VL3X MIDI Reference

What's controllable & how fast

Verified against VL3X firmware & VL3/x Pilot codebase, March 2026

1. What's Controllable

Each VL3X preset stores 472 parameters. The device also has 131 system parameters (input, output, MIDI, tone, footswitch). Here's the control surface:

597

SysEx Parameters

MIDI CCs

Not Live-Writable

Key insight: SysEx reaches 597 parameters (466 preset + 131 system). MIDI CC covers 28, all of which SysEx can also reach. CC gives you toggles. SysEx gives you actual values; Delay TIME, Reverb DECAY, Amp GAIN, Harmony STYLE. With SysEx, you control everything.

2. Preset Parameters (472 total)

Each preset stores 472 values. 464 are writable via SysEx 0x22 in real time.

Category	Count	SysEx 0x22	Examples
Vocal	206	Yes	Harmony, Double, Reverb, Delay, EQ, HardTune, Choir, Transducer
Guitar	131	Yes	Amp, Delay, Reverb, Comp, Drive, Wah, Octaver, uMod
Mixer	42	Yes	Levels, pans, widths, routing sends
Global Enables	25	Partial	Per-effect global/preset mode flags
Hit Control	23	Partial	HIT button behavior per effect
Button Map	18	Yes	Footswitch function assignments
Looper	17	Yes	Loop levels, trigger slots, track config
Pedal Control	3	Partial	Expression pedal assignments
Internal	7	No (8 offsets)	CrossDomain button map, backing track pointers

Result: 464 of 472 preset parameters writable via SysEx 0x22. Only 8 offsets (button map cross-domain + backing track) lack SysEx IDs.

3. System Parameters (131 total)

Global settings that apply across all presets. All 131 are SysEx-writable.

Section	Examples
Input	Input Type, Phantom Power, Guitar Input Level
Output	XLR Output, USB Output Mode, Headphone Level
MIDI	MIDI Source (USB/DIN), Channel, SysEx ID
Tone	Global EQ bands, Adaptive Tone
Mixer	Output routing, monitor config
Footswitch	FS assignments, expression pedal config
Mic Control	Mic control settings, roomsense
Limiter	HP limiter, RoomSense limiter
System	Contrast, Tuner Reference, HIT behavior

4. SysEx vs MIDI CC

SysEx (0x22 Parameter Write)

597 parameters (466 preset + 131 system)
Full value ranges (0–100, enums, signed)
Delay TIME, Reverb DECAY, Amp GAIN
Harmony STYLE, Double TYPE, EQ bands
Mixer levels, pans, widths
Requires Editor Enable (0x15) first

MIDI CC (28 controls)

28 CCs (all also reachable via SysEx)
Mostly ON/OFF toggles (0–63 = OFF, 64–127 = ON)
CC 30: Harmony Key (12 values)
CC 31: Harmony Scale (7 values)
CC 1: Vibrato Boost (continuous 0–127)
No editor enable required

Preset recall: Program Change + Bank Select (CC 32) is the ONLY way to switch presets. No SysEx equivalent exists.

5. Complete MIDI CC List (28 CCs)

Guitar (10 CCs)

CC	Function	Values
16	Rhythmic	Toggle
17	Delay	Toggle
19	Compressor	Toggle
21	μMod	Toggle
23	Octaver	Toggle
25	Amp	Toggle
27	Wah	Toggle
29	Boost	Toggle
46	Reverb	Toggle
47	HIT	Toggle

Vocal (15 CCs)

CC	Function	Values
1	Harmony Vibrato Boost	0–127 (continuous)
30	Harmony Key	0–11 (C through B)
31	Harmony Scale	0–6 (MAJ1–CUST)
50	Vocoder/Synth	Toggle
51	Rhythmic	Toggle
56	HIT	Toggle
104	Choir	Toggle
110	Harmony	Toggle
111	Double	Toggle
112	Reverb	Toggle
113	HardTune	Toggle
116	μMod	Toggle
117	Delay	Toggle
118	Transducer	Toggle
119	Harmony Hold	Toggle

System (3 CCs)

CC	Function	Values
32	Bank Select LSB	0–3 (banks of 128 presets)
115	Step	1–n (step number)
123	All Notes Off	Any value

Toggle values: 0–63 = OFF, 64–127 = ON. VL3X uses CC 32 (LSB) for bank select, not CC 0 (MSB).

6. USB vs DIN-5 Timing

DIN-5 wire speed

DIN MIDI runs at 31,250 bits/sec. Each byte takes 10 bits on the wire (start + 8 data + stop):

~320 microseconds per byte
3-byte message (PC or CC): ~1 ms
8 bytes (Bank + PC): ~2.5 ms
14-byte SysEx: ~4.5 ms

Messages transmit sequentially, so multi-message actions naturally spread out.

USB batching

USB MIDI is scheduled in time slices (typically 1 ms frames). Multiple messages can pack into a single frame, so bursts arrive together instead of dripping in serially.

Real-world comparison

Scenario	DIN-5	USB
One preset change (CC0 + CC32 + PC)	~2.5 ms	<1 ms
Editor Enable SysEx (14 bytes)	~4.5 ms	<1 ms
5 parameter changes (70 bytes)	~22 ms	<1 ms
Full preset-load burst	~30–50 ms	<2 ms

Foot controller overhead

Many DIN foot controllers add latency before transmitting:

Button scan loop: 5–10 ms
Debounce settling: 10–20 ms
Message generation: 1–2 ms

Typical DIN + controller: 20–35 ms before the VL3X sees the first byte
Then add DIN transmission time on top

Bottom line: DIN-5 is fine for occasional preset changes. USB wins for multi-step actions, rapid bursts, and anything that needs to feel tight. Even for plain PC/CC, USB delivers commands as a clean burst instead of a serial drip.

7. Human Perception

Delay	Perception
<10 ms	Feels instant
10–20 ms	Subtle; sensitive players may notice
20–50 ms	Noticeable lag, sluggish feel
50–100 ms	Obvious delay, can affect timing
>100 ms	Disruptive

In context

Setup	Typical latency	Perception
USB MIDI (direct)	<2 ms	Transparent
DIN-5 (cable only)	2–5 ms	Usually transparent
DIN-5 + foot controller	20–35 ms	Edge of perception
DIN-5 + controller + burst	50–80 ms	Clearly perceptible

8. Inter-Message Delays (Verified)

Tested over 100+ iterations per timing combination. These are the recommended delays for reliable operation:

USB MIDI (direct connection)

Operation	Minimum	Recommended
After PC/CC preset switch	0 ms	0–20 ms
After Editor Enable (0x15)	0 ms	0–20 ms
Between parameter writes (0x22)	0 ms	0–10 ms
Between parameter reads (0x47)	2 ms	2 ms
Between chunk reads (0x45)	10 ms	10 ms
After query, before reading response	300 ms	300 ms

DIN-5 MIDI / external controllers

Operation	Recommended
Between parameter writes	20–50 ms
Between bulk data chunks	30–50 ms
After preset header	50–100 ms
After final chunk (commit time)	100–300 ms

Preset write sequence

Operation	Delay after
Preset header (0x20)	50–100 ms
Between data chunks (0x21)	20–30 ms
After final chunk	100–300 ms

Connection topology matters: Mac → USB → VL3X works at 0 ms minimum. DIN-5 with foot controllers needs 20–50 ms.