EIOSIS AirEq – The Gear Gods Review

The Eiosis AirEq. Where do I begin? Well, some people will just want to know if it’s good or not, others will want something more in depth. For those of you who want the short version of this review, this is the best multi-purpose transparent EQ currently available. Anyone who wants to know why I think it is such, please follow me to the next paragraph.


Hey there! I’m glad you were able to make it. Now, you might be asking yourself. Really, Alex? The best transparent EQ? I try very hard here not to exaggerate when it comes to reviews, but in my humble opinion, yes. It indeed is. At half that cost of most plugins, you can get AirEQ and you will have an EQ that pretty much no other can match in terms of versatility and transparency. If you were forced to only use one EQ plugin for anything and everything, I cant imagine a better one to have than this. Now, this EQ doesn’t add “color” to the sound the way analog EQ’s do. That being said, EQ “color” is not necessary to making a great mix. In my time with it I pretty much would always start with AirEQ and work it to my needs, If there was an element of my mix that I felt would be easier solved by using an analog modeled EQ, thats when I would apply it. And honestly with using AirEQ, I feel less of a need to use an analog EQ. I can usually get what I want out of AirEQ alone.

Eiosis is headed up by Fabrice Gabriel, co-founder of Slate Digital and the man behind all algorithms their plugins use. He built quite a reputation with Slate Digital so going in I knew that chances were this was going to be a good plugin.But enough of that for now, lets talk about the plugin!

What is AirEq? Simply put, it is a parametric EQ – but it’s loaded with features that really take it beyond that. If the first paradigm of EQs are analog, and the second paradigm is digital, then AirEq might resemble something of a third paradigm shift. This is mostly due to special curves AirEq has . These curves employ concepts and ideas from a variety of EQs, old and new, with some of Fabrice’s own ideas put into the mix.

Here’s a bit more in-depth of an explanation from Dr. Ford at this year’s Winter NAMM:

Lets start with the “Water” curve. It has a very smooth sound to it, transparent and is very musical. Meaning, the curve sounds great on almost anything, even if you are using drastic settings. It works best on things like guitars, vocals, and keyboards.

The “Fire” curve is a much more focused EQ curve. One which is typically achieved through raising the “Q” parameter on an EQ. The problem with having high Q’s on a normal EQ’s is that it always introduces nasty resonances and undesirable ringing to the sound. The “Fire” curve pretty much solves that problem. There is little to no resonances and ringing introduced to the sound when using “Fire”. This curve works best on things like drums.

I had never heard an EQ able to sound the way this one does and while I had some idea of how it might have been achieved it, I really wanted to know more of the technical side of these curves and how they were achieved. Fabrice was very kind in letting me ask some questions I had regarding AirEQ and his answers did not disappoint.

The water curve – it seems similar to the concept of Pultec EQs, in that it’s attenuating a boosted frequency. If so, what is the water curve doing differently than, say, what the Pultec does?

In Pultec EQ, you have a cut and a boost in the same range of frequencies, but you don’t get the same kind of shape that with AirEQ at all. The Water curve is providing a equalization response which is the closest sounding to the same standard equalization settings, but with an impulse response which is about twice shorter.
That’s the technical explanation, now the musical explanation is that the Water is smoother, more transparent, more natural.
The link between the technical and the musical explanation is that when an impulse response is shorter, the phase response is also smoother, and the ear perceive the resonances as smoother because they overlap more with the original sound which is equalized.

Is the Fire curve based on any ideas or concepts like the Water curve is? If so, what? And what does Fire do differently?

Absolutely, as I said the Water curve is based on the sound of a regular bell filter, with the same “spectral” envelope, but the impulse response being about twice shorter.

For the Fire, it’s the opposite : the filter curve can be up to twice as steep, meaning more focused, but with the impulse response of the same length.
Usually when you want to adjust a more focused part of the spectrum, you have to increase the Q factor, thus increasing the length of the impulse response, thus increasing the “ringing”, “resonance”, “boominess”, etc.. of the equalization sound.

With the Fire, it’s more focused, it would be equivalent to a higher Q-Factor, except that the impulse response is of the same length.

I adjusted the Fire curve by ear to get the same impression of tonal balance, but more focused, tight, without any ringiness.

Is there any reason you decided not to have an “Auto Gain” or “Constant Gain Monitoring” function in the EQ? Or might it come in a future update?

There already is one ! :)

It’s not automatic YET, but if you use the input meter as Diff (right-click on the meter), you can display the RMS Difference, which shows the difference between the input and the output.
You then just have to adjust the input gain to bring down the RMS Diff meter to zero.

In the near future, this is gonna be more automatic!

I think at some point in the past I saw a hardware controller for AirEq, what ever became of that? Are you still planning on releasing a controller for AirEq in the future?

Yes indeed, we are still working on it, we have some very big challenges regarding the components, because they need to be reliable, robust and affordable.
We don’t want to build an unit which is intended to be used by professional which would not be very reliable, and that’s the main challenge here!

Do you feel like AirEq and VMR’s EQs can co-exist and compliment each other? I know you worked on VMR too, so I feel like if anyone has insight to this question it would be you.

AirEQ and VMR EQs are really different things, AirEQ is intended to be very transparent, versatile, where VMR EQs are colorful and intended to be used where color is needed.
Some sound engineers use AirEQ along their analog gear, because AirEQ allows them to fix some balance issues the most transparently possible, so I would say that AirEQ and the VMR are very complementary !

Personally I use AirEQ as my main track EQ, that I used to fix the balance, remove resonances, enhance some parts transparently, rolloff the high or lows, etc..
And then I pull up the VMR to add some flavor either with EQ or compression, or more especially I play with the different drives of the VMR modules.
We modeled very precisely the harmonics and saturation of each unit, so it’s nice to play with those units!

Thanks to Fabrice and Eiosis for their time. For more information and to purchase AirEq, visit www.eiosis.com.

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Alex Nasla is a keyboardist, producer and mixing engineer. He keeps busy making audio plugins for Rosen Digital, is audio director at multimedia company Toxic Creativity and is involved in 3 different musical endeavors.