There is no single general solution for all corporate, civic and institutional applications where speech intelligibility at meetings and conferences is so critical. Computer professionals have more and more audiovisual functions and many are forced to think analogically rather than digital. This role change includes the responsibility of making good decisions when choosing microphones. This article is addressed to all those dedicated to sound in the world of meetings and video conferences, whether their knowledge belongs to the computer or audiovisual field.
Factors to Consider When Selecting Microphones
The optimal audio solution for a meeting depends on a number of factors, such as:
Number of Attendees
Number of speakers
What does “presentation style” mean?
One to Various: a person who addresses an audience (e.g. class)
Miscellaneous to Various: All the attendees speak when they have the opportunity (example: forum)
Hybrid: Special cases of online communication from several to several with restricted access to microphones or with priorities (examples: town halls, courthouses, boardrooms and debates with audience)
In addition, consideration should be given to whether or not a sound reinforcement system exists.
Determine Your Space
The following is our short study guide with various microphone options for seven common meeting and conference environments. Determine which space most closely resembles yours and follow the recommendations.
# 1 Small Meeting Room – Huddle Room
Description: Room with a capacity of between 4 and 8 people, usually located around a round table.
Sound Reinforcement: There is usually no need for sound reinforcement in basic meeting spaces. However, many of these rooms incorporate audio or video teleconferencing systems that can be portable or permanent.
Microphones: These rooms do not have amplification systems, so it is a perfect situation for surface microphones. If the system does not have its own dedicated microphones, try locating a pair of wired or wireless surface microphones on the table. A good alternative is to locate one or two small condenser microphones hanging above the table.
# 2 Meeting Room
Description: This is a larger version of the previous example. This room has a capacity of between 6 and 30 people located in one or more large tables, normally seated in round so that the participants can see each other face to face.
Sound Reinforcement: If the room has well-controlled acoustics (without too much reverberation), it may not need sound reinforcement. However, in this type of rooms are usually made recordings and teleconferences. In these cases, microphones will be needed.
Microphones: When using four or more microphones, we recommend turning off those that are not being used at that time. The easiest way is to use microphones with built-in switches and entrust speakers with the task of manipulating their own microphones. Another good option is to use a dedicated discussion system or automatic mixer that eliminates that responsibility to the participants by allowing them to focus on the meeting itself. The discussion system also has the advantage of integrating a small sound system into each of the microphone stations, which virtually eliminates any possibility of feedback and allows people at opposite ends of a large table to hear each other.
In most cases it is decided to use a table microphone for each participant, although it is usually sufficient to use a microphone every two people. Goose neck microphones on the table are the preferred choice in meeting rooms as they are not covered with papers, although surface microphones can also be used. If the tables are mobile, gooseneck microphones can provide flexibility and quick setup. The speaker can use a wireless headband or lapel microphone.
# 3 Training Room / Classroom
Description: It is the classic “one to several” communication scenario, with up to 30 students in chairs or tables in front of the instructor / teacher.
Sound Reinforcement: The bigger and reverberant the room, the greater the need to have a sound reinforcement system in the front of the room, directed towards the audience. Smaller rooms that do not need a sound system may still need microphone for web content playback, video conferencing and / or recording of the online presentation. Maximizing intelligibility is critical in any learning environment.
Microphones: The speaker can be placed on a podium but you will probably need to scroll during the presentation to use the whiteboard or any other presentation tool. In order to integrate hands-free voice pickup the preferred solution is a headset or lapel wireless microphone.
Students’ questions can be captured from a distance learning link in different ways. A dedicated microphone can be located on a specific desk or on a microphone stand, or a wireless microphone can be provided that is passed from hand to hand as needed. The installation of hanging microphones located above the public should only be considered when there is no sound reinforcement system and only in rooms that have good acoustics. If the class is intended to be quite interactive, consideration should be given to the use of a microphone system with automatic mixer or discussion system.
# 4 Auditorium – Lecture Hall
Description: It is a larger version than the classroom with an audience of 50 people or more. The larger rooms can accommodate more than 200 people and usually have rows of seats at different heights.
Sound Reinforcement: At a conference no microphones are needed for all members of the audience, but an amplification system designed to achieve high intelligibility is definitely required. Fortunately, the auditoriums have a relatively stable use, allowing for a dedicated system design.
Microphones: As in the classroom, the best choice for the speaker is a wireless headband or lapel microphone to give you the ability to hold both hands free or a goose neck or podium microphone. If the speaker is not going to use a lot of visual content, a wireless microphone is also an excellent choice.
Student participation is a major challenge in auditoriums as both students and the instructor may have difficulty hearing the questions. This is an ideal location to locate one or two dedicated microphone stations in the aisles, in a certain position to minimize the threat of feedback. Another option is to deliver to the audience a wireless microphone that is passed from hand to hand. Despite being in the “wrong site” of the amplification system, the wireless microphone should be located close enough to the speaker to reduce the risk of feedback.
For the instructor, consider installing a dedicated monitor, especially to hear audience questions in the room and in distant locations, when necessary. As we have explained before, pendant microphones may not be very efficient in capturing questions from the audience in a sound reinforcement situation unless the output of the amplification system is connected in a way that avoids feedback.
# 5 Video Conference
Description: Video conferencing systems allow two or more remote sites to communicate via simultaneous audio and video transmissions over telephone lines or broadband connections to allow real-time interaction between different groups of people. These systems are very useful for both meetings and educational purposes.
Sound Reinforcement: There are two types of systems: the dedicated and the desktop. They can be based on traditional telephony or an enterprise-wide voice over internet system.
Microphones: The major audio problems that occur in video conferences tend to be linked to the location of the microphone. Microphones that are far away produce an empty and indistinct sound and increase the possibility of echo problems. A good advice is to place the microphones at close range of all participants to improve sound quality and also improve the acoustic echo performance (AEC) of the system.
Generally speaking, consider videoconferencing just like any other sound reinforcement situation, and remember to minimize the visibility of microphones in presentations or meetings.
# 6 Board Room
Description: The boardroom differs from the common meeting room where they are usually incorporated control systems so that participants can concentrate on the procedure and not on the amplification equipment. Generally, the control system, such as those manufactured by AMX®, Crestron® and Extron®, is programmed by the room designer to allow the use of any necessary equipment through a touch remote control.
Sound reinforcement usually applies only when using video conferencing or video playback systems.
Microphones: Microphones are common in boardrooms, either for video conferencing or as a recording medium for recording purposes. Automatic microphone systems are very popular in boardrooms as they capture the processes without the need for a system operator inside the room.
In the boardroom, aesthetics is always a very important element. Permanent microphones that require drilling expensive conference tables to connect their cables can be a challenge. This is why there has been an increase in the popularity of wireless desktop microphones, which can be easily removed when not in use. Even several models offer audio encryption for security purposes.
# 7 City Hall / Hearing Room / Large Conference Rooms
Description: The larger conference room, the greater the need to use advanced systems. When the president of a company speaks to a large group of people, and there is also a large audience, a comprehensive sound system with advanced functions is needed. International conferences are even more demanding as they must have tools for the task of interpretation.
Microphones: The starting point is automatic microphone systems. The ability to minimize the number of open microphones facilitates the maintenance of intelligibility and ensures that all speakers are heard. In addition, many of the automatic microphone systems allow the speaker’s microphone to take precedence over the others.
Many sites can benefit even more by using a discussion system or conference system. These systems solve one of the main problems of meeting sound reinforcement by incorporating a small speaker into the base of the gooseneck microphone. Of course, each site is different and some may not be included in this guide. Some have very specific user requirements that are reflected in the sound systems they use.