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Deep FM bass on Roland JD/JV/XV series

jdt

Compatibility: JV-80 and up

Although Super JV/JD have the FXM section that is based on a frequency modulation, it is actually quite limited terms of real FM sounds – it is more oriented towards spicing the sound with a specific character (or making it more ‘wild’ as Roland manual says). For real FM sounds we must look elsewhere.

Super JV/JD is not an FM synth, but it has a nice LFO that can run pretty fast, and with a little experience in real FM programming it is not hard to recreate some basic FM sounds. Please keep in mind that we talk about really basic FM sounds created from only two operators (Yamaha DX-7 for example has 6 operators). And even those ”two operators” we will build on Super JV/JD are very primitive, compared to any real FM synth.

Deep FM Bass
We will create one of the deepest basses ever, that goes subsonic, much below 20 Hz. I first built this bass on the Yamaha SY-77 some long time ago, but since it requires only two operators, i recently came to idea to try to emulate it on the JV/JD synth. Ok, it will not sound as powerful as the real one, but it will demonstrate that it is possible to do some primitive FM on the JD, JV, XP, XV synth line.

We will be using two operators. The WG (tone generator) will be the carrier, and LFO will be the modulator. Sound will be made by the classic two point down ramp envelope applied on the modulator – that is, the modulator level starts loud and then fades away. On the real FM synth you would do that with an envelope. Unfortunately on the Super JV you can’t apply an envelope (ENV) to modulate the level of LFO, so on the first sight it appears our FM sound won’t function properly. But there is a workaround for that issue. We will build the envelope on the LFO using ramp, which Roland just calls LFO Fade In/Out function. In other words you got simple two point envelope that can be applied to LFO – i know it is primitive, but better something than nothing. With this ramp you can create dozens of bells and metallic percussion, if used the right way. Here is detailed procedure:

  • Initialize the sound
  • Enable T1, disable all other tones
  • Go to Control and set Key Assign to MONO
  • Set WG1 to Sine
  • Go to Pitch, set Coarse Tune to -12
  • Go to LFO and set it to SAW-DW
  • Jump to TVA1 and disable velocity (V-Sens=0)

You probably noticed that we used Saw wave in the LFO instead of Sine wave. We had to use the saw to add more punch to the sound, because JV is not a real FM synth, and with a sine wave LFO, the sound becomes too muddy in the low C1-C2 region. However, later you can try switching LFO to sine wave and try C2-C4 notes that will sound better with it. You will also use sine wave in the LFO for all metallic and bell sounds. Or to be precise, you should use sine wave LFO in almost all FM sounds, except those in low pitch range where you will use SAW-DW wave to compensate the lack of punch.

  • Within LFO set Depth Pitch: +50
  • Set Fade Mode: ON-OUT (this is our ramp down envelope)
  • Go to TVA and make a short sound using following parameters
  • Time: 0 20 42 42
  • Level: 127 127 0
  • Now hit A1 and C2 few times
  • For shorter and more distinctive bass set time to: 0 10 42 42

Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from this to proceed to investigate the reason. – Leonardo da Vinci

Comment (1)

  1. Gary

    Going to give this a go on my XP30 tonight I think. So we can “do” FM (albeit very simply) as well as PWM. If only there was a way to simulate osc sync on an unexpanded XP30 (The vintage cards are rarer than hen’s teeth it seems).

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