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Computer Audiophile

Don Hills

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About Don Hills

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  1. MQA technical analysis

    Thanks, Mans. That's cleared some of the fog (and created some more... ) Plenty for me to think about. Regards...
  2. MQA technical analysis

    Thank you. I am now confused at a higher level, because in the vaporware thread I recall you saying that the encryption could be applied to "higher" bits of the undecoded (streamed) data. I'll need to review the threads and see what I missed. I'm trying to work out the place of the encryption in the process. My current understanding is as follows. Can you answer a true/false for each step please? (1) Currently, the "high res" part (> 24 KHz) is encoded into 8 bits and then (2) encrypted before being added below the upper 15 bits of each sample. (Bit 8 reserved for the control stream.) (3) The encryption can be applied to more of the 24 bits of the sample, effectively reducing the bit depth of the 0-24 KHz data. For example, there might be 7 bits of 0-24 KHz audio and 16 bits of encrypted data. This would require the control stream to be positioned "higher" in the 24 bit word, above the encrypted portion, and the format does apparently allow for this. Thanking you in anticipation...
  3. MQA technical analysis

    @mansr, did you ever get any further with this? I originally read it that the bit reversal was present in the undecoded stream, but on re-reading you appear to be saying that the core decoder reverses the bits before feeding them to the renderer. This would appear to be of limited utility, it simply enforces the use of an MQA renderer. It also sounds trivial to work around.
  4. MQA is Vaporware

    In that case, why are you wasting your time here?
  5. Why does consumer audio SUCK?

    Here, maybe. The wider audiophile population, maybe not so much. Do they? I guess I'll find out when I retire. Admirable. Sadly, such altruism is rare in this business.
  6. Why does consumer audio SUCK?

    It wouldn't be expensive enough for the majority of audiophiles, and personally I'd be uncomfortable putting it in a boutique case and selling it at an enormous markup. There are DACs with poor noise rejection, some of them expensive. There are DACs with excellent noise rejection, some of them very cheap. If I were looking for a new DAC, I would make a short list of DACs with excellent noise rejection and good measured performance, audition them and pick the one I liked the best, using price as a tie breaker.
  7. Why does consumer audio SUCK?

    Fixed it for you...
  8. MQA is Vaporware

    In addition, the encoding filter used to split the audio into the 0-24 KHz and 24-48 KHz bands may be less than optimum for audio quality. It doesn't matter for core decode because a complementary filter is used to rejoin the bands, but it will affect the sound when played undecoded. @mansr, did you plot the coefficients of the rejoining filter? It should tell us about the encoding filter.
  9. MQA is Vaporware

    Opus101's description is considerably simplified but correct. Try this: https://en.wikipedia.org/wiki/Ringing_artifacts If you prefer your education in video form, start here: https://www.youtube.com/watch?v=FG9jemV1T7I You may find the section from 3:00 to 16:00 most relevant. Next, go here: https://www.youtube.com/watch?v=cIQ9IXSUzuM I strongly recommend watching the whole video. Pay particular attention from about the 17:20 mark. The tl;dr summary: "Ringing" happens when the filter has to cut off energy at or above its cutoff frequency. Good luck trying to find a musical instrument that produces any significant energy above 96 KHz, and even more luck finding a microphone capable of recording it.
  10. MQA is Vaporware

    It's not a key part of the folding. You can achieve the same result (reversibly converting the "folded" part to pseudo-noise so as to hide it under the 0-24 KHz signal) without encryption. MQA works like HDCP. You can copy the source file freely. But you can't play it at full resolution without the licensed decoder.
  11. MQA is Vaporware

    The DRM mechanism is present in all MQA files. Strong encryption is used to encode the "hi res" part of the data (the 24-48 KHz part stored in the lowest 8 or so bits of each sample.) Currently the upper bits ( 0-24 KHz, 15-17 bits) are unencrypted, but the format allows for encrypting most of the upper bits as well. As I've explained to you before, I believe it'll play out the same as HDCP has done for the HDMI standard. No enforcement of rights in the initial stages until the format becomes ubiquitous, then increasing enforcement. As for revenue stream, it's not so much about revenue. It's about control. The labels see their loss of revenue as being caused by a loss of control. They want the control back.
  12. MQA is Vaporware

    To add to what Samuel said, CA is not a zero sum game. It's not space limited. More posts on MQA doesn't have to mean less posts on other topics. If you're seeing fewer posts on other topics, it may be that the people who usually post on those other topics are presently posting on MQA topics instead. If you appreciate their wisdom on those other topics, why do you not appreciate their wisdom about MQA?
  13. MQA is Vaporware

    He should have been "respectful" from the beginning, then he wouldn't have to slowly and painfully earn his reputation back.
  14. MQA is Vaporware

    Indeed. Note that it proves you don't need 24 bits to get "exemplary resolution of low level detail" - 15 to 17 bits is quite adequate. But regardless, it isn't the sound that was heard in the studio by the artists and producer who signed off on it. (*) We won't get that until we start getting music which was recorded from scratch using MQA enabled ADCs. (*) The original music was auditioned and approved using standard PCM ADCs and DACs. They tweaked it until it sounded the way they wanted. You need to use a "standard" PCM DAC to listen to it. Processing it later with MQA may make it sound different, and you may prefer it, but it's not what was originally heard and approved.
  15. MQA is Vaporware

    That doesn't answer the question, where do they expect the profits to come from? (I have my own opinion, but I'm not in a position to know so I'm interested in Lee's thoughts.) As for distinguishing between collusion and cooperation, I don't see either as having played a part. Can you expand on your thinking?