Can you reccomend an AM synth plugin?

[fmr]

From KV331Audio's website about Synthmaster: "VA, Additive, Wavetable, Wavescanning, Phase Modulation, Frequency Modulation, Pulse Width Modulation, Ring Modulation, Amplitude Modulation, Physical Modeling and SFZ Sample Playback synthesis" and yes I recommend it.

I am ALWAYS forgetting Synthmaster. It does basically ANYTHING...

[generaldiomedes]

I'm not sure if any of the synths mentioned have presets that are based solely on AM synthesis, or have controls that are dedicated to shaping sounds made with AM synthesis

Spire is pretty simple - one knob to change the modulation frequency, another to fade the operator between sine and pulse. There are presets which solely use 'AMSync' mode.

VPS Avenger has more options such as additional operator waveforms. http://www.vengeance-storage.com/Avenge ... nglish.pdf page 25. I haven't played with Avenger's AM that much as I haven't owned it as long as Spire, but but both have demos you can download.

[aciddose]

Ringmod is a form of AM.

AM typically refers to "two quadrant" modulation. "Single side-band" or "quadrature" modulation is an improvement where one of the side-bands and the carrier are suppressed to reduce the wasted energy in transmitting the signal.

Ring modulation is "four quadrant" modulation where negative amplitudes are allowed. This suppresses the carrier on its own but still generates a redundant duplicate side-band (two of them are present, sum + difference.)

What we typically refer to as "FM" is in fact equivalent to ring modulation applied to frequency. In "FM" negative frequencies are allowed which takes advantage of not just the frequency of the carrier but also its phase to encode even more information into the same bandwidth.

Basic two quadrant frequency modulation is not often useful musically as any modulated tone/carrier has its pitch shifted "out of tune" in complex and difficult to predict ways.

So no: AM does not equal FM more than ring modulation equals AM.

In fact ring mod is more like FM than AM, which is a partial (reduced depth) version of ring mod. In that sense ring mod is like FM; AM is like vibrato.

[werp]

I don't need an AM synth what with not getting out of bed until the pm.

[fmr]

In that sense ring mod is like FM; AM is like vibrato.

AM is NOT like vibrato. AM is tremolo.

Vibrato is modulation applied to frequency (by a low frequency oscillator). Tremolo is modulation applied to amplitude (by also a low frequency oscillator).

Regarding synthesis methods:

AM "IS" tremolo with a audio rate oscillator modulator.

FM "IS" vibrato with a audio rate oscillator modulator.

RM is neither of them. But all of them are close to each other, as I and others said before.

[Ingonator]

The term "Ring modulation" explained at Wikipedia:
https://en.wikipedia.org/wiki/Ring_modulation

There it is also mentioend that in the ARP Odyssey and some others the ring modulator actually seemed to be a XOR function.

A XOR function is also included with some of the waveshapes of Osc 2 in the Waldorf Pulse 2 (which oi got here). With those Osc 2 could do XOR with either Osc 1 or Osc 3 depending on the mode (called "X1-PWM" or "X3-PWM").
Besides that Osc 3 could be routed to modulate the level/amplitude of Osc 2 which results in AM and/or ring modulation. When this routing is used the Osc 3 level adjusts the modulation depth.
Osc 3 could be also routed to the Cutoff for doing filter FM.

As mentioned earlier my Novation Bass Station 2 has a "Ring" amount knob in the Osc mixer and the Ultranova has 2 different ones using Osc 1 + Osc 3 and Osc 2 + Osc 3 (same with Waldorf Nave).

The Ensoniq ESQ1 i got here besides Osc Sync of Osc 1+2 also has an option to add AM there (at least it is called AM at the synth) while i am not sure if in this case technically it is actually ring modulation. Possible that the terms AM and ring modulation are sometimes used in a wrong way, same with FM and PM (= phase modulation).

[ghettosynth]

In that sense ring mod is like FM; AM is like vibrato.

AM is NOT like vibrato. AM is tremolo.

Vibrato is modulation applied to frequency (by a low frequency oscillator). Tremolo is modulation applied to amplitude (by also a low frequency oscillator).

Regarding synthesis methods:

AM "IS" tremolo with a audio rate oscillator modulator.

FM "IS" vibrato with a audio rate oscillator modulator.

RM is neither of them. But all of them are close to each other, as I and others said before.

RM, when thought of as is it used in synthesizers, is a form of AM. While what results from any modulation process is some combination of the input frequencies, there is a subtle technical difference. In FM modulation, the frequency of the carrier is being modulated. In AM and RM, the amplitude of the carrier is being modulated.

From the wikipedia page:

Ring modulation is a signal-processing function in electronics, an implementation of amplitude modulation or frequency mixing, performed by multiplying two signals, where one is typically a sine wave or another simple waveform.

So we can apply four quadrant multiplication to frequency or amplitude, but frequency is not what we typically think of in applying a ring modulator in a synthesizer. We drive the ring modulator with the output of an oscillator, hence, it is "an implementation of amplitude modulation."

These terms were used much more commonly for radio circuits long before they ever were thought about for electronic synthesizers. A ring modulator, or ring mixer, gets its name from the common "diode ring" mixer. The schematic of a ring mixer looks like a ring of diodes.

With RM, although the carrier is suppressed, it's frequency is not changing. You can unbalance a ring mixer and the carrier will start to bleed through.

[Ingonator]

These terms were used much more commonly for radio circuits long before they ever were thought about for electronic synthesizers. A ring modulator, or ring mixer, gets its name from the common "diode ring" mixer. The schematic of a ring mixer looks like a ring of diodes.

In the Wikipedia link posted above it is mentioend that ring modulation was invented around 1934 and patented in 1935. The term "ring" indeed seemed to come from the shape of the circuit (explained at Wikipedia too).

[ghettosynth]

These terms were used much more commonly for radio circuits long before they ever were thought about for electronic synthesizers. A ring modulator, or ring mixer, gets its name from the common "diode ring" mixer. The schematic of a ring mixer looks like a ring of diodes.

In the Wikipedia link posted above it is mentioend that ring modulation was invented around 1934 and patented in 1935. The term "ring" indeed seemed to come from the shape of the circuit (explained at Wikipedia too).

That sounds about right. I didn't see it on the page but I'm quite familiar with this from building radio circuits, a hobby that comes and goes for me but has been with me since I was a kid. Ring mixers are extremely common in radio circuits and are a part of virtually all modern communications radios.

You can build a diode ring modulator for your modular in the same way. You just need the right diodes and some audio transformers. Ken Stone of cat girl synth used to sell a kit.

[Ingonator]

Just checked the shape of the Ring modulator output of my real analog Novation Bass Station 2 (= "Ring" knob in te Osc mixer) and compared the ahpe to teh single Oscs and a mix of them.

Here is a combined picture based on 6 single screenshots using a free oscilloscope plugin:
https://dl.dropboxusercontent.com/u/532 ... t%2001.png


From top left to lower right those are:
- Osc 1 Sine wave at octave 8'
- Osc 2 Sine wave at octave 2'
- Osc 1 + 2 mixed at maximum levels
- Ring modulator output of Osc 1+2 (Osc 1+2 levels at 0 in the mixer)
- combined oiutput of teh ring modulator and both Oscs (all at maximum level)
- ring modulator output with Osc 1 Sine wave set to octave 16' (= one octave lower than the first example)

[fmr]

In that sense ring mod is like FM; AM is like vibrato.

AM is NOT like vibrato. AM is tremolo.

Vibrato is modulation applied to frequency (by a low frequency oscillator). Tremolo is modulation applied to amplitude (by also a low frequency oscillator).

RM, when thought of as is it used in synthesizers, is a form of AM. While what results from any modulation process is some combination of the input frequencies, there is a subtle technical difference. In FM modulation, the frequency of the carrier is being modulated. In AM and RM, the amplitude of the carrier is being modulated.

I didn't deny that RM is "a form of AM". Actually, the mistake I pointed, and that caused my post, was calling vibrato to AM, a very common mistake. When using a low frequency oscillator, we can have vibrato if we modulate the frequency. But if we modulate the amplitude what we have is called tremolo, NOT vibrato. And the result is not the same, alhtough it may be close in certain circumstances. acidose post is basically correct, except when he says that thing about vibrato, and when he compares RM and FM. These two are quite different, even sonically.

About the difference between RM and AM in synthesis terms - Let's grab some help from Curtis Roads, and the book "The Computer Music Tutorial":

"Like RM, AM generates a pair of sidebands for every sinusoidal component in the carrier and the modulator. .../... The sonic difference between RM and AM is that the AM spectrum contains the carrier frequency as well. The amplitude of the sidebands increases in proportion to the amount of modulation, but never exceeds half the level of the carrier"

This is the main difference. In RM, the carrier frequency disappears, according to Curtis Roads, when the frequency of the modulator is in the audible range (which is when we actually have "our" RM synthesis). Even if it doesn't disappears, as some here said, certainly its frequency will me much lower than the one of the sidebands, resulting in quite different spectra. AM will always be much "mellower", which is indeed what we can easily check in real life, and maybe the reason why it doesn't get so much interest as RM and FM.

Furthermore, if C and M are an integer ratio of one another, the sidebands generated are harmonic. Otherwise, they are inharmonic. That's why RM is often used to produce sounds that are difined as "clangorous" or "metallic".

Another curious effect mentioned is that, in analog implementations, depending on the type of diodes, the circuits introduce extraneous frequencies. One example quoted is that, in circuits based is silicon diodes, the diodes clip the carrier, truning it into a quasi-square wave, when it reaches the momentary level of the modulator, creating the effect of several sums and diferences on odd harmonics of the carrier (maybe this is where the "clangorous" effect comes from).

AFAIK, nothing of this happens in "pure" AM.

[Ingonator]

Just checked the shape of the Ring modulator output of my real analog Novation Bass Station 2 (= "Ring" knob in te Osc mixer) and compared the ahpe to teh single Oscs and a mix of them.

Here is a combined picture based on 6 single screenshots using a free oscilloscope plugin:
https://dl.dropboxusercontent.com/u/532 ... t%2001.png


From top left to lower right those are:
- Osc 1 Sine wave at octave 8'
- Osc 2 Sine wave at octave 2'
- Osc 1 + 2 mixed at maximum levels
- Ring modulator output of Osc 1+2 (Osc 1+2 levels at 0 in the mixer)
- combined oiutput of teh ring modulator and both Oscs (all at maximum level)
- ring modulator output with Osc 1 Sine wave set to octave 16' (= one octave lower than the first example)

Just tested the Ring modulation and FM in Waldorf Largo with two Sine oscillators comparable to the previous ringmod tset done with the Bass Station 2. Like there one oscilator had a pitch of 2 octaves higher than the other one.
For both methods (RM ) ring modulation and FM )= frequency modulation) i made two screenshots using Osc 2 as a modulator and Osc 1 as a carrier and vice versa. The FM amount was set to maximum.

Here is a picture created from combin ing 4 screenshots of the oscilloscope plugin:
https://dl.dropboxusercontent.com/u/532 ... t%2001.png


The two ringmod results look mostly similar but the x-axis seems to be flipped which results in a mirror image. Sound wise, oposing to the two FM examples, theer is no difference.

[fmr]

Just tested the Ring modulation and FM in Waldorf Largo with two Sine oscillators comparable to the previous ringmod test done with the Bass Station 2. Like there one oscilator had a pitch of 2 octaves higher than the other one.
For both methods (RM ) ring modulation and FM )= frequency modulation) i made two screenshots using Osc 2 as a modulator and Osc 1 as a carrier and vice versa. The FM amount was set to maximum.

The point is not comparing RM with RM, or RM and FM - FM is out of the question here.

The issue here is AM vs RM, and to which extent does the differ from each other. So, comparing different settings of RM and/or RM with FM is pointless, IMO.

[Ingonator]

Just tested the Ring modulation and FM in Waldorf Largo with two Sine oscillators comparable to the previous ringmod test done with the Bass Station 2. Like there one oscilator had a pitch of 2 octaves higher than the other one.
For both methods (RM ) ring modulation and FM )= frequency modulation) i made two screenshots using Osc 2 as a modulator and Osc 1 as a carrier and vice versa. The FM amount was set to maximum.

The point is not comparing RM and FM - FM is out of the question here.

The issue here is AM vs RM, and to which extent does the differ from each other. So, comparing different settings of RM and/or RM with FM is pointless, IMO.

I used similar oscillator settings to compare the result of ring modulation and FM in Largo. To keep it simple i used simple Sine waveforms. I do not think taht this kind of comparison this is wrong.
FWIW in teh Bass Station 2 example i only used the ring modulation.

Someone mentioned that AM and FM are quite similar or comparable. Obviously in practical use this not the case, at least when comparing ring modulation which is a kind of AM and actual audio rate FM (not vibrato which i done with a LFO).

Anyway i do not see a problem with directly comparing AM, RM (= ring modulation) and FM.
FWIW all those are technolgies that also seem to be used in radios.

In Largo i could not route the oscilators to the volume to get "real" AM but only use teh ring modulator or route an Oscillator to another one or to the filter. One synth that might do all 3 options is e.g. DUNE 2.5.

Last but lot least i try to not just talk about theory but also give some real world examples using different synths (so far one real analog and one fully digital one).

[fmr]

Someone mentioned that AM and FM are quite similar or comparable. Obviously in practical use this not the case, at least when comparing ring modulation which is a kind of AM and actual audio rate FM (not vibrato which i done with a LFO).

Anyway i do not see a problem with directly comparing AM, RM (= ring modulation) and FM.
FWIW all those are technolgies that also seem to be used in radios.

As I already pointed, AM with LFOs doesn't produce vibrato, produces tremolo. These are different things. Vibrato is frequency modulation (FM).

Besides, the fact that all the technologies (AM, RM, and FM) came from radio is again pointless. They are used in a totally different contest here, and the results are, therefore, different, We aren't trying to tune radio stations, we are trying to produce sound (oscillations).

AFIR noone said that AM and FM were similar. What was said was that RM as "a form" of AM. What is in debate here is to which extent these two (AM and RM) are similar/different and produce similar/different results.

That FM is different and produces different results is already established, AFAIK, and was never in question. And comparing RM in different devices is pointless too - if it's RM the results have to be comparable, unless it was done with analog circuits, in which case the way the circuits were build may have implications as I also wrote earlier.

In the examples you posted there isn't any AM example, just RM, which may lead people to the erroneous conclusion that RM and AM are the same thing, when they aren't. RM is a "special case" of AM.