Boss RC-500 and MC8 - Clear Function

Hi Everybody,

I’ve just finished my first programming session with the MC8. Before I get to my question, here are some shout-outs:

  • First to JohnPaulMusicUK for all the great youtubes on the Boss looper products. The one on the RC-500 and the MC8 really helped in this recent round! Here it is: []. Similarly, all of his responses both here and on his youtube channel are thoughtful and helpful. The man deserves a coffee!

  • Second, I REALLY want to appreciate AaronShortMusic for his excellent step-by-step RC-500 and MC8 youtube []. I just spent several hours replicating every step. It moved me a great deal toward understanding the workflow of the MC8.

  • Finally, thanks Morningstar, for a fantastic product and amazing support! I have to say that I fought with my KMI Softstep2 for months before giving up and availing myself of Sweetwater’s generous return policy. Morningstar is in a completely different category, even if the Softstep2 was a good design.

I was able to program in all of Aaron’s settings into the Morningstar online editor, except one. I’m set up with a home page and an RC-500 page. On the latter I can mem+, mem-, Rhythm play/stop, all start/stop, and trigger effects. But–and here is my question–I couldn’t get the clear function to work. I’ve pasted screenshots of the Morningstar MIDI Editor below.

The 4 Msgs displayed in the screenshot are supposed to 1) scroll up; 2&3) pause twice; & 3) scroll down, resulting in a clear function workaround since Boss has not provided a more straightforward clear function. When I trigger this in RC500 memory #36 (the one with all of my Morningstar template edits), it does not clear the #36 memories, and instead jumps me to RC500 memory #2. I’ve obviously missed something, but I’ve been poking around and can’t tell what. This was the procedure Aaron laid out in his youtube referenced above, though I messed around with the upper and lower preset limits. Otherwise I think I followed all the steps. I also went back through the settings he identified for the RC500, and I think they match. I’m posting this to AaronShort’s Youtube as well, but it seemed fair to post it here as well. Any ideas?

Thanks again, All! Whatever the result of the clear question, I feel like I can start experimenting on the MC8 now. I’m really looking forward to setting up my MC8 with Ableton Live!

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Hello @Firstinversion.
You just posted a image of the first message so I’ll try to guess the rest from your descrition.
First of all, Aaron and you should use PC Number Scroll / Increse By 1 and Send instead of PC Scroll Up because it gives you greater flexibility. Now the problem.
It seems to me that your Counter slot 0 has been initialized with value 1 and so if you send a message’ PC Number Scroll / Increse by 1 and Send’ the result will be sendind a PC2 that puts the RC-500 in memory 2. If you scroll up until you reach memory #36 before you test, I think it will work.
Let me tell you that there are Clear messages in RC-500 to do the job:
T1 CLEAR, T2 CLEAR, CUR CLEAR. The problem is that you only can ASSIGN 8 witch is very little for implementing all funtions needed.
Hope this helps.

Hey XLooper, and thanks!

I messed around for awhile, but no matter what I tried, the MC8 always jumped back to memory #2 instead of decreasing or increasing by 1 memory. Even with your suggestions, I haven’t been able to get past that in an effort to clear both RC500 tracks with one press. I’ve been trying to stack T1 clear & T2 clear on to one bank preset. I added delays of 1260 ms to give the RC500 time to adjust to the second clear command. But, I couldn’t get it to take effect. I’m probably out of my depth, trying this particular debug, and may go back to something simpler until I get a better sense of the MC8’s workflow.

I do see what you mean about the assign slots getting used up quickly. Well, it’s better than 2 or 3 I suppose.

Thanks for trying!

–Adam H.

Hey XLooper,

I am just following up to continue learning how to do things in this area of the MC8/RC500. Honestly, I am just trying to find my way around. I tried just doing a simple clear selected track. Nothing happened. I used just 1 message. My settings for Bank 2, preset A:

Msj 1:

Action: Press
Type: Control Change
Pos: Both
cc#: 2
cc value: 127

On the RC500, I chose Assign 2:

cc#: 2
SRC mode: Moment
Target: Cur Clear
Target Min: —
Target Max: —

My RC500 is set to receive on Channel 2
I have a midi cable plugged into the MC8’s multiport #1, and the other end plugged into the RC500’s midi IN. Nothing is plugged into the RC500’s midi out.

Also, I want to note that controlling the following from the MC8 are working fine: Rhythm Play/Stop, All Start/Stop, Rhythm Variation, and Trigger Fx.

Any ideas?


Hi again @Firstinversion. Now I’m figuring what’s your problem.
Saddly, this information isn’t in any Boss publication.
Be aware that some Boss funtions (REC/PLY, PLY/STP, UND/RED, CLR) need two CC steps to complete with values 127 and 0. Others like TRK SELECT use just one CC (with value 0 to track1 and value 127 to track2).
So, in your case you should send the following messages with Press A
Msj 1: Press CC 2 127
Msj 2: Press CC 2 0

To clear all the track with one press. In Boss you ASSIGN
In MorningStar controler we should have the messages
CC3 0 (select track 1)
CC2 127 (clear track)
CC2 0
CC3 127 (select track 2)
CC2 127 (clear track)
CC2 0

Now you have open field to do incredible things with your MC8 and RC500.
The imagination is the limit :crazy_face:

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Hi José,

This use case is working really well to help me understand the MC8’s programming language. Thanks so much for your steps, and for knowing the unpublished idiosyncrasies of non-Morningstar products! I’ve done some experiments, and have a few followup questions.

First, I tried the simple clear track function, and it now works, using the cc 127/0 combo. It also helps for me to know that inserting multiple press action messages does not mean that I have to press the MC8 button multiple times :-)!

Then I tried the more complex “clear all tracks” experiment. Following all directions, I got the RC500 to clear the first track with one button press, but not the second track. Any ideas? I have one. I’ve heard that the RC500 sometimes needs a delay inserted between message instructions to recognize that a second instruction is being given. If this is the issue, in the Morningstar online editor, how do I insert a new blank message between two established messages?


You’ll need to use a Delay message, which pauses the MC8 for a defined period of time before it resumes executing commands.Start with 100-150 ms, and increase the time if necessary until the RC500 successfully registers both Clear Track commands.

Thanks! I understand that part, but how do I insert a new message line between two established message lines?

Click-and-drag a blank message up from below the existing messages; pretty much anything that the Web Editor presents in list form can be reordered this way.

I am entering the delays, but am getting no results. To give you more data, I have entered the instructions you gave below, assigning a msj # to each. I inserted delays between 2&3, 3&4 with no effect. I started with low milliseconds (100-150), and increased to max 1260, all with no change to the attempt to clear track 2.

In MorningStar controller we should have the messages

  1. CC3 0 (select track 1)
  2. CC2 127 (clear track)
  3. CC2 0
  4. CC3 127 (select track 2)
  5. CC2 127 (clear track)
  6. CC2 0

Any suggestions?


Let’s start by simplifying. We know from your previous experiments that the message 1-3 combination works to select and clear track 1. If you add message 4 to the preset, but not messages 5-6, does the preset successfully clear track 1 and select track 2?

OK, after reviewing the above chain of postings and the RC500 manual more closely, I think I might see what the problem is. The TRK SELECT command doesn’t allow you to select individual tracks directly - it toggles the selected track when activated. So if you’re on T1, activating TRK SELECT changes to T2, and vice versa. With that in mind, try this sequence of commands:

  1. CC2 127
  2. CC2 0
  3. CC3 127
  4. CC3 0
  5. CC2 127
  6. CC2 0
  7. CC3 127
  8. CC3 0

Here’s the logic: each pair of commands simulates a button press (value 127) and release (value 0). You want to clear both tracks and end on the track that was selected when you started. So, first we clear the currently-selected track (commands 1 and 2). We then use TRK SELECT to change to the other track (commands 3 and 4). We clear that track (commands 5 and 6) and then use TRK SELECT again (commands 7 and 8) to get back to the track that we started from.

Sorry it took so long for me to wrap my head around this - I’m not familiar with the RC500, so I should have just followed my usual strategy and RTFM’d before I started shooting my mouth off. :grinning: Based on the manual and Aaron’s video, I think this will work. Try it out and let us know!

Thanks so much for trying! The logic makes sense, but sadly I got no change. I’ll lay out a bit more of my process, in case it may help. I start with loops on Tr1 & Tr2. I press All Start/Stop to assure they are there. The white leds on each channel indicate that they are present. I created a new preset with your updated 8-msj string. I pressed All Start/Stop again to stop all tracks. Then I pressed my new Clear All command. I got the same result I’ve been getting since Xlooper’s reply 11 hrs ago: Track 1 has been erased. Track 1 is selected. Track 2 still holds data and will play if I trigger it. I did confirm that all midi channels on the new clear all preset are the same: channel 2, which is the receive channel on the RC500. If it helps, in the Morningstar editor, the Position is Both in all cases. Also, every action is a press, except before responding I also tried entering delays between steps 2&3 & steps 5&6, just to see if they would have any effect. Both were 1260 ms. I also tried all of these things both with the MC8 in edit mode, and also out of edit mode. I’m stumped.

OK, so we have some data: we know the Clear Selected Track command works. (You were on Track 1 when you engaged the preset, right?) Next thing I would try is to just put messages 3+4 in a preset by themselves and see if they toggle the selected track. If not, try just message 3. That might give us a better indication of the stumbling block.

EDIT: It wouldn’t hurt to double-check that the Assign setting for TRK SELECT is in fact on Momentary, just to rule that out as a potential source of error.

I will post a photo of my tested preset in next post.

Ok. This preset works and is exactly what I posted earlier.
@celticelk is wrong about messages for TRK SELECT. Also don’t need delays.
I bet that you forgot to program the ASSIGN CC #3 TRK SELECT on the RC-500 memory where you’re making the test or If you did it, you didn’t save it.
Can you verify it?

Well, it wouldn’t be the first time I was wrong. :grinning_face_with_smiling_eyes: That’s not how the RC500 parameters manual describes the function, though. Does BOSS just have bad documentation generally?

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The Parameters Manual doesn’t say nothing about what values to use on CC#.
Did you tested what you’re saying?

Yes, BOSS generally has bad documentation. It didn’t stop me from using their stuff because it is very reliable.
During my testing I found that the Parameters Manual is missing the command CUR PLY/STP. It exists on the RC-500 and works fine. Allready reported to Boss.

Well, Drat. XLooper you were correct that somewhere along the line I switched the ASSIGN CC #3 TRK SELECT on the RC500 to another clear command. I just updated to your last instructions, and indeed it works perfectly. Thanks both of you for bearing with me! What I do get out of it is a very basic understanding of how to sequence MC8 commands, along with a model for how approach ongoing programming. This is far more than I ever got from Keith Macmillen Instruments, which is why I finally returned the Softstep2. So, your time has yielded a happy customer. I promise to post good reviews in the places I inhabit!

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