Joy of Synths #7: Oscillators & Sales
A non-musician’s guide to creating sounds for podcasts, videos, and sampling for music using analog synthesizers.
OSCILLATORS
Oscillators serve two functions on any synthesizer. They are tone generators and they are control voltage (CV) modulation sources. They achieve different tones through a main frequency dial, modulation inputs, and resulting waveshapes. All of this is happening all at once. However, let’s break it down step by step so you can make informed decisions about semi-modular instrument choice.
Sound Frequency
You’re likely familiar with a sound wave graphic that has a semi circle going up for half a circle and then down for the lower part of the circle. This up and down is a wave cycle. Wave cycles are measure in Hertz, or Hz. 1,000 Hertz is a kiloHertz, or kHz. And yes, it’s capital H.
One wave cycle is 1 Hz, so its frequency is 1 Hz. It may help to think however frequently it cycles in a period of time is its frequency.
Human hearing is said to reside between frequencies of 20 and 20,000 Hertz. Below human hearing range are sub-audio frequencies.
An oscillator may be able to oscillate at these lower sub-audio frequencies to audio rate frequencies. This may be a low frequency oscillator, or LFO.
A full range oscillator may serve double duty as an LFO or stay within the bounds of audio rate frequencies.
EQ: Skip Intro
Disclaimer: This part is full of EQ half truths and misdirections. Still, it’s less important to know the math and science and just comprehend that EQ can change the character of a carefully sculpted sound. And EQ can sculpt sound into something else you choose. Frankly, it's more cost effective to mess with EQ with software.
If you were to look at audio rate freqs in a software parametric equalizer (EQ), the controls allow you to manipulate bands, or Qs (quality) of EQ, which more or less is the steepness of the curve (affecting frequencies) you are raising (gaining) or lowering (attenuating). If you have a stereo EQ of any sort, it should have lows for low range bass, mids, and highs.
In other words, EQ controls allow for either pass thru, attenuation or amplification a frequency range, or band. So you’re either cutting or boosting frequencies
Messing about with EQ changes the character of the sound. This is NOT exactly the same as a low pass filter, or any filter that allows for outputs for low pass, band pass, or high pass, or variations there of. But it’s similar in that you’ll have a dial to raise the parked upon frequency of the main dial.
EQ Eurorack Modules
I bought two 5 bank EQ eurorack modules and found them underwhelming and nearly transparent. It did not cut frequencies like a proper low-pass or multi-function low/high/band-pass filter. Severe EQ-ing is more easily accomplished with software like Logic Pro.
Monitoring for EQ- This is important!
How you listen to your synth influences the choices you make for sound creation. Be careful with your headphone or speaker monitoring selection. I listened to my synth with gamer headphones. The synth was generating such glorious bass!
Only, it wasn’t. The recorded files were absent the boom. The headsets had a frequency response that emphasized booming bass for maximum game play immersion.
Is the sound playing through the headphones really there on the recorded file? Or are your headphones adding an EQ to the sound?
The smart call is to hook up headphones to the recorder, not the synth, so you hear what’s there. The smarter call is to make sure the headphone has a flat frequency response, meaning there are no peaks or valleys.
You can use a software parametric equalizer to further alter the sound and replicate that bass. However, this is where a sound mastering environment and audio meters (and knowing how to read them) can allow you to achieve very specific sounds.
HOWEVER, and this is a huge however, smarter people have told me that you generate mixes and masters for the platform and listening environment of the end user. This means a lot of specific mixes per platform. In the simplest terms, if the end user is listening on AirPods, evaluate the mix while listening to Air Pods. Evaluate the mix on iPhone speakers. If they are playing on a car stereo, listen to the mix through a car stereo.
Alas, I’ve derailed this talk of oscillators into mixing and mastering. Still, it’s important to know about frequency response. It’s like filming with a camera but never checking the focus. You may get lucky with sharp focus images. Or you’ll likely wind up with blurry files headed for the trash bin.
There’s only so much a basic mix can do to bring out bass if you’ve used a high pass filter on everything, effectively cutting out the lower end bass frequencies. Sound creation is a series of decisions, so yes, look at the frequency response curve of a headset or speaker. And beware that a recording headset will sound less impressive than an equally priced consumer headset. It’s not boosting or attenuating frequencies. What’s there is there, or course, considering that the headphone jack isn’t introducing hiss and noise. Ugh. Let’s return to oscillators.
Starting Up: Analog Warm-ups
With an analog synthesizer we are not dealing with sound in the natural world. A synthesizer synthesizes sound. An oscillator converts voltage to a tone.
Analog oscillators generate waveshapes in the form of square, pulse, triangle, or sawtooth/ramp, or sine waves. For reference, the up and down semi-circle is a sine wave.
Unlike a digital oscillator, an analog oscillator is imperfect. It may drift out of tune, or change tone as it warms up. For example, the B Model D manual advises waiting 10 minutes after power up before playing. In my opinion, this presents a two-for-one deal in the context of recording a sound library.
Waveshapes & Harmonics
The waveshape is determined by the Oscillator. Early scientific oscillators were used in developing electronic music. Those were pure tone sine waves. These do not have harmonics.
(AVOIDING THE SCIENCE)
In doing research for Joy of Synths, I read a lot of early electronic music books in the Harvard, MIT, Miami, and Philadelphia Free Library. The books tend to focus on the science of sound because it was a brave new development.
Having learned this, I recognized that this study didn’t help with creating a sound library. It helped me from wasting so much time trying to produce a sound. The secret is connecting a controller to your synth and pressing keys until you hear a sound. Don’t make my mistake and try to play a synth sans a controller. It’s fun to do, but it’s a lof of misses before you hit, and easy to overlook what all the modules are there for.
Harmonics
Acoustic instruments produce a baseline “note.” So if you were to play an acoustic piano and pressed a key, you’d have that key note and other vibrations. There are tones above this note, which are called overtones, or harmonics.
Harmonics are given numbers of 1,2,3,4,5, etc. These harmonics can be odd, even, or all numbers, or integers, with different energy as the overtone step increases.
Oscillator waveshapes have different harmonics. A sawtooth wave is said to have all harmonics. So if you want a richer sound to cut apart with a Low Pass filter, start with the sawtooth.
A way to build up sound is by using a mixer to blend different waveshape outputs. This is as simple as putting the square wave ouput into input 1 of a mixer, and a sawtooth into input 2, then work the volume dials until you’re happy with the sound.
Note that this is straight up mixing audio. It’s not waveshaping.
WAVE FOLDING SINE WAVES AND SQUARE WAVES
Sine waves are pure tones that don’t have harmonics. This is why these were wavefolded in West Coast style oscillators like the Capt’n Big O- to mess up the shape of this sine wave to produce harmonics.
One oscillator developer said you can’t successfully wavefold square waves. It only makes sense with sine waves.
The re-issue Buchla Tip Top Audio Oscillator does NOT wavefold. It mixes from one waveshape to the other. I was not a fan of it.
The Voltage Research Lab is a near-perfect all-in-one synth. It has a wavefolding oscillator with warp circuit that produces really interesting sounds. The descendant West Pest and Taiga oscillators are born of this oscillator. The Capt’n Big-O lacked its warp circuit.
Oscillators, Oscillating
There’s more to say about oscillators, but hopefully this is enough for you to feel comfortable knowing enough to get recording. The final suggestion is to start with the frequency dial at midway. If it’s full right it may be too high of a frequency to be audible. If it’s full left it may be too slow of a frequency. And make sure your filter’s frequency dial is at mid-way too. Full left will block all sound from a low pass filter, and full right will be the unfiltered sound but possibly too much if you are boosting and modulating frequencies.
Holiday Sales Begin
Pittsburgh Modular.com is offering a handful of noodles, aka patch cables for orders over $150 while supplies last. I think this just announced today, 11/15. They say it’s roughly 30 cables. Given that 5 cables are about $10, that’s a gift of $60. They also have 20% off modules. So a few minutes ago I ordered the Stereo Okapi Mixer for $130 after discount, plus some non-discounted dials to bring the total before shipping to over $150.
Why a Stereo Okapi Mixer? While I love mono-synths in mono, I’ve accumulated so much I’d like to mix to left and right channels. While a proper mixer can do that job, an advantage of a Eurorack module is that it’s way smaller. Anyways, I’m a fan of Judas Priest’s use of left and right panning guitar solos, so, yeah. I wanted the free patch cables. Subtracting that puts this order at $210 value for $150. Hopefully this ships ASAP so I can play with it during my time off over the Holidays.
Amazon says the Solina String Ensemble I ordered in October will arrive on Monday. That’s really cryptic, because they are not selling any in the US. Amazon has other open orders that are to arrive on Saturday that haven’t shipped as of Wednesday. So it’s possible I may have a Solina to mess with.
Pretty much every synth reseller will have a sale for Black Friday or CyberMonday. I’m declaring myself out of the game. I didn’t wake up this morning expecting to buy a Stereo Mixer and dials for $159 total. Plus I’m dedicating my attention to recording rather than sale scrolling and searching out price drops, which is fool’s gold if you go looking for it. Yes, I scored the Solina for $199 not $299, and a Model D for $30, but that’s luck not anything more. Plus I have a Swing coming…
End Note 11/15/2023
Joy #8 will arrive on 12/1/23 and focus on controllers, as most non-keyed/sequencer analog synths current day are “voices” that require something else to control them by voltage or MIDI.
The controller of focus is most specifically this affiliate link to Behringer Swing 32 Key USB/MIDI/CV Controller. Per Joy of Synths #6, I’m taking advantage of Amazon’s Holiday return policy to see if this is the right controller for me. The Swing controller has CV outputs and an arpeggiator plus sequencer. Its MIDI has velocity and aftertouch, which are nice if the synthesizer responds to those MIDI controls. Sweetwater has the Swing for (non-affil link) half the price at $69 but stock is to arrive around Feb 2024. That price is insanely low- I’ve bought a used USB MIDI only Arturia controller for about that price. Not sure if this is a new normal price or a true limited time price drop. Amazon still prices higher than Sweetwater on Behringer products so it’s worth it to comparison shop.
And just because it’s worth it to tool with the K2 and possibly return it, here’s an affiliate link to Behringer K2 on Amazon.
This issue is sponsored by CoWolves. Buy vinyl at https://discogs.com/seller/cowolves.
All Content Copyright 2023 Anthony Torres, All Rights Reserved.