Sound is made up of vibrations that travel through the air in waves. These waves have different frequencies, which we perceive as different pitches. Understanding the frequency spectrum is essential for anyone working with audio, whether it’s recording, mixing, or mastering. In this beginner’s guide, we will cover the basics of the audio frequency spectrum.
The frequency range of human hearing is generally considered to be from 20 Hz to 20,000 Hz. However, some people can hear frequencies beyond this range, and many factors can affect our ability to perceive different frequencies, such as age, hearing damage, and environmental factors.
The frequency spectrum is the range of frequencies present in a sound. When we analyze the frequency spectrum of a sound, we can see which frequencies are dominant and which are missing. This information can be used to adjust the sound to improve its overall quality.
The frequency spectrum is typically divided into several frequency bands, each with its own characteristics. The most common frequency bands used in audio are:
- Sub-bass (20 Hz – 60 Hz)
- Bass (60 Hz – 250 Hz)
- Low midrange (250 Hz – 500 Hz)
- Midrange (500 Hz – 2 kHz)
- Upper midrange (2 kHz – 4 kHz)
- Presence (4 kHz – 6 kHz)
- Brilliance (6 kHz – 20 kHz)
Equalization (EQ) is the process of adjusting the frequency balance of a sound. This can be done by boosting or cutting certain frequencies to improve the overall sound. For example, if a recording sounds too bass-heavy, you can use EQ to reduce the amount of bass frequencies.
Filters are used to remove unwanted frequencies from a sound. The two most common types of filters are high-pass filters and low-pass filters. A high-pass filter removes frequencies below a certain point, while a low-pass filter removes frequencies above a certain point.
Harmonics are frequencies that are multiples of a sound’s fundamental frequency. For example, if a sound has a fundamental frequency of 100 Hz, the second harmonic would be 200 Hz, the third harmonic would be 300 Hz, and so on. Harmonics are an essential component of the sound of musical instruments, and understanding them is crucial for creating a realistic and natural-sounding recording.
Low Frequencies (20 Hz – 250 Hz)
The low-frequency range, also known as the bass range, is where you’ll find the low-end energy in a mix. This range is crucial in creating a solid foundation for your music, providing warmth and body to the sound. However, too much low-end can cause the mix to sound muddy and undefined. To clean up the low-end, you can use high-pass filters to remove unwanted frequencies.
Low-Mid Frequencies (250 Hz – 500 Hz)
The low-mid range is where you’ll find the body of most instruments and vocals. This range provides clarity and presence to your mix, making it sound full and balanced. However, too much low-mid can cause the mix to sound boxy and nasal. To avoid this, you can use parametric EQ to remove any unwanted frequencies in this range.
Mid Frequencies (500 Hz – 2,000 Hz)
The mid-range is where you’ll find the majority of the harmonics in most instruments and vocals. This range provides character and definition to the sound, making it more recognizable and distinguishable. However, too much mid-range can cause the mix to sound harsh and piercing. To tame the mid-range, you can use a wide-band parametric EQ to reduce any offending frequencies.
High-Mid Frequencies (2,000 Hz – 4,000 Hz)
The high-mid range is where you’ll find the sibilance in vocals and the attack of many instruments. This range provides clarity and articulation to the sound, making it easier to hear and understand. However, too much high-mid can cause the mix to sound shrill and abrasive. To control the high-mid, you can use a narrow-band parametric EQ to reduce any harsh or piercing frequencies.
High Frequencies (4,000 Hz – 20,000 Hz)
The high-frequency range, also known as the treble range, is where you’ll find the brightness and sparkle in a mix. This range provides air and space to the sound, making it sound open and airy. However, too much high-end can cause the mix to sound harsh and ear-piercing. To tame the high-end, you can use a shelving EQ to roll off any excessive frequencies.
Understanding the audio frequency spectrum is essential for anyone working with audio. By analyzing the frequency spectrum of a sound and adjusting it using EQ and filters, you can create a more balanced and polished recording. By familiarizing yourself with the different frequency bands and harmonics, you will be able to create more natural and realistic recordings that sound great on any system. Remember, practice is key, so keep experimenting and learning to improve your understanding of the audio frequency spectrum.
If you want to understand music production terms read our Recording Studio Dictionary