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 ...

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...

01/06/2026

Dolby Sets the New Standard for Premium Entertainment at CES 2026

January 6 2026, 05:30 (PST) Dolby Sets the New Standard for Premium Entertainment at CES 2026 Throughout the week, Dolby brings to life the latest innovatio...

02/05/2026

Dalet Flex LTS Delivers Smarter Search, Faster Editing, and an AI-Ready Foundation for Modern Media

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

01/05/2026

NBCUniversal's Peacock to Be First Streamer to Integrate Dolby's Full Suite of Premium Picture and Sound Innovations

January 5 2026, 18:30 (PST) NBCUniversal's Peacock to Be First Streamer to ...

14/04/2026

ToolsOnAir and Omnistream Bring Mobile SRT Contribution into Professional 24/7 Playout and Live News Workflows

ToolsOnAir and Omnistream Bring Mobile SRT Contribution into Professional 24/7 P...

14/04/2026

NAB 2026: Haivision Launches Falkon X4 5G Mobile Video Transmitter

Haivision has announced the Falkon X4, a 5G mobile video transmitter for live broadcast and remote production. The device will be showcased at NAB Show 2026. ...

14/04/2026

SVG New Sponsor Spotlight: Stripe TVs Matthew Pavey on Making Live-Production Tech More Portable, Intuitive, and Accessible

Founded by veterans of the production-truck world, Stripe TV was born out of a d...

14/04/2026

Studio Berlin Adds LDX 135 and LDX 180 Camera Systems from Grass Valley

Grass Valley has expanded its partnership with Studio Berlin, supplying 12 LDX 135 UHD/HDR camera systems and 12 LDX 180 Super 35mm cinematic cameras, including...

14/04/2026

LTN Appoints Mark Romano and Edward Cox to Vice President Roles

LTN has announced two senior appointments ahead of NAB Show 2026: Mark Romano as Vice President, Multichannel Platforms, and Edward Cox as Vice President, Sales...

14/04/2026

Agor and Sennheiser to Deploy Largest Spectera System to Date at Eurovision Song Contest 2026

Sennheiser and Italian rental company Agor have begun preparations for their Eu...

14/04/2026

DAZN and ADI Predictstreet Announce Prediction Market Partnership Ahead of FIFA World Cup 2026

DAZN and ADI Predictstreet have announced a partnership to integrate ADI Predict...

14/04/2026

Deltatre Completes Digital Platform for Serie A as Part of Four-Season Partnership

Deltatre has announced the completion of a direct-to-fan website and app for Leg...

14/04/2026

NAB 2026: Daktronics to Exhibit with Grass Valley

Daktronics, will exhibit at NAB Show 2026 in partnership with Grass Valley at Booth C2408, Las Vegas Convention Center, April 19-22. Daktronics will showcase a...

14/04/2026

NAB 2026: Backblaze to Host Partner Showcases

Backblaze will host a series of partner presentations at NAB Show 2026 (Booth N1259, North Hall), open to all exhibition hall badge holders. Showcase partners i...

14/04/2026

NAB 2026: BRAHMA AI to Exhibit Enterprise AI Content Platform

BRAHMA AI will exhibit at NAB Show 2026 (Booth W2415, West Hall), demonstrating its Enterprise AI Content Platform for media, entertainment, sports, and technol...

14/04/2026

Bridge Technologies VB440 Integrated into NEP Platform

Bridge Technologies has announced that its VB440 production probe has been integrated into NEP Platform, NEP Group's software orchestration system. The inte...

14/04/2026

NAB 2026: Clear-Com to Demonstrate Expanded Intercom Ecosystem

Clear-Com will introduce new products and demonstrate its communications ecosystem for broadcast and live production at NAB Show 2026 (Booth C5807, April 19-22)...

14/04/2026

NAB 2026: EZDRM to Introduce Revenue Security Prism Framework

EZDRM will use NAB Show 2026 (Booth W2260) to introduce the Revenue Security Prism, a framework for combining multiple security technologies to protect streamin...

14/04/2026

NAB 2026: Telos Alliance Product Preview

Telos Alliance will introduce the following products at NAB Show 2026: TV and Media Telos Infinity MK2 Panels: A new generation of hardware control panels for...

14/04/2026

NAB 2026: Panasonic to Showcase IP and IT Production Solutions

Panasonic Video and Audio Systems North America will exhibit at NAB Show 2026 (Booth C3509), demonstrating IP- and IT-based production solutions for sports, bro...

14/04/2026

Behind the Mic: WNBA Adds Sue Bird, Sophie Cunningham to Networks Commentary Teams; John Buccigross Signed to ESPN Extension

Behind The Mic provides a roundup of recent news regarding on-air talent, includ...

14/04/2026

NAB 2026: Blackmagic Design Announces Multiple New Products

Blackmagic Design will exhibit at NAB Show 2026 (Booth N2502). CEO Grant Petty s product announcement livestream is available at youtube.com. The company announ...

14/04/2026

Thomas Riedel Acquires ARRI, Adding Camera and Lighting Component to Riedel Group Portfolio

The deal establishes a close strategic alignment' between the iconic cinema...

14/04/2026

Taming the Untamed: Producing the 2026 Absa Cape EPIC Mountain-Bike Race

BIGSHOT Media, with support from Teradek, produced untamed African mountain-bike race' with daily coverage and highlights show The 2026 Absa Cape EPIC, an...

14/04/2026

SVG Announces Sports AI Innovation Lab to Advance the Use of AI in Live Production

The Sports Video Group (SVG) today announced the launch of the SVG AI Innovation...

14/04/2026

AIR Music Tech release Fabric Vintage Synths Vol.1

Captures a trio of renowned polysynths The latest software to join AIR Music Tech's extensive catalogue captures the sound of three sought-after polysyn...

14/04/2026

United Plugins introduce UnitedFreeBundle

Free offering includes 10 powerful plug-ins United Plugins have announced the launch of a new bundle that brings together 10 of their pro-audio plug-ins, an...

14/04/2026

Celemony update Tonalic

Julian Coryell joins virtual session player line-up Announced at NAMM 2026, Celemony's Tonalic kits DAW users out with real performances by world-class ...

14/04/2026

Supporting Safe Space Flights with WESCAM MX-Series Imaging Systems

WESCAM MX -Series EO/IR Systems Provide Critical Visibility During NASA Re-Entry Operations....

14/04/2026

L3Harris Demonstrates Autonomous Electronic Warfare Capability During US Army Experiment

DiSCO reduces uncertainty during the fog of war in modern threat environments an...

14/04/2026

GOES-19 One Year Later: Protecting Communities Through Advanced Technology

GOES-19 imagery captured by L3Harris-built Advanced Baseline Imager technology helps forecasters issue life-saving weather warnings. Credit: NOAA/NASA...

14/04/2026

Reimagining Earth Measurement for the AI Era: L3Harris and Xoople Develop a New Spacebourne Capability

For decades, understanding the physical world from space has required a trade-of...

14/04/2026

Nielsen Appoints Roberto Ruiz to Lead Measurement Science

Ruiz has helped fuel growth for both client-side and media companies, including, most recently, TelevisaUnivision. He will spearhead transformation, innovatio...

14/04/2026

LTN Appoints Mark Romano, Edward Cox to Leadership Positions

Share Copy link Facebook X Linkedin Bluesky Email...

14/04/2026

Grass Valley Adds Telestream Vantage, Pulse and UP to AMPP

Share Copy link Facebook X Linkedin Bluesky Email...

14/04/2026

XenData Announces Backup, Archive and Cloud-Connect for LucidLink

Share Copy link Facebook X Linkedin Bluesky Email...

14/04/2026

Thomas Riedel Acquires ARRI

Share Copy link Facebook X Linkedin Bluesky Email...

14/04/2026

Shotoku Introduces the World to Aura P2 PTZ Prompter Pann...

Shotoku Introduces the World to Aura P2 PTZ Prompter Panner at NAB 2026 New system removes PTZ pan restrictions for teleprompter-based productions Shotoku US...

14/04/2026

Telestream and Grass Valley Connect Live and File-Based W...

Integration of Vantage, Pulse, and Telestream UP with Grass Valley AMPP Ecosystem enables scalable, interoperable workflows spanning live production and file-ba...

14/04/2026

Dalet Appoints Brian Doheny as President and Chief Revenu...

Enterprise growth leader to scale Dalet's next phase of innovation and global expansion New York, NY April 14, 2026 Dalet, a leading technology and ser...

14/04/2026

Berklee Celebrates Prince's Legacy in Two-Night Signature Series Event

Berklee Celebrates Prince's Legacy in Two-Night Signature Series Event Directed by Tia Fuller, the Prince Project (April 16-17) brings together more than ...

14/04/2026

Arooj Aftab Is Anything but Predictable

Arooj Aftab Is Anything but Predictable The singular artist explores the juxtaposition of grief and joy, dark and light, in her distinctive sound. April 14, ...

14/04/2026

Appear Expands X Platform from Core to Edge at NAB Show 2...

Appear launches include XM estate management and new X Platform processing enhancements to add density for next-generation hybrid & IP workflows, X5 is also now...

14/04/2026

Synamedia turns OTT content into TikTok-style feeds with...

Addressing the needs of a new generation's viewing habits, Synamedia launches GO Shorts. The AI-powered module turns existing catalogues into TikTok-style ...

14/04/2026

NAB 2026 - Vubiquity and Eluvio Showcase Streaming Soluti...

Vubiquity, an Amdocs company and global leader in technology-led media services, will be showcasing a new end-to-end streaming solution in collaboration with El...

14/04/2026

LiveU Announces Expanded Collaboration with Sony at NAB S...

LiveU today announced a significant expansion of its collaboration with Sony Corporation, introducing integrated support for Sony's file-based workflow solu...

14/04/2026

BBC World Service TV selects Open Broadcast Systems for I...

Open Broadcast Systems (https://www.obe.tv/) has announced that BBC World Service has selected its decoders for IP Television distribution. The high-quality, lo...

14/04/2026

Blackmagic Design Announces DaVinci Resolve 21

Blackmagic Design Announces DaVinci Resolve 21 Brie Clayton April 14, 2026 0 Comments Major update adds new Photo page bringing Hollywood's most a...