Adding It All Up

Happy Holidays! The rainy season has arrived in Southern California and the temperature has dropped to below 50 degrees for the first time this year. Thankfully, my new roof was finished just in time and the interior of my home is free from leaks. I’m heading to Aspen for a few early season ski days before Christmas and New Years.

The HD-Audio Challenge: Update

Almost 600 individuals have requested access to the 20 HD-Audio Challenge II tracks, 200 have confirmed that they have successfully downloaded the files and 50 have submitted their results. Thanks to everyone for your interest in this project. I would encourage more of you to proceed with the downloading, listening, and submissions. Please take some time and follow through with this survey. I won’t be providing the answers until sometime in January, so you have plenty of time to participate.

I’ve started compiling the results using an Excel spreadsheet. For each track, there are only four options:

The Response Form for a Track

As I begin the process of recording the raw data and trying to extract meaningful information from it, I’m not sure how to best proceed. Here’s a small section of the spreadsheet:

The Submission Spreadsheet

This is where I need the advice and assistance of someone that is skilled in statistics and data analysis. I’m not sure how to deal with the “No Choice” category. No choice means the files were listened to but the participant was unable to pick which one was the high–resolution file — they couldn’t make a choice because the two versions sounded the same. Additionally, some individuals didn’t include tracks that fell outside of their musical tastes or for some other reason they didn’t feel qualified to include those selections. For example, more that a few people restricted their listening to the classical compositions.

So what’s the appropriate way to determine the “percentage” of correct selections? It seems obvious that the total number of tracks considered should be limited to those that were attempted. But the “No Choice” option creates a dilemma. Being unable to pick the hi-res music selection from the standard-resolution version because they both sounded identical presents a statistical problem. Should they be counted as incorrect answers? That response can — and probably should — be interpreted as an incorrect answer because the participant was NOT able to pick the hi-res version.

However, I can see an argument for using only the “true” and “false” answers in the percentage. There was a reader that offered to get involved with this project when I announced it months ago, but I’ve misplaced his/her email. If you’re willing, have the requisite knowledge and experience, and have the time to help, please send me note.

Holiday Discounts on the Book, Discs & Files

There are still a few days left to get your favorite audiophile the “gold standard” reference book on high-end audio — or just get a copy for yourself. The paperback version of Music and Audio: A User Guide to Better Sound is available through the end of the month at half price using the coupon MAAG50Percent.

And don’t forget to add to your collection of award-winning recordings from AIX Records at 50% off for the holidays. Use coupon code AIX50Percent during check out.

I received the following kind words from a recent customer:

Thanks Dr. Mark – I have both the files & the physical media.
Amazingly fast service and the music & sound quality is STUNNING – really enjoying it. A wonderful holiday to you – keep up the great work!

And finally…I’ve been working hard on the iTrax.com website for high-resolution downloads. It’s a big project and not ready for prime time yet. If you would like WAV or FLAC files in stereo or 5.1 surround, simply let me know via email and I’ll send you the files.

6 thoughts on “Adding It All Up

  • Kreylix

    You’re trying to determine if a listener can tell if a track is MQA high rez. No Choice answer seems totally like a False to me.

    • Admin

      Actually, MQA has no part in this survey (a lossy process would be a completely different study.) The question I would like answered is whether audiophile listeners can pick out a high-resolution track over a CD version of the same track.

      • Michal Urban

        I was wondering where the MQA question came from… perhaps the MCQ track code in your illustration looks confusingly similar?

  • Dave G

    I think that posting ‘in-progress’ data should be avoided. If you say “Less than 50% of respondents have gotten it right”, that has the potential to either introduce expectation bias or discourage participation. Just my 2¢.

    • Admin

      You’re probably right…


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