TC-Helicon VoiceWorks MIDI System Exclusive

General Message Format

All numerical values are in HEXADECIMAL notation unless otherwise indicated. Decimal equivalents appear in brackets.

General message format:

• F0: MIDI System Exclusive message start
• 00 01 38: TC-Helicon manufacturer ID
• <Device ID>: System Exclusive Device ID (user parameter)
• 4C: VoiceWorks model ID
• <Message ID>: VoiceWorks message type identifier
• <Data>: Data depends on message type
• F7: MIDI System Exclusive message terminator

Preset Numbers

Preset numbers are represented in SysEx messages as 2 bytes (14-bit value). The first byte contains the 7 least significant bits, and the second byte contains the 7 most significant bits. Preset number zero represents the currently edited preset.

Example: Factory preset number 67 (decimal) is translated to bytes 43 (LSB) and 00 (MSB).

Example: User preset number 48 (decimal) is represented as bytes 14 (LSB) and 01 (MSB).

Data Packing (24-bit words to 4x7-bit bytes)

Data is packed to represent a 24-bit value as 4 bytes of 7 bits each, as SysEx data is limited to 7 bits per byte. The first three bytes hold bits 0-6, 7-13, and 14-20 of the 24-bit value, respectively. The fourth byte holds bits 21-23 as LSBs with remaining bits as zeros.

Example: A 24-bit parameter value of 0x266 is represented as 66 04 00 00 in a SysEx package.

Decoding:

• Byte 1: 66 hex = 1100110 (abcdefg)
• Byte 2: 04 hex = 0000100 (hijklmn)
• Byte 3: 00 hex = 0000000 (opqrstu)
• Byte 4: 00 hex = 0000000 (****vwx)

Final 24-bit Value: vwxopqrstuvwxyzabcdefg (0x000266)

Message Data Format

The format of data used in different SysEx messages varies. Below are descriptions for each message type.

SysEx Message Types and Identifiers

VoiceWorks Data Request Messages

Preset Request (45)

<Data>: 2 bytes representing the requested preset number (see Preset Numbers section).

Parameter Request (47)

<Data>: 2 bytes. The first byte defines the parameter group, and the second byte identifies the parameter within the group.

Shift Map Request (51)

<Data>: 1 byte. The value is ignored. The response will be a Shift Map Data message.

Song Request (14)

<Data>: 1 byte specifying the song number (0 is the first song). The response will be a Song Data message.

Setup Map Request (15)

<Data>: 1 byte. The value is ignored. The response will be a Setup Data message.

VoiceWorks Data Messages

Preset Receive Notification (34)

<Data>: 1 byte. 1 indicates success, 0 indicates failure. This message is sent after receiving a SysEx preset to confirm successful storage.

Preset Data (20)

<Data>: 388 bytes organized as:

• 2 bytes: Preset number
• 12 bytes: Preset name (ASCII characters)
• 1 byte: Number of notes in custom scale
• 16 bytes: Custom correction scale (uses data packing)
• 64 bytes: Custom shift map for each voice (uses data packing)
• 292 bytes: 73x24-bit values for each parameter (uses data packing)
• 1 byte: Checksum of the data marked 'cs'

Custom Correction Scale: Represented internally as 12x8-bit values packed into 4x24-bit words. An offset of 0x32 is applied before packing. The SysEx data is created by packing these words into 7-bit bytes.

Custom Shift Maps: Represented internally as 4 sets of 12 values, each specifying a shift amount. An offset of 0x32 is applied before packing into 4x24-bit words. SysEx data is created by packing these words into 7-bit bytes.

Checksum: A 1-byte value representing the 7 least significant bits of the sum of all bytes contributing to the checksum.

Parameter Data (22)

<Data>: 4 bytes. The first two bytes identify the parameter (group and ID). The last two bytes represent the parameter value as a 14-bit 2's complement signed value.

Example: Control Voice #4 bypass state.

F0 00013800 4C 2200440000 F7

• F0: SysEx start
• 000138: TC-Helicon manufacturer ID
• 00: SysEx Device ID
• 4C: VoiceWorks model ID
• 22: Message Type (Parameter Data)
• 00: Parameter Group ID
• 44: Parameter ID (Voice #4 bypass state)
• 0000: Parameter Data (Value 0, decimal)
• F7: SysEx end

Shift Map Data (31)

<Data>: 48 bytes. Each byte represents the shift mapping for a chromatic scale note. Values range from 0 (-24 semitones) to 36 (+24 semitones), with 30 (48 decimal) for +24 semitones and 36 (54 decimal) for N/C (no change). This format is easier to read and manipulate than when included in a preset dump.

Song Data (12)

<Data>: 138 bytes. Includes song number, 16-byte song name, 120 bytes of song data (30 steps x 4 bytes/step), and a 1-byte checksum.

24-bit Word Step Format: aaaaaaaaddddbbbbbeeecccccc

• a: Preset number
• b: Root
• c: Type (chord or scale number)
• d: Mode (scale=0, chord=1, shift=2, notes=3)
• e: Status (0x2 for active, 0x0 for end)

Setup Data (13)

<Data>: 197 bytes. Contains 49 setup parameters packed into 196 7-bit bytes, followed by a checksum byte.

Parameter Grouping and Listing

Preset Parameters (Group 0)

* For Harmony Mode dependent parameters, see the VoiceWorks Manual for details.

Setup Parameters (Group 1)