Xequence and Roland Sound Canvas Problems

jwmmakerofmusic

I tried to use the forum search first, but I couldn’t find the answer to my issue.

I purchased Xequence and its “unlimited parts” IAP. I love the fact the pianoroll and arranger are reminiscent of Nanostudio in many aspects. I figured “since I already have the ‘all-in-one’ mixer (AUM), why not the ‘all-in-one’ MIDI sequencer”.

Anyways, one of the main goals with Xequence was to control Roland Sound Canvas for the explicit purpose of quickly marking down musical ideas and sketches (and then of course replace the sounds later given it’s VERY dead simple to reassign the MIDI output of Xequence). The problem is, either Xequence is sending unnecessary bank controller data, or Sound Canvas is misinterpreting something.

I make sure that background audio is on in Sound Canvas, autosleep is disabled, MIDI in is receptive, and only then do I select a sound. When programming the notes, the sound I selected reverts to something else. I have Piano 1, and it changes to an electric guitar. Later when I restarted both apps, I selected Piano 1, and the Sound Canvas snuck it over to Piano 2. It seems the sound selection switches the moment I enter the piano roll or I double-tap the “stop” button in Xequence (double-tapping kills any stuck notes).

I’ve tested controlling Sound Canvas with Auria and Cubasis, and everything worked fine. I tested Xequence with other apps (multitimbral, singular, and AUM), and everything worked fine. The issue is with pairing up Sound Canvas and Xequence. Could there have been a setting somewhere I might’ve missed? Which app is responsible for the kerfuffle? Any help and/or advice you can give me would be greatly appreciated. Thanks.

rs2000

You could analyze the Midi stream sent by Xequence using a Midi Monitor like Midi Scope, Midi Tool, Midi Wrench or, if you own AB3, Midiflow Monitor.

SevenSystems

@jwmmakerofmusic: Thanks for the report. Xequence doesn't "consciously" send any program or bank changes, however, there might of course be a bug. As a quick test, can you try disabling both "Panic on Stop" and "Always use Panic" in Settings -> MIDI / Recording and try if the problem persists?

EDIT: also try removing all controllers from the Xequence instrument (set them to "-")

jwmmakerofmusic

@SevenSystems said:
@jwmmakerofmusic: Thanks for the report. Xequence doesn't "consciously" send any program or bank changes, however, there might of course be a bug. As a quick test, can you try disabling both "Panic on Stop" and "Always use Panic" in Settings -> MIDI / Recording and try if the problem persists?

EDIT: also try removing all controllers from the Xequence instrument (set them to "-")

Hi there. I’m glad to hear back from you. So, I started a new MIDI project, set all of the settings to what you recommended, programmed the notes, opened Roland Sound Canvas, hooked the MIDI out from Xequence to Sound Canvas, played it back, and at first it played back the default piano voice (since I didn’t bother to select a different voice for this test). All of a sudden, I pressed “stop”, pressed “play” again, and the sound had changed to “whistle”.

So, it may have to do with the stop button or even double-tapping the stop button, even when the settings were changed as suggested. I am on iOS 11.1 on the iPad Pro 12.9” (2017) and 512gb. Thanks again for reaching out.

@rs2000 said:
You could analyze the Midi stream sent by Xequence using a Midi Monitor like Midi Scope, Midi Tool, Midi Wrench or, if you own AB3, Midiflow Monitor.

Which one would you say is your favourite mate? This could come very much in handy.

Purpan

Hi. Just to add that I've had the same issue with these two apps.

rs2000

@jwmmakerofmusic said:

@rs2000 said:
You could analyze the Midi stream sent by Xequence using a Midi Monitor like Midi Scope, Midi Tool, Midi Wrench or, if you own AB3, Midiflow Monitor.

Which one would you say is your favourite mate? This could come very much in handy.

I'd recommend to try Midi Scope first. Make sure you enable the correct virtual / "Network" MIDI port first and enable all messages (except RealTime) you'd like to see by activating the respective green check marks.

Samu

If iOS SoundCanvas behaves oddly it's time to make Roland aware of it
(The best you will get is a reply that the issue has been forwarded to the developers for an evaluation).

SevenSystems

I have done a brief check using MidiScope and have seen nothing out of the ordinary coming from Xequence: On stopping, it does send "All Notes Off" and "Reset All Controllers". There seems to be a "feature" in CoreMIDI though that also sends a "System Reset" (0xFF)... not sure if Sound Canvas chokes on that. Will investigate further when I'm back in the office!

hellquist

@jwmmakerofmusic said:

@rs2000 said:
You could analyze the Midi stream sent by Xequence using a Midi Monitor like Midi Scope, Midi Tool, Midi Wrench or, if you own AB3, Midiflow Monitor.

Which one would you say is your favourite mate? This could come very much in handy.

FWIW: My fave is "old" Midiflow, which also has this functionality and which doesn't depend on AB3.

SevenSystems

@jwmmakerofmusic @Purpan -- cannot currently reproduce this on iOS 10, will try on iOS 11 later.

Two more things to try:
1. Disable "MIDI Thru" in Xequence
2. Enable "Reset protection" in Sound Canvas

Purpan

I just tried those but it still didn't stop the program changes, alas. (I fully accept it's a Roland issue, of course, but I sem to recall it wasn't an issue in earlier versions of Xequence so I don't know if something's changed?)

SevenSystems

@Purpan @jwmmakerofmusic -- OK, just tried everything I could think of on iOS 11, and I still can't reproduce it.

Does this issue also occur with NO OTHER APPS running? No Audiobus, no AUM, etc... just Xequence and Sound Canvas?

If so, then could one of you send me the Xequence project where this occurs? (You can access it through the Files app). I can send you an email address via PM.

Thanks for the help in debugging.

jwmmakerofmusic

@SevenSystems

Hi again mate. So, I decided to record the screen.

https://www.dropbox.com/s/zl3haoytuo8jji5/Roland Sound Canvas and Xequence.mp4

I’m guessing background play audio doesn’t show up in a screen recording, but here’s the gist. Once I go back into Xequence after auditioning the sounds in Sound Canvas, I played the sequence twice which played back the cello sound. Then after tapping “stop” a few times in a row, I played the sequence back again. The third time through, it played back a piano. Sure enough, there’s the Piano 2 patch.

If you have access to Sound Canvas, be sure to follow the steps as shown in the video. Here’s the project file.

https://www.dropbox.com/s/4lzr82m1xtvdqj4/Test.xeq

Cheers, and good luck.

jwmmakerofmusic

@SevenSystems

For the sake of thoroughness, I decided to download Xequence and Roland Sound Canvas onto my iPhone SE (iOS 11.1, 128gb) to test things, and I can confirm that I have the same issue on there. Cheers mate.

SevenSystems

@jwmmakerofmusic @Purpan: Thanks very much for your help. I think I've found the issue, though it's a bit complex: There seems to be a buffer overflow (a programming error) in Sound Canvas, which leads to unpredictable behavior when it receives a lot of MIDI data at once (in your case, these were random program changes; in my case, I got random very low notes playing out of nowhere).

When you press Stop in Xequence while it is already stopped, it sends a MIDI "Panic" (128 Note-Off messages at once) to all instruments. This "overwhelms" Sound Canvas.

This behavior cannot be changed -- however, if you disable "Panic on Stop" and "Always use Panic" in Settings, it will not do this at any other time. So, for the time being, if you disable these two settings and avoid tapping Stop while already stopped, this should not happen. (hard to think of that all the time, I know...)

For the next update, I've implemented a workaround that detects Sound Canvas and never sends a Panic to it, which should fix the issue.

I would recommend using some kind of MIDI filter, but that's not possible unfortunately, because it isn't a specific MIDI event that's causing the problem, but the amount of MIDI events in a short amount of time. I don't think there's any kind of "rate limiting" filter available...

jwmmakerofmusic

@SevenSystems said:
@jwmmakerofmusic @Purpan: Thanks very much for your help. I think I've found the issue, though it's a bit complex: There seems to be a buffer overflow (a programming error) in Sound Canvas, which leads to unpredictable behavior when it receives a lot of MIDI data at once (in your case, these were random program changes; in my case, I got random very low notes playing out of nowhere).

When you press Stop in Xequence while it is already stopped, it sends a MIDI "Panic" (128 Note-Off messages at once) to all instruments. This "overwhelms" Sound Canvas.

This behavior cannot be changed -- however, if you disable "Panic on Stop" and "Always use Panic" in Settings, it will not do this at any other time. So, for the time being, if you disable these two settings and avoid tapping Stop while already stopped, this should not happen. (hard to think of that all the time, I know...)

For the next update, I've implemented a workaround that detects Sound Canvas and never sends a Panic to it, which should fix the issue.

I would recommend using some kind of MIDI filter, but that's not possible unfortunately, because it isn't a specific MIDI event that's causing the problem, but the amount of MIDI events in a short amount of time. I don't think there's any kind of "rate limiting" filter available...

That’s a pretty cool workaround. Thanks for your hard work mate.

Purpan

Yes, thanks very much indeed.

rs2000

So this only happens when STOP is hit twice?
Rate limiting is in Xequence itself, it's in the developer's hand

SevenSystems

@rs2000: If what you guys are seeing is the same as what I was seeing (and which went away as soon as I disabled the panic), then yes, this should only happen if you hit Stop when Xequence is already stopped, AS LONG AS "Always use Panic" and "Panic on Stop" are disabled.

This is all pretty intricate stuff to maximize compatibility with buggy MIDI receivers, which don't always react to the proper "All notes off" message correctly. Maybe a flowchart can help:

• When "Stop" is tapped while Xequence is stopped, a Panic is ALWAYS sent to all instruments.
• When "Stop" is tapped while Xequence is running, a Panic is sent to all instruments ONLY IF "Panic on Stop" or "Always use Panic" are enabled. Otherwise, a normal "AllNotesOff" is sent.
• When Song position is changed while playing, only an "AllNotesOff" is sent.
• When the song is edited during playback, a Panic is sent to all instruments potentially affected by the edit IF "Always use Panic" is enabled, otherwise, "AllNotesOff" is sent.

This may seem crazy, but believe me, you don't want hanging notes while composing and this list makes it pretty damn sure that it doesn't happen!

EDIT: Yeah, I could of course rate-limit the 128 note off events, but I always assume that all other software is bug-free!