Thank you Eddie for you tutorial!

You're very welcome.

How do I change this 3rd parameter of my hex data?

What does the manual say those three bytes are?

This is the template I created from your tutorial.

F0 – Beginning of SysEx message
41 – Roland Manufacture ID
10 – Device ID
00 00 3C – Model ID (AX Synth)
12 - Command ID (DT1)

SS - Checksum start

1F 00 20 3F - Address

33 – Data
4F – Checksum

F7 – End of SysEx message



This MIDI Implementation from the manual about the LFO


** [Partial LFO]
+------------------------------------------------------------------------------+
| Offset | |
| Address | Description |
|-------------+----------------------------------------------------------------|


|# 00 04 | 0000 aaaa | |
| 00 05 | 0000 bbbb | |
| 00 06 | 0000 cccc | |
| 00 07 | 0000 dddd | Rate (0 - 1023) | | | | 0 - 1023 |


I does look like the value is 07H * (0-127) = 1023. But I don't know how to get a number that size into 1 hex byte.(?)

This is the command I'm using now but if I substitute 00 I only raise the LFO rate from 0% to 13%. If I change it to 01 I get from 13% to 26%.

F0 41 10 00 00 3C 12 SS 1F 00 20 6E [?? DT S1] F7


I'm stumped on how to manipulate a second variable.

Can you post a link to the User Guide? I need to see more info.

Here is the link to the midi data.

https://www.roland.com/global/support/by_product/ax-edge/owners_manuals/41a1363e-6e46-4068-9010-d912dc5af007/

10 – Device ID

Be sure that 10h is indeed your Device ID.

00 00 3C – Model ID (AX Synth)

This is wrong, according to the manual it should be 00 00 00 52 as shown on page 4 of the link you provided.

|# 00 04 | 0000 aaaa | |
| 00 05 | 0000 bbbb | |
| 00 06 | 0000 cccc | |
| 00 07 | 0000 dddd | Rate (0 - 1023) | | | | 0 - 1023 |

The clue to this part is the first paragraph in section 3 on page 6. (This is also called "nibbled data" as described in section 4 on page 20.)
Essentially, what you have to do is convert the value you want into hexadecimal and then split the 2 bytes into four nibbles and use those values as the least significant nibble of 4 bytes of data.
For example, the decimal value 1023 is 03FF in hexadecimal. Take each digit and use it as the second nibble in four bytes like this: 00 03 0F 0F
and the decimal value 1 is 0001 in hexadecimal, when nibblized it is 00 00 00 01

Let me know if this is not clear.

Yeah!!!!!! SUCCESS!!! THANK YOU MASTER YODA!!!!! (Eddie,MIDI Jedi!)

I needed to change my data type to accommodate for 4 bytes of data ... DT1: 4bit/4bit. It was set at DT0: 7bit.

I changed my variable to DT1: 4bit/4bit and set the range from 0-7 and now I have a precise LFO slider on my controller.

NOTE: The device ID correct. Roland only has a midi implementation document for the AX-Edge but all the parameters correspond to the AX-Synth as well.

I must study this nibble hex data ...

THANK YOU SO MUCH!!