Lossless Tracks Blogspot
Ortiz Ullery
Over the years, we've seen websites, blogs, and videos try ways to demonstrate the sound of a hi-fi device or for the adventurous, even try to convey the sound quality of listening rooms. For example, there are binaural recordings at audio shows, soundroom demos, speaker comparison samples, etc. This is not an easy task because high-fidelity is about nuances and slight variations; not wholesale "obvious" differences for many devices like DACs or high performance amplifiers. Unlike what you might read in audio reviews, assuming you have a decent DAC already, a replacement would be unlikely to result in obvious changes in characteristics like bass response or claims that jitter effects are somehow obviously audible! Sorry folks, a lot of that kind of talk is just fantasy.
While it is convenient to view and listen to typical YouTube clips, I think we can all appreciate that sound quality would be highly affected by: the recording microphone, room acoustics, set-up quality, the lossy audio compression from YouTube among others that I may have missed. Dissociating the effect of the different components would be impossible. And obviously any time you use a transducer to convert the sound pressure into electrical signal (ie. speaker, microphone), there will be a significant reduction in resolution if we're trying to determine the effect of something like a DAC!
Then there's the issue of what music is being used? Is it music that audiophiles have general access to? Is it material that audiophiles/music lovers would even generally listen to? Obviously this bit is very subjective but I think there's something to be said about esoteric test material that might be recorded amazingly well, but just not adequately popular to have "mainstream" level acceptance. When "subjectivist" audiophiles complain that test tones are artificial and synthetic, is it that much different from listening to a handful of albums that barely anyone cares about? ;-)
While thinking about this recently, and having measured enough devices over the years and showed you numerous graphs and synthetic test material, why not expand this by giving you the opportunity to listen for yourself? Using the highest quality "recording" of devices that I can...
With that in mind let's lay down what I'm going to try to start doing with some of my future DAC/source measurements and reviews; I'll include a link to a hi-res recorded playback from the device so that you can listen for yourself and compare at home.
The ADC will be set to linear phase, steep filtering. Given the 96kHz samplerate, we're looking at filter roll-off out beyond 40kHz, obviously an octave beyond even ideal (teenager, early-20's) hearing acuity.
2. Let's use a selection of test music, nothing terribly esoteric, at least good production quality, for subjective evaluation. Here are the tracks I selected based on some of the stuff I listen to:
Age of the recordings range from 1988 to 2021. We have classical, world/ethnic, live jazz, female vocal, male vocal, and modern pop represented. As described, each will bring certain characteristics to listen for like the strong dynamics in the Stravinsky piece (this is not the HDCD version but sourced from 24/88.2 Reference Recordings hi-res), the clarity of "Japanese Roots", live ambiance of The Ray Brown Trio, guitar and voice on "Fields of Gold", bass authority on the Benjamin Clementine track, and louder compressed dynamics of "Love Again".
Some might wonder why I didn't include a techno or EDM track. Well, already the Dua Lipa track employs quite a bit of studio processing - artificial sweeteners for the ears, and maybe eyes as well but that's subjective ;-). In general, I think it's more useful to assess whether a DAC or CD player sounds "natural" as in the tonality of voices and acoustic instruments that can engage our judgements based on previous real-life experiences of these types of sounds. Playback quality of electronic music probably can already be assessed quite well with the results of measurements (synthetic test tones for synthetic music!).
4. Let's stick with lossless 16/44.1 source. No need to argue or debate over hi-res these days I think (see here, and here). Even if you can hear a difference with hi-res, all indications point to the difference being minuscule. The reality is that for the foreseeable future, stuff that we consume will be CD-resolution 16/44.1 or equivalent (like upsampled and pseudo-hi-res). I believe there are 24-bit versions of Dua Lipa and Benjamin Clementine out there, but seriously folks, these kinds of low-DR albums (as discussed here years ago) do not warrant spending money on and would be an absolute waste of storage as well.
For future reference, I'll just call this test track and the way the DAC recordings performed the "AMPT". When doing the AMPT recordings, I'll make sure to include a few seconds of silence at the start to allow you to examine/hear the "sound of silence" from the device; very important to listen for hum for example. Also, in order to allow for easier "apples-to-apples" comparisons, the recorded track volume with be normalized to -27.2dB +/- 0.1dB average RMS amplitude using Adobe Audition 14 (2021); this is at -3dB of the source amplitude. This will allow for overhead such as the Dua Lipa track with +0.9dB true peaks. IMO, the high-resolution, very low jitter, studio-quality RME ADC (for the record 18kΩ XLR, 9kΩ RCA input impedance) will easily capture all that we need from these 16/44.1 digital-to-analogue conversions.
** VERY IMPORTANT: If you want to compare direct playback of the original track above on your system to some of the recordings of DACs I'll be posting below, make sure to increase the volume of the recording of the DACs by +3dB. I've noticed over the years of running blind tests that some people don't bother controlling volume and then make all kinds of claims of what they heard. Also, make sure to turn off any extra processing when listening (such as volume normalization, EQ and such which may affect quality).
As in the past with blind tests, the tracks are being used based on the principle of "fair use" for the purpose of education and testing. Only short portions of the music tracks are used (significantly
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