I’ll answer this in two parts, so apologies if this is a bit long … and will note out the outset that I don’t use EQ in every listening scenario. I do not, for example, find that I need it/like it with the Abyss Phi or Utopia, but I do use it for things like the Sony MDR-Z1R.
First, if you’re using Audirvana+ you can use “Audio Units” within it (look under “Preferences | Audio Units”), which are plug-ins that add all sorts of sound-processing capabilities, including EQ. There are several “Audio Units” included as part of macOS/OS X, which include three different EQ capabilities:
- AUGraphicEQ - A simple 10 or 31 band Graphic Equalizer.
- AUParametricEQ - A very simple single band parametric equalizer. You can get up to four bands by setting it up for more than one “Audio Unit” plug-in slot.
- AUNBandEQ - 8 to 16 band (selectable) parametric equalizer, with multiple options for parameter types.
They’re a bit primitive compared to the third-party/commercial options but they’re free.
You can also find/buy third-party EQ tools that work as “Audio Units” and can be used within Audirvana+.
My personal favorites are from DMG Audio. For most people their “EQuick” product is probably the best way to go, as it’s not only the cheapest solution they have but also by far the easiest to use and is more than flexible enough for most purposes. I run this on my laptop for when I’m on the go.
At home, and in the studio, I use their ““EQuilibrium”” product, which is really a professional tool intended for serious multi-tracking work and has every parameter for everything it does exposed and accessible. It’s overkill, and probably confusing, for most “listening for pleasure” type scenarios.
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I also have a Schiit Loki. I picked it up to with the intent to play around with it and review it. It’s a nice little unit and works extremely well - especially for those that prefer their EQ done in analog hardware. And a nice touch is that you can simply press a button to engage or defeat the EQ, depending on when you desire it.
Since my sources are either Roon or Audirvana+ I’ve just stuck with software EQ as it’s one less box and my chains are, with one exception, all using balanced connections, but if I was using a player that had no EQ options then I’d be more than happy to use the Loki.