Hi!
Recently I've been having trouble with Synthesia - when I start playing, many notes just remain being pressed on screen and I can't continue playing because the app doesn't recognize the other keys I press. Everything worked just fine for the last 3 months and now, out of the blue, this problem occured. I have an 88-key flexible roll-up synthesizer (https://www.ebay.com/itm/272979879988) and a brand new USB-MIDI cable, bought in a music store, it is said to be of good quality.
Please help me, I was finally getting to the good stuff in my piano playing...
Endless tones preventing me from learning
When describing problems, always mention your OS and game version (shown at the bottom of the title screen).
If your keyboard has USB or MIDI ports, there is a tremendously high chance (>99%) it will work with Synthesia. See what you'll need on the keyboards page.
If your keyboard has USB or MIDI ports, there is a tremendously high chance (>99%) it will work with Synthesia. See what you'll need on the keyboards page.
I haven't heard much about roll-up pianos (more bad than good, unfortunately) but it doesn't strike me as unreasonable given the rubber nature of material, that continuous use over several months wouldn't simply cause it to start breaking down. I wonder if they don't just have a shorter shelf life than "real" digital pianos.
That said, it doesn't hurt to double-check. Does your USB-to-MIDI adapter look like this one or like any of these?
That said, it doesn't hurt to double-check. Does your USB-to-MIDI adapter look like this one or like any of these?
I really don't have space for a real piano or even a keyboard right now so roll-up piano was a great idea... I would love to have the real thing one day but right now I really can't put it anywhere... When I play without Synthesia, I have no trouble, everything sounds as it should... My cable doesn't look like any of those you showed me... So I guess I will have to freestyle then or use music sheets? Damn, I really liked Synthesia... 
The best guess, based on very little information, is that the keyboard is going bad. But it is probably worth a bit more investigation before you give up. The fact that the keyboard plays properly in stand-alone mode is hopeful. I would expect MIDI Out and the stand-alone to both fail if it is a keyboard problem.
Does your MIDI-USB cable have an LED that flashes when you press a key? If so, do you get one flash when you press a key and a second flash when you release the key?
If you have a Windows computer, you could try using the free MIDI-OX to see exactly what MIDI messages are being sent by your keyboard. MIDI-OX take a bit of effort to understand at first, but it is a very useful tool for all kinds of things involving MIDI.
Since you bought the MIDI-USB cable at a music store, maybe they would help you by allowing you to try your keyboard connected to something with one of their MIDI cables and/or connecting one of their keyboards with your cable.
Does your MIDI-USB cable have an LED that flashes when you press a key? If so, do you get one flash when you press a key and a second flash when you release the key?
If you have a Windows computer, you could try using the free MIDI-OX to see exactly what MIDI messages are being sent by your keyboard. MIDI-OX take a bit of effort to understand at first, but it is a very useful tool for all kinds of things involving MIDI.
Since you bought the MIDI-USB cable at a music store, maybe they would help you by allowing you to try your keyboard connected to something with one of their MIDI cables and/or connecting one of their keyboards with your cable.
The flash means a MIDI message has passed through the cable. MIDI sends a Note On message when you press a key and a Note Off message when you release the key. So two flashes is a very hopeful sign that the two messages are being sent.
If you slowly play single notes, does Synthesia work properly? In other words, do the notes start hanging only when you play lots of notes quickly? Poorly designed MIDI equipment sometimes fails when you start throwing too many notes at it.
If you slowly play single notes, does Synthesia work properly? In other words, do the notes start hanging only when you play lots of notes quickly? Poorly designed MIDI equipment sometimes fails when you start throwing too many notes at it.