Jan Meier's Crossfeed, Explained

If you have ever listened to a record mixed for speakers through headphones, you have noticed something subtle but unsettling. The stereo image feels too wide, too hard. Instruments that were meant to sit in space feel glued to either side of your head. Ping-pong panning from old records becomes borderline uncomfortable. That sensation has a name, and the fix has been around for decades.

The reason it happens is simple. When you listen to speakers, your left ear still hears the right speaker, slightly delayed and slightly filtered by the shape of your head. The same is true on the other side. That natural acoustic blending is what gives speaker playback its sense of space. Headphones bypass it entirely. The left signal goes to the left ear, full stop.

Jan Meier, a German engineer who has been making niche headphone amplifiers out of Bochum since the late nineties, built his name on fixing exactly this problem. His CROSS-FEED circuit, still printed on the front panels of Corda amplifiers, takes a little of the opposite channel, low-passes it, delays it, and mixes it back into each side at a reduced level. It sounds like a trick, but it works. Recordings stop feeling pinned to the skull and start feeling like they came from somewhere.

Digital implementations do the same thing with filter coefficients instead of capacitors. You choose a delay that matches a plausible speaker angle, a low-pass corner around the top end of where head shadow starts attenuating, and a mix level that sits six to twelve decibels below the direct channel. Tune those three knobs and you are essentially modelling a small room inside the headphones.

I added a proper crossfeed stage to the output tools in Zenteek because I wanted it for my own listening. Speaker-mixed albums, especially jazz and classical and almost anything from before the nineties, finally sound like they were supposed to - wide, but coherent, with a center that holds together.