How do you prevent speakers who are hard to understand?

The short answer

Speakers who are hard to understand almost never have a single cause. It is the sum of the room’s acoustics, the choice and placement of the microphone, controlling feedback and the behaviour of the speaker themselves. If you want clear speech, address all of these elements together. One good microphone will not rescue a reverberant room, and a perfect room does not help if the speaker talks past the microphone.

Start with the acoustics

The room is the foundation. Hard surfaces such as glass, concrete and smooth walls reflect sound, causing speech to reverberate and words to run into each other. Soft materials such as curtains, carpet, people and furniture absorb it instead.

• Assess the room for reverberation beforehand: clap your hands and listen to how long the reverb lasts
• An empty, hard room sounds very different from a full room with an audience
• Aim loudspeakers at the audience, not at hard back walls
• In a strongly reverberant space, more targeted sound closer to the audience works better than simply turning up the volume

Turning up the volume in a reverberant room makes the problem bigger, not smaller. The reverb only gets louder and the speech becomes even less clear.

Choose the right microphone

The type of microphone determines how much voice and how much surroundings you pick up. For speech you want a microphone that mainly captures the voice and shuts out the room.

• Lavalier or headset: keeps a fixed distance from the mouth and delivers constant volume, ideal for speakers who move around
• Handheld microphone: gives the speaker control, provided they keep it close enough to the mouth
• Lectern or stand microphone: fine for a speaker who stays in one place

Preferably choose directional microphones that pick up sound from the front and dampen the sides. That reduces reverberation and feedback in one go.

Pay attention to placement

Even the best microphone fails in the wrong spot. Distance from the mouth is decisive: every time the distance doubles, the volume drops considerably.

• Lavalier: place it high on the chest, away from clothing that rustles
• Headset: position the capsule just beside the corner of the mouth, not directly in front of the breath
• Handheld microphone: a hand’s width from the mouth, do not let it drop to chin height
• Keep microphones far enough from the loudspeakers to avoid feedback

A common mistake is placing the lavalier under a blazer or scarf. Every rustling item of clothing then comes through loudly.

Control feedback

That sharp whistling tone occurs when amplified sound goes back into the microphone. Prevention is better than turning it down.

• Keep microphones behind or beside the loudspeakers, never in front of them
• Mute microphones that are not being used
• Do not set the volume higher than necessary; better a well-placed loudspeaker closer to the audience
• Have a technician filter out disruptive frequencies before feedback occurs

With several open microphones the risk rises quickly. Someone operating the mixing desk live is then the difference between clean sound and squealing.

Technology and human behaviour together

The best technology comes to nothing with a speaker who does not know how to handle a microphone. Brief speakers beforehand.

• Speak calmly and articulate, even with amplification
• Keep the handheld microphone consistently close to the mouth, even when walking away from the lectern
• Do not turn your head away from a lectern microphone
• For audience questions, wait until the person asking has a microphone, and repeat the question if necessary
• Do not tap the microphone to test it, simply talk during the sound check

A short sound check with the actual speakers, not just with the equipment, removes most problems in advance. You immediately hear who speaks too quietly or talks past the microphone.

Checklist for clear speech

• Room assessed for reverberation and loudspeakers aimed at the audience
• Microphone type chosen based on the speaker’s movement and position
• Microphone at the right distance and spot, free of rustling clothing
• Feedback risk limited through placement and volume
• Unused microphones muted
• Speakers briefly instructed on microphone use
• Sound check carried out with the actual speakers
• Technician present to make adjustments during the session

In closing

Intelligibility is teamwork between the room, the technology and the speaker. Anyone who focuses only on the microphone misses half of it. Assess the acoustics, choose and place the microphone deliberately, keep feedback under control and prepare your speakers. Do you want to be certain that every word gets through, even at the back of the room? HuurAV assesses the acoustics, chooses the right microphones and provides support during your event. Feel free to request advice for your gathering in Amsterdam and the surrounding area.