Do you want to improve your music but have no idea how to?
Do you want a great live sound but always fall flat?
Did you know that using high pass filter audio can IMPROVE the quality of your mixes?
This article will show you what High Pass Filters is, how it functions, and how to fully utilize it in your future mixes!
Learning this technique will improve your mixes and deepen your knowledge of music, audio, and sound as a whole!
Audio Pass Filters
Before learning what HPFs are and what they do, let’s start with the basics of Audio Pass Filters.
Audio Pass Filters are filters designed to amplify or attenuate entire ranges of frequencies.
In other words, these filters are in charge of REMOVING unwanted noise and low-end audio signals and are responsible for improving the tone of the original audio.
The amount of amplification or attenuation for frequencies lower or higher depends on the filter design.
There are TWO TYPES of audio pass filters – a high pass filter (HPF) and a low pass filter (LPF).
A HIGH PASS FILTER (HPF) filters low frequencies and allows higher frequencies to pass, while a LOW PASS FILTER (LPF) is the opposite; it filters high frequencies and allows lower frequencies to pass.
For every professional setting, these are ESSENTIAL in making the highest quality of music.
Studios, artists, and performers alike use these filters to produce the best music with the best technology.
What Does High Pass Filter Audio Do?
High Pass Filters are Audio Pass Filters that REMOVES all frequencies below a set point and ALLOWS frequencies above that cutoff to pass through.
It allows any high frequency to pass above the cutoff point while attenuating low frequencies below the cutoff frequency.
Low frequencies are ACCESSIBLE for a sound source to pick up because they have longer wavelengths than high frequencies. These are usually LOW END.
In contrast, low pass filters ATTENUATE frequencies above a certain cutoff frequency, and bandpass filters attenuate certain frequencies both above and below the band.
Both filters have similarities in allowing frequencies to pass and cutoff frequencies.
For example, low pass filters and high pass filters operate the same way wherein both filters cut and pass any frequency that they are supposed to cut and let through.
High pass filters and low pass filters are EQUALIZATION TOOLS essential to audio engineering because of their means to increase the quality of the audio and music.
The Components of a High Pass Filter
These are the essential components of a High Pass Filter.
This section will show you what they are, why they are crucial, and what makes them necessary to the High Pass Filter.
Cutoff Frequency
The cutoff frequency is the frequency below which the signal is attenuated for high pass filters.
The filter passes all the frequencies above its cut-off frequency and blocks them below the cutoff frequency for high pass filters.
Audio electronics like a line, amplifiers, and electronic filters have frequencies below which the power output of a circuit has fallen to a given proportion of power in the passband.
Generally speaking, the cutoff frequency is at -3dB. A fall of 3dB in the frequencies is the corresponding estimate of 1/2 the passband power.
That said, settings that use a knob allow most high pass filter settings to have infinitely variable cutoff frequencies.
It allows the user to creatively manipulate their desired frequency settings. This allows for more precise cutoffs.
Audio technology that uses a switch is limited to specifically selected frequencies. This also makes audio high pass filters’ settings not infinitely variable.
The switch limits the frequencies.
Filter Slope
The filter slope showcases the steepness of the filter.
It pertains to how quickly the filter attenuates the frequencies after passing the cutoff frequency.
The slope is measured in decibels per octave (dB). This works by signifying that the signal is reduced by a set number of dB below the cutoff frequency.
Common slopes in the filter slope are 6dB, 12dB, 18dB, and 24dB.
6dB is a gentle slope in professional terms, while 24dB is a steep slope.
The following image showcases what an average filter slope looks like.
When using this chart for high pass filters, the slope determines the attenuation rate.
Generally speaking, a steep slope would mean a drastic attenuation over a small range of frequencies.
Meanwhile, a gentle slope would mean a more gradual attenuation over a more extensive range of frequencies.
Adjusting the slope of a high pass filter gives the engineer more freedom to change between severe and gradual attenuation.
Applications of a High Pass Filter
High Pass Filters are NOT LIMITED to music! You can also use them for radio and communication mediums!
Radiofrequency devices can be used alongside low-pass filters to create a specific bandwidth filter that can remove unwanted harmonics even in the lowest frequency.
It is common knowledge within the audio industry that some microphones have built-in filters and various polar patterns.
These microphones are often found in many digital audio workstations and mixing consoles.
Telecommunication services and other services in the communication industry utilize these filters by incorporating their tools with digital signal processors.
For example, high pass filters are used for directional microphones due to their sensitivity in their respective directions.
When telecommunicators want to record the best audio, the microphones need filters to capture the purest audio.
How to Use HPF in Your Mix
This article section will show you the different ways on how to use HPF in your mixes and production! You’ll be surprised at how effective the audio pass filters are when it comes to audio!
Remove Unwanted Harmonics
Instruments in the low-end use a high pass filter to REMOVE unwanted harmonics.
Having an EQ with a spectrum analyzer allows you to access the whole frequency range. You can identify the high and low frequencies and determine the cutoff frequency!
Use HPF to remove the muddying quality of midrange instruments and take the risk of giving the low-end bass instruments.
Filtering Out Low-End Noise
It is often a misconception that makes others think high pass filters should be avoided when mixing low-frequency content.
Use low-frequency content to IMPROVE the sound of your instruments, with the addition of high-pass information that competes with the other instruments!
Sub-frequencies can be removed because frequencies lower than your average frequency can result in unwanted sound being recorded.
High pass filters are not exclusive in recording bass instruments like the bass guitar; they can also focus vocals and other mid-ranged instruments.
You can improve the mid-range audio’s mix clarity by minimizing the muddying effect of low-end information.
High passing frequencies in your mixes remove unwanted noise and tighten the low end properly.
This also fixes the issues of low mids and highs. You can make those sounds more present and powerful.
The Abbey Road Trick
This was named after the famous ABBEY ROAD STUDIOS because the trick was born there.
Placing an EQ after a reverb plugin is one of the easiest ways to clean up your mix using audio pass filters.
When you roll off the high and low frequencies, it removes all unwanted sounds from audio sources that compete with the other instruments.
The roll-off prevents total frequency reverbs from eating up space.
The space can be used to fill up with whatever suits your needs, be it improving the mix or adding additional audio for experimentation.
When to Use High Pass Filter
The High Pass Filter will do you WONDERS if you use them correctly! Here are the best ways to fully utilize the filter to make your music sound FANTASTIC!
Reducing Competition Between Instruments in the Lower Frequencies
The kick drum and bass guitar fill the low end; those instruments competing against one another causes a MUDDYING EFFECT.
Cleaning up the frequency band is the priority when other instruments are not used.
The instruments offer nothing to the low pass information undergoing high-pass filtering.
Accentuating Frequencies
High pass filters are ESSENTIAL for drumming and percussion instruments that keep time constant.
A high pass filter is required when accentuating the fundamentals of percussion instruments with resonance. The filter offers a form of resonance nearing its cutoff frequency.
Controlling Course Tone
Audio pass filters lead to beneficial tonal results because they set the limited audible bandwidth of a signal.
With shelving EQ, the filters manipulate the frequencies by attenuating or boosting them depending on what the user wants.
An HPF can shape low-frequency content to control the tonal effect.
Automating
Automating can extend the effects to any audio source when using standalone high pass filters.
An automated high pass filter is GREAT for experimentation and testing how the filters operate!
When to Not Use High Pass Filter
Although the High Pass Filter can give you professional-level music, there are times where you should NOT USE IT.
Here are some situations wherein using high pass filters will BADLY AFFECT your audio!
Depth
You do not want to use a high pass filter when aiming for depth.
This is what the low pass filter is GOOD at!
The low pass filter removes a lot of top-end, which results in elements being pushed back.
Because of this, you make space for other elements to be included in the mix. It adds subtle effects to the audio that the high pass filter could never achieve.
Minimizing Clashing
Minimizing the clashing of multiple audios from the same instrument is what the low pass filter can do!
When you apply a high pass filter, you’ll end up with more muddy audio in the mixing, making the music feel AWKWARD AND BLOATED.
Meanwhile, if you apply a low pass filter, the frequencies attenuate, adding other elements to the mix and minimizing the clashing.
Balancing Tracks
Using too much clarity and overusing high pass filters in the mix is NEVER a good idea.
It’s like how too much of anything is wrong!
It is always a great refresher to try and experiment with other mixing techniques.
Don’t just rely on filtering and equalizing all the time!
Reducing Plosives
Have you ever wondered why some musicians have those filters over their microphones?
Those are called pop filters, and the reason for those being over microphones is to avoid plosives or p-pops.
This results from an air blast produced from the mouth and enters the microphone as a vibration, causing a sudden boom that can be a nuisance to hear.
You SHOULD NOT use high pass filters in this situation because it will make those p-pops heard even more.
Do you want to avoid this?
Use an equalizer to help improve the audio you want.
This means reducing as much low-frequency content that needs to be reduced if it means better audio.
High Pass Filter Products to Buy
Here are some of the BEST High Pass Filter products for you to buy if you consider buying one for yourself!
A high pass filter is a standard in audio technology, so it wouldn’t hurt to purchase one!
BEHRINGER Synthesizer (923 Filters)
ROLLS SX95
RDL ST-HP3
FAQs
Here are some frequently asked questions regarding the topic! Here are questions that you may still have even after reading the article!
What Are the Differences Between Signal and Noise?
From a general perspective, NOISE is any unwanted sound nuisance for hearing.
At the same time, a signal is an electromagnetic field that conveys information about the behavior of some phenomenon.
From a music perspective, both signal and noise are components of an audio signal.
To elaborate, noise is part of every waveform.
Audio pass filters, either high pass or low pass, are then used to eliminate noise in specific range frequencies—the filters aid in eliminating offending audio signal content that affects the primary signal.
A low pass filter is used to remove unwanted sound and high-frequency signals.
How So?
For example, when performing as a ‘sub’ mic on a kick drum within a frequency band, the low pass filter establishes the limited bandwidth of a low-frequency transducer.
A high pass filter is a STANDARD in music production and digital audio workstations because they differentiate low-frequency content and program signals.
To accomplish this, you need audio pass filters with a cutoff frequency below the program’s necessary range of frequency.
High pass filters are used to attenuate extraneous low-frequency content. These could be mechanical rumbles like air conditioners’ noise or vocal plosives.
What Is Shelving EQ?
A shelving EQ is responsible for attenuating or boosting a frequency above or below a certain cutoff point.
Shelving is used to boost or amplify a frequency equally beyond a certain point.
This means that one can manipulate a frequency in whatever way they want to achieve specific audio and music.
Shelving is stable in audio production because you can change how your audio will sound like.
Do you want to adjust your sound for a live sound? ADJUST THE FREQUENCIES!
Do you want to adjust your sound for a studio recording? ADJUST THE FREQUENCIES!
There’s so much you can do in experimenting with the frequency spectrum.
Who knows? During experimentation, you discover the PERFECT sound for the music you are making. That is the beauty of the equalizers and changing a frequency.
Do the Sizes of Microphones Matter? Why or Why Not?
The TL: DR answer to this question is YES, THE SIZE MATTERS!
Microphones do not solely focus on vocals and other singers; they are also used for other instruments!
Generally speaking, large microphones have a capsule microphone diaphragm of 1 inch (25.4mm). Meanwhile, small microphones have a capsule microphone diaphragm of 1/2 inch (12.7mm).
Some large microphones and small microphones can be more prominent and more minor.
The Difference Between Large and Small Microphones
Large microphones, because of their size, can capture more acoustic energy. It also generates a higher signal voltage.
Large microphones also have a better noise performance than small microphones. However, the advantages of large microphones end here.
Small microphones have a better transient response, extended high-frequency response, and consistent pickup pattern.
For example, large microphones are mainly used for vocalists, while small microphones are preferred for almost any instrument like the kick drums.
Small microphones also have better accuracy and consistency compared to large microphones.
In short, large microphones give you a “larger than life” vibe, while small microphones give you the purest and natural sound.
What’s the Importance of Using a High Pass Filter for Recording Audio?
Recording audio is very taxing due to the number of nuances that audio can be affected.
From environment noise, mechanical rumbling noises, and even musical instruments like the hi-hat being hit. There are many factors to consider before you start recording audio.
The function of audio high pass filters is to cut off low-frequency noise and allow higher frequencies to pass through.
For example, when a drummer is ready to record his part, everything he does in the set is heard, from sticks clashing to hearing rustling noises from the snare drum.
This is why HPFs are ESSENTIAL in recording drums.
This removes unnecessary sounds and other elements that can be picked up by a sound source that can affect recording audio.
What Is Phase Shift in Music?
Phase shift is an audio effect that takes advantage of the interaction of sound waves when they go out of phase.
It is a prevalent mixing technique used by musicians because SPLITTING an audio signal into two can create various interesting sweeping effects that can be used in music.
These can be significantly heard when using high quality studio monitors.
Final Thoughts
Using High Pass Filter will only YIELD quality music and audio in your mixes.
Have you ever wondered why professional artists sound amazing? It’s because their technology and knowledge of audio are what makes them sound amazing!
When producing music, mixing consoles and any mixing technique will never be enough to make the best quality of music.
Learning and understanding the signal chain, sound sources, high and low frequencies, and other aspects of audio is what makes music at its finest.
Small details like low-end and discrete-time can SIGNIFICANTLY affect the final product. If you want a great mix with no unnecessary noises and low-end sounds that should not be heard, use a HIGH PASS FILTER!
While you’re at it, it’s best to invest in good quality headphones too!
