Equalisers

However, in practice, since recording conditions are not always ideal, there are often small or larger issues where the equalizer becomes a valuable tool. Types of Equalizers: There are many types of equalizers, but the two most fundamental types are parametric and shelving equalizers, which are named after their characteristic curve. Ideally, if a recording were very good—that is, an excellent musician with a good instrument, a flat microphone through a transparent microphone preamp, in a room with good acoustics, recorded using an analog-to-digital converter (A/D converter) that does not alter the tonal balance—then there would be no need for an equalizer, and the sound would be better. This is because the less processing we need to do, the better and more natural the sound will be.

Semi-Parametric Equalizers

Similar to parametric equalizers but with less detailed control, as the bandwidth (Q factor) is usually fixed. In a semi-parametric equalizer, you can typically adjust the center frequency and the gain or cut, but you don’t have control over the bandwidth of the frequency band (Q factor), which remains constant. This means you can select which frequency to boost or reduce, but you cannot adjust how wide or narrow the affected frequency range will be. This type of equalizer is simpler to use than a fully parametric one, but it offers less precision. They are often used in situations where quicker and easier sound adjustments are needed, without the complexity and detailed control offered by a parametric equalizer. They are ideal for recordings that don’t require highly detailed frequency processing.

Dynamic Equalizers

Dynamic equalizers combine the function of a traditional equalizer with a dynamic audio processor, such as a compressor or expander. Unlike static equalizers that apply fixed frequency settings, dynamic equalizers adjust frequencies dynamically, depending on the signal’s level. Essentially, a dynamic equalizer allows you to adjust the boost or cut of specific frequencies only when the signal exceeds or falls below a set threshold. This type of processing is particularly useful when you want to handle certain frequencies only when they become too loud or too quiet.

Main features of dynamic equalizers:

Threshold: The signal level at which the equalizer starts applying boost or cut to specific frequencies.

Gain Reduction/Boost: The level of boost or cut of the frequencies when the signal crosses the threshold.

Attack/Release Times: The time it takes for the dynamic equalization to engage or disengage.

Dynamic equalizers are useful for:

Eliminating annoying frequencies that only appear at certain moments (e.g., harsh vocal sounds or excessive bass on specific notes).

Maintaining balance in the mix without applying static frequency adjustments, but only when necessary.

They are often used in mastering and mixing, where more advanced control over frequency and dynamics is required.

Shelving Equalizers

Shelving equalizers are used to boost or reduce all frequencies above or below a certain frequency, rather than affecting only a narrow band like parametric equalizers. They are primarily used to adjust the extremes of the frequency spectrum, meaning the lows (bass) and highs (treble).

Key features:

Low Shelving: Boosts or cuts all frequencies below a certain point (e.g., 100Hz), affecting the overall bass in the sound.

High Shelving: Boosts or cuts all frequencies above a certain point (e.g., 10kHz), affecting the treble and clarity of the sound.

Applications:

Low Frequencies (Bass): Low shelving equalizers are used to adjust the bass, either boosting it for a fuller sound or cutting it if it's too overwhelming.

High Frequencies (Treble): High shelving equalizers adjust the treble, making it sharper or softer, depending on the needs of the mix or mastering.

Shelving equalizers are simple to use and ideal for general tonal adjustments, making them perfect for quick adjustments of low and high frequencies in various types of audio.

The sound quality offered by an equalizer depends on its electronic circuits and available features.

Professional equalizers typically offer:

• Analog or digital technology: Analog equalizers are often preferred for the warmth they add to the sound, while digital ones provide precision and more flexible processing capabilities.

• Multiple frequency bands: The more frequency bands an equalizer has, the more detailed and flexible control it offers over the sound.

• Presets: Some digital equalizers offer built-in presets that can be used for different music genres or recordings, allowing for quicker adjustments.

Equalizers can be used at various stages of recording and mixing:

• During recording: To shape the signal from microphones or instruments before it moves on to further processing.

• In the mixing process: Equalizers are used to shape the sound of each channel and remove unwanted frequencies, achieving a balanced sound.

• Mastering: In the final stage, equalizers help improve the overall frequency response of a track or album, ensuring that the sound is balanced and accurate.

When selecting an equalizer for your studio, consider the following:

• Precision of adjustments: Parametric equalizers offer maximum control over settings, while graphic equalizers are more suited for general adjustments.

• Flexibility: A dynamic equalizer can be more versatile for complex recordings, as it adapts based on the signal’s intensity.

• Analog or digital: If you're looking for authentic analog sound, an analog equalizer is the best choice, whereas if you need precision and flexibility, opt for a digital one.

Although, in theory, the equalizer doesn’t create sound (as the sound is captured during recording) and is considered a "necessary evil" for correcting issues, it is the most useful and essential tool in the hands of sound engineers. As always, we should strive to improve our aesthetics and listening skills to ensure proper use and avoid excess. Usually, less is more.

The choice of the right equalizer for your studio depends on your needs, the type of music or sound you are working with, and your preference between analog and digital technology. A good equalizer will allow you to shape the sound with precision and achieve the best possible audio result in every recording and mix.

The team at Athens Pro Audio is always ready and available to guide and inform you on all technical and non-technical matters, helping you choose the right equipment to meet your specific needs.

AthensProAudio Team ©