Sign in with
Sign up | Sign in
Your question

USB cable quality confusion

Last response: in Computer Peripherals
July 25, 2010 4:06:47 AM

Hey, here's a problem I've been having lately:

I have a keyboard hooked up to my pc via USB to do some music production. The setup works fine with the USB cable that it came with. But since it's only about 1.5 meters long I purchased a 3 meter cable to replace it. but the performance is terrible: the notes get stuck and wont stop playing when I stop pressing a key/s.

Now from what I've read the MIDI protocol that the keyboard uses to comunicate with the PC sends out "MIDI messages" for every time you press a key and everytime you release it (1 MIDI "Note On" message & then 1 MIDI "Note Off" message for every note played). My problem is that with the longer cable the "Note Off" message doesn't make it to the PC (or gets misinterpreted) so the note keeps playing.

I've read some more on this matter but I don't want to bore you with the details if they're not required, the main thing that bugs me is could the change from 1.5 to 3 meters really explain such a performance hit? I'm really hoping that the quality of the cable is the issue since it's a no-name brand, but I dont want to go buy a better/more expensive cable if that's not the problem.

Any clues???
July 25, 2010 9:27:49 AM

Apparently the max length is 5metres so if you have added the 3 metre cable to the 1.5 metre you are approaching the limits. But if you've only substituted the 3 for the 1.5 the issue may be with the new cable.

Try swapping it in case it's faulty (unlikely with just 4 conductors plus shielding) or badly shielded. Maybe go for a slightly shorter one just to be safe.
July 25, 2010 8:38:27 PM

Thanks for the input! You were right the 2nd time: the 3 m cable is a replacement of the 1.5 since it's just too short for my setup.

Ok I'll try another cable... (Admittedly the 3 m one i bought didn't have the certified USB2.0 logo on it, I didnt notice it at the time, maybe that's the issue)

Anyway, i'm thinking that maybe there are different kinds of USB cables geared towards "live" use - that is, where the errors in the transmission are as few as possible so that the signal reaches the PC as fast as possible without data confirmation or whatever the USB protocol uses to confirm data integrity. It's just a hunch, but I suspect that in situations where the data stream is constant and meant to be processed live, the error correction should be kept to a minimum, if it is bypassed for that matter.

Any thoughts?? Are there such cables for "live" use?
July 25, 2010 9:18:51 PM

I honestly don't know, MIDI remains a mystery to me.