Learn what really makes up the difference between analogue style EQ units and their plugin emulations
Unlike characterful reverbs and dynamic compressors, when it comes to EQ plugins, it’s often hard to tell the difference between them. This is especially true with digital EQs, whose default curves, cuts and boosts are often, mathematically, exactly the same between two plugins.
To differentiate themselves, digital EQs need to offer a better and faster user experience, often dynamic EQ (TDR Nova GE), better analysis (Sonible smart:eq 3), and extra digital benefits like masking detection (FabFilter Pro-Q 3) and motion (Minimal Audio Morph EQ).
But analogue EQs don’t run in the same race for features. Instead, analogue EQs, like analogue compressors, can trade on their character, vibe, and ‘that special something’. Here’s why…
Why analogue?
EQ and filtering was once a problem to be solved by electronic engineers, not DSP coders. The most classic use of filter circuits was in telephone networks, filtering signals down so they could be more easily transmitted, but still well understood.
Later, when filtering – and then EQ – found its way into the music studio, there were all sorts of technologies, techniques and electronic components that could offer a different route towards shaping the frequency spectrum. And each of those, thanks to being a real, physical system with its own operational quirks, did its job in a way that worked, felt and sounded slightly different to each other option.
Here we’ll discuss what the differences are between some of recording history’s most well-loved units, and we’ll explain exactly what’s so well-loved about them along the way.
Pultec – Softube Tube-Tech Complete Collection
The Pultec is a truly respected EQ unit from yesteryear, and as such, it’s got a complicated history, multiple revisions, and many emulations to pick between.
Coming from Pulse Techniques LLC (hence the name), the Pultec is renowned as a brilliant ‘passive EQ’ unit. Most often, when people refer to ‘a Pultec’, they’re talking about the EQP-1A model, also known as a ‘Program EQ’, although others exist, including the MEQ-5 mid-band EQ. There’s a lot of names, letters and numbers to think about, but we’re trying to simplify this – read on.
Passive EQ?
Passive EQ basically means that the frequencies being cut are ‘soaked up’ by the electronic components, and then the whole signal is boosted back again by tube amplification. It’s this tube amplification that is likely the source of the famous Pultec mojo, which is also said to have something of a dynamic response thanks to those analogue amplifiers.
That mojo doesn’t stop there though – there’s the ‘Pultec low end trick’ to discuss! This was a technique discovered by recording engineers, who would apply both a boost and a cut at the same time. While you may think these two settings would cancel each other out, the slightly different frequencies and behaviour of the two circuits would actually lead to a low-end boost with a dip just after it. Don’t take our word for it, here’s Fab Dupont showing you on a frequency analyzer!
//embed: https://www.youtube.com/watch?v=nkC0PpEFdL8
Softube’s Pultec emulation package, Tube-Tech Complete Collection, offers models of the most sought-after Pultec goodies in one package.
There are many other plugin emulations of the Pultec and its associated range out there, with passive EQs available from Apogee, Kuassa, and even a dynamic option from Klevgrand. While you’re checking those out, stop by the Pulse Techniques website to see modern hardware units that the company continues to produce.
Parallel EQ – Pulsar Massive
Thought we were finished with passive EQ? Strap yourself back in, there’s more to this legendary EQ technology.
What happens when you take the components and performance of a Pultec, then strap eight of them together into a stereo four-band EQ? That’s exactly the idea behind the Manley Massive Passive, although instead of ‘strapping them together’, we’re certain the process was more like ‘carefully engineering and conglomerating them into a single, usable unit’. More transformers, more tubes, way more character.
Parallel EQ
What’s more, the Massive Passive operated as a parallel EQ device. Each band actually duplicates your signal before all bands are summed back together and reduced in volume. The result is that you can make dramatic EQ boosts and cuts that still feel very musical and blend in better overall.
Pulsar Massive is a recreation of the Massive Passive that adds in digital creature comforts like a software EQ curve. Manley continue to make Massive Passive units, and their manual for it offers real insights into both the unit itself and EQ in general… if you have time on your hands.
Fixed-Band Magic – Soundtoys Sie-Q
Analogue EQ units can feel pretty basic to a modern DAW user. Today, we’re all used to turning a frequency control to find the exact place we want to target, but all the classics units in this article offered only fixed frequency settings to snap between. This next plugin is no exception.
Soundtoys’ Sie-Q emulates the Siemens W295b equalizer – not exactly a household name, but one that impresses with its tone, giving the character producers aspire to at low, medium and high ranges. This same EQ range is also emulated in Tone Empire Neural Q.
While fixed frequency bands feel limiting – and that’s because they technically are – these EQs and their clicky frequency selection are still highly respected by professional engineers – including mastering engineers.
Not every EQ job is a surgical cut with a 96dB filter. For broad-brush ‘colouring’, fixed frequency selection can take some weight off your mind, reducing your options and letting you use your ears. These fixed frequencies and their corresponding curve shapes were chosen by the makers of vintage EQ units for a reason, and they can easily work to enhance your sound.
Absolute Character – UAD Hitsville Collection
Universal Audio is a recent addition to Plugin Boutique, and their Hitsville Collection is a great example of what an analogue EQ can do to your tracks that a digital one would miss out on. By going for clinical, clean and surgical, digital EQs can miss out on character. drive and warmth. Just check out UAD’s own demos of the Hitsville Collection below…
Given that the EQ circuits in question were at the heart of many Motown recordings, the character of the EQ you choose can help to give your finished mixes the feel and nostalgia that’s hard to capture with other types of plugin. Especially when you’ve picked and chosen the analogue EQ you’re using based on the type of sound you’re aiming to hark back to.
Modern Analogue – SSL Fusion Violet EQ
Using an analogue EQ doesn’t pigeonhole you into the vintage crowd. EQ circuits are still being developed and innovated IRL. Take SSL’s Fusion series of processors, which mark “the first new Solid State Logic analogue EQ circuit in more than 25 years” with Violet EQ. The SSL name was already respected for solid tones worthy of a super-reliable high-end mixing console, so it’s nice to see a considered approach to their development timeline.
The appeal here is the feel of the circuits that finally won a place on the SSL line after so much time. But with a modern analogue EQ like Violet EQ, you get the character of analogue EQ but with some of the perks demanded by today’s producers: FAT mode gives you an extra low-end resonance when the high-pass is engaged, for example.
There are plenty more analogue EQs to try on Plugin Boutique, and if vintage vibes aren’t essential for you, check out what some of today’s space-station-esque digital EQs can do for your sound as well.
