September is our Bday month, so, this year, we went absolutely mad and we are offering a 40% Off in all our products by using the code PiggyBirthday!! So, let everyone know we went mad and share the love!!!
This great animation short for which we had the honour and pleasure to score and do all sound design is finally available on YouTube!!
Also, the good guys at FXlda are planning to make this a Full Movie. That’s why they’ve created a found rising campaign. You can collaborate with this project at their Indiegogo page So, what are you waiting? If you loved the short, help the guys make this project happen!!
In the last couple of months, we’ve found out that los of our products (specially presets) are all over pirate sites for download them. We don’t mind at all, it just means that our products are really good!! If you can’t afford our products, or wanna try them before buying, it’s ok, go ahead, do a search and download them, but, if you can afford them or you really like what we do, we encourage you to buy them. Remember, we are a really small company, and to keep up making good stuff at a good price, we need some profit. Trust us, in an ideal world, we would be designing presets just for the fun of it and giving them away for free. So, if you like what we do, and your wallet allows it, go ahead and buy our presets from us or from the guys at adsrsounds.com
Today, I’ll talk about the one thing that no other synthesis method uses: the filter.
As you probably imagine, the filter, does filter something, in this case, the harmonic content produced by the oscillator.
So, basically, the filter shapes the tonal characteristics of the raw sound. In other words, it re shapes the waveforms produced by an oscillator. It can make the sound darker, or brighter. or thinner or fatter, etc.
There are various types of filters, being low pass filter and high pass filter, the most common ones in synthesisers. As their name states, low pass filter, let frequencies lower than the cutoff point pass, and gradually, frequencies higher than the cutoff point start to roll off; on the other hand, the high pass filter, does exactly the opposite: frequencies lower than the cutoff point are rolled off, and the higher frequencies are allowed to pass. In any synthesiser, the cutoff point is variable, and is the user who defines it. Another common filter type is bandpass filter, this, as it name suggest, it allows only a band of frequencies to pass, rolling off higher and lower frequencies, it’s like using a high pass and lowpass filter in tandem. Similar to the bandpass, is the notch filter, this, does the opposite: one band of frequencies is attenuated and higher and lower frequencies pass.
Most filter designs in synths also add an emphasis control. This, as it names states, boosts the cutoff point frequency, making this frequency highly audible and resonant. This is why in many synthesiser, this is labeled as resonance. In some other designs, it’s labeled as peak. Anyway, Emphasis (as in most Moog synthesisers) or Resonance (as in most Roland synths), or Peak (as in most Korg synths), they all mean the same, an extra boost right on the cutoff frequency.
So, lets say that we are dealing with a low pass filter with the cutoff point set at 8khz, we know for sure that all frequencies above 8khz will be rolled off until they disappear. Lets say we will add resonance (or peak, or emphasis), this will boost the 8khz frequency (and some of the near frequencies, too).
In most analog synths, the boost produced by the resonance can even produce a sine wave, transforming the filter in an oscillator. This is called self oscillation, and it’s quite beautiful when used in a musical way, in fact, as we will see later on, you can totally play melodies with a self oscillating filter.
Besides having different filter types, there are also different slopes, some low pass filters will roll off frequencies above the cutoff point for 6 dB per octave, some others for 12 dB per octave, some for 18 dB and some for 24 dB per octave. The most used slopes are 24 dB and 12 dB per octave. This are also called 4-pole filter (24 dB/oct) and 2-pole filter (12 dB/oct).
Almost every synth has a low pass filter. Some others also add a second filter, mostly a high pass filter. Some other synths uses what is called a multimode filter, having at least low pass, high pass and bandpass filter modes that are defined by the user. Every analog filter design has its own tonal qualities, and every major synth is recognisable for its filter. Think about a Roland Tb-303… well, it’s hard not to recognise its sound, and that is not because of the oscillator; the oscillator in the 303 can only produce standard sawtooth or pulse waves, something that pretty much any synth can do, but its filter design is unique, specially when you crank up the resonance. In the case of the 303, it’s a 3 pole 18 dB per octave low pass filter. Now, think of the Minimoog… that absolutely fat sound is hard to confuse with the sound from the 303, and that’s because of the filter; the famous Moog filter is a 4-pole 24 dB per octave ladder low pass filter, and it’s quite unique and musical. Another example of this, is the Oberheim filter, they sound brighter, more polite, more gentle than the Moog, some people say their sound is creamier… Well, they use a 2-pole 12 dB per octave filter. And then you’ve got the classic Yamaha CS-80… think of all those sounds from Vangelis, well, the Yamaha CS-80 used 2 different filters in cascade, a 2-pole 12 dB per octave low pass and, then another 2-pole 12 dB per octave High pass filter; none of them was able of self-oscillation, so, even though you crank up the resonance, filters would not produce sound on their own.
Quite an opposite case comes when talking about the Korg Ms-20, although it has a low pass and a high pass filter set in cascade, and despite they are just 1-pole 6 dB per octave filters, they will self oscillate, and they will start to scream a lot when you start cranking up resonances. And then, there are the Curtis chips used by SCI and nowadays by DSI, this filters are switchable between 4-pole and 2-pole, they are clean, even though in the 4-pole mode it will self-oscillate, it’s a filter somewhat creamy, very musical. Then the Steiner-Parker 2-pole multimode filter, used in many modular systems and recently in the Arturia Microbrute and Minibrute models, it’s also a very musical filter, with lots of character.
Thanks to Dr. Robert Moog, who came up in the late 60s with the Voltage Controlled Filter or VCF, cutoff points can track the keyboard voltages, so, for example, lower notes will sound darker than higher ones. VCF, also, let the user produce sweeps by closing and opening the filter with a knob, also, thanks to VCF, we can modulate the filter with an envelope generator or an LFO, or control the cutoff point by velocity, aftertouch or a mod wheel, or even a expression pedal.
Some designs can make the filter track the keyboard, as I’ve said before, in this designs, if the filter can self-oscillate, you can tune the filter to an specific note and play, like if it was an oscillator. Pretty cool, right?
In some other designs, like the DSI MoPho, the Oscillator can modulate the filter. This is called audio modulation, and it works in a pretty similar way than FM synthesis.
Most filters sound absolutely great if you overload the signal before the filter, this was a trick used pretty much in the Minimoog, where one would take the phones output, to the input of the minimoog, and then the signal gets overdriven by feedback before the filter. Nowadays, almost every modern analog synth has some means to achieve this feedback overdrive without using a cable.
Speaking of audio inputs, a lot of synths have an audio input for you to filter external sources, so, the VCF can be used as a processor, too. You should definitely try that out with drums, or guitars!
So, filter is what gives character to a synth. No analog filter design is perfect, and that’s the beauty of it. In digital synths, when you crank up the resonance, if you sweep the cutoff point you will hear some stepping, some unnatural quantising due to digital limitations… this is something you don’t hear in analog synths (unless of course the filter is digitally controlled or quantised by poor midi resolution). No filter is a bad filter, every filter has its own charm! Oh, BTW… you can definitely create some wah wah style effects using the filter!
See you in 15 days when we talk about the Amplifier!
Well, today, we are starting our first series of educative posts about synthesis! Specially subtractive synthesis.
Why is it called subtractive synthesis? Very easy: it implies the use of a filter to cutoff or emphasise some of the harmonic content of the raw sound in order to shape it.
In this kind of synthesis, we’ve got three essential modules or parts for creating the sound: the oscillator, the filter and the amplifier. Anything with these three blocks in that specific order is a subtractive synth (miscalled by many as analog synth)!
Now, let’s get started with the very first of these basic components: the oscillator.
As you might think, the oscillator is what actually produces pitch. The oscillator in a synth does exactly the same as a string in a guitar: oscillate in an audible (or not… more on that later) range, say 20hz to 20khz. It’s the sound source. Unlike a guitar string, an oscillator is always doing its thing: oscillate, we’ll see more on this when we talk about the amp. An oscillator can output diverse wave forms, typically those are:
These are ordered from less harmonic content to more harmonic content.
A sine wave has no harmonic content at all, it’s just a pure tone, and at the other end, noise, has no fundamental tone. Sine wave, as it has no harmonic content, is not a suitable wave for subtractive synths. Why? it just has nothing to filter. Remember, no harmonic content = nothing to filter = useless for subtractive synthesis.
The triangle wave, sounds dark. It only has odd harmonics, which roll off pretty fast, and that’s why it sounds so dark.
Then, Sawtooth wave and Ramp or inverse sawtooth wave, who sonically have no differences at all, are brighter sounding, even buzzy, it reminds me very much to the sound of the Farfisa Compact… Anyway, all of this happens because this waves have much more harmonic content than the triangle, and, because it has all the harmonics, odd and even.
Moving on, we find the pulses, and here, I’m gonna talk about the pulse width. A square wave, is a pulse with 50% width. It has only odd harmonics, but, they don’t roll off as fast as what happens in the triangle. The sound produced by the different pulse widths differ pretty much one from another, from silence (0% pulse width) to nasal, to kind of plucked strings. Most oscillator designs provide some way to change in real time the pulse width when outputting a pulse wave.
Some designs, like the Juno 6, 60 and 160 series, are able to output all the wave shapes at once or mix them in any combination. Other designs like some Moog synths, allow you to output anything in between two different wave shapes, for example, anything in between a triangle and a sawtooth.
Some modern designs like the Arturia Minibrute and Microbrute have some controls to vary wave shapes like triangle and sawtooth, by folding them. Other designs, like the one found in the Waldorf Rocket, can output duplicated and detuned sawtooths from just one oscillator. In fact, this was first introduced by Roland in the early 90s in some of their digital synths. This wave shape is known as Supersaw, and it can be heard as lead in numerous trance hits, specially during the 90s.
Most synths implement two or three oscillators in their design, letting the user detune one against the other. This creates the typical fat sound heard in basses and leads. Many of this multiple oscillator designs can be hard synced, making one oscillator master, and another, slave. This means that when you detune the slave oscillator against the master oscillator you will hear for a while the detuned harmonics from the slave while it is forced to be in sync with the master oscillator. Very complex and scream-ish sounds can be achieved detuning the slave oscillator in sync mode. This can be typically heard in many Prophet 5 leads.
Now, a very different matter is how is the oscillator pitch being produced and controlled. Remember this guy is always oscillating. So, in the late 60s, Dr. Bob Moog came out with the first (usable) way to solve this issue: the Voltage Controlled Oscillator or VCO. This, as its name suggest, provides means to control the oscillator’s pitch with very low voltage signals. In fact, this signals are so low that the most adopted standard provides 1 volt per octave. This means that every 1/12 volt, there’s a change in 1 semitone in pitch.
He also came out that the best solution to control and determine how voltage is being sent to the VCO, this was to use an organ type keyboard to send different voltages from each key. So, in this case, in a range of 1 octave, lets say from C2 to C3, we have a difference of 1 volt between C2 and C3, so, if C2 is providing 1,5 volts, C3 will be providing 2,5 volts. Easy. That also means that C#2 will provide 1,500833 volts exactly, in this case, and so on.
This was the standard until the 80s and microprocessors. At that time, VCOs, were a little bit unstable, cause, any change in temperature, will make the pitch drift. So, the now affordable microprocessors, did exactly this (and still do), but in the digital domain. These is called DCO (digital controlled oscillator). Some great synths like the Roland Juno (6, 60 and 160) used DCO, and despite the oscillators are digitally controlled, they still are analogue synths.
As microprocessors came even cheaper, oscillators evolved for being digitally controlled to being entirely digital, meaning that the waves are being created in the digital domain.
DCOs and Digital Oscillators produces pitch that are so stable, that they even sound cold or thin, lifeless.
That’s why, in modern designs, like some DCO synths produced by Dave Smith’s Instruments, have some function to make the pitch a little less unstable, which is perceived as a warmer, more organic sound. Remember, VAs and soft synths, they all use digital oscillators (as if they had a choice…). Analog synths can use DCOs, but mostly use VCOs. Each has its pros and cons. For example, digital oscillators, are capable of producing really complex and bizarre wave shapes that are just impossible for a VCO or DCO for that matter. But, yet, VCOs, are warmer, and in general are perceived as more organic than digital.
Oh, I almost forget: Noise. Noise is really complex, because it has all frequencies at the same level, this means noise has no fundamental pitch, in fact, you can’t tune noise. Obviously, noise is not used to produce melodies or basslines, but, it’s very useful for creating percussion sounds like hi hats or snare drums, or for creating sound effects like wind, seashore, explosions, etc. Most synths that incorporate noise, have a dedicated oscillator for noise. The only synth that I can recall that incorporates noise as a waveform for an oscillator, is the Korg Ms-20, but, I’m sure there are some more out there.
Well, I believe that this, pretty much covers everything you need to know about oscillators. If you have any questions, you can add them below in the comments and I’ll try to answer (if I know the answer, of course). Thanks for reading, and if you like what we do, share it with the rest of the world!!
Finally on YouTube! We were involved in the sound design and foley of this great short film!
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Yeah! The golden era is back!!! Check out this great mini sound set for Massive. Emulations of classic sounds from classical machines!