Wednesday, 21 February 2007

FM Part 6

Making a simple FM synth, part 6: Adding envelopes to the carrier and the modulator.

Watch the video

  • Obviously envelopes make a massive difference to the sound.
  • (0:55) Some of Reaktor's envelopes, like the ADSR, have a G input which triggers the envelope with an amplitude proportional to the size of the gate signal: if you send the number 0.1 into the G input, the envelope will trigger quietly; if you send the number 1.0, it'll trigger more loudly. Other envelopes have a Trig input which works differently: any gate signal, no matter how large, just opens the envelope at full amplitude - or, as in the example of the D envelope used later in the video, at the amplitude passed to the envelope module's A input.
  • ...Well, it's not a DX7 yet, but it makes a nice techno bass sound. I'll stash it somewhere to develop later...

FM Part 5

Making a simple FM synth, part 5: Making a panel control to control the modulator's amplitude (FM Amount).

Watch the video

  • Now we've got control over the amount of FM and the interval between the carrier and the modulator, suddenly we can make all sorts of changes to the tone of the synth.
  • (0:25) I often find it really useful to start an instrument with constants controlling various aspects of the sound, because they let you get a feel for the range of values that'll work for the synth.

FM Part 4

Making a simple FM synth, part 4: Making a panel control to control the modulator's pitch relative to the pitch of the carrier.

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  • I'm doing a lot of Show Hints in this video: the little cursor & "i" button in the structure toolbar is active, which means that when I mouseover a wire or a module, I'll see pop-ups showing info about the module or the signal in the wire. Very, very handy.
  • (1:02) I always like to pay a bit of attention to the step size and mouse resolution of my panel controls, because you can control how smoothly they respond, and the level of detail they give you.
  • (1:56) I'm setting all my modules to mono here - which is what the orange square means in the bottom-right corner of each module. A polyphonic module has a yellow square. I like mono.
  • (2:00, using the Add module) It might be worth replaying this bit: it's little things like this... using Add modules to mix signals, and doing maths in general to your sounds... that make Reaktor so powerful.
  • (3:05) ...Or a bit like pulse-width modulation.
  • (3:23) 5 semi-tones, or MIDI notes, is the musical interval of a 4th (C to F or A to D). A 5th (C to G or A to E) is 7 semi-tones or MIDI notes. It feels like when the modulator's 12 or 24 or 36 notes up from the carrier, you get the most musical FM harmonics. Musical intervals give musical harmonics.
  • (5:36) Here, I'm turning up the FM amount, not changing the interval between the modulator and the carrier. More FM means louder harmonics, and changing the interval changes the sequence of harmonics produced.

FM Part 3

Making a simple FM synth, part 3: Playing with frequencies

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  • (2:30) MINUS frequencies??? This makes sense... at NAMM this year, the Technicians of the Museum of Techno spoke to Cynthia Webster of, who makes an analog FM oscillator called the Zeroscillator. She's very proud that the oscillator is "through-zero", so if you tell it to play a negative frequency, it'll cycle through its waveform in reverse direction. I'm going to get a Reaktor oscilloscope going, I think, to investigate this... I'd like to see what it looks like.
  • Watch the modulator's A input value going up and down... it feels like larger values, more frequency modulation, make for brighter sounds.

FM Part 2

Making a simple FM synth, part 2: adding a second oscillator (operator in FM-speak) to drive the frequency of the carrier up and down.

This video shows the impact of frequency modulation on the carrier's timbre (tone).

Watch the video

  • (0:20) In subtractive synths, and in Reaktor, tone-generating modules are often called oscillators. In FM, they're called operators. A carrier operator is an operator whose output you listen to... a modulator operator is an operator used primarily to modulate the frequency of a carrier.
  • (0:58) The modulator's A input defines its amplitude - how loud it is. normally, you'd expect an oscillator's amplitude to be somewhere in the range 0 ... 1. But we want to generate a signal to drive the carrier's frequency up and down, and we're going to be using some big numbers (in the hundreds and thousands), so I'll be using quite large values for the modulator's amplitude...
  • (1.22) "65 times every second:" MIDI note 36 is the pitch of my low C note; the 36th key on the longest possible MIDI keyboard. That corresponds to an oscillator's waveform cycling... or a piano string vibrating... at 65.4Hz (65.4 cycles per second, its frequency). Any number passed to an oscillator's F input will be added to its frequency. What we're doing here is adding the modulator's output, scaled up by some amount, to the carrier's frequency.

FM Part 1

Making a simple FM synth, part 1: getting a sound out of Reaktor, and instruments in a Reaktor ensemble.

Watch the video

  • I've chosen quite a low note to play with so you might need to put your headphones on if your PC speakers don't go all the way down!
  • (1:50) I hope this all makes sense. One of the early challenges when you're learning Reaktor is getting it to make a sound at all... I'm hoping to get round that by starting really simply (just the one oscillator). Basically, if you've got a very simple structure that isn't sounding, and you think it should be, check that you've got all your inputs wired up.

Reaktor Diary: Intro

Over the past year I've been learning to build instruments and ensembles with Native Instruments' Reaktor 5. I love it - it's beautifully designed, it sounds amazing, and there are all sorts of instruments to download from the NI user library.

At the same time, I haven't found many books or deep online tutorials about Reaktor, beyond simple stuff like constructing a basic subtractive synth. That seems a bit of a shame, because R5's such a good way to explore synth design and electronic sound.

So I started exploring R5 while using it in my own tracks. And I thought I might try to share some of what I've discovered, in case it has any value for other people. So I've started this video diary. It's going to be a little bit freeform, and I'm no grand master, but I suppose it still might be useful to people who are getting to grips with what Reaktor can do.

I hope you enjoy it, and feel free to drop me a line with your feedback. Thanks!