What is Linear Phase EQ?
Before moving into linear phase EQ particularly, we believe it is essential to go over the fundamentals of typical equalization and its relationship to phase in an effort to set the stage, so to talk, about how highly effective linear phase EQ truly is.
A minimum phase EQ is simply one other name in your normal, everyday equalizer. With all of those common equalizers that we use daily, we experience phase shifts because of the latency created by altering the amplitude of particular frequency bands. This latency or delay of the frequencies causes what’s often called a phase smear.
Smearing leaves audible artifacts within the sign which will be undesirable. Many times you can’t hear smearing at all, at different times you might like what it’s doing, however, in several scenarios, you may want an equalizer that retains the phase constant.
Equalization, or EQ, is undoubtedly one of the difficult points of mixing and mastering to get a hold of. Even the smallest adjustments in frequencies can drastically alter the character of a track or complete tune.
In case you’re not prudent with your EQing, you may go beyond the point of no return and wind up in a dangerous place. Nonetheless, it’s crucial to make use of EQ in each mixing and mastering process. And on the subject of mixing and mastering, there’s a particular kind of EQ that may actually come in useful: linear phase EQ.
What is a Linear Phase EQ?
Linear phase EQ additionally shifts phase, however instead of solely shifting the frequencies being boosted or attenuated, it shifts the phase of your entire signal. This gives you the power to make the frequency changes you need, without affecting the phase relationship of different frequencies in your audio.
Linear phase EQ is a product of digital technology. Digital recording has made our lives an entire lot extra convenient, but it’s nonetheless comparatively new as far as recording history is concerned. For many years, folks made records on consoles and tape machines, and that’s a sound people came to know. A part of what we do in the box is imparted a few of that analog mojo back right into a crystal clear digital recording through all kinds of analog emulated plugins.
Linear phase EQ is just not potential in the analog area. Generally, that’s the fantastic thing about digital. The linear phase is equalization that doesn’t have an effect on the phase of a sound supply. It retains the relationship linear across the spectrum so you may boost and cut the signal with no opposed unwanted effects.
The entire point of linear phase EQ was to offer engineers the choice to avoid phase smearing altogether. As with most things in audio, nevertheless, there are tradeoffs. Pre-ringing is the most important drawback of utilizing a linear phase; the technology inside these EQs analyzes the frequency signal, then shifts the processed audio to keep it in time.
Throughout this shift, you generally get an echo right before an enormous transient, which is known as a pre-ring. It’s audible and might have an effect on transients pretty badly.
To verify the phase relationship is unbroken, linear phase EQs delay the signal narrowly. Then, your DAW routinely tries to make up for that latency, pulling it back so it performs on time. However, doing this creates pre-ringing.
Pre-ringing is a side-effect of the signal being processed backward. It appears like a reverse reverberated model of the sound spliced at the start of the transient. Pre-ringing can be managed by how you set your EQing, so you’ll be able to keep away from it if you’re cautious.
Should we use Linear EQ all the time?
Typically, it will be pointless because the audible artifacts that you just get from a minimum phase EQ will not be detected in your track anyway. Secondly, it’s not an “all the time tool” but more of a specialty tool that may work alongside your different production instruments.
As a matter of fact, there are even some minimum phase EQs that may be converted from minimum to linear phase with just one click.
Linear-phase equalizers are largely utilized in a mastering setting as most mastering houses could have a Weiss EQ1-LP someplace within the building. This doesn’t imply that a linear-phase EQ can be utilized in mastering situations only, however it does imply that most often a linear-phase EQ is going to be used sparingly as a substitute for getting used on every track of a track where an equalizer is required.
We personally don’t use a linear-phase EQ often, however generally, we discover that we use one to deal with subfrequencies on tracks we’re requested to mix.
Typically we run right into a muddy mix down there (very low frequencies) that the client couldn’t hear on their system that must be cleaned up. In these conditions we find a linear-phase EQ to be simply what is required for the job.
When should you use the Linear Phase EQ?
Utilizing linear phase EQ could be helpful if you find yourself processing an audio source with a number of microphones on it. An apparent instance of this could be drums. Even with gating and different plugins in place to isolate every drum, there’ll nonetheless be some bleed from different drums coming into every microphone.
The kick drum will get into the snare mic, the snare into the tom mics, and so forth. Adjusting the phase relationships between all of the microphones with EQ may have an effect on the sound of the drum kit fairly drastically.
That is the place using linear part EQ may come in useful. You can also make the changes you need without inflicting any phase smearing among the many different drum mics.
Linear phase EQ may be helpful for any instruments recorded in stereo, such as acoustic guitars. Within the recording process, these mics are positioned carefully in order that they’re in phase and seize the most accurate stereo image possible. Adjusting the phase relationship between the 2 mics with EQ may have an effect on the tone of the guitars in undesirable methods.
Linear phase EQ may very well be helpful in parallel processing chains, such as parallel compression or distortion. Adjusting the phase relationship between the supply audio and the parallel processed audio may alter the tone of the track in unintended ways. Utilizing linear phase EQ right here would be sure that this doesn’t occur.
So we tried to explain what actually is the linear phase EQ and what you can process with this tool and when to avoid it. The benefits are huge if you are having trouble with some phasing when EQing the low frequencies, and as we stated this is the place where we use it the most.
Do not be afraid to try it out, even if you are not hearing any audible artifacts before applying it. Every test is good to train your ear and get used to a new weapon in your arsenal.
If you have some questions about the Linear Phase EQ process, please let us know in the comment section below and we will be more than happy to reply to you!