FredericV Posted August 24, 2017 Share Posted August 24, 2017 17 hours ago, fung0 said: As a journalist who's spent decades reviewing all kinds of electronic equipment, including audio gear, I can offer some perspective. First, let me point out that it's difficult to buy a good review by letting the reviewer keep a bad product. Also, practically speaking, it's impossible for reviewers of expensive equipment to remain current without at least some 'long term loans.' But in the case of MQA, specifically, what would reviewers get to keep? If it's a DAC, its real value doesn't depend on its MQA capability. The manufacturer will probably be very happy if the review says "It's a terrific DAC, but the MQA stuff is a waste of time." This actually happened in The Netherlands. Ruud Jonker, a very technical person, also a mastering & studio engineer, and an IT specialist, and also reviewer for Music Emotion, wrote a very good review about the Mytek Brooklyn, but had serious reservations about MQA. Ruud is not a parrot which copy pastes the official marketing version, which is good. So even with a core feature the reviewer does not like, a product can still stand for all it's other features. I use the Mytek not for MQA, but as a tool to see what resolution (bit depth + sample rate) is going into the DAC coming out of our music server. The Mytek can clearly figure out if S32_LE PCM data is 24 bit with zero padding or 32 bit, which for DSP makes a difference Nikhil 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 4, 2017 Share Posted September 4, 2017 3 hours ago, Shadders said: What would be good is an idiots guide as to the claims made by MQA Ltd, and the actual truth - so those people who have no technical capability can see the opposing (truthful ??) facts. I can see the question and answer session on this site, so if some of those key answers were commented upon - as an example : "Q82 i) “MQA have around 13 Bit of “lossless” information and everything below 14 Bit is “lossy” This is incorrect. In general, the MQA system can reach in excess of either 23-bit dynamic range capability or 3–6 bits below the content noise in the audio band." How is 23 bits of dynamic range possible, if 17 bits of the 24 bits distribution file are already borrowed to reconstruct the partial ultrasonics? Remember that MQA can't describe any ultrasonic frequencies above 44.1 or 48K (depending if the original resolution is a multiple of 44.1 or 48K), as the second unfold is minimum phase upsampling + weird filters. The first unfold adds one octave compared to the undecoded version. The second unfold does not recover any new entropy, and does not recover any extra additional octaves. Why can MQA get away with only 13 bits of resolution (in case of MQA CD) or 17 bits (in case of 24 bit distribution files)? This is very easy to explain: No music content has 24 bits of actual resolution. I recently had the chance to record K's Choice in Koor (= in choir), an acoustic concert with a 240 voices choir in deSingel in Antwerp. This concert hall has an RT60 of 2,03 seconds, which is ideal:https://desingel.be/nl/info/blauwe-zaal Let's look at RT60. RT60 basically debunks the need for 24 bit:http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/revtim.html Quote The choice of the relative intensity to use is of course arbitrary, but there is a good rationale for using 60 dB since the loudest crescendo for most orchestral music is about 100 dB and a typical room background level for a good music-making area is about 40 dB. Thus the standard reverberation time is seen to be about the time for the loudest crescendo of the orchestra to die away to the level of the room background. The 60 dB range is about the range of dynamic levels for orchestral music. So if an orchestra has about 60dB of dynamic range, we need 10 bits of resolution. So if MQA claims "3–6 bits below the content noise in the audio band", this can actually be true, but MQA also debunks the need for 24 audio bit depth. MQA CD can perfectly get away with 10 bits of musical content + and 3 extra bits below the content noise in the audio band for some extra headroom, to land at only 13 bits of actual audio+noise, and 3 secret encrypted DRM bits, do recover some lossy ultrasonics and add one extra lossy octave compared to redbook quality. With 24 bit distribution files, they most likely have 16 bits for the baseband audio, and 8 encrypted lossy DRM'ed bits to add an extra octave. So again, with 24 bit distribution files and 10 bits of real audio data like the dynamic range of a typical hall like deSingel in Antwerp, the claim of "6 bits below the content noise in the audio band " can be true. MQA basically debunks the need for 24 bits of audio bit depth Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted September 6, 2017 Popular Post Share Posted September 6, 2017 3 hours ago, Bob Stern said: Regardless of Warner's present intention, Meridian's streaming format is specifically designed to implement DRM copy protection. The US counterpart of their 2013 patent application is at: https://www.google.com/patents/US20160005411 We all know by now MQA is not a lossless but lossy codec. So why does the patent has incorrect information, see bold text below? Quote 1. A method of providing a streamable PCM signal allowing conditional access to a lossless presentation of an original PCM signal, the streamable PCM signal having the same sample rate and bit-depth as the original PCM signal and providing a controlled audio quality when played on standard players, the method comprising the steps of: reversibly degrading a representation of the original PCM signal in dependence on degradation information for degrading the original PCM signal; Let's unblur some of the terms: 1. "conditional access" = DRM = digital rights restrictions management = crippled by design, as rights have been taken away and sold back to you by means of having to buy a licensed player or DAC. This DRM can go very far, including transaction servers and phone home: Quote The methods of the current invention can support several commercial models for distributing audio in which the delivered file can convey a compatible but reduced quality but whose full quality can be decoded and confirmed by methods which combine Song and Device and User keys. The distribution methods may be: “Informative” where the decoder confirms that a legitimate stream is decoded by a legitimate decoder; “Restrictive” where the transaction server can limit the full quality playback to combinations of Users and Devices; “Trace” wherein songs contain embedded information which may displayed in whole or in part during playback or forensically, the removal of which prevents subsequent lossless recovery; “Positive” where the previous methods can provide an enhanced yet restricted distribution wherein the server permits copies to be gifted from one User to another. Which means MQA can be a phone home format. With real lossless highres like the good old 24/192 downloads we had for almost 10 years, there is no conditional access. No crippling, no degrading. No phone home. 2. reversibly degrading a representation of the original PCM signal -> this can never be true with a lossy codec like MQA, see below 3. degrading = crippling by design This degrading can go very far according to the patent: Quote A further variant is to combine the degradation and burying into a single operation. This can be done for example using the burying method described later, in particular making use of the lossless pre-emphasis methods shown in FIG. 13 and FIG. 14 of published International patent application WO2013/061062, which is hereby incorporated by reference. One degradation method consists of generating white pseudorandom noise, lowpass filtering the noise with for example four cascaded first-order filters each with a −3 dB point of 700 Hz, thus providing a combined ultimate slope of 24 dB/8 ve. The filtered noise signal may now be added to a constant slightly less than unity to provide the multiplier h shown in FIGS. 13 and 14 in published International patent application WO2013/061062. If the noise has suitable amplitude, the resulting degradation may be perceptually similar to that produced by lossy compression algorithms such as MP3. Lossy codecs are not fully reversible, once the damage is done and the entropy has been reduced, that information is gone. Nothing is going to bring it back. Just like MP3: 320kbps can sound transparant, but transparant is not lossless. MQA is not the master, but an approximation of the master, therefore MQA would be better described as Master Quality Approximated: MQA can't encode any audio frequencies above 48 Khz, so it will always be an approximation. So is the patent misleading? Bob has stated that MQA is an approximation, but at the same time trying to convince us it's lossless, if we should believe the patent. None of the audio press I have encountered so far really understands MQA, they are just copy/pasting the marketing. Making (deliberate) mistakes in patents and maintaining dual truth standards (mixing lossy/lossless/transparant as if they were synonyms) does not make it easier for the audio press to understand what's going on under the hood. MQA fits perfectly in the model where you no longer own music, and every playback of a file is done using a transaction & token, via a transaction server, so they can follow the users perfectly. They can listen to an approximation, believing this is the master, while it's not, while the system phones home the user habbits. So if MQA denies DRM, the above patent proves otherwise. So some of the claims of MQA must be quack. mcgillroy, Shadders and MikeyFresh 2 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 6, 2017 Share Posted September 6, 2017 20 minutes ago, lucretius said: But you can copy MQA files, assuming you can purchase them. The DSD file on an SACD was never intended to be copied. Also, the "quality degraded version" you speak of does not really seem that "degraded" as far as I can tell listening to tracks from Tidal. For now the distribution method is "Informative", but the patent allows DRM to be applied in totally different ways, and they can change their game once MQA has a bigger market penetration:https://www.google.com/patents/US20160005411 Quote The methods of the current invention can support several commercial models for distributing audio in which the delivered file can convey a compatible but reduced quality but whose full quality can be decoded and confirmed by methods which combine Song and Device and User keys. The distribution methods may be: “Informative” where the decoder confirms that a legitimate stream is decoded by a legitimate decoder; “Restrictive” where the transaction server can limit the full quality playback to combinations of Users and Devices; “Trace” wherein songs contain embedded information which may displayed in whole or in part during playback or forensically, the removal of which prevents subsequent lossless recovery; “Positive” where the previous methods can provide an enhanced yet restricted distribution wherein the server permits copies to be gifted from one User to another. and: Quote It is assumed that the account holder will possess one or more players, each of which is able to decrypt an item that has been encrypted with a user key specific to the account holder, and also possibly with shared user keys or a universal user key that is common to everyone. The method encrypts the song key with an appropriate user key so that only players that know that user key may retrieve the song key, which is generally common between performances of the method on a given song. This feature allows the steps of reversibly degrading and embedding to be performed once and the result stored in a server, only the remaining steps being repeated for each transaction relating to a given song. With MQA you don't own the master, but the right to play it back either in a crippled way (where this can be manipulated to sound like CD or all the way downgraded below MP3 quality), or in an approximated way (which also undoes some of the crippling). Their DRM allows phone home, and they can change their game. MQA is indeed very bad for music. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 6, 2017 Share Posted September 6, 2017 2 hours ago, mcgillroy said: Especially since we don't know how key-managment is implemented. Is MQA controlling the PKI and handling root-keys + signing processes? Anybody shed some light on this? Michael can you ask Bob if you get the chance? It's a fact that studio's still don't have access to an encoder. So MQA holds all the cards related to signing the files. No mastering engineer signs the files. It's all done in an MQA facility. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 8, 2017 Share Posted September 8, 2017 4 hours ago, Fokus said: Yes. You can record from the Tidal desktop app. It is a bit laborious. The desktop version of Tidal uses encrypted flac files. So you can't intercept the flac files over http, as the file looks like garbage. But Tidal also has non-encrypted versions for devices that don't support encryption. These files are protected with a token system. Tidal files played via the desktop app and chrome are already encrypted. Add MQA to the mix, and we have: - encryption of the flac file without using HTTPS - ecnryption / obfuscation of the pseudo highres part of the MQA file used for the unfold - authentication via MQA - DRM with degrading up to MP3 levels (see the patent) for those without an MQA decoder MQA hardware decoding modules have the possibility to add an ID number, which increments for every module sold. Phone home DRM based on the ID of the MQA decoder is technically possible looking at their patent, but impractical for now. It would require a lot of middleware to be added to Tidal to have per customer locked MQA files. It would also imply modifying some flags in the files, or use an out of band system to check if the customer has the right to play the file, which will add a lot of complexity and break current implementations. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 12, 2017 Share Posted September 12, 2017 It seems MQA has their own loudness war on unaware players While reading [0025] ... [0027] of the patent, which describe the deliberate degrading of the sound by messing with the gain, https://www.google.com/patents/US20160005411 it mentions Peter Craven's patent: Quote The representation is deliberately degraded in a reversible manner, for example by applying a time-varying gain as described in published International patent application WO2013/061062, incorporated herein by reference, so as to provide a lower sound quality when the song is played by an unaware player as if it were a standard PCM signal. So which artist would allow the deliberate degrading of their work, as mentioned in 26? Quote The first purpose is to allow the degradation to be reversed on playback; the second is to allow the degradation to be selected on artistic, aesthetic or commercial grounds by the artist or his representative and to be consistent for all account-holders who may purchase the song. The real issue is their artificial loudness war. Let's look at their gain manipulation:https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2013061062 Abstract: Quote Some methods employ complimentary amplification and attenuation, while others employ gain redistribution. Pre-emphasis and soft clipping techniques are described as methods of losslessly reducing the peak excursion of the PCM audio signal. The above & claim 32 basically describes compression: Quote 32. A method according to any of claims 26 to 31 , further comprising the step of: losslessly pre-emphasising (70) the digital audio signal in order to reduce the amplitude of frequency components that have high energy. So it seems MQA has their own version of the loudness war (=dynamic range compression / gain manipulation) as a feature, to cripple playback on non-licensed or MQA unaware players, in order to make the difference with decoded MQA bigger. Please convince me how this is not bad for music. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 14, 2017 Share Posted September 14, 2017 https://www.gearslutz.com/board/12847173-post86.htmlRMAF has cancelled the MQA Panel. Quote This was to be Sat 12noon in prime time with Richard Schram owner of Parasound moderating. MQA rep Mike Jbara bailed first on his desire to talk with me ahead of the panel, then RMAF cancelled the panel. Coincidence or pattern? You decide. I would bet my savings they were pressured to do so by Jbara or Stuart in the face of a serious panel with serious questions. They must be very afraid of Brian Lucey and those with real questions Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 18, 2017 Share Posted September 18, 2017 More info on the RMAF MQA panel cancellation. MQA: Avoiding Confrontation By Mark Waldrep: http://www.realhd-audio.com/?p=6046 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 18, 2017 Share Posted September 18, 2017 1 hour ago, The Computer Audiophile said: Berkeley is in a unique position, having spent millions of dollars on research for the previous company Pacific Microsonics. https://www.gearslutz.com/board/mastering-forum/1101429-mqa-39.html Quote Further, the founder of PM, now Berkeley Audio AGREES THAT MQA on PCM is destructive, he sees this stage as a necessary evil to get to all MQA world, round trip for all. Grammy award winning engineer Brian Lucey who is against MQA, uses PM converters. So why did Berkeley make a 180 degree turn? Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 19, 2017 Share Posted September 19, 2017 3 hours ago, miguelito said: "My assessment is that MQA is definitely different, and usually better. Not night and day better, but better. Think about it. This is music arriving in your room via the Internet, for a fairly minimal monthly charge—an exponentially increasing body of recordings for playback with sound quality that’s, at the very least, as good as the best present high-resolution digital files." When no more technical arguments are left, the MQA key opnion makers always fallback to one of these 2 options: - you must go listen - or post their standard time domain argument, with some copy paste journalism So what did we do? We bought an MQA DAC, put it in a nearfield setup with Amphion Two 18, a big Vitus amp, and listened to DXD vs MQA files from 2L.no I was first tempted by more echo & reverb in the MQA files, but something was missing in voices. It also sounded thinner. These are subtle not day and night differences, but the fact that the DXD sounds different from the MQA version, de-authenticated the A in MQA. Only one can be the studiomaster quality. Studio's like 2L.no have worked years ago on their DXD masters. These were already available in 2013 when we entered the music server world. Those DXD files are 2L.no's reference of the studio sound. 2 years later MQA enters the market. Now the MQA version with de-blur via their weird filters is supposed to be the new definition of master quality, while it's actually a post-processed version of the original master, de-authenticating the originality. Since day 1 I find the A in MQA misleading and false advertising. The A should be Augmented or Approximated, otherwise it's misleading. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 24, 2017 Share Posted September 24, 2017 11 hours ago, james45974 said: When will the first manufacturer get the idea that they have been hoodwinked to give away their family jewels (their DAC tech to MQA for filter implementation) and walk away. Are MQA's NDA's in two ways? Do they protect both parties? What if MQA / Bob Stuart violates the copyright of the DAC designs of their MQA partners? What are the penalties? Or is it just a one way document, like most EULA's, where one party sets all the rules, and the other party has to blindly accept? Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 24, 2017 Share Posted September 24, 2017 4 hours ago, Shadders said: Hi, What is intriguing is that MQA Ltd have to approve the DAC design. Why would you need to approve the actual physical design of the DAC, if all MQA is, is just an IC ? Could it be something to do with the requirement that the digitally unfolded signal cannot be sampled - for recording. Does the design of the DAC have to include the physical protection of the DAC IC and MQA chip interface ? Regards, Shadders. In some implementations, MQA is basically an XMOS board with I2S in and I2S out, this allows all inputs to go through the MQA decoder. In other implementations , the MQA decoder is sitting on the USB input board, so instead of USB -> internal I2S, the board has USB->I2S->MQA->I2S to backplane. This only works for USB. In other implementations, a full MQA software decoder (doing first unfold + renderer) is sitting on an ARM based board, which also functions as network bridge. Shadders 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 26, 2017 Share Posted September 26, 2017 17 hours ago, Shadders said: Hi FredericV, Thanks. The design seems easier than the secrecy that surrounds it. Is a network interface required in all designs ? Thanks and regards, Shadders. DAC's with MQA don't check the network (for now) and lack a network interface, but DAC's support a unique serial for each decoder, which in theory can be tied to a user via DRM, when reading their patent. It can even be done offline, just like a DVD player checking if the region code on the disk matches what is in the firmware. For MQA files, that could be (speculation) matching the serial nr of the dac to the serial nr encoded in the MQA file for a given user. So DRM could in theory encode some flags in a file so that it only plays on certain serial nr's of dac's (basically an access list). This would require some kind of synchronization scheme, where to user can enter the serial nr of his DAC when buying MQA files. Or the serial nr could be read via USB. But for this to work, there need to be an infrastructure that manages the ACL's and DRM. So while current MQA files are not limited to certain users via DRM and access lists, once MQA starts to gain momentum, that could all change. It's already mentioned in their patent. Shadders 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 26, 2017 Share Posted September 26, 2017 5 hours ago, realhifi said: Just noticed this ad for NAD’s new receivers. The ad is in Sound & Vision which is as mainstream as A/V gets. Look closely at bottom left of ad that lists features of the receiver. Looks like slightly more than vaporware at this juncture. Nothing new here, an NAD with a buesound raspberry alike ARM board. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted September 27, 2017 Popular Post Share Posted September 27, 2017 Does it make any sense that MQA is allowing tube dac's to be certified? So is MQA undoing the coloration of the tube sound (1)? Or does it allow the tube sound to be applied onto the unfolded lossy pseudo highress (pseudo as everything above 48 Khz is fake as replaced by aliasing artefacts) (2) ? If (1) is true, what's the point in having a tube DAC anyway? If (2) is true, it's not authentic to the DAC that was used in the studio, as I don't know many studio's that master using tube dacs. If (2) is true, does make it sense to apply on of the 32 weird filters, that fight with the transient response / harmonics of the tubes. A lot of studio's use Mytek, Antelope, .... I used to sell Antelope to studio's a long time ago. I also used to sell tube amps when I was still a hifi reseller, so I know a lot about the issues of tube gear. When tubes or tape gear is used in studio's, it's to give the recording extra coloration, saturation and warmth. It's used as an effect. Some studio's master digitally, then run it through tape as a saturation effect. So when applying MQA to gear that aready colors the sound, who makes the decision which artefacts need to stay in the product, and which needs to be removed by MQA? The same applies to recordings made with analog gear with colorations, to give it's distinctive sound. Shadders and esldude 1 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted September 27, 2017 Popular Post Share Posted September 27, 2017 3 minutes ago, mav52 said: And Fredrick sent me this one ; CanEVER ZeroUno plus a DAC /pre The fact that MQA is certifying tubedac's (which add distortion praised by many audiophiles), debunks the whole idea of having the studio sound at home. plissken and Shadders 2 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted September 27, 2017 Popular Post Share Posted September 27, 2017 1 hour ago, firedog said: Why? the tube DAC has the tube on the DAC analog output to the amp/speakers. Not on the MQA processing. Every DAC, amp, and set of speakers colors the sound in some way. Tube or not. The essence of MQA is that the DAC does not color and outputs the same "analog signal" as in the studio as it is supposed to be an end-to-end system for AD-transport-DA. By having tubes in the DAC, they break that chain. So MQA has dual standards. esldude and Shadders 1 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 27, 2017 Share Posted September 27, 2017 Just now, firedog said: No, I think you are over interpreting it. The analog output section of the DAC (not the DA converter itself) has a tube. So as far as the end result, it's no different than using a non-tube dac and a tube preamp. So why should MQA care? I used to sell tube dacs/amps/cd-players, and solid state dac's. The output sounds completely different. What is your affiliation with MQA? Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted September 27, 2017 Popular Post Share Posted September 27, 2017 29 minutes ago, firedog said: They sure do, which is exactly what proves my point - all DACs color, tube or not. MQA or not. You are conflating the D/A conversion section of a DAC, which then sends the signal it has produced to the analog output section - which sounds different on every model of DAC. Zero affiliation with MQA, which means I can claim to understand it just as well as you do. Please show me the proof of your claim that MQA has said an MQA DAC will "add no color" and all MQA DACs will sound the same. Your interpretation of what they are saying is simply incorrect. MQA is selling an authenticated end-to-end analog solution. They claim to have a DAC specific custom filtering. This it leaves no margin for tube coloration. Shadders and esldude 1 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted September 27, 2017 Share Posted September 27, 2017 5 minutes ago, firedog said: Apparently MQA only cares that the DA conversion is properly "deblurred", as they refer to it in their universe. Once that has happened, they don't care if you pass the signal through a tube, a transistor, an output transformer or a whatever. In their terms, once they've supplied you with the properly reconstructed signal they've done what they promised - if you want to muck it up after that, it is your choice. To measure the transient response of a dac and how it deviates from the ideal transient response (like in my metrum adagio, MQA can't correct anything, it has no pre- nor postringing), you need to play transients, and record the analog DAC output, then look at the transient response to see the ringing artefacts, and correct them as a total system (e.g. in case of MQA using weird filters). It's not possible to measure a tube DAC without the tube, or measure it's response as if it's a solid state DAC. It simply does not work like that. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
Popular Post FredericV Posted October 2, 2017 Popular Post Share Posted October 2, 2017 Last weekend we were an exhibitor at the X-FI 2017 show in The Netherlands where our server was being presented in three rooms, including our own demo room where we had carte blanche. We had a lot of fun playing both audiophile and real music including Manley based masters from Jazz Profilactika, a befriended new Jazz band, from which we received their 24 bit master files one day before the show. We also did a little test with MQA files from 2L.no Demonstrated using Antelope's Platinum DAC + separate 10M atomic clock + separate Voltikus, and the excellent active John Watkinson speakers which are not very well known, but among the best which I have heard so far. https://www.flickr.com/photos/147070590@N02/36730762584/in/dateposted/ The co-designer of the Legends is Kommer Kleijn, a "professor" type of guy who is also a respected 3D stereographerhttp://www.kommer.com/ The lead designer is the guy who wrote the "bible" about digital audio:https://www.amazon.co.uk/Art-Digital-Audio-John-Watkinson/dp/0240515870 I have no affiliation with this speaker brand except that they make a great demo partner. I have no affiliation with Antelope either, in the past we were reseller for a couple of years until we decided to go into the music server business. I now use Metrum Adagio for my own test & dev. I list the specs so that others won't say our system is not revealing enough to do such test. We also fixed the flutter echo of the room using acoustic panels. Just to make the test setup right. Just before the end of the show on Sunday, we played the following test on our server: 1. DXD master from 2L.no, a classical piece 2. mqa version of the above, with a live version of the sox method as disclosed on Darko's site. We tried to make this test as blind and unexpected as possible, so after the DXD file played (a classical piece), we said we were going to play a different version of the same file. So we played the upsampled MQA version, than asked if they could hear the difference. They could not. I begged them to please reveal any difference, if any ... nobody in the room was able to tell them apart. So for me, this is case closed. Why waste any more time with MQA or trying to figure out the secret parts, if the sox method can do the above? The MQA people will fight us and say sox is not the real thing, but sox is pseudo MQA just like what Auralic is doing. But who cares if we achieve the above. The end result is what counts. MQA fans always say our hearing is analog and the number of bits don't matter, and the end result is what's count. Another eye opener was that an AES engineer which I heard talking about MQA in a Chinese restaurant in Veldhoven and later was in the bar of our conference center, told me our hearing has 5µs of temporal resolution based on the fact that we can locate a sound source with 2 to 3 degrees of accuracy and a calculation based on the distance of sound sources, he explained how he came to this number. I was too tired to completely remember how he did that calc. The 50µs that MQA is claiming is not enough. He explained that for a true end-to-end system that can duplicate the in air response of a source, it would need a microphone that can capture much higher frequencies, and the samplerate would have to be much higher than 192K to achieve 5µs. He calculated that it would at least need an analog bandwidth of 200 Khz, so sampling at 384K won't even cut it. It would also require microphones that can capture all the harmonics of S-sounds and cymbals, which cannot be seen in regular spectral plots, as they average because of the integration window and these transients are very short. It's like measuring the average sound level of an airport at night, when only a few planes fly by and keep you out of your sleep. The average will still not show this. He was present at an MQA introduction show using very expensive speakers and being demo'ed by Hans Beekhuyzen. He told me the S sounds are all wrong with fully decoded MQA, and that he would never dare to give such a bad demo. This demo was at a very well respected ultra high-end boutique dealer. The interesting part about this AES engineer is that he sent all his remarks to Hans and another well known MQA opinion maker, but Hans completely ignored this. We talked for more than an hour, maybe this guy can post his technical arguments, I still have his card But for me, this is now case closed. I'm happy that thanks to MQA I put a lot of effort in tweaking our own DSP and I learned so much more about filters, and that we found the sox method and it's correct settings which we posted on Darko, so other devs can start using it. But I'm not a fan of their anti-ringing and weird filters that try to clean up post-ringing. I also briefly talked to the leading MQA opinion maker in the Netherlands. He also visited our room, liked the sound. Shook hands and got a message on FB today that he wanted to cease fire. We won't change these people. It is pointless. They won't change my opinion. The fact that we have topics like this is good as this discussion is kept away from the regular press, but in talking with the MQA people, at a certain point, there is nothing new to bring. This is the reason why the topic at gearslutz was locked: they landed into name calling. Let's agree to disagree and shake hands. Shadders, Tsarnik, Siltech817 and 1 other 2 1 1 Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted October 2, 2017 Share Posted October 2, 2017 1 hour ago, crenca said: Thanks for the write up Frederic. Just to be clear, the active speakers do not have a DAC (and thus a 2nd A>D>A conversion) correct? The speakers have XLR & IEC power inputs at the bottom. Internally every speaker has four amps. All processing / filtering is in the analog domain. There is no extra AD/DA Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted October 4, 2017 Share Posted October 4, 2017 1 hour ago, Pure Vinyl Club said: Hi, FredericV. How could you play on Antelope Zodiac Platinum (which is not MQA) native MQA files? Please explain in more detail the whole process of listening ... The zodiac platinum will accept 24 bit in any samplerate up to 384K, so those decimated MQA files which are typically 24/44.1 or 24/48 will just play, but with a higher noise floor as 9 bits contain the control data and secret DRM encrypted MQA non-nyquist data, which a normal dac will play as noise. When using sox based resampling, the difference between the original DXD master (in case of 2L.no) and upsampled MQA using nothing more than the 24/44.1 or 24/48 files and no licensed decoder, becomes so small it cannot be distinguished under blind testing, even on the most expensive sets. Most are guessing or can't tell them apart. In the test we did on the show, nobody could even numerate any difference between both. Anyone can peer review the test:http://www.digitalaudioreview.net/2017/07/kih-46-mqas-missing-link/ Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
FredericV Posted October 5, 2017 Share Posted October 5, 2017 41 minutes ago, psjug said: Because air attenuates ultrasonic frequencies transmitted >3m. So a terrible problem (sarcasm). See Page4 here http://www.aes.org/tmpFiles/elib/20171005/17501.pdf So this means in a 1000 seat concert hall like de Singel in Antwerp most of the ultrasonics are gone, because of the distance: I was in the 7th row and at least more than 10m from the choir. Video done with Nikon D750 and no tripod (I was to make photo's but it was so impressive I started recording): My colleague Kommer Kleijn made me aware of the above curves, and that this is an actual problem in PA design. It's even more a problem outdoor, with changing weather conditions, temperature, humidity .... I made recordings of this hall, and indeed, the highest frequencies are severely attenuated. The unamplified sound of the choir is also much better than the artist K''s Choice playing via the PA. Furthermore this hall also has reflector panels, making the traveled distance of sound even longer, which is mixed with the directional sound. For those listeners in the rear rows of the hall, all the ultrasonics are gone. Sarcasm indeed. Designer of the 432 EVO music server and Linux specialist Discoverer of the independent open source sox based mqa playback method with optional one cycle postringing. Link to comment
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