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How To EQ Speech For Maximum Intelligibility

To convey a message, speech must be crystal clear. Do you know how to overcome the intelligibility issues which plague your service?
This article is provided by Behind The Mixer.

Don’t we all have stories of misheard words? 

It could have been a song lyric or maybe you misheard your spouse? 

Maybe they mumbled a word or it just wasn’t clear what was said. 

This has been the cause for a few hilarious moments at our dinner table.  The problem is that unclear words are a distraction from the message. 

In the church environment, the pastor’s words must be clear and we can ensure this maximum intelligibility through proper speech EQ.

There are four topics to consider when it comes to the EQ’ing needs for the spoken word. 

1. Microphone Location
We are fortunate in that most pastors now use wireless microphones.  This means that the distance between the mic and their mouth is pretty consistent. 

In the case of the headpiece, this is especially true.  In the case of the lapel mic, remember they should drop their chin to their chest and put the mic directly below that point. 

Long ago, I was taught “a fist away from the chin.” The point here is that we want the best sound isolation we can possibly get while having a good gain structure in place.  Remember, the closer to the source, the more the proximity effect comes into the equation and you’ll need to EQ out some of that added bass.

2. Speaker’s Natural Voice 
Just as every guitar has a unique sound, so does every person.  You want to bring out the best qualities of their voice.  You don’t want them to sound like a different person. 

Their vocal characteristics are also “what you have to work with.”  This means you’ll need to know how to deal with quiet speakers, bassy talkers, and nasally preachers, just to list a few.  Not everyone has a great radio voice.

3. Presence of Background Music
Depending on your church, your pastor might talk with a running soundtrack.  There is definitely an art to being able to play the right music for this. 

However, any type of music bed means you now have to make a space for the voice amidst the instrumentals.  Instrumentals can easily blur the spoken word so you’ll have to plan on tweaking the EQ for the musicians as well. 

4. The Environment
Just because a vocal boost at 400Hz sounds good in one room doesn’t mean it will sound good in another room.  One of this site’s readers runs audio outside…in Egypt. 

Any EQ work must take the environment into account.  The settings for a “quiet room” won’t be the same for an echo-y room or an outdoor venue.

Now that we’ve got those out of the way, let’s turn to…

The frequency make-up of speech

Our speaking voice has three frequency ranges that need to be understood
1. Fundamentals 
The fundamental frequencies of speech occur roughly between 85Hz and 250Hz.

2. Vowels
Vowels sounds contain the maximum energy and power of the voice, occurring between 350Hz and 2KHz.

3. Consonants
Consonants occur between 1.5KHz and 4KHz.  They contain little energy but are essential to intelligibility.

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In short, this means that the “power” of the voice does not equate to the intelligibility of the voice.  Think of it like this…just because a person has a booming voice doesn’t mean they are easy to understand. 

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