The Roland JD-Xi
When I temporarily had to live in a single bedroom, I got a Roland JD-Xi as a small all-in-one synth to make music until I could have a real recording studio again. That experiment did not work out; none of the songs I wrote on the JD-Xi went on to that album. I put the JD-Xi in storage and dismissed it until a few weeks ago.
Back in 2016, there were a couple of issues with the JD-Xi which have since been fixed:
- There was no sound editor; while sounds can be edited on the JD-Xi, it is done with seven buttons. Lots of menu diving.
- The panel was difficult to read.
Roland fixed the issue with the panel by providing free plastic layovers which can be put on the JD-Xi panel to make it easier to read.
The digital synth
Let’s look at the sound of the JD-Xi. The digital side has two engines: It has Roland’s “SN-S” (Supernatural Synthesis), as well as an engine for playing back drum samples. There is also a one-oscillator one-voice analog synth.
Here, I have posted a comparison of the analog and digital sounds in the JD-Xi, with a simple PWM (pulse width modulation) waveform in an ascending C major scale: JDXi Digital vs. Analog. Try and tell which one is digital and which one is analog; the answer is that the first scale is digital and the second scale is analog (highlight this text to see the spoiler).
As you can hear, even after going to some effort to get the digital PCM to sound just like the analog PCM, there is a certain bite and buzzyness to the analog sound which the digital does not have. To simulate how this will sound in a completed track, I use the JD-Xi’s “flanger” to add a nice chorus to both sounds.
In addition, there are issues with the JD-Xi PWM waveforms aliasing in the upper octaves (these sounds were made on the JD-Xi’s big brother, the Jupiter-80, but the JD-Xi has the exact same issue).
The digital synth, to my ears, sounds a little nice and mellow. Listening to entire tracks made with the JD-Xi, there is a certain lounge lizard vibe to the sound.
Not to say the SN-S digital synth engine in the JD-Xi is bad. It’s quite good. My favorite musician, Jonn Serrie, has used the Jupiter-80 on his last two albums and it sounds wonderful (especially though Serrie’s Eventide Space reverb unit). The JD-Xi has a slightly reduced form of the virtual analog engine in the Jupiter 80 (128 instead of 256 base voices; fewer waveforms in the PCM section), but it sounds just the same.
The digitally simulated analog synth engine allows up to three one-oscillator “partials” to be stacked; each partial has two LFOs, two ADSR envelopes, a single oscillator with eight waveform types (Sawtooth, Square, PWM square, triangle, sine, noise, super saw, and PCM), all of which have variations (three each of sawtooth, square, PWM square, triangle, and sine; two noise types; detune for super saw; and 160 different PCM waveforms—note that the Jupiter 80 has 363 PCM waveforms), a filter with seven different filter types (four lowpass filters, a high pass filter, a bandpass filter, and a peaking filter), a simple attack-decay pitch envelope, and probably a couple of features I missed.
While the synth engine does not have oscillator sync nor does it allow one oscillator to modulate the pitch of another one, it does have a simple ring modulation, where oscillator 1 can modulate the amplitude of oscillator 2, allowing for some kinds of bell tones.
Where the JD-Xi synth engine really shines is with pad sounds. Even using only a single oscillator, by using the JD-Xi’s “super saw” waveform and built in flanger as a chorus, it can make very thick 128-voice pads. It sounds even thicker if stacking multiple sawtooth partials.
Here’s a great example of some very nice space music pads done with the JD-Xi; for a certain kind of smooth jazz, space music, or ambient feel, the JD-Xi’s digital synth really sounds good.
The analog synth
While the JD-Xi does have a built-in distortion which can give its digital side some punch, it also has a true analog synthesizer.
The analog synth is roughly equivalent to my old ARP AXXE in features: A single oscillator with PWM support. Unlike the old ARP, the JD-Xi’s analog synth has two (not one) ADSR envelopes, triangle wave support, a two-stage pitch envelop, and a sub-oscillator.
To my ears, the JD-Xi’s analog synth has a very “acid” sound to it; one can get a very classic “acid house” bass sound by slowly modulating by hand a resonant filter. The sound has that analog bite to it, and can also work nicely for lead sounds.
While the analog synth is very basic, and monophonic, it does well the kinds of sounds the digital synth doesn’t do well (acid bass lines; brash leads), and is the perfect complement to the digital synth.
Note that early versions of the JD-Xi has issues with the filter stepping; Roland fixed this issue with a firmware update.
The drums should get a mention here. This is essentially a rompler drum machine with some 453 different sounds; it’s possible to stack up to four different drum sounds, change the pitch of the drum sounds, apply one of six different filters (3xlow pass, band pass, high pass, and peaking) to the drum sound, and apply a separate pitch, filter, and amplitude envelope to each drum sound.
It’s a nice little drum machine with a lot of nice sounds to it.
The JD-Xi has a four part polyphonic sequencer. It can perform real time recording, step time recording, and the drum sounds can be edited TR-808 style using sixteen buttons on the right hand side for each step of the sound. Two digital synth sounds, a drum set, and the analog sequencer can all be sequenced.
The sequencer’s biggest flaw is that it does not have a song mode; patterns have to be chained by hand. Another flaw is that it only supports 4/4 time.
The sequencer is really nice for quickly writing a basic drum + bassline + synth line song, which can then be put on a multitrack tape to make for a full song.
For live playing, it’s possible to play entire songs, such as this nice relaxing piece.
Note that earlier versions of the JD-Xi did not support “swing” in drum patterns, but this was fixed in a firmware update.
The JDXi has both DIN MIDI sockets (for hooking it to a real keyboard) and a USB connection. When connected to a computer, it works nicely as a sound and MIDI card; right now I am listening to a song being played on my computer through the JDXi’s output.
The USB connection also allows patches to be edited on the PC.
There is an input on the back, as well as stereo outs, and a 1/4" headphone jack. While individual outputs would have been nice, I don’t expect to have them on an all-in-one $500 synthesizer.
MIDI implementation is very basic: MIDI channel 1 is the first digital synth, channel 2 is the second digital synth, channel 3 is the analog synth, and channel 10 plays the drums. These channel assignments can not be changed.
Likewise, MIDI CC support is very basic: All of the front panel knobs can be adjusted with a combination of MIDI CC and NRPN, and a few other parameters without front panel knobs (e.g. MIDI CC can adjust DCA/VCA attack, decay, and release, but sustain is missing) can also be adjusted. For example, pulse width can be adjusted with NRPN; PWM depth can not be adjusted with MIDI CC nor NRPN. MIDI CC destinations can not be reassigned.
The JD-Xi has a few built in effects, including a few different distortions, a flanger/chorus, phaser, delay, and reverb.
The flanger also acts as a really nice sounding chorus effect which really thickens up a pad sound. The delay has a fun stereo ping-pong mode and up to 2.6 seconds of delay time. The reverb can be thin and metallic sounding, but can add a little body to a sound if the tail is not made too long; an external reverb unit is recommended for ambient or space music.
The effects are the same for all sounds, and the effects chain is fixed (distortion sounds → chorus and other modulation sounds → delay → reverb), but individual sounds can choose where they are patched in to the effect chain (at the start, after distortion, after modulation, after the delay effect, or no effects at all).
Where I find the JD-Xi to be really powerful is that it makes composing dance songs easier: I can lay down a basic beat, then once it sounds promising, record each part one by one in to my digital multitrack. Each part has to be recorded one at a time; once this is done, it’s possible to set EQ to make each part sound as good as possible, as well as adding more parts to the song.
The other area where the JD-Xi really stands out is with space music and ambient pads: This is where the digital engine really delivers, especially with 40 to 128 voices of polyphony. The drum engine sounds really nice and is remarkably flexible, and the analog synth provides the bite the digital synth may lack.
While marketed as a low-cost “starter” synth, its incredibly deep digital engine, excellent sampled drum sounds, and analog synth allows it to add something to almost any song I write.
I look forward to making the JD-Xi part of my music making workflow.