Frequency Fundamentals

Welcome back to the continuation of the frequency training series. For the next 5 articles, we will expand, break down and analyze this topic in much greater detail. For those who are just now joining us, let me say just one thing:

Stop! Do NOT read any further!

As a matter of fact, go back and first read the introduction overview to frequency training. You’ll need the background information! Trust me, it’s not filler, and will save you much unneeded frustration! Go on…we’ll wait.

From this point on I’ll assume we are all caught up. (The beauty being, you can always go back and re-read and review….remember, no one is chasing you here. Work slowly, at your own pace. I’ll probably repeat that at some point in this series, so I ask your forgiveness and understanding ahead of time!)

Last time we left off with an overview of the nature of sound, and more specifically, the way it is measured (frequency, measured in Hertz, or Hz). Along with this, were some “must know” basic frequencies with exercises for recognizing and identifying them.

Reference frequencies

Briefly now, let’s take one tiny step back. (I think now is good time to revisit this.)
I always have, and still do recommend that you find whatever reference frequencies you are comfortable using as the anchor to your training….BUT….at the same time I usually suggest using the piano. After all, everything is laid out symmetrically and with predictable repetition, which is the main reason it is the preferred method of travel for teaching music theory. Those same reasons are also why the piano/keyboard is excellent for our purposes here as well.

Moving on, if you remember, the range of the piano is 27.50Hz (A0) – 4186.01Hz (C8)…and although it’s a spectacular place to train for the above reasons…KEEP IN MIND….that the full human hearing range is from 20Hz-20000Hz or 20 kHz. (Or at least that’s what it is when you are born and your ears are undamaged.)

You’ll like this now!…The actual pitches are somewhere between D#-E at 19.4Hz-20.6Hz respectively, and D#-E at 19912.1Hz-21096.2Hz. As you can see, the actual low and high pitches aren’t clear D’s or E’s, but rather something in between (‘microtonal’ pitches that don’t quite fall on exact notes). This last paragraph is crucial to know – go back, re-read and memorize it.

Okay, now that we have that covered, we will put our beloved piano on the back burner for a while, and continue with more “must know” tones, sounds, and of course the frequencies of said sounds!

The Drum Kit

A GREAT place to park it for a minute is the drum kit. It is, after all the main time keeper with the kick drum being the heartbeat. As an audio pro, I could probably count on one hand how many times you won’t end up recording/working with drums or some form of percussion!

This is where we are going to spend some time, as the drum kit will provide us with many lessons, including compound/complex frequencies, and harmonics; both which we’ll address in later installments.

[If you’re not familiar with the various parts of a standard drum kit, check out Nick Long’s introductory article “A Roll Around The Drum Kit”]

For now, consider that these drum samples we’ll focus on are made up of multiple frequencies at various points. The only frequency we will concern ourselves with for the time being is the main/dominant frequency…that is, the main frequency the tone is centered around. Another term for this is the fundamental frequency.

To avoid confusion, I will refrain from using the term fundamental (for now) because it implies knowledge of the things we haven’t arrived at yet. For our purposes now, we will call it, the main or dominant frequency.

The samples used in the audio clips are from my trusty Roland R-8 drum machine. It’s an old and widely used machine, and I guarantee that at one point or another you have heard these sounds in commercials, soundtracks, and even traditional music releases!

Cliché?

Yes….but a great reference!

  1. Kick drum – the one chosen is the “standard” type kick that can be used in ANY music.
  2. Snare drum – same reasoning as above for the snare.
  3. Floor tom and 3 mounted toms – ditto, same reasons.

The “drum” parts of the drum kit will be our examples for this article. In the next article (part 2) we’ll add the metallic percussion portion of the kit.


There are countless…and I mean COUNTLESS drum sounds that you will encounter. However, we are focusing (as always) on the basics…the building blocks, if you will. For instance, once you understand the properties of a kick drum, then ANY other kick drum will usually (with a few exceptions) fall inside the same frequency range. It might not be exact, but it will get you in the ball park. For now…that’s what we’re shooting for. Reference anchors, that’s what we’re building – remember that!

Here are the numbers you will need:

Note value: A# or Bb (a few cents off)

Note value: A (a few cents off)

Note value: C….by far, usually the lowest frequency drum and NOT the kick as often mistaken. (If anything the kick needs to cut, and punch)

Note value: F

Note value: C (a few cents off)

Note value: D (a few cents off)

Note: Drums (as most sounds) are rich with multiple frequencies. For instance, the initial “kick” of the kick might be at 114-5 Hz, BUT…it has many supporting key frequency points before and after the “dominant” one. Keep this fresh in your mind when we dive into the compound material.

One more thing: the 4 toms above are actually tuned lower than most “traditional” set ups. (It was that way for a particular project I worked on) As you will see in the bottom chart, I have some basic ranges that drums in general are tuned to, but consider that there are NO hard and fast rules for this. The only valuable suggestion to keep in mind is that sometimes it is wise to tune the drums to the key of the song you will be recording…ESPECIALLY intricate music! After all frequencies ARE pitches right?

General guidelines for drum frequencies
  • Kick Drums – usually 80-130-150 Hz
  • Snares – usually 120-250 Hz
  • Floor Toms – usually 60-80-110 Hz
    (most of the time the lowest drum tone)
  • Regular Toms – Sky’s the limit! 100-500-600Hz
    (if you’re one of these progressive drummers with more toms than keys on a piano, well then….those numbers can go either way…from the low 80’s all the way to 1kHz….WOW!)

Homework

(You didn’t think I would forget?)

  1. Okay, same drill as in the previous articles homework; play each sample one at a time, over and over until you memorize the sound AND it’s corresponding dominant frequency.
  2. Only when you are familiar with these sounds, take a musical instrument (piano, guitar, bass, whatever you want) play the same pitches as the drum samples, and simply listen. Pay attention to the fact that even though you’re matching pitches, the overall sound characteristics of each tone are different. Why? We’ll answer that later, but for now, make notes of the differences you hear. Use your own adjectives, your own shorthand if you will. I’m trying to get you to hear these differences…so it’s imperative you describe these characteristics with your own descriptions!
  3. Same as step 2, only this time play the notes on your instrument at higher and lower octaves. Repeat listening exercise.
  4. Repeat steps 2 and 3, only this time play on note (step) higher or lower than the drum pitch. Then 2 notes higher or lower. Then 3. The 4. Listen to how the closer the interval (distance between the two notes) is; the more dissonant the sound. Then, also notice the farther away the 2 notes get; the more consonant the sound becomes. And finally as you are approaching (coming around) the original note again, notice how you drift back into dissonance.

    Refer to the Pitch & Harmony series for a thorough explanation of intervals. The purpose of this exercise is to get you to see how different sounds interact/harmonize with each other. This will give you an idea of why certain audio professionals insist on tuning the drum kit to the key of the song. The lesson being…ALL sounds are frequency based, and therefore generate a “pitch”. Good knowledge to have in your audio recording/producer’s bag of tricks!

We’ll end part 1 here. There is plenty for you to work on! As usual, don’t rush it. Part 2 will continue with the metallic percussion portion of our drum kit.

I will however leave you with a bonus mystery question:

On the audio drum samples I provided, I obviously also gave you the matching pitch. Based on that, what key was I concentrating on when I set up those specific drum pitches? What other key(s) (if any) could that set up be used for?

Answer will be revealed in part 2!

Remember, you can download the audio tracks above to listen offline, or on your portable music player! Any problems, just leave a comment below.