David Chesky’s name is practically synonymous with audiophile recording and the quest for a purer, more natural sound. Instead of close-miking instruments, recording them on multiple tracks, adding reverb, and mixing it all down, he records in great-sounding spaces in pristine stereo. Comparing what Chesky does to anything you heard on the Grammys last night is like comparing Humboldt Fog chevre to Kraft Singles.
Yet Chesky recently decided to discard recording techniques he developed over decades in favor of binaural recording, a method that uses microphones placed inside the ears of a dummy head. Binaural recording is intended for playback on headphones, which of course are ultra-hot right now, but Chesky has worked with Princeton University researcher Prof. Edgar Choueiri to develop methods of delivering the binaural experience through conventional speakers, a technique he calls Binaural+. You can see the full list of Chesky's Binaural+ recordings here.
Chesky spoke with me last week from his company’s NYC headquarters to explain his abrupt shift.
Sound+Vision: So why this sudden shift to binaural?
David Chesky: Because art has to go forward. We’ve done a million zillion regular recordings.
But it’s not just binaural. We’re doing Binaural+. If you play that on a set of headphones now, it really sounds 3D. In the future when you have crosstalk filters and play these recordings on normal speakers, you can make a 3D sound hologram in your house. It’s mind-blowing how good it sounds.
S+V: How does what you do differ from standard binaural recording?
DC: Normal binaural you can’t play on speakers because of the inherent equalization of your ear. But we figured out how to do both.
In audio we live in this world of crosstalk corruption. Sound from the right will sound different to your left ear; it’ll be delayed versus your right ear, and be lower in level, and the shape of your head and ears will change the sound, too. With headphones, it’s no problem because the left ear can’t hear what’s going in the right ear, and vice-versa. But if you have two speakers in front, you hear both at same time, and this corruption screws up the stereo cues.
S+V: How do you process the recording so it plays back on speakers?
DC: We add a diffuse EQ filter so that you can play it back on speakers. Without that filter, the sound will rip your head off, it’ll be ridiculously bright. We do it in Sonic Solutions. We have a filter algorithm that was supplied by Edgar. This makes it theoretically flat again.
S+V: Do you optimize the sound for headphones, or for speakers, or for some sort of happy in-between?
DC: I don’t think it’s a happy in-between. I think the filter improves both. Since the ear on the binaural recording head doesn’t match your ear, we have to make it theoretically match.
S+V: Does the listener need some sort of special processing to get the best results through speakers?
DC: It sounds great on speakers as-is, but to get the best results you need crosstalk cancellation circuitry. We have the hardware together and we're starting to demo that now.
S+V: You’ve spent decades of trial and error finding the best possible stereo recording microphones. How does the binaural rig compare to those?
DC: In some ways it sounds better than our old recordings because the mics are killer. It’s similar to two spaced omnidirectional mics. The transaparency, I think, is better.
S+V: Take us through the entire recording chain.
DC: We use two different binaural recording mics. The one we use most is a Brüel and Kjaer “Lars” 4100 head and torso simulator [shown in the photo at top]. It’s like a crash test dummy. We’re using the B&K microphones inside there. It’s made for audio testing. Nobody uses it to record with. We also use the Neumann head, which everyone calls “Fritz.”
S+V: What’s the difference between the two from a sound quality standpoint?
DC: It depends on the shape of your pinna. If your pinna matches Fritz, then Fritz sounds better. If your pinna matches Lars, it sounds better. Most of the recordings we’ve done with Lars. Explorations in Space and Time was done with Fritz.
S+V: So where does the signal go from the microphones?
DC: The mic preamp is in the head so the signal comes out line-level. We go from there through custom Crystal Cables and right into a custom analog-to-digital converter that MSB made for us. From there we record it onto a hard drive.
S+V: I know with your previous stereo recordings of a vocalist and a group, you would build a vocal booth in the space, close-mike the vocalist, pipe that out to speakers in the rear of the space to capture the natural reverb, then mix the direct sound into the stereo recording. Do you use this same process for binaural?
DC: No, we just use the binaural microphone and adjust the levels by moving the vocalist and the musicians relative to the mic. Binaural has to be completely pure. It won’t work if you start using a bunch of microphones.
S+V: What do you use to monitor the recordings while you’re making them?
DC: Right now, we have tons of headphones, but we’re using Stax and the Ultimate Ears custom-molded in-ears, the recording studio version. And we have some Beyers and some HiFiMans and Audezes. But mostly the Ultimate Ears custom-molded. Then we can get a really good idea of what’s going on in there. In-ear headphones work better because you don’t use your pinna. If you put those in you will swear you’re in the space.
S+V: How will your recordings sound if they’re played back on a headphone that’s not neutral-sounding—one with a lot of frequency shaping, like Beats?
DC: We monitor with the most accurate things we can. If you want to listen to it on whatever, that’s OK, but I want to know what’s going down on tape. After that people can enjoy whatever they like. It’s not about what’s real, it’s about what you enjoy. It’ll sound different on everything you listen to.
S+V: Are you still doing some of your recordings the old way?
DC: No. Conventional stereo recording, not matter how great, is like being a peeping Tom. You’re looking into the space, you’re not in the space. With surround sound, it’s like there’s one ring of sound sources around you. With binaural, it’s like a pebble dropped into water, with concentric rings coming out from the pebble. I can place it anywhere around you and at any distance from you.
S+V: How many binaural recordings have you done so far?
DC: I think we have about eight in the can. There’s a learning curve for us so we’ll be doing more. Probably about 10 a year.
S+V: And how are you distributing them? Are you offering CDs or just downloads?
DC: We still sell CDs, but if you want the best rollercoaster ride, you should get the 192 [kbps] or 96 off HDTracks.
S+V: For readers who want to check out your binaural recordings, what’s the best place to start?
DC: I think the best is Dr. Chesky's Sensational, Fantastic, and Simply Amazing Binaural Sound Show. You have rock bands, orchestras, choirs in churches… Anybody with headphones should try this just to see what potential is of their headphones. With normal stereo recordings, it sounds like all the music is coming from inside your head. With binaural you get the correct spatial cues.
S+V: Now that so many young people are listening through headphones, what do you think the future of audio reproduction is going to be like?
DC: I think kids are going to start going from cheap MP3 and $10 headphones to Astell & Kern players with $2,000 headphones. You and I grew up with speakers so that’s what we grew up wanting. But if you grow up with headphones, you’ll want headphones. One thing you can rest assured of, it’s going to be a hard drive thing. The days of silver discs are over. Kids are used to downloading.