The stunning Bacch SP sound processor

Recreates real 3D sound in regular loudspeakers

Here’s an inconvenient truth: however good your hifi is, stereo is always a compromise. The recording method, which has been around since the early 1950s, corrupts the true 3D nature of sound as it’s meant to be heard by our direction-sensitive ears. With stereo, sounds meant for the right ear are heard by the left and vice versa.

To approximate how we hear real sound, a more rigid left-right separation is required. As an experiment, if you set up loudspeakers with a mattress perpendicularly between them – so the left and right speakers are fairly isolated from one another – and place your head against it, you will hear something surprisingly more spatial. That’s why headphones offer a more stereophonic experience – although also more artificial because they are clamped to your head.

So there’s much excitement in über-audio circles at the moment over a new (actually, old and revived) recording method called binaural; instead of music being funnelled into microphones for either a left or right channel, it is picked up by a single recording device that resembles a human head, with a mic in each ear. When you listen to a binaural recording, you can hear exactly where the musicians are, even if they’re behind you. It’s quite uncanny.


Over the past year, binaural albums have become available to download and play on a computer using any audio software and headphones. But an applied physics professor and audio innovator at Princeton University has taken binaural up a level. Edgar Y Choueiri has built a sound processor called Bacch Stereo Purifier, using software to recreate real 3D sound in regular speakers. The effect is like a spooky hifi hologram: shockingly real.

Spookier still is that Prof Choueiri has discovered that about 60 per cent of old recordings going back to the birth of stereo, even those on vinyl, have this 3D quality hidden within them. The Beatles’ Abbey Road Studio recordings, for example, have this 3D “pop out” and sound unbelievable on the Bacch.

Choueiri builds the Bacch at Princeton and it’s sold, so far, in one store in Manhattan and another in Hong Kong. I strongly recommend going to hear it, but his company, Theoretica, will also ship and install anywhere. The Bacch is extraordinary. If I had the price of quite a nice car to spend on a hifi accessory, I would buy it in a heartbeat.


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