Hey, what’s up? This is Jatari, and today we’re talking about equalizers again. If you’ve missed the first part about EQ, that’s something you can always check out first, because today we’re going a bit deeper.

For this session, the focus is on the different types of EQ circuitry that can be used. We’ll look at:

• Passive equalizers
• Active equalizers
• Digital equalizers
• And how bit depth and sample rate affect EQ quality in digital audio

Each of these plays a very specific role in how sound is shaped, processed, and ultimately perceived.

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Passive Equalizers: How They Work and Why They Sound Pleasant

What Is a Passive EQ?

Passive equalizers make use of passive electronic components, such as

• Inductors
• Capacitors

In theory, a passive equalizer can only apply a cut.

This might sound counterintuitive at first, especially since we often talk about boosting frequencies—but the way passive EQs achieve this is a bit more nuanced.

How Passive EQ Boosting Actually Works

The process works like this:

• All frequencies are attenuated by a certain amount
• The frequencies that need to be boosted are attenuated less
• A second amplifier then boosts all frequencies evenly

Because the selected frequencies were not attenuated by the same amount as the others, they now appear boosted.

The “boost” isn’t created directly—it’s the result of selective attenuation combined with uniform amplification.

Advantages of Passive Equalizers

Passive EQs are highly valued for a few key reasons:

• Very low noise levels
• A very pleasant sound
• Commonly used in mastering situations

They’re often chosen when sound quality and smooth tonal shaping are the top priorities.

Disadvantages of Passive Equalizers

There are, however, some clear drawbacks:

• They are much more expensive
• They are larger in size
• Less flexible compared to modern alternatives

Because of these factors, passive EQs are less common in everyday mixing environments.

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Active Equalizers: Flexibility and Practicality

What Is an Active EQ?

Active equalizers use active electronic components. Unlike passive EQs, they are fully capable of creating a true boost.

How Active EQ Boosting Works

In an active EQ, boosting is achieved through a feedback loop:

• The selected frequency is sent back through the amplifier
• This process increases the level of that specific frequency

Because of this feedback-based design:

• Equalizing your signal can create a little bit of phasing

Advantages of Active Equalizers

Active EQs offer several practical benefits:

• Relatively low cost (depending on brand and model)
• Lightweight design
• Good boost and cut levels
• Widely available in both hardware and software formats

Disadvantages of Active Equalizers

The main downside is related to the components themselves:

• Active components can generate some noise

That said, this noise is generally at an acceptable level, especially in modern designs.

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Digital Equalizers: Precision, Power, and Debate

Digital EQ vs Analog EQ

When working digitally, we encounter a completely different category of equalizers.

Digital EQs are capable of:

• Much more boost and cut than traditional analog EQs
• Greater precision
• Quick resets and recall

They also tend to generate:

• Less noise
• Less phase shift

The Ongoing Discussion About Sound Character

Despite their advantages, there’s a long-standing discussion around digital EQs:

Digital equalizers are often described as sounding colder.

They don’t naturally add the extra coloration that analog gear does.

Improvements in Modern Digital EQs

Over the last decade, however, many manufacturers have:

• Greatly improved their algorithms
• Increased the overall quality of EQ plugins
• Added saturation and harmonics to emulate analog behavior

This has narrowed the gap significantly between digital and analog EQ sound.

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Digital Audio Basics: Bit Depth and Sample Rate

Let’s take a big leap forward and talk about digital audio, because most recordings today are done digitally—and this has a lot to do with EQ quality.

Standard CD Quality Settings

For CD-quality audio, the standard settings are

• 16-bit depth
• 44,100 Hz sample rate (often called 44.1)

What Bit Depth Means

Bit depth refers to how many bits are available to register the amplitude values of a signal.

• 16-bit audio has limited dynamic range
• Recording at 24-bit, for example:
  • Provides a greater dynamic range
  • Offers more headroom when mixing digitally

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Sample Rate and Frequency Representation

Understanding Sample Rate

The sample rate determines how often audio samples are stored per second.

Because a system needs at least two samples per completed cycle:

• A sample rate of 44.1 kHz can represent the entire audible frequency spectrum

For example:

• A sample rate of 20 kHz can only record signals up to 10 kHz

Why Higher Sample Rates Matter for EQ

Working at higher sample rates means:

• EQs have more values to work with
• This can result in better EQ results
• The same principle applies to:
  • Reverbs
  • Other digital processors

Higher sample rates give EQs more resolution and flexibility.

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Practical Limitations of Higher Settings

While higher bit depths and sample rates offer advantages, they also come with trade-offs:

• Not all audio interfaces support higher settings
• They require more processing power
• You may not be able to:
  reed
  • Record as many tracks
  • Mix as many channels simultaneously

This makes system capability an important consideration when choosing your workflow.

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Connecting Digital Audio Quality and Digital EQ

This discussion might feel a little off-topic—but it’s actually completely on-topic.

Understanding:

• Bit depth
• Sample rate

Directly helps explain:

• The quality of digital audio
• The quality of digital equalizers

Digital EQ performance is tightly linked to how audio is captured and processed at the source.

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Looking Ahead to Practical Applications

In the next tutorial, the focus shifts to a more practical approach:

• Inserting various equalizers
• Listening to the differences
• Exploring what can actually be done with them in real-world situations

This was Jatari, and this session was all about understanding the foundations behind EQ circuitry and digital audio quality.