i2m Musicport has never worked properly

The i2M musicport™ MIDI Converter & Hi-Z USB Audio Interface

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james
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Re: i2m Musicport has never worked properly

Post by james »

"Can you PM me your details" - how to understand (translate)?
Using the forum tools. You can click on the "PM" button and it will let you send me a private message. Then you don't need to post your details on the public forum.
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james
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Re: i2m Musicport has never worked properly

Post by james »

When you do this:
1. run the Sonuus I2M musicport - device is found - push the button"setup" - push the button"update firmware" , and select the i2M_musicport .sfu firmware update file.
2. flashing red
3. immediately gives an error and a flashing red on
After you click "update firmware" and select the update file, the editor should open the firmware update utility. If the firmware update utility hasn't been installed, the firmware update can't be done, so it will error to say it has failed. Make sure you have downloaded and installed the Sonuus firmware updater.

Here's what the firmware update utility looks like:

http://www.sonuus.com/images/FirmwareUpdater.png
Dmitry
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Re: i2m Musicport has never worked properly

Post by Dmitry »

Everything turned out! Thank you very much! I tried to update via the editor) it's my fault. now it works! :D
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james
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Re: i2m Musicport has never worked properly

Post by james »

Great. Thanks for letting me know.

We have plans to add a better error message to the i2M editor when it can't find the firmware loader (out other Editors do that now). Sorry for it confusing you.
Godfrey
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Re: i2m Musicport has never worked properly

Post by Godfrey »

Hi James
Just in case you haven't spotted it, I've emailed the files you asked for.
Thanks
G
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james
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Re: i2m Musicport has never worked properly

Post by james »

Hi Godfrey,

Yes, thanks. Actually, I'm looking at them right now and was going to get a reply together for you as soon as I can.

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james
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Re: i2m Musicport has never worked properly

Post by james »

Godfrey,

I have looked at the files you sent, and mostly the MIDI conversion looks good -- though I haven't carefully checked each note to check it is exactly as was played.

The main problems seem to be between the notes. Often after a note is stopped, something keeps ringing (most likely a harmonic on that string, or a neighbouring string) at a large enough level, and for long enough that it appears like a perfectly valid note. So, the i2M generates MIDI for it. Of course, this note doesn't last long, so it stops as soon as the new note is played. The result is a MIDI "glitch", a short-duration MIDI note that you didn't expect, but was actually there.

See the images I've attached which show different examples I found in what you sent. The audio is at the top (top scale is in seconds.milliseconds) and MIDI at the bottom. It's hard to see the detail of the MIDI, but you can see enough for me to explain what is happening.

In NiceChange1.png, the signal cleanly stops between the notes and you get a nice result: two MIDI notes with no glitches.

In MessyChange1.png and MessyChange2.png, you can see lots of signal between the notes. The i2M assumes this is intentional and you get MIDI glitch notes (it can't look forward in time to realise it's a glitch).

In NoteCorrection1.png, you can see the start of the new note is a bit messy, then it settles down to a nice stable state. The i2M did a good job of detecting this note, but it looks like it was a semitone out, so once it settles the i2M corrects this. The result is a small glitch as it triggers the new note. If pitch-bend is on, you don't get this glitch because pitch-bend will be used to correct this and it will be inaudible.

Mostly, this is a result of the very low latency of the i2M. If a signal appears for a short time and the i2M can measure it, it will do so, even if it's only a few 10s of ms long. The easy way to avoid that would be to add 200ms of latency, but that would make it quite unusable!

For recording, rather than live use, sequencers often have tools that let you filter out short-duration MIDI notes. In this case, such a filter would let you process the MIDI to remove most of the glitches.

I hope this makes things a bit clearer?
Attachments
A messy change between notes. The ringing between the two notes causes a glitch-note to be detected.
A messy change between notes. The ringing between the two notes causes a glitch-note to be detected.
MessyChange2.png (14.76 KiB) Viewed 9108 times
A messy change between notes. The ringing between the two notes causes a glitch-note to be detected.
A messy change between notes. The ringing between the two notes causes a glitch-note to be detected.
MessyChange1.png (14.79 KiB) Viewed 9108 times
A note correction: the pitch at note-on was difficult to measure accurately, so it is corrected after a short time.
A note correction: the pitch at note-on was difficult to measure accurately, so it is corrected after a short time.
NoteCorrection1.png (14.55 KiB) Viewed 9108 times
A nice change between two notes.
A nice change between two notes.
NiceChange1.png (14.33 KiB) Viewed 9108 times
Dmitry
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Re: i2m Musicport has never worked properly

Post by Dmitry »

"Latensy Test Mode" sound the same as the miganiiem "Sonuus" green and yellow, but it does not match the output indicator in the editor. And another indicator of the entrance to the editor do not sunbathe while playing the guitar, and the only way out is delayed. So it should be?
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james
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Re: i2m Musicport has never worked properly

Post by james »

The MIDI indicators on the editor may not be perfectly in time with MIDI that is sent and received. It is not a low-latency connection from the editor to the i2M. Instead, these MIDI indicators will simply show that there is "something" being sent or received.

To check the MIDI timing, the Sonuus logo will flash at exactly the same time the MIDI test notes are sent. You have to use your ears to listen to what you hear in your sequencer and compare this to the Sonuus logo.
Godfrey
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Re: i2m Musicport has never worked properly

Post by Godfrey »

Hi James

Thanks for your reply regarding the sample audio and MIDI files I sent you.

I understand what you are saying about any bits of audio noise between the notes giving rise to false MIDI notes however, in practical terms that doesn't really solve my problem. I can't imagine there are many people who can play a bass as consistently cleanly as it appears the i2M requires to work properly, certainly not without having to intensely concentrate on that rather than the creative element of the music.

Also, putting aside the issue of unwanted notes for a moment, this does not explain the wrong octave detection of the main notes. The audio is a simple D major scale ascending and descending. The i2M converted the first two notes to MIDI in the correct octave but then dropped to an octave lower and was pretty much all over the place from there on. It is has not been uncommon during the time I've spent trying to get the i2M to work for me to play the same note twice and get a different octave each time?

The reason I bought the i2M (over 2 years ago now) was for the simple process of coming up with ideas for melody lines using my most familiar instrument, bass, and recording them into MIDI from where I would be able to process them further. Because of all these problems I have never been able to do that.
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