|24-bits vs. 16-bits Audio - A Visual Analogy?|
As you know, the "High-Resolution Audio" movement is on. A major cornerstone of this is the belief that in the PCM world, 24-bit audio resolution imparts clear audible benefits (as opposed to the standard 16-bits for CD resolution). Indeed, most decent DACs these days are capable of measuring >16-bit dynamic range. Clearly, a push is being made for the subjective "virtues" of 24-bit audio for your headphones, into your home and into your car. The 8-bits of difference between 16-bits and 24-bits of PCM data provides 48dB of extra dynamic range or 256x the number of values to represent each PCM sample! Fantastic advertising buzz. The 24-bit "container" is certainly capable of significantly higher resolution.
Here's the question... Can you hear the difference? Evidently many people believe the difference is audibly significant.
So, you've tried "crowd funding" (and you're probably at this point still waiting for a product), it's time for another round of "crowd testing", folks! Here's what you do to participate:
1. Download the "24-bit Audio Test.zip" file:
WARNING: The test file is big (a taste of the storage demands for those who have not downloaded high-resolution audio). Approximately 200MB for a total of 6 musical samples at 24/96 lasting less than 12 minutes with fully tagged FLAC lossless compression.
Get the file from my FTP server:
Login = 24bit
Pass = test
Please have patience if the server load is high... Anyone able to help out with this, please drop me a note below!
Alternate download sites:
From Uploaded.net: http://ul.to/fqziwlfs
From FilePost.com: https://filepost.com/files/m5b3em11/24-bit_Audio_Test_(Hi-Res_24-96,_FLAC,_2014).zip/
2. Extract that ZIP to wherever you want for playback (computer folder, music archive, server, etc.)
Located within are 3 musical pieces in 24/96 FLAC, each piece with Sample A or Sample B versions. One of them (A or B) is the 24-bit original and the other contains a dithered 16-bit version which has been converted back to 24/96 so your DAC will basically be playing back the same bit/samplerate when you switch between tracks.
The samples are all classical pieces but with variation in instrumentation, vocals, and dynamics. Realize that it's not easy to find good high-resolution audio where the music is recorded and mixed to the highest standards with known provenance. Classical music as a genre is where some of the best recordings can be found.
Here are the tracks:
2. Vivaldi - Recitative and Aria from Cantata RV 679, "Che giova il sospirar, povero core" (performed by Tone Wik & Barokkanerne) - String orchestra with female vocals. Also DXD-recorded and available as a free download from 2L here. Again, I only extracted 2 minutes from the track. DR14 for this track.
3. Goldberg Variations BWV 988 - Aria (performed by Kimiko Ishizaka) as taken from the freely available Open Goldberg Variations 24/96 release. The recording was done at Teldex Studio in Berlin using the Bösendorfer 290 Imperial CEUS concert grand piano. Simple instrumentation for those who love and appreciate the sound of the piano. It's also a much slower piece which provides an opportunity to listen to the decay quality. Low-level spatial room acoustics also easily heard on this recording. Measured dynamic range is a reasonable DR12.
I've included the DR printout from foobar to demonstrate that peak and average volumes are identical for Samples A & B for each piece.
** Note that I'm using the samples under the principle of "fair use" for the purpose of education, research and commentary. I have no ties with Industry and have no financial gain by organizing this. As noted above, these tracks were selected based on excellent quality of the recording and I would highly recommend visiting the source links to sample more high-quality audio tracks in the high-resolution delivery formats (the 2L download page also includes DXD, multichannel and DSD samples).
3. Listen and compare Sample A with Sample B.
Can you hear a difference? Can you tell which one was the original 24-bit audio and which was dithered down to 16-bits?
Needless to say, you need to make sure your DAC / computer / streamer / etc. is capable of >16-bit performance!
I encourage the use of tools like foobar's ABX comparator to switch quickly between A & B. Make note of which Sample for each piece of music you believe is the original 24-bit track. Presumably, since the 24-bit version is higher resolution than the 16-bit one, there could/should be improved transparency, ambiance, definition, smoother decay, etc... For example, if you think the 24-bit sample is A for Bossa, B for Vivaldi, and A for Goldberg; keep track of that and make note of how confident you feel about your selection.
4. Make your voice heard on my survey form!
Go to the survey here:
I have 14 questions (15th optional) - it should not take long to fill out as most are multiple-choice tick boxes. As expected, I want to know whether you think A or B is the 24-bit track. I also want to know if you're guessing or confident - if you spent time listening, make it count by visiting the survey even if you don't think you can tell a difference. A 'negative' report is just as important as a 'positive' one. I also want to get a sense of your age, gender, tiny bit on musical and technical experience. Also, equipment used, and approximate cost of the audio gear. All data is anonymous and I have no access to your IP address (the web site will keep track of what country you're submitting the survey from - let's make this an international effort!).
I'm going to be busy with work and other responsibilities for the next while so this is the perfect time to gather some data. As I did with the MP3 test, I'll summarize the information and demonstrate the conclusions of this survey once it closes. I think about 2 months is adequate time for everyone who wants to get involved to have a good listen. Therefore, I will close the survey around June 20, 2014 - fill in the survey before that time! Note that IP filtering is ON so only 1 response from each IP please.
Finally, remember to relax, take your time, and have fun with this... Enjoy the music and see if one version "speaks" to you more than the other in terms of sonic quality. Feel free to share this test with friends / family / music lovers / audio reviewers / audio forums / enemies. Also, please try not to whip out the audio editor before doing the listening and completing the survey! Honesty is extremely important for an open "naturalistic" survey like this one. If you know which is which, please do not share it with others so as not to bias the results. Feel free to leave a comment down below if you run into any problems or need help. Thanks...
A few guys got to "beta-test" this little project and I want to thank 'Wombat' and 'Mnyb' especially for providing technical suggestions and detailed feedback on the Squeezebox Audiophile forum before this went "live"!
I've been enjoying some Ladysmith Black Mambazo over the last few evenings at home. As usual, with some of the more recent CDs I wish the dynamic range were higher especially for multilayered vocal music like this. I'll be sure to update when I get stuff like the pre-ordered Geek Out in my hands over the next while or if I've got some burning thoughts to share :-).
Enjoy the music... Happy Easter.