Final answer:
The noisier fricatives and affricates are referred to as obstruents, produced by obstructing airflow which results in their characteristic sound. They can also be voiced or voiceless.
Step-by-step explanation:
The noisier fricatives and affricates are called obstruents. These sounds are made by obstructing the airflow in some way, which results in a noisy sound characteristic of these types of consonants. Fricatives are produced by forcing air through a narrow channel created by placing two articulators close together. Affricates are complex sounds that begin as stops (which completely block the airflow) and release into a fricative.
It is important to note that obstruents can be further classified as voiced or voiceless depending on whether the vocal cords vibrate during the production of the sound. Voiced sounds include those like [v] and [z], while voiceless sounds include [f] and [s]. The loudness of these sounds is not characterized by intensity level or decibel, and frequency is heard as pitch, not volume.