Grid whine. Expected behavior?

  • Just curious.

    In an effort to use less stuff, I've been utilizing the built-in output on an 11" MacBook Air to route Sum or Meadowphysics or whatever into aleph. When I do do this I end up with an earful of grid whine. Is this the expected behavior of the built-in output?

    My audio interface doesn't make this sound when it is the primary output, but it limits my routing ability to use it this way.

    Just curious.

  • I have similar problems when I use certain gear together, and it's usually down to grounding. I have an ungrounded extension cable and that usually works. The other way I've found of solving it is just charging the macbook before my session and unplugging it when making music!

  • the grid pulls a lot of current, and the high frequency refresh can bleed into other power systems in some cases. check for ground loop conditions. lift power, change where things are plugged, try sharing a power strip, etc. last option is to use an ext5v to externally power the grid and effectively isolate it, but you'll need to figure out the proper grounding there too. if you don't have an ext5v i have heaps here.

  • this does seem particularly strange though. @tehn uses that same computer & i'm certain does not have issues with grid power noise in the power supply.

    i've occasionally experienced what kineticmonkey is talking about at gigs with huge lighting systems, but never in a domestic environment with relatively low current conditions.

    does the whine worsen when the grid has more lights turned on? could it be simply an existing ground problem that exists even without the grid attached?

  • I usually also have a guitar or bass amp on at the same time...