This page explains the causes and solutions for High Frequency Less and Reverberation.
These factors vary, but this page explains when a speaker (SP) installed in the wrong orientation can be a factor.
High Frequency Less
The high frequency volume is insufficient. Even if the overall volume is sufficient, the sound is difficult to hear.
Cause
Hearing consonants is important for accurately hearing speeches and announcements. English is a language made up of consecutive consonants, and in vowel-based languages like Japanese, it is important to distinguish between very short consonants at the beginning of words. This important consonant is produced by a high frequency band.
Hearing consonants is important for accurately hearing speeches and announcements. English is a language made up of consecutive consonants, and in vowel-based languages like Japanese, it is important to distinguish between very short consonants at the beginning of words. This important consonant is produced by a high frequency band.
In fact, the range in which the speaker (SP) can diffuse sound differs between high and low frequencies. At high frequencies it is narrow, but at low frequencies it is wide. In the diagram, high frequencies are represented in yellow and low frequencies in red. If the SP is mounted high relative to the audience as shown in this diagram, high frequencies will not reach the audience with sufficient volume. This means that the consonants don't come through loud enough, making it difficult for the audience to hear the speech.
This is not resolved by increasing the volume. This is because lower frequencies are louder than higher frequencies. This difference does not change even when the volume is increased. |
Solution
The solution is to direct SP to the audience as much as possible. Also, make sure that the high frequency bands cover your audience as widely as possible. Designers often consider positioning the SP so that the sound around 2kHz-4kHz can adequately cover the audience. The left figure is conveniently drawn for the purpose of this explanation, but please actually walk around the SP or use a simulator to confirm this phenomenon.
Of course, using an equalizer may be one solution, but before that it is important that the SP is installed correctly. |
Reverberation
Reverberation is caused by sound reflecting off walls and ceilings. Therefore, the occurrence situation depends on the shape of the building and the construction materials. The problem with reverberation in speeches and announcements is that it makes it difficult to hear the words. The earlier word overlaps the later word, masking important consonants. In other words, the sound emitted by the SP remains as a sound for a long time (by the way, in Japanese, reverberation is expressed by the character "remain''). In particular, low frequency reverberation often occurs.
Cause
Basically, the occurrence of reverberation may be a problem with the building, but the way the SP is installed will determine whether the problem will be exacerbated or reduced.
Basically, the occurrence of reverberation may be a problem with the building, but the way the SP is installed will determine whether the problem will be exacerbated or reduced.
Solution
The solution is to focus SP only on the audience as much as possible. Of course, it is not possible to completely eliminate reverberation, but the location and orientation of the SP is determined based on the idea of what should be done to reduce it as much as possible.
Of course, there are reflections on the floor, but the time difference between direct sound and reflected sound reaching audience's ears is very short. The second reflection may occur on the ceiling or wall, but the reflected sound will gradually become smaller, and at least it will be better than the above situation. Using line array SP is also effective. |
SPs are often treated as nuisances and tied high up on walls. In such a room, high-frequency consonants are difficult to hear, and low-frequency reverberations accumulate.
Listen to the sound of low frequency less and reverberation occurring together.
Listen to the sound of low frequency less and reverberation occurring together.
Feedback and Reverberation
Feedback is a sudden, loud "kee--n" sound. This occurs when the sound emitted from the speaker (SP) is input again to the microphone (MIC), causing a loop in the amplification process, and amplification occurs many times in a short period of time. If the amount of input to the microphone is small, no feedback will occur.
When reverberation occurs, a lot of sound returns to the MIC, making it easier for feedback to occur. Conversely, if the SP is installed correctly, reverberation and feedback will be less likely to occur.
Please also refer to this page regarding reverberation.
When reverberation occurs, a lot of sound returns to the MIC, making it easier for feedback to occur. Conversely, if the SP is installed correctly, reverberation and feedback will be less likely to occur.
Please also refer to this page regarding reverberation.