David Chesky is a well known in the audiophile community. An accomplished musician, composer, successful entrepreneur (with his brother Norman) and record producer of many wonderful recordings on the Chesky label. We’ve been friends for a long time…every since I started my label 14 years ago and we both would show up at the CES show or other audiophile events. We’ve been on panels together and share a love of contemporary music. It was great to see him again last week during the event at Jungle City Studios. I knew that HDtracks had secured a demonstration area on the 10th floor of the event (along with SuperHiRez) but I was pleasantly surprised to learn that David was also a presenter.
He started his presentation with a discussion of what he’s been working on lately including his collaboration with Edgar Choueiri, a member of the faculty at Princeton that has been working on refinements to binaural recording and playback that he calls “Pure Stereo”. David explained what’s wrong with traditional stereo recording and playback. Live concerts produce sound in front of the listener. We determine spatial location and depth because our two ears receive slightly different information. These include timing, timbral, phase and amplitude differences. Our brains use this information to calculate where an individual sound appears to come from AND how far away it is.
He went on to explain why traditional stereo speakers fail to deliver the information necessary to recreate a “pure stereo” experience. It’s called pure stereo because it maintains the exclusive left and right ear triggers that happen in live sound AND through binaural headphone listening. It’s when the sound that is intended for the left ear “pollutes” the information intended exclusively for the right ear as is the case with stereo speakers that spatial segregation is diminished. David’s right about this. Professor Choueiri has therefore developed a set of filters that eliminate or severely reduce the “crosstalk” between ears.
It’s not that traditional stereo can’t deliver a compelling model of space. Alan Blumlein, the inventor of stereo, showed that a pair of microphones and two discrete channels of information could capture and reproduce a sensation of depth and left-right distribution. The “Pure Stereo” effort attempts to take expand binaural techniques beyond the limitation of headphones.
It turns out that the best way to optimize the full 3D experience using the “binuaral plus” techniques he’s promoting is to have each listener’s pinnae (outer ear) measured and a personalized HRTF (head related transfer function) created. This is very similar to the Smyth Research “Room Realiser” that I’ve discussed here before. David envisions sending a small pair of microphones to each individual user and having them run some sweep tones through their speakers with the mics stuffed in your ears. The HRTFs that result are then used to process a standard stereo recording into a 3D image. Sounds interesting enough…I’ve heard a few of the “binaural plus” recording and not yet been suitably impressed, but I will withhold judgment until the final product is available (remember I received my Ph.D. with a component of my research into binaural recording).
When it came time to play some music, David chose a selection from his own ballet production, Zephyrtine. It was scored to full orchestra and clearly demonstrated high-resolution audio because of the extreme dynamics in the work. It ranged from very quiet to very loud over the 5 minutes that he played. The work was very interesting. The evening was full of 20th century orchestral music between Zappa and Chesky. I should have brought a recording of one of my two symphonic works. Although they were recorded using analog tape over 30 years ago, according to the MQ-A descriptor in the new definition for high-resolution audio they would qualify.
David Chesky is a believer in real high-resolution music. His productions are substantially different from my own, but he does understand the realities of the production process and the challenges of delivering high-resolution music via downloads. It turns out that he also had an HTC M8 Harman Kardon phone at their booth on the 10th floor. He gets it.