
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
Most recent headlines
05/01/2027
Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...
04/08/2026
Dalet, a leading technology and service provider for media-rich organizations, t...
04/07/2026
April 7 2026, 19:00 (PDT) Detective Conan: Fallen Angel of the Highway Opens in...
01/06/2026
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...
07/05/2026
In the first quarter 2026, SGL Carbon generated consolidated sales of 184.5 million, which was 49.8 million, or 21.3%, lower than in the prior year (Q1 2025: ...
07/05/2026
Rohde & Schwarz and Greenerwave achieve precise and fast ESA antenna characteriz...
07/05/2026
Two multi-role L3Harris products - the Red Wolf launched effects vehicle and SK...
07/05/2026
L3Harris will be developing key features of a secure and resilient digital infra...
07/05/2026
Alysa Liu and Shohei Ohtani Help Drive Viewership as 91 of the Top 100 Broadcast...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
Cobalt Digital Wins Two Future Best of Show Awards at 2026 NAB Show
Manufacturer Recognized by TV Tech and TVBEurope for Innovation in signal processing
Cobal...
07/05/2026
Software and hardware platforms, AI power and user-friendliness on show...
07/05/2026
Intinor will demonstrate its latest technical enhancements for the Direkt series at BroadcastAsia 2026. With a continued focus on reliable contribution and remo...
07/05/2026
Bitmovin has announced that MUBI has chosen Bitmovin as its cloud VOD encoding partner, replacing MUBI's legacy on premises encoding setup to improve scalab...
07/05/2026
Meet Graduates from Berklees Class of 2026 Members of this years graduating class reflect on their proudest moments at Berklee and look ahead to whats next.
...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
At BroadcastAsia 2026, Interra Systems will demonstrate its latest innovations in automated quality control (QC), real-time monitoring, and captioning. The comp...
07/05/2026
At this year's Broadcast Asia, PlayBox Neo is set to unveil recent innovations across its PlayBox Neo Suite and integrated range of broadcast media solution...
07/05/2026
Strategic three-year partnership marks delivery phase of BFBS' next-generation media vision
Media organisation and military charity BFBS (British Forces Br...
07/05/2026
Amagi, the agentic industry cloud platform for unified broadcast, streaming, and monetization, today announced the availability of its In-Content Ads offering v...
07/05/2026
Lightware Visual Engineering has developed Rack Taurus for rack-based environments such as education and corporate training spaces. It enables clean and simple ...
07/05/2026
Jigsaw24, the UK's leading media equipment supplier and systems integrator, will showcase its expanded end-to-end workflow capabilities at MPTS 2026, signal...
07/05/2026
Ease Live, an Evertz company, today announced that it has been granted a US Patent for its proprietary graphical overlay technology, the foundation for interact...
07/05/2026
Test & measurement innovator Leader Electronics of Europe will present an extensive range of Leader, PHABRIX and LeaderPhabrix test and measurement solutions at...
07/05/2026
At Broadcast Asia 2026 (Stand 5H3 8), LiveU is redefining live production with its most powerful IP-video EcoSystem to date built to help broadcasters and con...
07/05/2026
January 8, 2024
Colorfront (colorfront.com), a leader in high-performance, on-s...
07/05/2026
February 9, 2024
Colorfront (colorfront.com), the multi-award-winning pioneer i...
07/05/2026
March 20, 2024
NAB 2024, Las Vegas - Colorfront (colorfront.com), the multi-awa...
07/05/2026
April 1, 2025
CINEMACON, APRIL 1, 2025 - Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming syste...
07/05/2026
June 15, 2025
Colorfront (colorfront.com), an Academy and Emmy Award-winning de...
07/05/2026
June 15, 2025
Colorfront participated in the ICTA Barcelona Cinema Technology Summit on Sunday, June 15, 2025. Held at The Phenomena Experience, the event feat...
07/05/2026
July 1, 2025
Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming systems for motion pictures, OTT,...
07/05/2026
July 1, 2025
Passion and dedication will take you places. Come with us on a short trip to the heart of India, where Annapurna Studios is living-up to the inspi...
07/05/2026
July 3, 2025
Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming systems for motion pictures, OTT,...
07/05/2026
September 1, 2025
IBC 2025, Amsterdam - Colorfront (colorfront.com) - the Acade...
07/05/2026
April 17, 2026
LOS ANGELES - April 17, 2026 - Colorfront today announced Colorf...
07/05/2026
April 23, 2026
NAB 2026, Las Vegas - the Academy and Emmy Award-winning develop...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
Recreating the 1974 Doctor Who Time Tunnel in After Effects
Graham Quince May 6, 2026
0 Comments
The Time Tunnel from Doctor Who titles is one of th...
07/05/2026
Thursday 7 May 2026
Sky continues Sphere Abacus partnership with The Death of S...
07/05/2026
Thursday 7 May 2026
Sky Confirms Saturday Night Live UK will return this September for Series Two
Saturday Night Live UK will return for a second series, as S...
07/05/2026
Save 20% on the Sky Glass Gen 2 and Sky Glass Air TVsThursday 7 May 2026
How to watch the World Cup on Sky Glass
Tune into the World Cup on the BBC and ITV vi...
07/05/2026
Back to All News
Red Chillies Entertainment and Netflix Present the Trailer of ...
07/05/2026
Production sound mixer Dirk Sciarrotta has mixed Family Feud for 28 seasons. Thats up to 200 syndicated episodes per year, plus primetime celebrity specials - a...
07/05/2026
As audience expectations have evolved, Owen has stopped trying to hide microphones or excuse amplification. Instead, he treats sound as a fully immersive part o...
07/05/2026
Well known Irish faces pushed to the edge in new series of
Uncharted with Ray G...
07/05/2026
RT will premiere A Traveller Family, a compelling new documentary exploring the...