficiency of the systems,
• directionality,
• distance,
• maximum SPL,
• acoustic conditions.

Similarly, the number of columns guarantees nothing. Four properly selected and positioned systems can provide better coverage than eight sources working uncontrolled.

Therefore, the question how many speakers are needed for the sound reinforcement of a concert or event should only be considered after defining the space and requirements.

Likewise, greater sound reinforcement power does not automatically mean better sound.

What data allows the transition from estimation to actual
project?

The actual selection of the system requires significantly more than the number of participants.

The most important data are:

• the number of people,
• the type of event,
• the location,
• outdoor or indoor,
• the dimensions of the space,
• the width and depth of the audience,
• the position of the stage,
• the distance of the last listener,
• the nature of the program,
• the artists' rider,
• noise restrictions,
• the possibility of mounting or hanging the system.

For more complex events, a layout of the object or site plan is useful.

This allows for an assessment of whether a simple point source is sufficient or if a more elaborate system will be needed. The topic of differences between designs is developed in the article linear system or classic PA setups – what to choose for an event?

Only after gathering this information can one move from the rough estimate of "event for 500 people" to the actual PA design.

Summary

Sound reinforcement for 100, 300, 500, or 1000 people should not be chosen based on a ready-made calculator. The number of participants is useful for a first estimate of the scale of the event, but does not determine the necessary number of speakers, subwoofers, or power.

With around 100 people, the system can often be simple, while as the space increases, range, directionality, and dividing the audience into additional zones become increasingly important. However, there is no specific threshold at which a line array or delay automatically appears.

The best way to select a system is to combine information about the number of participants with the space plan, the nature of the program, the required SPL, and the acoustics. Only then can the actual configuration of the sound system be determined.

Frequently Asked Questions