What are Low Pass and High Pass Filters in Music

When it comes to the more technical parts of the production process, filtering is a very important aspect that helps in shaping and developing the characteristics of the signal. Low Pass & High Pass Filters are two commonly used types of VSTs that work in opposite ways to filter incoming signals. Low pass filters allow low frequencies to pass through and blocks out the high frequencies whereas a high pass filter works just the opposite way. While their applications may vary based on where they are being used, for the purpose of this article we take a comprehensive look at both and how they can be used in music production. In this in-depth article, we look at the fundamental difference between these two filter types and how they can be applied in music. (Also Read: Best Free Piano VSTs – Plugins Producers Love in 2025)

Types of Filters Used in Music Production:

1. Low Pass Filters
2. High Pass Filters
3. Band Pass Filters
4. Notch Filters
5. Shelf Filters
6. Bell Shaped Filters

For the purpose of this article, we will be exploring only Low Pass and High Pass filters.

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Difference between Low Pass filter and High Pass filter:

Filters are very effective tools in both music and signal processing during the final mix of a track. They act as another great feature in production by allowing certain frequency components of the signal to go through while attenuating others. Basic types are Low Pass Filter and High Pass Filter. We will discuss in detail both filters with regard to functionality, differences, and applications.

Both Low and High Pass Filters manage the passage of signals in terms of their frequency. These filters find their application in almost every signal processing system related to audio and radiofrequency. In LPF, any frequency below the cutoff frequency may pass through and all other frequencies are attenuated. In other words, HPF allows higher frequencies to pass and blocks everything below that. Low Pass filters are also known as high cut filters, similarly high pass filters are also known as low cut filters.

These can find multiple uses in various applications. We can see that the difference between these 2 filters is extremely vital.

Attenuation Response

Low-Pass Filter: The signal attenuates progressively as the frequency increases beyond the cutoff point. After the cutoff frequency, a long roll-off is added.

High-Pass Filter: The signal attenuates when frequencies drop below the cutoff frequency. Attenuation increases as the frequency grows lower.

Poles in Filters

There is something called “Poles” in filters as well. The most common types are 2-pole and 4-pole filters.

The number of poles in a filter determines its steepness of attenuation. Each pole represents 6dB of attenuation, so filters are commonly described as having 6dB (single-pole), 12dB (two-pole), or 24dB (four-pole) slopes.

To understand this in practice, let’s look at how a two-pole (12dB) lowpass filter works: When you set its cutoff frequency at 1kHz, frequencies one octave above (2kHz) will be reduced by 12dB. Continue up another octave to 4kHz, and the attenuation doubles to 24dB. This pattern continues as you move up in frequency. The higher the number of poles, the more aggressive the filtering effect becomes, creating a sharper cutoff slope in the frequency response.

Filters are one of the valuable tools for sound shaping during electronic music creation. They allow manipulation of frequency, creating a dynamic effect and enhancing the entire mix. Let’s look at the ways each filter type can be implemented in production.

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What is Resonance in Filters?

When we talk about resonance in filters, we’re describing how much the frequencies close to the cutoff point are amplified. This creates a distinctive peak in the frequency spectrum right before the filter begins its attenuation. A higher resonance setting results in a more pronounced “ringing” effect around the cutoff frequency, making those particular frequencies more noticeable in the overall sound. This parameter allows you to shape the character of the filtered sound by controlling the intensity of this frequency boost.

Resonance has various applications in music. Just the low pass filter with a high resonance applied on a saw synth gives rise to the popular “Acid” sound.

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Applications of Low-Pass and High-Pass Filters in Music Production

An LPF allows lower frequencies to pass through and even eliminates higher ones. This also makes it extremely useful for the purposes of warmness, removing harshness, and shaping specific textures of sounds. For example, you recorded a kick drum but found the hi-hat cymbals bled into the mic. This high-frequency signal will make it challenging to mix the cymbal tracks accurately.

That’s when a low-pass filter will come in handy. Insert it on the kick drum track and set the cut-off frequency output to 5–20 kHz, this is the general frequency range of a hi-hat. It will cut the high-frequency components while keeping the low frequencies of the kick drum audible.

Here are scenarios where high-pass filters are generally used. HPF applications are versatile, depending on the particular aspects of the song or music that they may be useful for.

Application for Bass. Not all bass construction elements need to fit into the low-frequency range, although bass is generally important to set a solid foundation for your track. Using a High Pass filter on your kick drum and or bass line will remove sub-bass frequencies that may interfere with other instruments or add to the muddiness. 

While it is common practice to use a high pass filter on each individual audio track, applying it to the master can help clean up any undesirable low-end frequencies from the overall mix. This becomes especially important to eliminate subsonic frequencies that serve no musically useful purpose but can clear up useful headroom in a mix, especially with speakers that do not reproduce the ultra-low frequency range well.

On top of using high-pass and low-pass filters, you can experiment with using Reverb to continue getting some more unique effects. Try things out and see what sounds good when you combine that with high-pass and low-pass filters.

These audio effects may seem small but it’s the little things, such as fading in with a low filter, that can make your projects pop. The more seriously you take your audio, the better your end products are going to be.

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Popular Low Pass and High Pass Filter VSTs

While filters accomplish an extremely simple task, multiple filters can be used to create some interesting and unique sound effects. There are plugins that can help you achieve these sounds. We’ve listed down some of the most popular and creative filter VST below:

• Cableguys FilterShaperXL
• SerumFX
• Fabfilter Volcano 3
• Soundtoys FilterFreak
• Cytomic The Drop

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Final Thoughts:

The choice lies in your preference. while both carry equal weight, the application can dictate what is to be used. By utilizing these filters, certain frequencies marked can be highlighted or eliminated; this gives you a more balanced mix, with each track residing in its own frequency range and respecting other track elements.

The circuits should employ both filters to protect speakers from damage. They also give the speakers frequency ranges that they can handle. Both of these are effective, and while doing so they ensure the maximum spacing for your frequencies to shine

All types of filters are more than helpful, they are indispensable when creating and balancing your mix. When applied the right way, they eliminate bad frequencies, leave room for signature sounds, and space in allowing pleasant creative effects on your productions. Their efficacy entirely depends on context, moderation, and experimentation. It does not matter whether you’re tightening up a vocal, smoothing a synth, or shaping a build; being able to use both high and low-pass filters will put an edge on your production chops and help you craft a mix that sounds even more professional. 

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