Dodger
Joined: 28/11/09
Posts: 198
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Linear Phase EQ
#812722 - 17/02/10 10:49 PM
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Hi just started using logic and have noticed that the channel EQ and Linear phase EQ look
exactly the same and really am just wondering....
what is a liner phase eq?
and how dose it differ from the normal EQ?
thanks Jack
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18369
Loc: Worcestershire
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Re: Linear Phase EQ
[Re: Dodger]
#812840 - 18/02/10 11:56 AM
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A linear phase filter has constant group delay, which means that all frequency components
of the signal suffer an equal delay time as they pass through the filter.
'Normal' equalisers aren't linear phase and have a group delay which varies with
frequency. So some frequncies come out the far end slightly earlier or later than other
frequecies. This results, inevitably in phase distortion -- but it is a distortion that we
are used to and associate with recorded sound, and it is what makes different equaliser
designs sound different.
hugh
--------------------
Technical Editor, Sound On Sound
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Dodger
Joined: 28/11/09
Posts: 198
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Re: Linear Phase EQ
[Re: Dodger]
#813298 - 19/02/10 09:38 PM
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thanks
so what are the applications of it ?
i heard it mentioned
once in a music tech lesson we didn't go into much because he said we didn't need to know
it and we need to get back to learning about wherever we were doing because we had gone
off on one (there are only 3 of us in the class its easy)
any back on subject
he said it was very processor heavy and can cause a lot of latency on channels applied on.
if the channel you put it on is going to have a lot of latency on it then surely that
defeats the object of having the linear EQ in the first place?
Jack
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Dodger
Joined: 28/11/09
Posts: 198
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Re: Linear Phase EQ
[Re: Dodger]
#813310 - 19/02/10 10:21 PM
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Also why am i on this little sort of rant ha ha
what is the difference between
the adaptive limiter and the normal limiter?
i was recommended to use one for
mastering? but i dont no why?
Thanks sorry if these questions are stupid..
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Mixedup
active member
Joined: 03/09/03
Posts: 4254
Loc: Cambridge, UK
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Re: Linear Phase EQ
[Re: Dodger]
#815907 - 02/03/10 07:58 AM
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Quote Dodger:
so what are the
applications of it ?
Think
surgical/clinical for linear phase EQ. For non-linear phase think character. Linear phase
EQs do tend to take more processing power. This SOS article might help. Also keep your eyes peeled for
forthcoming Mix Rescue articles that address this issue in a practical context.
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Martin Walker
Watcher Of The Skies
Joined: 28/02/01
Posts: 16381
Loc: Cornwall, UK
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Re: Linear Phase EQ
[Re: Dodger]
#816008 - 02/03/10 01:33 PM
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You may also find this review I wrote of Nugen Audio's SEQ Linear Phase plug-ins of help,
since towards the end I describe how various linear phase designs sound in practice: www.soundonsound.com/sos/jan08/articles/nugenplugins.htmTo
my ears, Waves' LinEQ has an uncanny knack of being able to alter spectral balance without
adding any character of its own; if you dial in more bass, for instance, you get more
bass, but the sound somehow doesn't seem to be any 'warmer'. This absolute neutrality is
ideal for some mastering applications, but not universally enjoyed. Martin
-------------------- YewTreeMagic
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Shambolic Charm
Joined: 13/07/05
Posts: 898
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Re: Linear Phase EQ
[Re: Dodger]
#816277 - 03/03/10 09:45 AM
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while were on the subject, are there any linear phase eq's that have a low latency?
-------------------- www.myspace.com/shambolic-charm
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Martin Walker
Watcher Of The Skies
Joined: 28/02/01
Posts: 16381
Loc: Cornwall, UK
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Re: Linear Phase EQ
[Re: Dodger]
#816364 - 03/03/10 02:12 PM
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Linear phase and low latency don't tend to go hand in hand I'm afraid  Martin
-------------------- YewTreeMagic
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MarcusH
Joined: 02/02/08
Posts: 438
Loc: Was Singapore - Now Mumbai
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Re: Linear Phase EQ
[Re: Dodger]
#816518 - 03/03/10 10:10 PM
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Can't find it now, but I saw a video on the internet showing magnified, the changes to the
waveform that Logic's normal Channel EQ makes. Using a kick drum track, the guy showed
that Logic's EQ definitely created 'ghosting' - a second hit was clearly visible. More
importantly, to my ears Channel EQ sounds dull and lacks clarity.
I do use
Logic's Linear Phase EQ however, and there's a good trick to using it. Logic lets you
switch between Channel EQ and Linear Phase EQ and the good bit is it keeps your
settings. That means you can use Channel EQ when you need low latency - e.g. for
tracking, and Linear Phase when you need good sound - e.g. for mixing.
In
terms of practical use, I use my third party EQ plugins to improve the sound, and I use
Linear Phase EQ for precise jobs, like filtering-out rumble or taking the ring out of a
drum sound.
--------------------
You live. You learn.
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