A Calgary Recording Studio Promises “Analog Warmth” - But What Does That Mean?

What Does “Analog Warmth” Even Mean?

Analog warmth is a term frequently used to describe the rich, pleasing, and “full” harmonic character of sound captured using analog equipment. The technical characteristics of analog devices impart a unique “character” onto the captured source, largely due to the behavior of analog circuitry (tubes, transistors) and harmonic saturation/distortion. In this blog post, we’re committing to a deep dive into the how’s and why’s of this process.

Timbre Over and Under Explained Simultaneously

When you play a C note on a piano and a C note on a guitar, it is the timbre of the sound that differentiates them to the human ear. Timbre can be thought of as the “colour” of the sound. Consider the colour “red.” Red can take on many shades and forms depending on what it is mixed with, but ultimately, no matter its particular character, it is still red, though there are certainly those who have their preferences as to which red is the best red.

When speaking sonically, A4 is always 440 Hz, which is the fundamental frequency of that note. However, timbre is defined by the unique harmonic overtones (notes that play above the fundamental frequency, depending on your instrument, due to the physical laws governing the instrument’s shape) that your instrument produces. These harmonic overtones are why you can recognize your mother’s voice from your father’s on the phone.

Our analog tube powered C800G atop our fully analog Oberheim synth.

Even and Odd Order Harmonics aka “Non-Linear Processing”

The manner in which harmonic overtones are produced is mathematically dependent on the equipment one uses to record. Often, harmonics are classified as either “even-order” or “odd-order.”

Even-order harmonics are produced when the frequencies above the fundamental maintain an octave-based relationship. For example, while the note A4 is always 440 Hz, an even-order harmonic would be a smaller tone generated atop it at exactly 880 Hz - an octave higher. Even-order harmonics, often generated via tube and transistor-based analog gear, are perceived as “smooth and warm” to the human ear. (We’re looking at you, Motown soul!)

Odd-order harmonics, on the other hand, are less harmonious than their even-order counterparts. They often sound harsh, rough, or excessive. However, their aggressive edge has been a hallmark of rockstars for ages, achieved through overdriven transistor-based preamps and other analog pieces.

All things considered, these harmonics are important because they fill out the sound spectrum in a way that is tried, tested, and satisfying to the human ear. The mathematically pleasurable timbre of even-order harmonics, or the aggressive and punchy tones produced by odd-order harmonics, are entirely lost when recording digitally. Digital systems strive for linearity, where a near-sterile tone is often the end result - a far cry from their analog ancestors.

Question: do you think the fuzzy tone of a VOX AC30 is even-order or odd-order?

(Spoiler alert for the end of the blog: Our opinion? Combining analog and digital is the way to go.)

Messing around with some analog gear in our studio. And don’t worry - we’ve swapped a lot of the Warm Audio gear out by the time of this blog.

Cough it Up Already - What’s Really Going On Under the Hood?

Analog equipment is comprised of tubes, transistors, resistors, capacitors, and inductors, all of which demonstrate nonlinear characteristics when recording. These “nonlinearities” are the primary reason behind the warmth you hear on old soul joints, jazz records, and those smooth Mac Miller projects.

Soft clipping occurs when an analog circuit is pushed beyond its operational limits. Where digital systems clip a hot signal, completely destroying vital information and effectively transforming the recording into a square wave, analog systems “round” the signal’s peaks rather than cutting them off. Unlike digital systems, analog hardware does not have a distinct threshold for signal clipping. Instead, it transitions smoothly into states of saturation when the signal gets too loud - contributing to the warmth discussed in this post.

Frequency response variations vary from one analog piece to another. Due to the physical properties of analog components, this equipment rarely provides a completely flat frequency response. Instead, it “boosts and cuts” the sound spectrum in a pleasurable manner at various frequencies. A vintage preamp, for instance, might boost the midrange in ways even the most surgical Pro-Q 4 user could never replicate, which is why some artists go nuts over their preamp choice.

Analog compression occurs due to the physical limits of tubes, transistors, and even tape recorders. These limits are governed by physical laws such as Ohm's Law and Kirchhoff's Laws. At high signal levels, the behaviors of analog components at their saturation point impose limitations that force the signal to comply, resulting in smooth and musical dynamic handling, something digital compression merely aims to emulate.

Last but not least, let’s hit on saturation. Thanks to soft clipping, frequency response variations, and analog compression, signals are distorted in a way that pleasurably imparts overtones (affecting timbre) above the fundamental frequency of the performed note. When a circuit is overloaded, the nonlinearities inherent to analog equipment introduce harmonic character, providing a warmer, fuller “glue” to the overall mix. This harmonious blending of elements and time-tested filling of the sound spectrum is something that simply does not occur in digital recording.

Calgarian artist Brian Hewlett utilzing a system which fuses both analog and digital in our studio.

Analog vs Digital: What’s “Better”?

First and foremost, if it sounds good - it sounds good. There’s no reason to get caught up in this discussion if you’re 100% happy with what you can achieve using a Focusrite and an SM7B. However, to put it plainly, digital signals are processed as a series of discrete numbers. This system offers exact and predictable behavior but leaves absolutely no room for signal saturation, instead producing hard, character-damaging clipping when pushed too far.

While digital is incredibly convenient, the nonlinearities of analog equipment make for a more interesting, character-rich, and time-tested sound. This is why digital-only producers are constantly aiming to emulate analog gear through modeled plugins. Music nerds will always seek the real deal, and all of us begin our ear training the moment we’re born - listening to famous records on the radio or digging through our families’ stashes of classics. Chances are, a large number of those records have already taken advantage of the analog characteristics we’re discussing in this blog post. You likely love those sounds, even if you’ve never heard the technical explanations until now.

So, our take? The convenient nature of digital, coupled with the desirable character analog imparts, is the way to go in 2025 and beyond. Curious to try some analog equipment for yourself? Feel free to book a session with us, and we’ll set you up!

Tearing up an analog mixer in our new Calgary recording studio.