I can’t see how it makes any difference to the upsampling whether the original master was analogue or digital. Once digitised, any info between the samples is lost, so upsampling in both cases is guessing at what should be between the samples, therefore the interpolation or whatever mathematical process is used can only do exactly the same for each. In what way can an analogue original master cause the interpolation of a digitised version to be different from the that of a digital original master?
The only difference I can see there being between the two types of original master on the resultant sound through a digital medium is the effect of the different AD converters from analog audio and the effect of the analogue recording process, the analog master ADC being after first capturing on tape, and the digital master ADC being before it is recorded: In an analogue master any sound from the analogue taping process will be added, and with multiple inputs that often will be twice, once laying down individual channel tracks, and adding to that the taping of the mastered combination. After that it goes through a single ADC, with the any effect on the sound that that adds. In a digital master there is no effect of analogue taping, but only the effect on the sound that the ADC has, though except with single mic recording the individual channels will have their own ADCs, which if of different types may have different effects on the sound of different instruments.
Bailyhill, there is no secret sauce here, really there isn’t, it’s all rather well established methods, applications and choices, other than the specific MQA lossy compression technique… and for example different proprietary filtering algorithms such as the WTA windowing techniques… more in a minute.
In any digital to analogue reconstruction, there is time domain / value interpolation… in other words, a sample value in a discrete sample series is theoretically representative of an analogue value for an infinitely small amount of time. Between these ‘pulses’ that are representing values for infinitely narrow points in time time , the reconstruction filter (a sinc response filter) allows the values to be representatively converted to a continuous signal (what we call an analogue signal). The analogue signal is reconstructed and interpolated between these infinitely narrow sample point representations… and interestingly because this signal is low pass filtered, these reconstructed interpolated analogue signals may exceed in value between the sample points…and care is required to avoid clipping.
All this is standard stuff… and not specifically MQA related. Any discrete bit stream DAC deals with these concepts.
The fun and variability of approach (the closest to the ingredients of your sauce) often comes around the implementation of the sinc response and low pass filter … there are different approaches to digital filtering with varying pro and cons regarding the distortion and aberrations introduced… … there are side effects to filtering and so different algorithms and approaches focus on different aspects … it becomes a design engineer’s choice in the design and implementation of their DAC, but it appears in the case of MQA some of that choice is taken away.
For example many DAC designs today for example oversample the signal such that the low pass digital filter can be more gradually introduced above the audio band causing less distortion into the resultant audio. Now there are different choices to the implementation of that low pass filter implementation again with different pros and cons … ie Naim use one way using recursive IIR filtering, whereas Chord use FIR sample window based filtering (convolving the discrete sample signal with a defined filter response series of samples or ‘taps’). Chord use a bespoke windowing algorithm, the WTA, as opposed to one of the standard established windowing algorithms.
I have seen a spreadsheet with 17,000 MQA albums, which translates to about 170,000 tracks at the moment. Get notice of an additional 50 new/reprocessed albums per week. Sony is reported to have a boatload encoded, but has not released any at this time.
Unfortunately FR the search facility for identifying masters isn’t very good, you really need to search for album/artist and see what they have in terms of masters, a bit of a pain.
So for example if you like say the Beatles open up a search it will list all the albums and you can see which ones are masters
Sorry FR just sharing my personal experience, I use Qobuz most of the time, I would ask Baihill how he does it, he maybe knows more about the Tidal search capabilities.
Fine for Tidal across the internet - MQA saves bandwidth and reduces Tidal’s data costs
However I stream from a NAS so I don’t need to save the bandwidth, and a losslessly encoded 24/192 file is better for my use than a lossy encoded 24/192 file!
i just took tidal for 1 month, it was free. I subscribe in general to tidal 1 month every 6, to discover new albums.
Mqa was mentioned so i wanted to see. But i could find less than 10 albums of my interest.
However, paradoxically, MQA is not as efficient in compression using FLAC as PCM, so sometimes MQA could actually consume more bandwidth… or certainly not compress down as much as you think…
I was on the EuroStar train at the time of my email, traveling back from Brussels to London after the European Variable Star Conference where I presented a paper on sCMOS detectors for Astronomy, and left out a couple of key words by mistake that led to some confusion. The spreadsheet that I referred to is released MQA material and its posted on the MQA Facebook page regularly. It was not a TIDAL search. In addition, there are licensing arrangements between TIDAL and the music companies that must the completed after the MQA encoding, which may be in the pipeline at this time, preventing them from being available by TIDAL. Also TIDAL may not wish to provide all the available albums. There are about 50 newly released or “remastered/encoded” albums coming per week. I estimate that there are 10 tracks per album–just for ease of estimating. And just like regular files, there are regional differences where not all material is available in all regions due to the licensing.
Like you all, I do find the search function in TIDAL and ROON a bit limiting and not up to our Google experience. It may be a hardware limitation? One member posted on the Roon Forum that getting search engines correct is a very difficult task that he had experience with in his day job.
I was also told that Sony is encoding a lot of material, but has not released any of it yet. Perhaps they are waiting to make a big release and do a lot of PR–don’t know. This is unlike the other two giants (Universal and Warner) who seem to be working thru at some rate.
However if you force the MQA compression to down convert MQA to fit a 24/192kHz stream into a 24/48kHz carrier (which seems to be the one generally being ‘pushed’ by MQA) or even worse a 16/44.1kHz carrier, then it almost always beats FLAC at the expense of a notable loss of information fidelity.
