Roland JV\XV PWM
Posted: Sun Sep 14, 2008 4:04 pm
The ability of the Roland JVs\XVs to conduct Pulse Width Modulation was discussed in brief here recently, so I figured I'd go ahead and steal from some old Roland statements that went into how to achieve it.
The only JV synth I own is the MC-505, which though still capable of the effect, isn't capable of doing it in a way akin to how the more standard JVs, XPs, XVs, Fantoms, etc. could implement it due to the lack of sub-sonic waves as part of it's rom set.
I'm sure some one around here has a more standard JV lying around, so perhaps one of you could upload some samples.
I'll look at uploading some samples myself, but again, I do not have the means of achieving the typically expected results. (though I do have a hoover patch I made that was based on the same philosophy....it's implementation was still a bit odd).
In any regard, the following is from an old Roland document concerning programming of the JV and describes how to achieve PWM effects.
Roland Corporation U.S. SN55 PROGRAMMING THE SUPER JV SYNTHESIZERS
Subsonic Waves can be used as the modulator in Structures 3 and 4 to produce some rich, harmonically
dynamic sounds. Some of these sounds might remind you of pulse-width modulation effects.
Modulating the amplitude of Wave 1 with the output of Wave 2 can drive Wave 1 into clipping, which
produces a more square-ish waveform. In other words, as the amplitude of Wave 2 increases, Wave
1 becomes increasingly clipped. The character of the resulting sound depends on the Waves and frequencies
that are selected for Waves 1 and 2.
To hear this in action, start by initializing a Patch. Activate Tone 2 by pressing the Tone Switch 2 button—
Tone 1 should already be activated—and select Structure 3 in the last page of the Common
menu.
Now we need a Wave in the subaudio range. Several low-frequency Waves are provided, starting with
Int-B 183 (Low Saw). The smoothest modulation is produced by the Low Sine Wave (Int-B 189) or the
Low Triangle Wave (Int-B 190). You can use other Waves, such as the Low Saw or Low Square, but
they generally produce a pop in the sound when they snap from one extreme to the other in their cycle.
For now, assign Int-B 190 (Low Triangle) to Tone 2 (in the first page of the Wave menu), which will provide
the modulator. Then, assign Wave Int-B 045 (Triangle) to Tone 1, which will act as the carrier.
At this point, you should be able to hear the effect I’m after, although it probably seems a bit hyper.
We can mellow it out by slowing down the rate of change, which means reducing the frequency of
Wave 2.
Navigate to the first page of the Pitch menu, and set the Coarse parameter for Tone 2 to approximately
-18; this should slow things down a bit. However, the effect changes speed depending on what notes
you play. This is because Wave 2 is tracking the keyboard, so its frequency increases as you play higher
notes. You can stop Wave 2 from tracking the keyboard by setting the value for KeyFlw to 0.
Now you have the basic effect. Further tweaking can be applied in several areas. First, you can
accentuate the effect by increasing the Booster value in the Struct page of the Common menu.
Additional control can be obtained using the Gain parameter in the Wave menu; this lets you adjust
the level of each Wave individually, which the Booster does not permit. Also, check out how this
sounds using other Waves. In particular, try changing the Wave used for Tone 1; this should provide
a broad range of musically useful sounds.
On aside, the amount of depth that Roland put into the JV line and that has even carried over into the XV line I think has long been misunderstood and underestimated. (ala, even the MC-505 is an absolute power horse of a synth)
It's funny, because even in the modern day V-Synth, much of the JV and XV lineage carried over....TONS OF IT in fact. In many ways, one almost feels like their looking at a JV / XV when looking at the V (IMO)....I sort of consider it the next step forward from the XV. The JV and XV of course, being descendants of the D-50.
The only JV synth I own is the MC-505, which though still capable of the effect, isn't capable of doing it in a way akin to how the more standard JVs, XPs, XVs, Fantoms, etc. could implement it due to the lack of sub-sonic waves as part of it's rom set.
I'm sure some one around here has a more standard JV lying around, so perhaps one of you could upload some samples.
I'll look at uploading some samples myself, but again, I do not have the means of achieving the typically expected results. (though I do have a hoover patch I made that was based on the same philosophy....it's implementation was still a bit odd).
In any regard, the following is from an old Roland document concerning programming of the JV and describes how to achieve PWM effects.
Roland Corporation U.S. SN55 PROGRAMMING THE SUPER JV SYNTHESIZERS
Subsonic Waves can be used as the modulator in Structures 3 and 4 to produce some rich, harmonically
dynamic sounds. Some of these sounds might remind you of pulse-width modulation effects.
Modulating the amplitude of Wave 1 with the output of Wave 2 can drive Wave 1 into clipping, which
produces a more square-ish waveform. In other words, as the amplitude of Wave 2 increases, Wave
1 becomes increasingly clipped. The character of the resulting sound depends on the Waves and frequencies
that are selected for Waves 1 and 2.
To hear this in action, start by initializing a Patch. Activate Tone 2 by pressing the Tone Switch 2 button—
Tone 1 should already be activated—and select Structure 3 in the last page of the Common
menu.
Now we need a Wave in the subaudio range. Several low-frequency Waves are provided, starting with
Int-B 183 (Low Saw). The smoothest modulation is produced by the Low Sine Wave (Int-B 189) or the
Low Triangle Wave (Int-B 190). You can use other Waves, such as the Low Saw or Low Square, but
they generally produce a pop in the sound when they snap from one extreme to the other in their cycle.
For now, assign Int-B 190 (Low Triangle) to Tone 2 (in the first page of the Wave menu), which will provide
the modulator. Then, assign Wave Int-B 045 (Triangle) to Tone 1, which will act as the carrier.
At this point, you should be able to hear the effect I’m after, although it probably seems a bit hyper.
We can mellow it out by slowing down the rate of change, which means reducing the frequency of
Wave 2.
Navigate to the first page of the Pitch menu, and set the Coarse parameter for Tone 2 to approximately
-18; this should slow things down a bit. However, the effect changes speed depending on what notes
you play. This is because Wave 2 is tracking the keyboard, so its frequency increases as you play higher
notes. You can stop Wave 2 from tracking the keyboard by setting the value for KeyFlw to 0.
Now you have the basic effect. Further tweaking can be applied in several areas. First, you can
accentuate the effect by increasing the Booster value in the Struct page of the Common menu.
Additional control can be obtained using the Gain parameter in the Wave menu; this lets you adjust
the level of each Wave individually, which the Booster does not permit. Also, check out how this
sounds using other Waves. In particular, try changing the Wave used for Tone 1; this should provide
a broad range of musically useful sounds.
On aside, the amount of depth that Roland put into the JV line and that has even carried over into the XV line I think has long been misunderstood and underestimated. (ala, even the MC-505 is an absolute power horse of a synth)
It's funny, because even in the modern day V-Synth, much of the JV and XV lineage carried over....TONS OF IT in fact. In many ways, one almost feels like their looking at a JV / XV when looking at the V (IMO)....I sort of consider it the next step forward from the XV. The JV and XV of course, being descendants of the D-50.