I just bought a used Macbook and connected it to an old Kawai Digital Piano via Midi to USB, but the midi signal barely works.
I am sure I got the connection right, since the mac can read some of the midi signals.
The test results below are tested with the MIDI Message Monitoring tool within MainStage 3.



The Problem
A note message can only be received after hitting the same key for several times.
No matter how many keys I pressed at the same time, only 1 midi message can be received by the computer.
(e.g. I hit C2,D2,E2 at the same time, the computer only receives D2)
What's worse is that once a key is ON, it never goes OFF. (Keys are stuck as shown in the pic below)



Which one is likely to be the point of failure?
1) Used Macbook Air 2012 4GB Ram with loose USB port
2) Weird Looking Midi to USB cable
3) Very old Kawai L1 Digital Piano with loose key action

5€$ MIDI-USB adapters are known to cause problems. I have even read about pedals information transformed to notes... just a flipped bit. (https://www.steinberg.net/forums/viewtopic.php?t=115252)

You may perhaps switch to a 30$ adapter (M-Audio MIDI sport)...


But I can’t promise it would solve the issue.

The USB port of the Mac can be tested with a USB drive.

Does the piano only have midi ports or is there a USB to host option as well, if so might try that with a standard printer USB cable to try it out.

A powered usb hub could solve it - have had the same issue.

I’ve read that American alphabet agencies have the ability to remotely interfere with USB connections. Probably using some form of EMF, but possibly with some technology we don’t know about.

If you have pissed off the NSA lately, you are just out of luck getting your VIs to work!

LOL!

see if your computer software has midi setup, be sure you don't have unwanted filters enabled. If the piano is playing normally despite the loose action, then the cable or computer / software would likely be at fault. If the computer is old, maybe the contacts for the midi out are oxidized. Also be sure the midi cable has the correct midi-out and midi-in pairing, since either connector can be put in either jack, and if reversed would either not work or possibly work erratically. So the port labeled midi-out on the piano should accept the midi-in plug and the reverse likewise for the other port.

From my personal experience, it’s most likely ‘2) Weird Looking MIDI to USB Cable’. I’ve always had problems with cheap converter cables like that and avoid those like the plague. I’d test other MIDI connection solutions first to see if it solves the problem. (i.e. Better cable, powered hub, or MIDI through an audio interface).

Note: From the Kawai L1 keyboard manual, looks like there is no ‘USB to Host’ port, only the two 5-pin MIDI DINs. https://www.kawaius-tsd.com/OM/DIGITAL/L1.pdf

I purchased an audio interface from Amazon that looks virtually identical. These seem to be sold under different brands sometimes with very minor differences.

Mine works fine. But there were a massive number of "reviews" complaining about flakey operations. When I purchased the interface, I assumed 50% probability of it working and got lucky.

Just bought a cheap (but cute) headphone amplifier, with a similar plethora of bad mentions on Amazon...mine seems to be fine. I expect most of an item's satisfied customers wouldn't be provoked into posting a "review".

EDIT--BTW Newer, belated thanks for your Elitebook 8460P tip (for Pianoteq) a while ago. Got one cheapish, works good, no glitches.

Agreed. It's best to stick with a branded MIDI to USB cable from Yamaha, Roland, M-Audio, etc.

Kind regards,
James
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I also have two of those Amazon cheapo USB-to-MIDI adapters, they have worked just fine for me. One is on my vintage KX88, the other on my old Alesis QS8 (I love both actions). I totally forget they are there unless I see their little lights blinking away, which is a good sign.

Update:
It's because of the cheap MIDI interface.
I bought a 4x more expensive Roland MIDI interface and everything works fine now.....
Thanks for all the advice.

Thanks for the update.

Glad to hear that the more expensive, branded interface works properly.

Kind regards,
James
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