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About Dazed&Confused

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  • Turn Table
    Not since 1988
  • Digital Source 1
  • Digital Source 2
    innuOS Zenith Mk2
  • DAC
    The Oppo & Lyndorf
  • Integrated Amp
    Lyngdorf TDAi 3400
  • My Speakers
    PMC OB1i
  • Trade Status
    I am not in the Hi-Fi trade

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  1. After chasing accuracy for quite a long time, I am reaching the conclusion that accurate is not necessarily the same thing as lifelike, and for certain types of recordings they are often rather different things.
  2. What he said. I use a BK sub, which are good value for money and work seamlessly with PMCs
  3. Hi I've had a PMC 5.1 set up for a long time now, with a good few different configurations of amp hardware. There are many different brands of amps that are popular with different groups of PMC user - for example Bryston, Cyrus, Naim, NORD, Rega - all of which work very well in their own way. My advice would be to forget trying to find an all-in-one AV receiver that's good for music and movies because the choice is quite limited and there's a good chance you'll end up disappointed anyway. I would say use a decent stereo amp with an HT bypass, and run the pre-outs from an AV receiver through that. David.
  4. I use some after market, screened power cables for their convenience. Because I have a hifi that is integrated with a multi-channel AV set-up, the back of my kit is a massive tangle of different leads, cables, and interconnects, which are difficult to access. Hifi component manufacturers recommend that people should cross their power cables perpendicular to their speaker cables and interconnects, rather than run them in parallel, as there is sound engineering theory and evidence that running the mains in parallel can cause interference with the signal. This recommendation is published in at least two of my user manuals, by component manufacturers who do not sell mains cables and are not affiliated with any other company that does. Arranging the mains cable in this way would be a pain in the arse to me, so instead I use some very well screened, good value-for-money mains cables. The quality of the mains supply, whether it is in my house or in the miles and miles of transmission coming to my house, is entirely irrelevant to my reason for using screened power cables.
  5. How about a battery pack? I wouldn't have thought a DAC would need much current, would it?
  6. Yes, you're right, of course. I vaguely remember being surprised to read, when I was younger and more naive, that Hifi magazines tend to employ people onto their writing staff from the 'humanities' rather than science or engineering - people who can write good copy and have an appreciation of marketing, who can be taught the basics of the relevant lingo, rather than people with the necessary technical knowledge , who with practice could hone their ability to convey the relevant information to the layman with clarity and brevity. I wonder if there is also an element of these magazines providing messages without explanation (withholding information) with the purpose of keeping their readers dependent on what they say, rather than being empowered to figure things out for themselves, so that they are conditioned to "just do as we say" and thus buy into all the advertising and promotion. A very cynical use of trust. That's interesting. I won PMC who, I presume you know, have a studio heritage, but they espouse the idea of 'running in' their speakers. They also say the person who builds each speakers gives them a thorough listening test before they leave the factory.
  7. Hi Nopiano Thank you for taking the trouble to reply. As I understand it, the job of the surrounds is to allow the driver to move freely and then return to its original position as quickly and precisely as possible, so obviously the manufacturers wouldn't want it to continue to soften and become more flexible past a point of optimum performance. It does seem very odd to me that this process can supposedly take hundreds of hours yet the suppliers of the material are still able to provide sufficiently accurate data, and the designers are able to perform sufficiently accurate calculations, to make all this predictable enough to select the right material parameters for the job of each speker design. There is a Wikipedia page here https://en.wikipedia.org/wiki/Thiele/Small_parameters Here's an extract - the second paragraph mentions change in compliance of the surrounds. Much of it goes over my head but, if I'm understanding it correctly, speakers should be 'run in' after a matter of minutes, not hours - The mechanical components in typical speaker drivers may change over time. Paper, a popular material in cone fabrication, absorbs moisture easily and unless treated may lose some structural rigidity over time. This may be reduced by coating with water-impregnable material such as various plastic resins. Cracks compromise structural rigidity and if large enough are generally non-repairable. Temperature has a strong, generally reversible effect; typical suspension materials become stiffer at lower temperatures. The suspension experiences fatigue, and also undergoes changes from chemical and environmental effects associated with aging such as exposure to ultraviolet light, and oxidation which affect foam and natural rubber components badly, though butyl, nitrile, SBR rubber, and rubber-plastic alloys (such as Santoprene) are more stable. The polyester type of polyurethane foam is highly prone to disintegration after 10 to 15 years. The changes in behavior from aging may often be positive, though since the environment that they are used in is a major factor the effects are not easily predicted. Gilbert Briggs, founder of Wharfedale Loudspeakers in the UK, undertook several studies of aging effects in speaker drivers in the 1950s and 1960s, publishing some of the data in his books, notably Loudspeakers. There are also mechanical changes which occur in the moving components during use. In this case, however, most of the changes seem to occur early in the life of the driver, and are almost certainly due to relaxation in flexing mechanical parts of the driver (e.g., surround, spider, etc.). Several studies have been published documenting substantial changes in the T/S parameters over the first few hours of use, some parameters changing as much as 15%+ over these initial periods. The proprietor of the firm GR Research has publicly reported several such investigations of several manufacturers' drivers. Other studies suggest little change, or reversible changes after only the first few minutes. This variability is largely related to the particular characteristics of specific materials, and reputable manufacturers attempt to take them into account. While there are a great many anecdotal reports of the audible effects of such changes in published speaker reviews, the relationship of such early changes to subjective sound quality reports is not completely clear. Some changes early in driver life are complementary (such as a reduction in Fs accompanied by a rise in Vas) and result in minimal net changes (small fractions of a dB) in frequency response. If the performance of speaker system is critical, as with high order (complex) or heavily equalized systems, it is sensible to measure T/S parameters after a period of run-in (some hours, typically, using program material), and to model the effects of normal parameter changes on driver performance. There is some discussion on the topic at the start of this video from 'Audioholics'. They see to say the same thing (that 'run in' happens very quickly). I have to say though, that even though hey refer to empirical evidence, I find them to be unecessarily cynical rather than taking a mor eschewed, skeptical position. I think it would be much more sensible for WhatHifi to say something along the lines of - we recommend spending a good few hours if not days listening to your new speakers, before making a conclusive judgement on what you think of the quality of their sound and stereo image they can achieve in your room; it's likely that your brain will take quite a while to adapt to them. Many manufacturers state that their speakers need time for a mechanical 'run in' but the evidence for this is not clear.
  8. I do wish, when people on this forum make claims like this - especially when they're an established member, with the appearance of authority (trustworthy knowledge) - that they would provide a reason for why they believe this to be the case, such as a theoretical rationale or empirical evidence.
  9. The sound characteristics of a speaker's interaction with a room is very unpredictable, as there are so many variables. Plus there are personal preferences to take into account. As some other people have said, a room with no life at all doesn't sound good to many people. Theoretically, a wooden floor offers more flexibility as you can always add rugs.
  10. There is a part of point three that is okay - which is to mount bookshelf speakers properly. Point one is very dubious - I've never seen any evidence that speakers measure differently after being 'run in'. David
  11. If there really is any possibility of a significant difference between the two cables (which I doubt), then it would make sense to me to put the better one (the one that preserves the signal the best) between the preamp and the power amp, because this is where the signal has been attenuated and is therefore more prone to a decrease in signal-to-noise ratio caused by the introduction of noise.
  12. For transparency, some information about a further development - Tazman has contacted me today to say he's realised he made a mistake about the dimensions of the Size 2 Podiums, which makes them unsuitable for him. So I am returning Tazman's deposit and instead I'm taking a deposit from tarkus to purchase my Podiums. I'll leave this thread here until the sale has been completed. David.
  13. I think I must be missing the point they are trying to make. What this graph seems to be showing to me is that despite differences in the magnitude of vibration between the spikes and the GAIA, especially below 700Hz, there was zero difference in the frequency response of the speakers, and therefore that the GAIA made no difference to the sound quality coming from the speakers.
  14. No Keith, you are definitely incorrect there - the question I asked was what are the potential physical explanations for the difference in sound that I clearly heard; I didn't limit the scope of my question to being specifically about an audible resonance caused by structural borne vibration. You seem like a very knowledgeable guy to me, and I really value your input and appreciate you being here (i'm a measurement fan after all), but please don't try to tell me what my question is or isn't allowed to be. Have you seen any 'before' and 'after' REW plots regarding speaker 'decoupling' (isolation), such that you could share the evidence? Or is your thinking that if there was any such evidence out there, we would be aware of it by now? I'm quite curious as to why you haven't taken measurements of the effects (or non effects) of isolation devices yourself - I would have thought you'd be keen on the pursuit of furthering the knowledge, and have easy access to the relevant products and equipment. What is your explanation for what I heard? Thanks, David