... searched the forum and seen Airfoil is usually suggested as a way to stream audio but... can't find a feedback confirming/denying it actually works fine with Decibel
Works as well as it can. Doesn't work as well as Airplay does with iTunes, or the hacked API Swinsian uses.
My experience is wireless: files are on a USB2 Western Digital hard drive connected to Airport Extreme, connected to an Airport Express via Cat5, AirportExpress to stereo via RCA cables - music player (Decibel, Cog, Audirvana, etc. via Airfoil or Swinsian/iTunes via Airplay) on laptop wirelessly talking to Airport Extreme. Best file to test I've found is Close to the Edge by Yes. It begins with silence leading to a steady crescendo (yeah, I know that's redundant) of birds tweeting at about 1:00 into playing, at which point there's this HUGE burst of the band in full. No matter the player, if it's through Airfoil there's up to 2 seconds of silence at that moment then various hiccups. If playing ALAC in iTunes or FLAC in Swinsian it's flawless.