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Outstanding Linear phase EQ Tutorial

Discussion in 'F.O.H.' started by nialldoran, Jan 30, 2014.

  1. nialldoran

    nialldoran Member

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    I don't know if you guys have seen this video, but it really, really helped me understand the difference between linear phase EQ and minimal phase, the difference is insane and what it can do to your mix is scary, i try and use my ears as much as possible but knowing the science of this and what to listen out for will definitely help in future,

    some of this is fairly straight forward stuff and he goes through the basics of phase relationships, but when he then applies and shows what non-linear phase can do to negatively affect the EQ you are trying to implement, it blew my mind.

    it's completely worth 19 minutes of your time

     
    #1 nialldoran, Jan 30, 2014
    Last edited by a moderator: Nov 20, 2015
  2. egan.

    egan. daylightdies.com

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    This is a great video which provides concrete examples of a misunderstood concept. Still, I can't help but think a bunch of people are going to totally miss the point and start scoping their EQ's all the time.
     
  3. sjokarn

    sjokarn Member

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    This made me take a bunch of EQ´s and check filters and stuff through white noise just for fun :).
     
  4. nialldoran

    nialldoran Member

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    Yeah the main thing the got me with the video was the HP and LP filters, just crazy that it can be attenuating frequencies before the filter is where its suppose to be and by such a huge amount, really calls into question what i hear when EQ drum kits, think this has scared me off of using the solo button now, :lol:
     
  5. Machinated

    Machinated Member

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    Very good video. A good reminder to use your ears, flip polarity switches to check, and think about where in your chain youre using filters.
     
  6. Vice//Versa

    Vice//Versa Dude among dudes

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    This was insanely insightful :)
     
  7. Red Phoenix

    Red Phoenix Member

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    i also ran into such a phase problem yesterday. i had several mics to record my cab.. one mic had too much lows but sounded good so i put a lowcut only on that mic..but that lead to phase cancelation and sounded shit. with a linear phase eq it was ok.

    the vst plugin analyser is awseome! =D
     
  8. mharwood

    mharwood Member

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    Definitely worth the time, thanks for the heads up!
     
  9. NecroDM

    NecroDM br00taliz0r

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    +1

    Thanks!
     
  10. HOFX

    HOFX Member

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    Thanks for posting.
     
  11. Nimvi

    Nimvi Member

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    This was great! Really filled in a grey area in my audio knowledge. Thank you very much :)
     
  12. nialldoran

    nialldoran Member

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    really glad people are getting use out of this and that people had the same holes in their knowledge i did, wish i could take credit for it haha, but i just stumbled across it
     
  13. KillFrenzy

    KillFrenzy Member

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    Great video! Very enlightening.
    Thanks!
     
  14. TheWinterSnow

    TheWinterSnow Den Mørke Natt

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    I have been using linear phase eq in certain applications most of my AE experience. One thing that he does not mention is the actual perceived effect of phase delay relative to other frequencies in a transient. When you say have a kick and you want to tighten up the lows by running a highpass, the low end becomes delayed relative to the other frequencies. Your perception of lows and highs are based on which frequency you hear last, this is very similar and part of the Haas effect, if the last decaying frequency is low, then it sounds boomy and muddy, if the low frequency came early and the last thing you hear is the sharp transient spike of the highs, you will have a tighter, clickier sound. That is why you can have a single kick sound absolutely massive in size and it doesn't eat up any low frequency headroom or vice versa, have a very thin kick that eats up massive amounts of headroom in the lows.

    Introducing phase distortions can effect you you perceive the source, since it is really important to control low end and keep it big but tight, I have always looked at Linear Phase EQ to keep the lows tight when sculpting the information in that region.
     
  15. nialldoran

    nialldoran Member

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    great post man, that's really interesting, do you have any good articles or anything that talks about phase delay specifically ? i'd love to learn a bit more about all this,

    EDIT:
    just to clarify when you say it can delay frequencies relative to others, is it the same issue the guy in the video i posted talks about at 1:20 when he switches to linear phase mode and it effects how the initial transient is percieved?
     
  16. crillemannen

    crillemannen Member

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    Thanks for the post!

    Always nice to get some more in-depth knowledge of how it works.
     
  17. Ermz

    Ermz ¯\(°_o)/¯

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    Great video. Thanks for sharing.

    One thing I find interesting is how much of the science seems to contradict using Linear Phase EQ for low-end because of this pre-ringing, yet every single time I cycle it on my bass guitar processing it sounds way tighter, thicker, punchier and subbier than minimum phase modes. This applies equally when doing low shelves on the entire mix in linear phase mode. I've never been able to create pre-ringing that was so severe it actually impacted the mix.
     
  18. nialldoran

    nialldoran Member

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    absolutely agree with you Ermz, i personally haven't experienced the pre-ringing that the guy demonstrates in the video but he said he purposefully constructed this extreme example for explanation purposes,

    i think it's super important to be aware of the possibilities in these scenarios in case it ever happens, but as long as the linear phase makes the low end SOUND better then that's whats important i think.
     
  19. AudioGeekZine

    AudioGeekZine arsehole know-it-all

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    Never gave it much thought. It turns out the issue is more complicated than I expected and with no clear answer.
    Use minimum phase unless it's in parallel or on coincident sources, unless it sounds better.

    I do remember times when something sounds good soloed but thin in context and the solution wasn't intuitive, I guess that was phase shift.

    Interesting stuff.
     
  20. bryan_kilco

    bryan_kilco Member

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    I still can't fully wrap my head around all of this, but it is helpful so far in my understanding.

    Basically, boosting and cutting with an EQ causes your phase to change on said track?
     

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