Next Wednesday, I’m involved in a research project on high-resolution audio. I’ve managed to get myself more involved than I originally intended as the supplier of the source files, the audio engineer in charge of setting up and testing the equipment, and the person making the selections between the file types. The organizers hired an outfit out of the Washington DC area to conduct the research. The basic question they want answered is whether the general public can tell the difference between a standard 256 kbps MP3 file and a 96 kHz/24-bit source recording. That’s it.
I volunteered to assist by supplying a few of my high-resolution files. It’s important…in fact, essential…that the participants are presented with a real difference. Unlike the Boston Audio Society study and resulting AES paper from some years ago that used standard definition recordings vs. CD-resolution down conversions of the tracks. It should have come as no big surprise to the BAS to discover that no one could tell the difference between the “so-called” high-resolution albums supplied by members of the society and the CD versions…there was no difference in fidelity since virtually all of them were sourced from older analog tape masters! Knowledgeable audio people still cite this highly flawed study as “proof” that high-resolution audio is irrelevant. I saw a post just this past week.
Anyway, this new research project will at least be starting with files that provide very different levels of fidelity to the listeners. I took the very same files that Scott Wilkinson used for his non-rigorous study through AVS Forum last summer and I converted/compressed the 44.1 kHz/16-bit CD spec files to 256 kbps MP3 format. As you may recall, those members of the AVS community that had systems capable of high-resolution audio playback did beat the odds and were able to identify which file was which. The number of individuals that participated was very low and no real conclusions could or should be drawn from the casual study, but it was an interesting effort.
I don’t expect much from the new study. It will be conducted in a Beverly Hills research facility, which is basically a business type conference room with glass walls (including a one-way mirror for observation) and a large table in the middle of the space. Teac and Sony are providing the playback equipment. I have the amplifier, headphone amp, and DAC from Teac. The speakers (retail for around $250 each) claim to be able to deliver better than 20 kHz. We’ll also be using headphones…although I don’t know the model at this point.
The files are ready. I’ll post them to the FTP site so that all of you can challenge yourself. They are all 96 kHz/24-bit PCM stereo files (so that they can be played simultaneously and be randomly selected) but the quality of audio ranges from the original source, to CD spec, and finally 256 kbps MP3. The levels are matched. I will be using my laptop running Pro Tools 10 and switching between the stereo tracks using the SOLO buttons on the virtual console. The switching is completely seamless and noise free.
When I listen to these files sitting at my computer, I can’t tell the difference between them. In the studio, I can…without fail (I got 5 out of 5 on the ABX test at AVS last summer). Will the people that are participating in the study be able to tell them apart? My guess is that they won’t. The results of the study will find that the general public is unable to perceive any difference between a good quality MP3 file and a bona fide high-resolution original. Then where do we go?
You can visit the FTP site and check out the files for yourself. I will randomly label them A, B, and C. I’d love to hear from readers about what you hear. Please don’t cheat and look at the spectra etc. Just listen to them and send me an email identifying which one you believe to be the source, which is the CD version, and which is the MP3 file. I’ll collect the information and report back. It would be great to know what system you used to audition the files.
I’m still looking to raise the $3700 needed to fund a booth at the 2015 International CES. I’ve received some very generous contributions but still need to raise additional funds (I’ve received about $2200 so far). Please consider contributing any amount. I write these posts everyday in the hopes that readers will benefit from my network, knowledge and experience. I hope you consider them worth a few dollars. You can get additional information at my post of December 2, 2014. Thanks.