Recent content by DDF

  1. DDF

    Simulation Analysis - Screws in Waveguide

    @René - Acculution.com thanks for sharing your expertise. This type of analysis is immensely powerful ASR tests show that loudspeaker port pipe-resonance remains a significant source of colouration. Given that grills and diffraction are well studied and shared in the public domain, it would...
  2. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I think the argument is simple and we're speaking at cross purposes. You're assuming the bottom bits don't really exist as they're noise and can be repurposed for ultrasonic information that can't possibly be heard, in concert with a "deblurring" process that could be implemented with all pass...
  3. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I also appreciate Kal's multi channel music reviews. Mr. Atkinson has also contributed interesting articles on speaker measurement in the past, one in particular that resulted in follow up for me. He is committed and honest. But I stand behind every word I wrote.
  4. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I edited my post to add the word "streaming". As shown in this long trail of posts, true lossless files (HiFi setting) are being replaced on Tidal by adulterated files adding the MQA fold in the bottom 3 bits. And as posted earlier, it appears they will be delivered this way by the record...
  5. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I've worked in very advanced professional audio engineering teams for years. I've also worked in other advanced technology engineering teams for years and worked in the 90's on technology now rolled out into Google Nest and Home Pods, these even use one of my patents. An appeal to authority...
  6. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I've been in this hobby for 40 years and a professional engineer for 30 including 15 in audio (highly complex aspects including codecs) and have always left room for the audio press indulgences. This is the final straw. While there are flaws in goldenboys test methods, the overall conclusions...
  7. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    Why expect an audio press untrained in engineering to weigh in on audio engineering matters? They're not able to. They're trained and highly skilled in writing and so weave a mythology that entertains and engrosses people, but doesn't educate them. The problem comes when confusing the two.
  8. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    So, we have fake hi res MQA, >20kHz high frequencies synthesized from the <20Khz in band audio. They then started changing "lossless" files by stealing the 3 bottom bits to fill with aliasing noise of these fake high frequencies. Given how good the AAC coder is, it's possible Tidal's Premium...
  9. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    It lowers their operational costs. This cost reduction changes the product's very nature hoisted on (previously) unsuspecting consumers. In a less sleazy world than audio, this would drive a new product name, or part number etc.
  10. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    Thanks, but these dont adress the most important question: what is the noise level created by down folded ultrasonics? Nearing 50 pages, and best estimate available is just from knowing mqas technique of chucking the bottom 3 bits: -78 dBFS. This is bad enough but likely inaudible if volume...
  11. DDF

    MQA Deep Dive - I published music on tidal to test MQA

    I'm debating. Whats missing in this discussion is an objective test of the noise added to 44.1 by downfolding realistic but aggressive ultrasonics. I spent years in the lab testing lossy codecs, and @amirm is right, high level ultrasonic tone bursts or square waves will tell you nothing about...
  12. DDF

    How Do I Keep My Apartment Neighbor From Hearing My Subwoofer?

    Place the sub close to your listening chair so you can reduce its volume. Some fit under a couch or coffee table. You'll need to have local power, run wire under a rug or use wireless, maybe add delay for blend, or more low pass filtering so it's not localizable. Use PEQ to tame peaks at...
  13. DDF

    Introducing Directiva - An ASR open source platform speaker project

    You can also think of a wide baffle like a power response equalizer. For flat on axis, a wide baffle moves the power response dip to a lower frequency than for a narrow baffle. Here's a detailed LS-1 analysis I made comparing wide to narrow baffle, assuming equal woofer and tweeter native...
  14. DDF

    Introducing Directiva - An ASR open source platform speaker project

    Back when Rick asked for some suggestions for the tweeter, I offered the DXT as a possibility, but my #1 recommendation was SB26ADC-000-4 for its better distortion performance (posted earlier, my bad). Rick had initially suggested the SB26STWGC-4. but the top end is rough and would need extra...
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