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MLXXX

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About MLXXX

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    Brisbane (ex-DTV Forum member)
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  1. Well that is certainly interesting. Am not familiar with "extreme" upsampling; will need to investigate what is involved.
  2. Did you take the precaution of resampling the downsampled audio back up to the same SR as the original file, in order to present the DAC with the same sample rate (so it would use the same reconstruction filtering parameters for its analogue output)? I find Audacity can do downsampling and resampling fine. And foobar2000 with ABX plug-in can then be used to compare the original and twice resampled file. If you can ABX a difference I'd be interested in whether you find that only occurring with a downsampling to 44.1kHz rather than 48.0kHz. I'd also be interested in how "profound" or "minor" the differences are for your ears. (As for myself, I can no longer do meaningful tests even at 44.1kHz, as the upper limit of my hearing peters out at a little above 10kHz.)
  3. DSP is commonly done using floating point representation of amplitudes. In that situation there is no clipping in intermediate stages of the data manipulation. I agree with Ittaku here. Dither isn't needed in the above precise situation of a digital signal for an output device at 24 bits. Truncation would suffice. The least significant bits of 24-bit audio will inevitably be buried in noise, and well below audibility. (On the other hand, using dither for the 24th bit wouldn't actually do any harm.)
  4. By way of comparison, here is what looks to be the same design of test pattern, as displayed on a flat screen 4K television (source: review of Panasonic Viera TH-65AX900A):- "Switching this off restored my test patterns to perfect, full resolution display (see second image). You aren’t going to see your high-resolution photos look any better for the foreseeable future than on this TV. * * * I don't know whether the blur in the green lines in the image above was due to the camera used for the review article, but if we assume the above image is accurate, and not an artefact of photography, green was not displayed with single pixel resolution. Tonight I've tried with my own TV, a 75" Samsung Q75, getting it to read a thumb drive with the 4K test pattern file downloadable from http://hifi-writer.com/wpblog/?p=4400. (Although it is only a jpeg file, it has single pixel resolution.) With default settings, my Samsung Q75 does not render the 1-pixel wide green lines clearly when reading the thumbdrive image, interspersing some red between those lines (as I was able to confirm by inspecting the screen with a magnifying glass). It renders the black 1-pixel wide lines very clearly, and the blue and red lines fairly clearly. The photo below taken of my Q75 screen tonight has sufficient resolution that it reveals the colour subpixels making up the white background. Care needs to be taken when interpreting the very fine detail of these sorts of images because the physical layout of the subpixels of the camera sensor can interfere a little. (The camera used was a Panasonic DMC-G85). I would still be keen to see a photo demonstrating that single pixel UHD resolution has been achieved using advanced pixel shifting. As Owen has pointed out, the image in the review article in French does not include the extreme left and extreme right blocks of the standard test pattern that we can assume would have been used. Those missing blocks are where the UHD performance would be tested using lines only a single pixel wide. So the most demanding blocks of the test pattern, arguably the main feature of interest in evaluating the "4K" performance, have not been revealed. Close-up view of 75" Samsung Q75 QLED TV displaying vertical lines of a UHD test pattern:-
  5. I've seen a lot of posts mention chromatic aberration in relation to the W2700. I'm still trying to find confirmation by way of a clear photograph of a UHD test image that advanced ("4 times clockwise") pixel shifting that in theory should work so as to give true 4K resolution is in fact delivering that. Why this really basic and obvious test doesn't seem to appear in user threads, or in most formal reviews, escapes me. I've found a review in French that includes a glowing account of the resolution achieved but the image used to show that is not all that clear. Here is the Google Translation version of the relevant part of the review:- Sharpness / sharpness: The purchaser of a 4K projector looks for image accuracy and gain in definition. These improvements can not be obtained if an effort is not made on the quality of the optics. This point, BenQ engineers have integrated well and offer for years on their models all-glass blocks. BenQ W2700 4K 2 Sharpness Chart The W2700 is no exception to this rule and, despite its 4K simulation process, my Ultra High Definition pattern can not make the difference with the rendering of a native 4K projector like the Sony VW270 or the JVC N5 . Better still, I find that the DLP gives a better transcript and separation of the lines. The precision of the 4K image offered by the new BenQ is exemplary, both on the edges and in the center of the screen. It should be borne in mind however that this projector is marketed at 1599 €. The original version of the above review in French is at: https://www.passionhomecinema.fr/blog/index.php/28/03/2019/test-benq-w2700-lavis-de-gregory/
  6. I suggest you should be more concerned about screen contrast (inkiness of the blacks, brilliance of the whites) than whether the panel looks flimsy. (I'm sure the Samsung screens are sturdy enough not to flex or break once the TV is in position for viewing.) I tend to agree with that. Perhaps if the buyer will be restricting themselves to free to air TV and is not very concerned at all with picture quality, just chasing screen size, the approach of going for a very cheap 75" TV could work for them. @Al.M, would you be intending to connect to a sound bar or hi-fi system? The cheaper TVs tend to have quite limited sound quality from their built-in speakers.
  7. I've looked at several reviews of the BenQ W5700 but none of them includes a close up of a 4K test pattern. Has anyone else spotted such a test pattern, with the alternating black and white lines 1 pixel wide actually visible? Theoretically, if the pixel size were kept small, this method would give the equivalent of true 3840x2160, on a time-multiplexed basis. Edit: I've now found such a review for the BenQ W2700. It's at https://7review.com/benq-w2700-review/ :- Performance The first thing I did after connecting up the projector was run my standard Ultra-HD resolution test pattern. I’m pleased to report that the projector resolved the pixel-wide-or- tall lines so that they could be individually discerned (see image opposite). To be clear, they are a little smudged, not as cleanly etched as they are on an Ultra-HD TV. I reckon that could be achieved with a design change, such that the mirrors on the DMD and the spaces between them were of similar dimensions. That would eliminate the remaining partial overlap between the shifted pixels. But that would also mean considerably reduced brightness since there’d be a markedly smaller reflective surface. Anyway, while imperfect, the line separation was the best I’ve yet seen from this breed of XPR DLP projectors. ▲ Close-up detail of the UHD test pattern delivered as video and captured photographically. The individual lines of pixels visible are a single pixel wide with a single pixel separation, showing that full 4K is delivered accurately.
  8. From what you've posted there was a very adverse effect on your vinyl playback. How serious were the effects on your other equipment? * * * At my place we've had security cameras connected using ethernet over power for the last 7 years or so. The ethernet adaptors came with the cameras. There's been no effect on any of the audio equipment as far as we've noticed. At one stage we tried to connect a Foxtel box to the internet using the ethernet over power adaptor Foxtel provided with the box. However it wouldn't work unless the security camera ethernet over power was switched off, so we didn't persist with ethernet over power for that Foxtel box. (We considered running ethernet cable to remote parts of the house but instead we find the wi-fi modem does most of the house and a Netgear wi-fi repeater can service the remainder.)
  9. If he can already read some English he could learn the specific technical vocabulary used in work orders and instructions, and the non-technical words that might come up such as road, kitchen, and bedroom. Difficulties could arise if any of the written material was in handwriting. Most of us don't write very clearly.
  10. It may have been designed so long ago that it incorporates a 10kHz whistle filter. That was useful when Australian medium wave band AM stations were spaced 10kHz apart, rather than the current spacing of 9kHz (which took effect in November 1978). Yes the treble response would far exceed that of ordinary AM tuners incorporated into AVRs, or portable radios, or car radios. The downside is the much increased risk of picking up interference (especially at night) and signals from stations on adjacent frequencies. What I find a bit disappointing is the level of THD with AM radio reception, even when using a design focusing on audio quality, such as yours. The AM medium wave broadcasters in Australia are licensed to transmit audio at up to 9kHz and will do so, but many broadcasters will boost the mid-frequencies in order to achieve a punchy sound on non-wideband radios (which would represent over 99% of AM radios in current use in Australia).
  11. Boat people or other "illegal immigrants" housed and fed at government expense in detention centres; that is to say people who wanted to come to Australia to share our prosperity (and perhaps escape a harsh political regime) represent a difficult case. Some of them are suffering psychological trauma, and we read that some have taken their own lives. It is a very sad situation indeed. The citizens of affluent countries of the world enjoy their prosperity knowing that elsewhere human beings are struggling with the basics of life: water, food, shelter, clothing, and the most basic of health services. Citizens of some countries can be arrested on a political whim, tortured, or executed. News services may be highly censored, and full of propaganda. Fred Hollows led the provision of certain health services for isolated Aboriginal communities in Australia. He travelled overseas to help train technicians to perform basic cataract surgery that restored vision to many people who had been functionally blind for years and who had had no prospect of being able to afford the surgery without his personal intervention or because of the programs he helped set up. I find discussing whether the Australian government should fund the launching of additional telecommunication satellites so that a person in a remote part of Australia can enjoy a download speed better than the ADSL speed that many people in cities currently have and use, not something that excites a sense of urgency in me (or outrage if it were deferred). I think that people in remote parts of Australia will always tend to receive a less timely, and a less abundant, level of government services. To use an extreme example, the Australian government has never provided next day delivery of standard letters to remote communities. Australia Post does not criss-cross Australia with aircraft, and landing strips, so that any letter bearing a $1 stamp posted by 6pm local time will be collected from that part of Australia and delivered the very next day to any other address in Australia. The true cost of delivery per standard letter could be $500, $1000, or even more, for some remote parts of Australia, if such a program were started up.
  12. Because you've raised the question, I'll offer the usual kind of explanation in response, a kind of explanation I'm sure you must have seen before. For most types of services it is inherently cheaper per resident taxpayer, and more efficient, to provide the service in a region with many taxpayers than a region with few taxpayers. The taxation revenue from some sparsely populated parts of Australia is so low it is insufficient to fund the provision of any local services. Example Water $1000 worth of mains water piping in a densely populated suburb may be able to provide water connections to many homes, but $1000 worth of mains water piping in a rural community may barely stretch to the next farm. In many parts of Australia there is no mains water supply at all: it is cheaper to sink a bore into an artesian basin, use rainwater stored in a tank, extract moisture from the air using refrigeration or desiccants, or have water delivered by road transport. The broader debate I agree there is a broader debate over such things as what services should be regulated by government to reach a minimum standard, and what should be provided to the public "free of charge" using taxpayer revenue. The NBN would have been considered feasible to offer as a national service including remote areas, based on the availability of satellites. However there is only so much satellite bandwidth in orbit over Australia. It obviously isn't feasible to serve the whole of remote Australia with a handful of satellites, without resorting to bitrate limitations to some degree. It surprises me a little to see satellite plans offering as high as 25Mbps.
  13. Very disappointing for you. (I purchased my 75" Q75 in Brisbane in mid-June from HN, and they delivered it the following day.)
  14. Yes with amplifiers we might find that relative to the source material and relative to the loudspeakers they are driving they are less likely suspects for reducing the musical quality of the sound. Loudspeakers are a minefield of distortions of various kinds. It would be hard to know where to begin in terms of measuring their contributions to lack of linearity, and their subjective impact on the music listening experience.
  15. I've just gone back to the time aligned A and B versions I loaded into Audacity, and played them back on my hi-fi speakers but alternating between the two versions in real time. I found I could hear a slight overall shift in the brightness of the tone as between the two versions. Whether I'd be able to hear a difference by listening to the original video without the advantage of being able to switch rapidly between A and B I don't know. I think a mistake people who prepare these sorts of comparisons make is that they begin with the assumption that there will be a clearly audible difference. As a consequence of having that mindset, they don't pay too much attention to ensuring strictly identical test conditions.
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