Linear Phase EQ - Question

I’m trying to understand why this is important (vs. zero latency EQ). I get the zero vs. non-zero latency bit, so I’m trying to understand why I would ever want to use non-zero latency EQ (which I’m inferring is part of linear phase EQ).

As I am interpreting the literature, linear phase EQ is important because as I change individual bands of the EQ I don’t have comb filtering if I didn’t already have it before the adjustment. Conversely, in a zero-latency EQ I can develop comb filtering depending on where the EQ band is as I’m changing it.

Is my understanding correct?

Aloha f.

Interesting question.

The way I understand it:

Linear-phase : preserve the characteristic shape of a waveform by shifting all frequencies by the same amount, making them ideal for applications such as mastering, where subtlety and transparency are paramount and latency is acceptable.


Shifting = the phase, correct?

My ears perceive this as a ‘shift in time’.


…which, to me, is the same thing.

Okay so question about usage. Since mixing involves being able to hear things in near real time, would you want to use zero-latency during playback and then linear during mixdown? I’m assuming so but want to double check with my betters.

You use what sounds best to you :sunglasses:

Liner Phase EQ may be useful in certain applications where you may notice a shift or comb filter sound eg parallel comp. but cant say I’ve ever worried about it?

Never used to have such decisions in the analog world :laughing:

Which is why things sound better now. :slight_smile: :slight_smile: :slight_smile:


What, because of liner phase eq’s :laughing:

Not just LP EQ’s tho’.
Many new digital enhancements over the years add to the chain.

1-Newer tech = more preciseness/granulation = more options = better sound.

‘Back-n-da-day’ (way before 8 tracks) along with my Nagra I actually did live ‘wire’ recordings.
(boardroom meetings/lectures/transcriptions etc)

The technology worked well back then but my mobile phone of today sounds much better
and would do a much job in a similar situation.

Because of technology, all recorded sound (including music) has gotten better
over time and will IMHO continue to do so until…who knows??


Hmm… Interesting points, but what about the content?

Certainly beats giving “demos” out on Cassette :mrgreen:

Not completely. ALL equalizers introduce latency – your use of the term “zero latency” is a misnomer. The difference is a linear-phase equalizer introduces latency is that is independent of frequency, that is to say, all frequencies that are passing through the filter are delayed by the same amount, so as a result there are no phase-related issues in the resulting signal. A minimum phase filter, however, introduces latency that is frequency-dependent, so only a certain band of frequencies will be time-delayed.

Both types have their uses. Sometimes it depends on the frequencies you’re altering – a minimum phase filter might sound better on low frequencies. A linear phase EQ introduces both pre- and post-ringing, which in some cases can be unpleasant. Also, if the processed signal is going to be mixed back in with the original signal to any degree, linear phase EQ can sound pretty bad (or good) because the entire processed signal will be out-of-phase with the unaffected signal.

In the old days, before digital linear-phase EQ’s were in use, most stuff was EQ’d “on the way in” in order to minimize some of these issues. On some of my old tapes I can hear some phase issues when I tried to do some fairly steep EQing when mixing through an analog board… not that it necessarily sounded bad, mind you :sunglasses:

This is an excellent point that I had not thought of. My outboard pre has an EQ section that I do not use because I tend to use microphones that emphasize (or not) qualities of the signal. Anything else I’d rather do in Cubase because I can always redo them if I realize that I didn’t get it right.

But this changes the game a bit. I may have to reconsider my process.

Channel strips are still very popular in part I think because older guys who are used to EQing (and compressing) while tracking are buying them. A couple old-timers at gearslutz have challenged me to be a real man and EQ and compress on the way in. I think there are 2 big advantages to this method: first, your tracks can benefit from a higher quality EQ and/or compressor than what is typically found on a mixing board or in a DAW; but more importantly, it helps you “sculpt” the song as you’re building it, and you’ll know what is and what isn’t going to work (as far as the arrangement, etc. goes), rather than find out later that it can’t be “fixed in the mix”

I don’t think I have a linear phase eq. I do have a linear phase dynamic eq.

just sayin…