Filter
Top Products
Chapter 8. Appendix
208
How to calculate the checksum (hexadecimal numbers are indicated by 'H')
The checksum is a value derived by adding the address, size and checksum itself
and inverting the lower 7 bits.
Here's an example of how the checksum is calculated. We will assume that in the
exclusive message we are transmitting, the address is aa bb ccH and the data or
size is dd ee ffH.
aa+bb+cc+dd+ee+ff = sum
sum ÷ 128 = quotient ... remainder
128 - remainder = checksum
<Example 1> Setting REVERB MACRO to ROOM 3
According to the "Parameter Address Map," the REVERB MACRO Address is 40 01
30H, and ROOM 3 is a value of 02H. Thus,
F0 41 10
42 12 40 01 30 02 ??
F7
(1) (2) (3) (4) (5) address data checksum (6)
(1) Exclusive Status, (2) ID (Roland), (3) Device ID (17),
(4) Model ID (GS), (5) Command ID (DT1), (6) End of Exclusive
Next we calculate the checksum.
40H+01H+30H+02H = 64+1+48+2 = 115 (sum)
115 (sum) ÷ 128 = 0 (quotient) ... 115 (remainder)
checksum = 128 - 115 (remainder) = 13 = 0DH
This means that F0 41 10 42 12 40 01 30 02 0D F7 is the message we transmit.
<Example 2> Requesting transmission of the LEVEL for DRUM MAP 1 NOTE NUM-
BER 75 (D#5; Claves)
NOTE NUMBER 75 (D#5) is 4BH in hexadecimal.
According to the "Parameter Address Map," LEVEL of NOTE NUMBER 75 (D#5;
Claves) in DRUM MAP 1 has an Address of 41 02 4BH and a Size of 00 00 01H.
Thus,
F0 41 10 42 11 41 02 4B 00 00 01 ?? F7
(1) (2) (3) (4) (5) address size checksum (6)
(1) Exclusive Status, (2) ID (Roland), (3) Device ID (17),
(4) Model ID (GS), (5) Command ID(RQ1), (6) End of Exclusive
Next we calculate the checksum.
41H+02H+4BH+00H+00H+01H = 65+2+75+0+0+1 = 143 (sum)
143 (sum) ÷ 128 = 1 (quotient) ... 15 (remainder)
checksum = 128 - 15 (remainder) = 113 = 71H
This means that F0 41 10 42 11 41 02 4B 00 00 01 71 F7 is the message we trans-
mit.
● About tuning
In MIDI, individual Parts are tuned by sending RPN #1 (Master Fine Tuning) to the
appropriate MIDI channel.
In MIDI, an entire device is tuned by either sending RPN #1 to all MIDI channels
being used, or by sending a System Exclusive MASTER TUNE (address 40 00
00H).
RPN #1 allows tuning to be specified in steps of approximately 0.012 cents (to be
precise, 100/8192 cent), and System Exclusive MASTER TUNE allows tuning in
steps of 0.1 cent. One cent is 1/100th of a semitone.
The values of RPN #1 (Master Fine Tuning) and System Exclusive MASTER TUNE
are added together to determine the actual pitch sounded by each Part.
Frequently used tuning values are given in the following table for your reference.
Values are in hexadecimal (decimal in parentheses).
+--------+--------+--------------+-------------------+
|Hz at A4| cent | RPN #1 | Sys.Ex. 40 00 00 |
+--------+--------+--------------+-------------------+
| 445.0 | +19.56 | 4C 43 (+1603)| 00 04 0C 04 (+196)|
| 444.0 | +15.67 | 4A 03 (+1283)| 00 04 09 0D (+157)|
| 443.0 | +11.76 | 47 44 (+ 964)| 00 04 07 06 (+118)|
| 442.0 | + 7.85 | 45 03 (+ 643)| 00 04 04 0F (+ 79)|
| 441.0 | + 3.93 | 42 42 (+ 322)| 00 04 02 07 (+ 39)|
| 440.0 | 0 | 40 00 ( 0 )| 00 04 00 00 ( 0)|
| 439.0 | - 3.94 | 3D 3D (- 323)| 00 03 0D 09 (- 39)|
| 438.0 | - 7.89 | 3A 7A (- 646)| 00 03 0B 01 (- 79)|
+--------+--------+--------------+-------------------+
<Example> Set the tuning of MIDI channel 3 to A4 = 442.0 Hz
Send RPN#1 to MIDI channel 3. From the above table, the value is 45 03H.
B2 64 00 MIDI ch.3, lower byte of RPN parameter number : 00H
(B2) 65 01 (MIDI ch.3) upper byte of RPN parameter number : 01H
(B2) 06 45 (MIDI ch.3) upper byte of parameter value : 45H
(B2) 26 03 (MIDI ch.3) lower byte of parameter value : 03H
(B2) 64 7F (MIDI ch.3) lower byte of RPN parameter number : 7FH
(B2) 65 7F (MIDI ch.3) upper byte of RPN parameter number : 7FH
● The Scale Tune Feature (address: 40 1x 40)
The scale Tune feature allows you to finely adjust the individual pitch of the notes
from C through B. Though the settings are made while working with one octave, the
fine adjustments will affect all octaves. By making the appropriate Scale Tune set-
tings, you can obtain a complete variety of tuning methods other than equal tem-
perament. As examples, three possible types of scale setting are explained below.
❍ Equal Temperament
This method of tuning divides the octave into 12 equal parts. It is currently the most
widely used form of tuning,
especially in occidental music. On this unit, the default settings for the Scale Tune
feature produce equal temperament.
❍ Just Temperament (Keytone C)
The three main chords resound much more beautifully than with equal tempera-
ment, but this benefit can only be obtained in one key. If transposed, the chords
tend to become ambiguous. The example given involves settings for a key in which
C is the keynote.
❍ Arabian Scale
By altering the setting for Scale Tune, you can obtain a variety of other tunings suit-
ed for ethnic music. For example, the settings introduced below will set the unit to
use the Arabian Scale.
Example Settings
Note name Equal Temperament Just Temperament (Keytone C) Arabian Scale
C0 0 -6
C# 0 -8 +45
D0 +4 -2
D# 0 +16 -12
E 0 -14 -51
F 0 -2 -8
F# 0 -10 +43
G0 +2 -4
G# 0 +14 +47
A 0 -16 0
A# 0 +14 -10
B 0 -12 -49
The values in the table are given in cents. Refer to the explanation of Scale Tuning
on page 198 to convert these values to hexadecimal, and transmit them as exclu-
sive data.
For example, to set the tune (C-B) of the Part1 Arabian Scale, send the data as fol-
lows:
F0 41 10 42 12 40 11 40 3A 6D 3E 34 0D 38 6B 3C 6F 40 36 0F 76 F7