Dr. AIX's POSTS — 07 March 2015

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The Audio Engineering Society is holding its 57th International Conference in Hollywood this weekend. I hadn’t originally planned to attend (the cost is over $700) but changed my mind when I was able to get an educator’s discount. The program was organized by Dr. Sean Olive and Brian McCarty is titled, “The Future of Audio Entertainment Technology: Cinema, Television, and the Internet”. It sounds like this would be right up my alley, but the papers and workshops are focused on cinema sound more than high-resolution audio. However, on Sunday the papers are focused on immersive sound, which should be more interesting for me.

I rarely drive to Hollywood…in fact, I don’t get east of the San Diego freeway very often. But after getting to the studio early to write yesterday’s post, I decided to take Santa Monica Boulevard east. The event is being held in one of the Chinese Theaters (it’s all about theater sound) so the venue makes perfect sense. Hollywood Boulevard and Highland is also the location of the Dolby Theater where American Idol is shot. I can’t say I’ve ever watched the show or been in side the theater but it has become the center of the new Hollywood.

My arrival was delayed by about 10 minutes because I couldn’t locate the entrance so I missed Brian McCarty’s opening remarks. However, I did get to hear Floyd Toole’s (a widely respected acoustician and researcher) keynote address, “Acoustics for the Theater and Home – Moving Forward on a Foundation of Common Acoustical Science”. He spoke to the many issues facing sound in movie theaters and supported his paper with numerous charts and graphs.

If you’ve been reading my posts for a while, you might remember I discussed the X-Curve that defines the frequency distribution in theaters (you can revisit the article by clicking here). The unfortunate situation in theaters is that they roll off the high frequencies while allowing the low frequencies (below about 500 Hz) to reach “steady state” levels. The low end builds up because of the room according to the charts that Dr. Toole displayed during his presentation.

In spite of numerous attempts to change the X Curve and deliver a more accurate and flat response during movie watching, the curve remains. The installed base of thousands of theaters isn’t likely to change the way they deliver audio to their patrons. Although, I find it interesting that digital cinema has found a home in most modern cineplexes. It’s not like it would too hard to do with the audio system that are already installed.

I’m headed back to the Dolby Theater for day 2 of the conference. There a number of sessions that sound interesting including the opening address. It’s by Dr. Robert T. Sataloff and Eelco Grimm. The title is, “Loudnss Wars at the Cinema: Noise Induced Impairment and Getting Our Dynamic Range Back”. It seems that the movie industry is suffering from the same problem as the music industry when it comes to dynamics.

This session is followed by, “Dynamics and Low Frequency Ratio in Popular Music Recordings Since 1965”.

I’ll fill you in tomorrow.

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About Author

Dr. AIX

Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(14) Readers Comments

  1. It would be fine to abandon the X Curve in theatre EQ if it wasn’t being used at both ends of the process.

    • The Pono link was inadvertent…but Craig, you need to read more carefully the product that you’re talking about. It is NOT on AIX Records…but rather a friend’s label called Hi-Res Music. I did the work for him from the analog masters. He decided to issue a collection of classical jazz albums using the DVD format.

      Gotta get your facts right before you launch a critical comment.

      • Hi Mark, I’m not Craig, and I don’t think your reply was about my comment? 🙂

        • Sorry Grant…

  2. Don’t know if this is related but I went to the Epic theater in Clermont FL to see Lucy some months back. First time I’d been to a theater in a VERY long time. Short story is a number of times during the showing, I put had to put my fingers in my ears and wish I had brought protection. I’m no wimp but wish I had my SPL meter with me, the peaks they were hitting were nuts. Maybe I’m just getting old but I think there’s more to it than just me?

  3. The cinema theaters nowadays are more and more offering concert videos in addition to the movies.
    I once attended one of these venues.
    The picture is big – which is great – but the sound was awfull 🙁
    They have a lot of work to do, before I go next time.

    The equipment (and/or the ‘tuning’ of the equipment) in the cinemas of today simply isn’t capable of offerning a (high quality) experience of music.

    By the way – next weeks ‘Home Theater Geeks’ show will be featuring some of the ‘makers’ of the AES conference – Future of …..’ as guests.

    • I’ve been sitting next to Scott Wilkinson, the Home theater Geek all weekend.

  4. I was already aware of the facts before I wrote my comment, but the bottom line is that your name is on a recording promoted as Hi-Res when by your current definition this is not a valid claim. Everyone bends when the winds of commerce are blowing, or almost everyone.
    This semi- dichotomy is no more or less important or valid than the over- blown, ongoing comments re: Pono that you regularly lay on thick. Simply because Neil Young’s energy hits the public in a way that yours or even David Chesky’ s outstanding efforts never will, you seek to bring Pono down. This is a big waste of energy on your part, because ” any publicity is good publicity” All I ask is that your comments regarding Pono be non-vitriolic and you balance your self- promoting criticisms with statements clearly pointing out the very positive values that Pono represents overall . ,”Just the facts” is fine, but how about all the facts, not just the ones you use to make your essentially divisive points.Fact #1is that almost singlehandedly ,Mr Young has awoken the public to the reason they don’t “listen like they used too” , and it’s called Mp-3 128.
    Somewhat like selling insurance, you have to make folks aware of the problem before you can encourage them to fix it. The instant popularity of Tidal’s 16/44 streaming service is a good example. But maybe you should go after them too, because I made a level matched comparison of the same track streamed on Tidal to the same track pulled directly off the disc, and it wasn’t even close; the CD playback killed the stream. So if you want to get on your high horse, you could easily find new topics.
    As you can observe, despite all the b.s., Pono is succeeding, and will ‘stick’, and over time smooth out the kinks. Furthermore, a Pono player can download HD Trax, iTrax, no obligation to use the Pono service. So WTF is the big stink about? NOTHING except exposing the poorly hidden agendas of ill-informed journalists looking for a colorful topic; please remember that ‘news’ is a business, and bad news sells best. If all the Pono articles were positive, there would inevitably still be some jerk who figures out a negative angle in the urge to differentiate (his/her) ‘ journalism’ from competitors. Please don’t be that person; it’s pointless and does not serve ‘ the cause’ in any meaningful way.

    • If you were aware that AIX Records didn’t produce or release the recording you mentioned, why did you say it was on my label? And why use it to attack me, again? I believed then and I still believe that analog tape is not high-resolution. The specifications don’t measure up. I have worked on many hundreds of albums but that doesn’t mean that my personal beliefs are in line with the producers of the project. Give me a break! The guy behind Hi-Res Music did what he thought would help sell his albums. Because I engineered the project and have my name on it, somehow my credibility is questioned? That’s why I asked you get your facts straight before going into attack mode. Who should be ashamed? It might be time for you to move on.

  5. Floyd Toole, knew the name made a light go on in my defective memory modules. Often referred to as the world leading authority on loudspeakers, as much of his writing I’ve read over the years can’t believe I had to Google him for the lights to go on. Sucks to get old.

  6. The “X” curve is present both in the dub stage and in theaters. If you mix with a track on a system EQ’d to it, then play on a system EQ’d to it, you do, in fact, end up “flat”. The goal being that the theater audience hears exactly what happened on the dub stage (assuming the theater is in fact EQed to the X-curve).

    The “X-curve” has a purpose, to provide a means for a soundtrack to be interchanged between large and small rooms. It’s not a single curve, it’s a set of curves related to room sizes. Yes, it’s inaccurate, but you do need some sort of X-curve, running flat will make things MUCH worse. Those proposing to eliminate it simply don’t understand why it’s there and what effect it has. They also don’t understand that if you summarily remove it in theaters, you’ll also summarily blow tweeters everywhere, create a second “standard” without any large-room/small-room interchange, and introduce yet another possible error in playback settings, as films now for 4 decades have been mixed in rooms with the X curve. If you suddenly eliminate it, you’ve created a major possible playback error problem.

    Bad sound in theaters is very real, but NOT the result of the X-curve, it’s the result of poor maintenance, poor theater operation, and most importantly, audience complacency. If everyone who didn’t like theater sound demanded a refund, the theaters would be fixed in a jiffy. Every pay-out has to be accounted for at a very high level, which prompts a visit from the theater tech right quick like. But we’d rather sit and watch the movie presented wrong all the way to the end than demand a refund and ruin our evening out, and would much rather just complain to our friends both real and virtual how bad theater sound is. So no complaints, no repairs, and theater sound remains bad. You could even remove the X-curve at both ends, you still wouldn’t solve the problem, and would instead introduce more problems.

    Yes, the X-curve isn’t quite right in the absolute sense. But it’s not all that wrong either, and certainly not at fault for crappy theater sound. An industry parallel would be the 75uS pre-emphasis curve in FM radio in the USA. It’s been out-moded for 40 years, but you can’t change it either (Dolby proved that in the 1970s). Sure, today we could do way better, but we can’t change the millions of existing FM radios, and we can’t live without some form of noise reduction in FM, so there it stays. Same problem, different industry.

    • Thanks to RealHD-Audio for the coverage of this groundbreaking event.

      I couldn’t let the comments of “cinema authority” “Jim” go by without a response. I have little tolerance with the neanderthals who keep knee-jerk responding to this issue without any understanding of the contemporary research that disproves these statements.

      Jim, your comments are just plain fiction. You’ve been drinking too much THX Koolaid. I suggest anyone interested in the failures of the x-curve and the SMPTE standards on cinema sound download the free-for-anyone B-Chain Report, released last October after almost four years of very substantial work.

      The statements I make next are not opinion, but documented in this referenced SMPTE report.

      IF the X-curve worked as intended Jim, you’d be right. But it doesn’t because no one is following it anymore. Dubbing rooms are cheating, and the theaters are cheating. This in addition to the fact that the standard for testing the theaters, pink noise and an RTA, hasn’t been used by any other part of the audio business since Nixon was president. The SMPTE report tested all the rooms (which were calibrated to the x-curve using this flawed old method) using dual FFT. And both dubbing rooms and movie theaters tested were all over the map.

      This on top of other work done by Newell, et. al. in Europe, which showed the same results.

      The statement “you’ll blow tweeters” is just wrong as well, and the peer-reviewed paper presented by Glenn Leembruggen at the Conference proved this is just another red herring.

      The fact is also that we don’t have a standard NOW. That’s clear when you listen to a lot of film sound mixes – which sound radically different (in a timbre sense) from each other. Floyd Toole describes it well- the “circle of confusion”.

      The purpose of the conference was in part to identify these anomalies in the production chain and start to eliminate them – and their corresponding high number of additional distribution masters. Why should cinema be the “odd man out” anymore? The rest of the audio business is running at (essentially) flat. The reasons for cinema to be different are long since ended.

      One thing rarely mentioned – while acoustical research clearly shows that the “motion” artifacts in sound are carried by audio above 6kHz, why are systems being put in with the “x-curve” deliberately sabotaging the acoustic effect that is desired? Enquiring minds want to know.

      Digital Cinema masters can carry both “x-curve” and “flat” mixes during a transition period, telling the DCP what they are via metadata.

      Your FM radio analogy is close, but not accurate. A better analogy is the use of the RIAA curve on vinyl records, which was done to COMPENSATE FOR THE DEFICIENCIES IN THE MEDIA. It was removed when CD’s appeared. The x-curve was done to compensate for the deficiencies in optical sound, and carried over to optical digital only to hide the problems with AC-3 data compression. We now use exclusively a full-bandwidth media.

      It’s time to fix the cinema mess and work towards REAL standards.

      • Thanks Brian for this great reply.

      • A couple of years ago I gave a presentation to my local AES branch, one topic covered being the X-Curve, and my findings were similar to some of Brian’s points. It can do more harm than good, but some calibration between mastering and playback is better than none.

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