Analog vs FM Synthesis The Stunning Differences

Ahh, Synthesis, this is a topic I have researched thoroughly the pasts days, and I devoted a lot of hours just to understand the basics of it. I found that the information was scattered all across the internet also I used a few books since I couldn’t find everything online. Because of the time I spend on research, I decided to comprise everything together in one neat, educative and fun article.
Are you excited? So am I!

Let’s start with the differences between Analog vs FM synthesis it’s known that: Analog has a more warm and deep sound compared to FM, also analog has a “drift” or a certain sound character which could be emulated in digital using motion sequence and pitch/filters. But due to differences in architecture many FM synths are unable to reproduce analog sounds faithfully.

As we saw above besides the specific limitations of the individual synthesizer and the lack of “character & depth” in FM, there is no big difference between analog and digital FM. Regarding phase modulation, it’s worth noting that its used more often in digital FM synthesizers than in analog which has strictly to do with computing reasons. Otherwise, when we compare analog and digital FM the results can be rather identical. But there are many more questions we have to answer for to paint a complete picture when it comes to analog vs digital FM and Synthesis altogether.

Stick with me and let’s explore this exciting topic side by side!

Is It Possible to Reach Frequencies with Digital That Are Unreachable with Analog?

In one word no. Actually, there are plenty of synths that can generate very high frequencies using Fm modulation. Analog Fm can also create sounds that are made with digital Fm, besides most modular oscillators have Fm inputs.

Why Is Fm Synthesis More Prevalent in Digital?

One of the Main reasons FM synthesis is most common in digital is because of the high price tag for having four to eight oscillators on an analog unit.

Also tracking to precision with an analog setup can be quite tricky since properly adjusting 8 oscillators can feel like a tedious task. Imagine that we’re talking about 8 analog oscillators per voice; therefore a six-voice analog synthesizer would have 48 analog oscillators(!).

And if that wasn’t enough since analog oscillators are more expensive to produce compared to an analog triangle or pulse oscs. Adding them would increase the cost even more and believe me, if you work with Fm you want to have analog sinewave oscillators for you to control. This is one of the main reasons why we rarely see analog synths with sine oscillators.

Temperature, and the Effect It Has on Analog Oscillators

Analog oscillators are very sensitive therefore temperature changes can affect them. At first, with simple subtractive sounds these small instabilities may not seem like a big issue, but if you try to create complex sounds using FM modulation these at first insignificant changes can dramatically affect the final result and mess up your whole patch.

The Basics of Synthesis: The 3 Elements of Sound

As you may already know, Synthesis is the process of adjusting the elements of sound. The three elements of sound are:

  1. Volume,
  2. Timber and
  3. Pitch.

If you can modify these three elements you can adjust any sound you can imagine. Also, every sound is a type of waveform or a combination of waveforms. The five most common waveforms are the squarewave, the sawtooth, the triangle, pulse wave, and the sinewave. All synthesizers use at least two of these waveforms to generate or modulate sounds.

These modulations are being realized with the help of seven components, these components are called: volume envelope, amplifier, oscillator, filter, LFO, filter envelope, and pitch envelope.

By understanding these 7 components, you’ll be able to create and modulate any sound you want with virtually any synthesizer hardware or software new or old.

Let’s dive right into it!

The Basics of Synthesis: The 7 Master Components for Modulating Any Sound

1) Volume Envelope

The volume envelope is simply the decrease and increase of the volume of a sound, these decreases, and increases (as well as the amount of attack, sustain and release) give the note its shape. These elements are what we call the volume envelope of a sound.

2) The Amplifiert

The amplifier, together with the commands that come from the volume envelope controls the volume of the sound, It actually makes things louder or softer.

3) The Oscillator

The oscillator controls the frequency of the sound, or otherwise called the pitch of the sound

4) The Filter

With the filter, we control the harmonic content of a sound, or otherwise called timber. In other words, a filter can make a sound appear brighter or darker, depending on the type of ffilter in the settings we use. If you want to get all geeky for a minute, we could say that the filter is decreasing or increasing the number of harmonics that are present in a sound.

Open the filter and you’ll hear the upper harmonics making the sound brighter. Now “close” the filter, and you’ll hear the lower harmonics, (by filtering out the upper harmonics), and therefore it becomes darker or duller.

5) The Filter Envelope

Now, commonly a filter will also have a filter envelope which we use to send instructions to the filter to control the brightness or dullness of a sound. Because of the filter envelope, we can create more complex sounds that can be a mixture of dark and bright tones within the same note. What’s more, the filter envelope has an effect on the volume envelope shaping the final result accordingly.

6) The Pitch Envelope

The filter envelope in combination with the oscillator affects the pitch of the sound, or in other words how high or low a sound will appear.

The pitch envelope sends instructions to the oscillator (we said that the oscillator controls the pitch, remember? ) these instruction contain information that will alter the rate and level of the pitch of a sound.

If you just had to remember one thing and done thing only regarding envelopes remember this:

“An envelope always changes one of the 3 elements of sound!”

Before we talked about these three elements, but for the sake of repetition, let’s review them once again.

The 3 elements of sound are:

  1. Volume,
  2. Timber,
  3. Pitch.

Now everything comes together, doesn’t it?

The reason we have 3 envelopes is for to control the 3 elements of sound, as we just saw these three envelope generators are called:

  1. Volume envelope
  2. Filter envelope, and
  3. Pitch envelope

The lesson here is that for every aspect of sound, we have on a synthesizer a component that controls and alters that specific element of sound.

And once you know how to use these three components in absolute synergy properly, you will be able to create even the most complex sounds!

7) The LFO

Lastly, we have the LFO which stands for low-frequency oscillator. A fascinating fact is that the LFO shares the same characteristics with the main oscillator but with one exception, the LFO vibrates (oscillates) at a very low frequency.

You may have heard about the LFO filter by Xfer Records, this VST which is used by many famous producers such as Deadmau5, Skrillex and Armin Van Buren is an amazing tool for manipulating and creating fresh sounds.

You see, the is LFO modulates bellow the frequency of 20Hz, therefore we can’t hear it, that’s why we don’t use an LFO as a sound source but rather as a sound modulator, since we hear its effect on the audible frequency spectrum for humans which starts from 20Hz and goes up to 20Khz (20.000Hz).

An easy way to think of an LFO is to perceive is as a digital vibrato or tremolo effect since we are modulating the amplitude (volume) of a sound.

What’s exciting is that we can also route the LFO to a filter and modulate the harmonic content of a sound. The effect will be similar but not quite the same as when we route the LFO to the amplitude (volume) of a sound

Lastly, we can also route the LFO to control the pulse of a sound which is of course called pulse-wave modulation creating new and interesting mixtures of sound.

Let’s Timetravel: The Birth of Synthesis!

The invention of the synthesizer cannot be attributed to one person, however, in my opinion, a few people contributed the most, two of whom are named Luening & Ussachevsky.

Back in the 1950s, the Columbia Princeton Electronic Music Center (their facilities were located at the Columbia University campus) was founded when Luening & Ussachevsky secured a thousand dollars from the Rockefeller Foundation to purchase the RCA sound synthesizer. A centerpiece for their music studio which later will be known as the RCA Mark II. It’s worth noting that by the year 1960, Columbia Princeton Electronic Music Center was quite famous about their innovative approach and their RCA Mark II.

Moving on, another famous pioneer of electronic music was Karlheinz Stockhausen who merged tape-based composition with Musique Concrete, (the art of creating music from recorded sounds and manipulating them through tape techniques). I guess you could say he had a very primitive version of the Sampler instrument found in Ableton Live 10 😀

Few people have influenced the development of electronic music as much as Stockhausen, he was even featured on the cover of Sgt. peppers lonely hearts club band by The Beatles, (pay close attention and you will see him placed Fifth from the left on the top row). Stockhausen composed almost 400 pieces of classical music, and he was known for his refusal to accept controversial forms and boundaries altogether.

One of his most famous masterpieces is called Gesang der Junglinge (Song of the Youths) which rumor has it its Paul McCartney’s favorite song. If you listen closely you can hear the influence his style had on some of the Beatles tracks. I am talking here about the reverse vocal technique which you can hear at the 1:00-minute mark.

What’s more when Sgt. pepper lonely hearts were in the making Stockhausen and John Lennon frequently spoke on the phone. He even said that “Lennon is the most important mediator between popular and serious music of the century”. I find this to be quite a compliment if you ask me.

Later, in the 1960s Stockhausen would create Kontakte (Contacts) the name which I believe Native Instruments were inspired by and created “The Kontakt library” (click on the link to visit their sales page). A massive collection of Vst’s and samples, which I highly recommend you to try out!

Kontakte is being viewed as one of the most significant compositions that forwarded the evolution of electronic music. Stockhausen combined live music performances and electronics using percussion instruments, a four-channel tape-recorder, and a piano.

If you do listen to Kontakte forget about your modern ears for a minute and try to approach it as if you live in the late 1950s, (click on this link to preview the song). You can imagine the impact and attention Stockhausen gained simply from this one track.

Since then a lot more individuals have contributed in the rise of Synthesis and the popularization of synthesizers. In total, about10 types of Synthesis have been discovered such as: Subtractive Synthesis, sample-based Synthesis, FM synthesis, vector synthesis, wavetable synthesis, Additive Synthesis, physical modeling, spectral Synthesis, granular Synthesis, and West Coast synthesis.

Without getting in great detail, we will discuss a few of them below.

What Is Subtractive Synthesis?

Subtractive Synthesis is the most common form of Synthesis that exists. It actually does what the name suggests it subtracts harmonics from a sound with the help of a filter and volume with the help of the volume envelope. What actually happens when this process is we remove enough elements fromWe are left with something completely new.

What Is Fm based Synthesis?

You may know is that back in the mid-1960s John Chowning discovered an entirely new form of Sound Synthesis, but what you probably don’t know is that Chowings discovery was actually an accident!

At a young age and while still a student of the Stanford University on a regular morning the “father of Fm synthesis” was experimenting with different types of vibrato, as he was messing around with the different frequencies he found that a new tone replaced the original when the vibrato effect disappeared from the modulated tone and the frequency of the modulating signal was increased beyond a certain point, this technique was later used in our now familiar FM radio.


As we saw there are no significant differences between analog & digital FM synthesis, we also explored the elements of a sound as weal their modulators plus we quickly visited a part of our musical history by exploring how Synthesis was created and by whom.

I hope you enjoyed reading the article as much as I enjoyed writing it!

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