Sony Pixel Power calrec Sony

Should You Use Highpass Filters when Mixing?

22/12/2023

Engineers sometimes advocate using high-pass filters to clean up the low end and tighten the sound. Others believe that because of issues inherent in highpass filters, they should be used sparingly, if at all. So, who's right? Well, as with many aspects of audio technology, they both are in some ways. Let's dive deeper, and then explore Studio One's clever highpass filtering solution.

But before getting into the details, let's look at the big picture. Joe Gilder did a video called THIS is Eating Up All Your Headroom in Your Productions where he shows how low-end energy can accumulate and reduce headroom with no sonic benefits. This is why engineers often apply a highpass filter to a final mix. So, let's look at the sources that can lead to this accumulation of low-frequency energy, and the right way to fix them within individual tracks before they start accumulating in your final mix.

The Case for Highpass Filtering

Sometimes, low-frequency artifacts that you don't want travel along with your audio. One potential issue is a directional microphone's proximity effect, where getting closer to the mic boosts bass unnaturally. Hitting guitar pickups accidentally can generate low-frequency sounds. Transposing samples down by a couple octaves may put energy in the sub-sonic range and even if you can't hear sub-sonic audio, it uses up headroom.

Highpass filtering has other applications. Too many instruments overlapping in low-frequency ranges can create a muddy sound. For example, you might want to reduce some of a guitar's low frequencies to avoid interfering with bass. This is usually what people mean by tightening up the sound.

The Case Against Highpass Filtering

Analog filters produce phase shifts, but the phase shifts in highpass filters with steep slopes are particularly drastic around the cutoff frequency. Most digital filters model analog filters, so they also have phase shifts. Fig. 1 shows a typical example of phase shift in a digital highpass filter with a 100 Hz cutoff and a 24 db/octave slope. The bright line is the filter curve, the darker line shows the amount of phase shift.

Figure 1: Phase shift around the cutoff frequency of a 24 dB/octave highpass filter. The horizontal axis goes from 20 Hz to 20 kHz, so the phase shift impacts the audio well into the midrange. The vertical axis covers -180 degrees to +180 degrees of phase shift.

Wow! That looks scary, doesn't it? It would look even scarier if the slope was steeper than 24 dB/octave. Fortunately, our hearing can't detect phase changes-unless the audio interacts with other audio. This is why if you set a phase shifter effect's dry/wet control to all wet or all dry with no modulation, the sound is the same. You hear the phase-shifted effect only when there's a mix of wet and dry sounds.

When mixing, this phase shift can matter if two signals with similar waveforms are in parallel. For example, consider bass through a DI in parallel with bass through an amp, or two mics at different distances from an acoustic guitar or group of backup singers. The worst-case scenario is multiple acoustic instruments being recorded simultaneously in an acoustic space-the inevitable leakage means the various tracks will have quite a bit of audio in common.

Differing mic distances from a source will cause phase shifts anyway, but using a typical highpass filter (e.g., to reduce p-pops with vocals) will accentuate the phase shifts. In either case, if the parallel tracks have enough audio in common, when they're mixed together phase shifts will alter the sound.

Solution #1: Don't Worry, Be Happy

In many cases, tracks won't be in parallel with other tracks that have similar or identical audio, so there won't be any audible degradation from phase changes caused by a highpass filter. If using a highpass filter does introduce phase problems, cutting with a shelf or peak filter instead can reduce the low frequencies (albeit not in the same way). These filter types produce less drastic phase changes.

Solution #2: The Pro EQ3's LLC Filter

Highpass filters with steep slopes are popular because of their ability to remove bass artifacts and tighten up the sound. But if you need to tighten up or reduce bass artifacts with multiple tracks, inserting all those highpass filters will contribute significant phase changes. Phase variations in the bass range can be a problem (as anyone who's tried to mix in a small, untreated room knows), so it's unfortunate that highpass filters are the best choice for solving these problems.

However, linear-phase highpass filters don't produce phase shifts-that's their outstanding characteristic. You can use as many linear-phase highpass filters as you want, and not introduce any phase shifts.

But that has its own complications, because linear-phase filters require a lot of processing power. Using several multi-stage, linear-phase EQs in a project can bring your CPU to its knees pretty quickly, as well as introduce an annoying amount of latency.

This is why Studio One's solution is particularly elegant. The Pro EQ3 has a single linear-phase highpass filter stage (fig. 2). This covers the most common need for a linear-phase filter in most projects, without the CPU burden of a multi-stage linear-phase EQ where you may not need linear-phase operation for the other stages anyway.

Figure 2: The LLC linear-phase highpass filter (outlined in white) is producing the low-frequency cut outlined in light blue.

Enabling the LLC stage contributes about 31 ms of latency compared to the 50-100 ms from a typical multi-stage linear EQ, and takes care of the frequency range where you're most likely to need a linear-phase EQ. If adding the LLC filter is still too CPU-intensive for a project, or if the latency is bothersome, you can alway
LINK: https://blog.presonus.com/2023/12/22/should-you-use-high-pass-filters-...
See more stories from presonus

Most recent headlines

05/01/2027

Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be demoed at CES 2026

Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...

06/09/2026

Dolby and MagentaTV Bring Fans Closer to the FIFA World Cup 2026 in Germany with Dolby Vision and Dolby Atmos

June 9 2026, 23:00 (PDT) Dolby and MagentaTV Bring Fans Closer to the FIFA Worl...

04/08/2026

Dalet Announces Commercial Availability of Dalia, Bringing Media-Aware Agentic AI to Enterprise Productions

Dalet, a leading technology and service provider for media-rich organizations, t...

04/07/2026

Detective Conan: Fallen Angel of the Highway Opens in Dolby Cinemas Across Japan, Presented in Dolby Atmos and Dolby ...

April 7 2026, 19:00 (PDT) Detective Conan: Fallen Angel of the Highway Opens in...

10/06/2026

SVG Sit-Down: Team Whistle's Joe Caporoso on Building World Cup Content Around Fans, Culture, IRL Experiences

DAZN-owned digital-media company launches three fan-first series leaning into cr...

10/06/2026

Clear-Com Appoints Jason Dino as Southwest Regional Sales Manager

Clear-Com has announced the appointment of Jason Dino as Southwest Regional Sales Manager USA, covering Southern California and the Southwest region. Dino joins...

10/06/2026

Caretta Research: 2026 World Cup Revenue Growth Due to More Matches; Rights Revenue Up 32%

An 11% decrease in number of global broadcast deals reflects the organization...

10/06/2026

Women Without Boundaries Awards Are Back!

The Women Without Boundaries Awards recognize women whose work is advancing the future of media, broadcast, AV, workplace technology, digital experience, and re...

10/06/2026

On Eve of World Cup Kickoff, FIFA and HBS Offer Deep Dive into IBC Operations, Commentary, and Ref Cam

Today is match day minus two for FIFA and HBS. On Thursday, there will be two ma...

10/06/2026

SES Supporting World's Biggest Soccer Tournament Broadcast Distribution Worldwide

SES is supporting broadcast distribution of the world's biggest football tou...

10/06/2026

BirdDog Achieves Full NDI 6.3 Compatibility Across Entire Product Line

NDI has announced that BirdDog has become the first hardware manufacturer to achieve full NDI 6.3 compatibility across its complete lineup of cameras, encoders,...

10/06/2026

Emmy Award-Winning Audio Team To Present at SVG Audio Symposium

Vince Caputo and Scott Carter, winners of the 2026 Sports Emmy for Outstanding Post Produced Audio have been announced as presenters for the 2026 SVG Advanced A...

10/06/2026

FOX One Set to Deliver World Cup in 4K; Personalization via AI Drives Experience

FOX One today unveiled a slate of new product features and enhancements designed to elevate the viewing experience for fans on the official streaming platform o...

10/06/2026

PWHL Scales Broadcast Operation in Season 3, Relying on World-Feed Model and Key Vendors

Primary production partners Dome Productions and Raycom Sports once again played...

10/06/2026

NFL Films Application Deadline for Women in Sports Filmmaking Experienceship, Augusts 26-29 in Mount Laurel, Closes June 18

The Women in Sports Filmmaking Experienceship is an immersive professional devel...

10/06/2026

NBAs In-House Broadcast Ops & Engineering Teams Power Global Finals Coverage From NYC, San Antonio

The league has expanded its HSAN architecture for the NBA Finals to manage more ...

10/06/2026

MoonPay X Games League Winter Draft Set for September 16 at Cosm Los Angeles

The inaugural MoonPay X Games League (XGL) Winter Draft will take place Wednesday, September 16, 2026 at Cosm Los Angeles from 7-9 p.m. PT. The event will strea...

10/06/2026

University of Oklahoma and Learfield Extend 30-Year Partnership, Announce Sooner Evolution Center

The University of Oklahoma (OU) Athletics Department and Learfield have announce...

10/06/2026

VSF Releases RIST Satellite-Hybrid Out-of-Band Specification

The Video Services Forum (VSF) has released TR-06-4 Part 8, a new specification for RIST Satellite-Hybrid: Out-of-Band Method. The specification creates a mecha...

10/06/2026

Riedel Artist Intercom Powers Live Neurovascular Conference in Lisbon

Riedel Communications provided the communications infrastructure for the 14th World Live Neurovascular Conference (WLNC) in Lisbon, supporting live medical proc...

10/06/2026

Sundance Film Festival 101: Films by LGBTQ+ Directors

A still from The Doom Generation by Gregg Araki (Courtesy of Sundance Institute) By Lucy Spicer Have you checked out our Sundance Film Festival 101 list yet...

10/06/2026

GearExpo UK: Interfaces & Mic Preamp Update

Get Hands-On with Interfaces & Mic Preamp Brands If youre after a new interface or preamp, then GearExpo UK is the place to be! Well have a whole host of au...

10/06/2026

MONO Music Conference 2026

November 13-14 2026, The Midway, San Francisco Following their recent rebranding, MONO Music Conference (formerly Music Expo) have officially announced thei...

10/06/2026

ebbandflow launch with deFORM

Debut instrument free for limited time deFORM is the debut release from newly founded developer ebbandflow, and it's being offered as a free download fo...

10/06/2026

Alone Australia Season 4: Meet the Cast

Alone Australia Season 4: Meet the Cast 10 June, 2026 Media releases WATCH THE TRAILER Smash-hit survival series Alone Australia drops its highly anticipa...

10/06/2026

DEADLY THEN, DEADLY NOW, DEADLY ALWAYS: SBS & NITV IGNITE NAIDOC WEEK 2026 WITH 50 YEARS OF DEADLY

DEADLY THEN, DEADLY NOW, DEADLY ALWAYS: SBS & NITV IGNITE NAIDOC WEEK 2026 WITH ...

10/06/2026

Rohde & Schwarz and TRUMPF advance laser-based drone defense with THORIS LCS

Rohde & Schwarz and TRUMPF advance laser-based drone defense with THORIS LCS Rohde & Schwarz is showcasing THORIS at ILA 2026: A sovereign, end to end counter...

10/06/2026

MAHLE and Rohde & Schwarz develop application for sensor testing of modern driver assistance systems

MAHLE and Rohde & Schwarz develop application for sensor testing of modern drive...

10/06/2026

NFVF CALL FOR FUNDING APPLICATIONS: PRODUCTION & DEVELOPMENT 2026/27

Production and Development Funding supports the creation of compelling, commercially viable, artistic and culturally relevant South African screen content. Deve...

10/06/2026

Nielsen launches Four-Screen Ad Deduplication measurement on YouTube campaigns in Japan

Media buyers and sellers can now compare YouTube reach from computer, mobile, an...

10/06/2026

Ecoflow X Launches as Experimentation Arm for Sustainabil...

Accedo, Humans not Robots, and the Institution of Engineering and Technology (IET) have announced the launch of Ecoflow X. Formerly an IBC Accelerator project, ...

10/06/2026

Frequency Appoints James Smith as General Manager - Monet...

Frequency, the engine powering the world's leading streaming television channels, today announced that James Smith has joined the company as General Manager...

10/06/2026

Riedel Artist at the Heart of the 14th World Live Neurova...

At the 14th World Live Neurovascular Conference (WLNC) in Lisbon, Riedel Communications provided the communications infrastructure for live medical procedures s...

10/06/2026

Globecast Unveils Content Exchange Platform Powered by Or...

Globecast, a leading provider of broadcast, media, and entertainment managed services, today announced the launch of its Content Exchange platform powered by Or...

10/06/2026

Venues and integrators shift toward professional recharge...

Klvr will showcase how venues, integrators and production teams are rethinking disposable battery usage at InfoComm 2026 (Las Vegas, June 17-19, booth #N6311). ...

10/06/2026

VSF Releases Specification for RIST Satellite Hybrid Out-...

The Video Services Forum (VSF) has further enhanced the Reliable Internet Streaming Transport (RIST) protocol by incorporating a new feature, RIST Satellite-Hyb...

10/06/2026

Microphone Maker Audix Adds Eric Reese as VP

Share Copy link Facebook X Linkedin Bluesky Email...

10/06/2026

How to watch every ICC Womens T20 World Cup 2026 match live on Sky Sports

Wednesday 10 June 2026 How to watch every ICC Women's T20 World Cup 2026 match live on Sky Sports Where is the ICC Women's T20 World Cup 2026 availabl...

10/06/2026

PRLA brings first-ever Beautifully Clean Oral Care TV campaign to screens nationwide with Sky

Wednesday 10 June 2026 P RLA brings first-ever Beautifully Clean Oral Care'...

10/06/2026

Sky reveals pulse-pounding first teaser trailer for upcoming crime drama Fightland

Wednesday 10 June 2026 Sky reveals pulse-pounding first teaser trailer for upco...

10/06/2026

Riedel Artist at the Heart of the 14th World Live Neurovascular Conference

Wuppertal June 10, 2026 Riedel Artist at the Heart of the 14th World Live Neurovascular ConferenceAt the 14th World Live Neurovascular Conference (WLNC) in Li...

10/06/2026

Netflix Showcases New Mobile Experience, Collections and Games Vision in APAC

Back to All News Netflix Showcases New Mobile Experience, Collections and Games Vision in APAC Product 10 June 2026 GlobalSouth KoreaJapan Link copied to c...

10/06/2026

Ready to Join? The Netflix Fan Club Arrives at Cannes Lions

Back to All News Ready to Join? The Netflix Fan Club Arrives at Cannes Lions Business 10 June 2026 Global Link copied to clipboard Download all assets N...

10/06/2026

June 10, 2026

Chemists snap together complex 3D molecules from highly reactive radicals-without losing their shape Scripps Research team develops stereoretentive radical-radi...

09/06/2026

Kiswe Expands Partnership With ONE Championship To LaunchGlobal Subscription Platform

Kiswe announces an expanded long-term partnership with ONE Championship (ONE), t...

09/06/2026

SiriusXM to Carry All 104 FIFA World Cup 2026 Matches via FOX Sports Commentary

SiriusXM will broadcast FOX Sports' English-language commentary for all 104 FIFA World Cup 2026 matches from June 11 through July 19, available to subscribe...

09/06/2026

EVS Broadcast Equipment Rebrands as EVS

EVS has announced it is changing its corporate name from EVS Broadcast Equipment to EVS, reflecting the company's expanded portfolio beyond broadcast equipm...

09/06/2026

FOX and NFL Announce Multi-Year Agreement for NFL Coverage in Mexico Starting in 2026

Fox Corporation and the NFL have announced a multi-year agreement to bring NFL c...

09/06/2026

FOX Sports and ReachTV to Carry All 104 FIFA World Cup 2026 Matches Across U.S. Airports

FOX Sports and ReachTV, an airport media network, have announced an agreement to...