If you hang around recording circles long, you’ll probably ask this question I got from Andrew:

Hey Joe, when should I use linear-phase EQ and why?

Linear-phase EQ is essentially a highly-accurate, “surgical” EQ.

Regular EQ’s have phase shift between the different bands. When you boost or cut 250 Hz, that frequency range is technically delayed by a tiny amount, which causes some…”smearing” is the word, I think.

Linear-phase EQ keeps all the frequencies 100% in phase. In other words, all the frequencies pass through the EQ at the same speed, resulting in zero phase issues between bands.

No, that’s not a super-technical definition, but I’m okay with that. ๐Ÿ™‚

So…it’s easy to assume that since linear-phase EQ gets rid of any “smearing” that it must be better, right?

Maybe it is…but does that really matter?

Think about it for a second.

My wife and I have been in our current house for two years. Are there bigger, better, fancier houses out there? Of course.

Does that make our house inferior? Not at all.

Linear-phase EQ is a fantastic tool. It’s wonderful. But that DOESN’T MEAN that you can’t get fantastic results with a “regular” EQ.

I can see how linear-phase EQ would be useful for mastering, but I bet most home studio owners can’t hear the difference.

Or if you CAN hear a difference, neither would probably sound “better” to you…they would just sound different.

I wouldn’t be terribly concerned with it. “Linear-Phase EQ” is a really cool marketing term, but give a great engineer an entry-level EQ and he’ll make magic happen.

This applies to almost everything you do in the studio. There will always be a better option out there, but you’ll be much better off learning HOW to use the tools you already have, rather than constantly upgrading to fancy new ones.

Don’t misunderstand me, I’m not AGAINST linear-phase EQ. I’m simply trying to keep you from putting your hopes in a piece of gear or software to do things that only YOU (the human) can do.

Before you can “graduate” to linear-phase EQ, I recommend becoming a MASTER of “regular” EQ. That involves really understanding the concept of EQ and how to use it to get great results. And practice, practice, practice.

The practice part is up to you. I can help with the learning part here:

www.UnderstandingEQ.com

  • Steele Solid

    The phase misalignment is sometimes useful with parallel processing, makes a very wide and fat sound.

  • bishopdante

    There is no computer science, maths, electronics or acoustics information in this document.

    • Bilge

      Most people would just say “it’s shit” and move on.

      • bishopdante

        I prefer to be more specific than most people, I have never posted “it’s shit” as an explanation for anything other than an actual piece of shit (or windows 2000 pc).

  • erik

    Agreed, Logic’s Linear Phase EQ is horrible at High Q settings. Like 5 and up. Do a > -12db dip in the mids on a ringy snare drum and you here a strange whistling artifact.

  • IzirAtig

    You didn’t mention pre ringing what linear eq causes.

    • I’m not sure what you mean by pre ringing?

      • JoshAFairhead

        A standard EQ will ring when you push the filter gain, particularly with narrow bandwidth (Q) values. This is because the filters are cascaded and fed back every sample (thus causing more phase shift if you push them and a ringing filter as it goes into self oscillation). This doesn’t happen with linear-phase EQs. For more information about DSP and how it works reference the monster that is “the computer music tutorial” by Curtis Roads.

        • T

          I think you are mixing up some things…you obviously don’t know what you are talking about! So – why do you comment in such a way!?

          • JoshAFairhead

            Thought you were a troll because of your statement but actually yeah yer right, thats nearly backward.

            I’m no dsp engineer but in regards to my comment it had reasoning and reference so it could be checked and maybe point an enthusiastic home studio engineer in the right direction if they’re curiosity brings em out of their depth.

            Yeah the answer was wrong but consider it bait ๐Ÿ˜‰

  • Nmbx1989

    Wow that was truly an amazing article. How I came across this posting is I’ve been researching different methods of mixing from my normal approach for the past 6 years. I’m a beast on mixing beats and vocals on FL STUDIO … (Parametric eq I’d what I use.) Any good tips on clarity with hip hop vocals? Or mastering with maximus?

    • Vocal clarity comes with removing muddyness in the low mids usually.

    • bishopdante

      My advice would be have your ears bricked up.

  • Webecomegods

    Great job on the write-up
    now just help us learn how to make them ; )
    Linear Phase RC circuits/ filters, straight DIY build eh? lol
    went Canadian there for a moment ๐Ÿ˜›
    Well with the new Galactic Super Wave coming our way
    and clairvoyancy just months away
    it won’t be long until I will be able to read your mind
    and learn that way (wow which will be so much easier)
    however, that is like a special christmas present for us all
    so, I don’t plan on ruining the surprise for anyone ๐Ÿ˜€

    sadly, there are still people that think the world will end
    in reality, a massive wave will manipulate our 2-helix genome to a triple-band helix
    thus bringing us one step closer in evolution :]

    well, just wanted to share that,
    don’t bother arguing me,ย 
    i am just the messenger ::3

    Love you guys,ย 
    see you all soon : *)
    Thee.aldeen : :ย 

    • Mind-reading, eh? That would make this easier. ๐Ÿ˜‰

  • Linear Phase EQ is great when you want to make a frequency band louder or quieter without changing other aspects of its relationship with the music around it – hence it’s sometimes very handy in Mastering as per Ian’s comment above. Ditto I don’t find much use for it in mixing and I don’t EQ tracking anyway. Another downside of LP is that you need to be careful – high Qs can cause horrible pre-ringing that can be quite audible. It’s another of those things to not over analyze – if you have one do some listening tests and if you don’t then don’t worry about it.

  • Xan

    Yes I can see how a phase delay might be an actual advantage especially when you are cutting a band. Slowing that band down a little gives you a slight bit ov extra cut for “free” albeit it is proly too small to notice.

    BBE processing does this to a greater extent. It delays the low band so the higher bands reach your ears first, which gives the impression ov boosted top end, even though it might not really be. It’s an interesting concept.

    Sometimes it’s useful, other times not.

    I guess you could say the phase delays on a non-lin EQ are a mini version ov that, although they wouldn’t be helpful if boosting is your aim. Perhaps that’s why on most EQs cutting what you don’t want sounds better? (As well as saving your headroom ov course) ๐Ÿ™‚

    • CamBam

      I’m thinking that BBE processing will make the beater sound on a kick drum really noticeable, right?

  • Andrew

    I think that’s my quote on Joe’s Article of today! AHHHH!!!! Jk

    Yeah I agree Joe. I couldn’t find any use for it in mixing (although I have seen/read some engineers use it for mixing which is why I was interested. And they used it in an out of the ordinary fashion: the mixing stage). Handy for Mastering though (I think any DAW comes with one. At least I know Logic comes with one). I like that you said it’s a “highly- accurate surgical EQ” which to me is the best way of looking at it as. Couldn’t have agreed more!

    Cool article! =)

    • He he…You’ve been immortalized in the HSC archives. ๐Ÿ™‚

  • I completely agree, Joe – in fact, I’d go one further and say that in many cases you actually WANT the phase smearing of a traditional EQ.

    All the “vintage” and “classic” EQs that people aspire to smeared the phase, after all. The big trend these days is to emulate that (and all the other features/flaws/voodoo of analogue gear) in software.

    And finally, linear-phase EQ always requires a hefty delay to the processing, even on modern CPUs. Plugin delay compensation can help, but is often flaky – it’s easier just to avoid the hassle.

    Don’t get me wrong, I’m a big advocate of linear phase EQ in mastering, as you know – but in mixing and tracking ? Not so much.

    Here’s an easy way for people to hear the difference – check out the DDMF LP10 EQ:

    DDMF LP10 EQ

    This actually allows variable phase on every band – so you can dial in a setting, listen to it as linear phase, minimum phase and everything in between, and decide which you prefer – and, whether you can even hear a difference in the first place ! Often with broad boosts and cuts, there’s not much to choose between them.

    Ian

    • Thanks Ian! I was actually thinking about you when I wrote this…hoping you’d still agree. ๐Ÿ™‚

    • Xan

      When I am mixing when I tend to use the linear phase EQs is when I apply the plugin to process a section ov track permanently. i.e. not on the channel but directly changing the track like you would do in a wave editor.

      That way the processing power it takes doesn’t slug out your mixing cause it’s basically applying, rendering then removing the plugin in one easy step.