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MLXXX

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About MLXXX

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  1. John, that's a very kind offer. Thanks. I only use headphones on special occasions (such as for comparing sound files on the net intended to demonstrate very small differences). They will sometimes reveal detail that gets obscured when listening with speakers but on the whole I don't find them as satisfying as listening with speakers. Even though certain deficiencies in a recording may become more apparent with good quality headphones (e.g. the THD and IMD of magnetic tape used in a studio recording, or an audible tape splice) that won't make the recording "unlistenable" for me just because I'm using using headphones. I have quite a high tolerance for sound quality deficiency for the right performances. For example I can enjoy opera recordings made in the first few years of the 20th century; if the quality (artistry) of the performance is exceptionally good. These early recording have virtually no bass, heavily rolled off treble, very high distortion, and an extremely poor signal to noise ratio! I suspect you are using the terms "resonance" and "vibrations" in very wide senses. It really shouldn't be necessary for me to travel to anyone's residence to learn about "audiophile noise floor", however generous such offers may be. Given how the expression "noise floor" appears in so many audiophile reviews and in so many threads of audiophile forums, one could reasonably expect there to detailed descriptions/definitions of what it is considered to be, and actual sound files demonstrating the phenomenon. If I can try to bring this post into the focus of the topic title, how would we know that a tweak that was stated to "reduce the noise floor" achieved that, or not? It would be useful to have an understanding of what is meant by "noise floor". Let's investigate... Step 1 First off, what definitions/descriptions are there? Almost all the definitions/descriptions I've found in Google searches have been of the engineering variety. Definition 1 Here's one from Wikipedia. It's an engineering style of definition of noise floor. This type of noise floor can actually be measured:- In signal theory, the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored. In radio communication and electronics, this may include thermal noise, black body, cosmic noise as well as atmospheric noise from distant thunderstorms and similar and any other unwanted man-made signals, sometimes referred to as incidental noise. If the dominant noise is generated within the measuring equipment (for example by a receiver with a poor noise figure) then this is an example of an instrumentation noise floor, as opposed to a physical noise floor. Definition 2 Here is a simply expressed definition/description, that again is of the classic engineering variety: The noise floor of a device or system is the amount of noise generated by the device itself with no signal present, it is measured in decibels. All electronic devices will generate a certain amount of noise, even a piece of wire! Minimizing the noise floor leads to expanded dynamic range, and cleaner recordings or sound production. Definition 3 The thread What does "lower noise floor" actually mean explains or tries to explain noise floor in the modern audiophile sense. It meanders quite a bit. Here are a few extracts from that thread that struck me as potentially relevant: When most people say the "noisefloor" is lower they are usually talking about a similar situation where the music itself is seeming to generate some low level sound which seems to fill in the space around the instruments. When it is decreased the space around instruments (voices etc) is decreased. Exactly what is happening hear is not really known, since it is very much a perceptual issue. I think it's often related to ability to retrieve ultra low level detail and portray 'space between the notes', and unravel individual track layering (I call it 'the edges of the tracks'). E.g. do you hear the composite block of multi-layered backing vocals as a single piece of audio, or do you hear/identify each individual take (track) that was mixed (comp'd) together? the electronic definition is basically the signal to noise ration in decibels. The audio definition is subjective...if 10 different instruments are playing counterpoint each at an lower volume than the other, at what point do the lower volume instruments get muddied or indistinguishable from louder instruments. I think sometimes, it is just impossible to describe these things, especially when based on our current common understanding of hearing, it doesn't seem to make sense that we can hear a lower noise floor. I guess the best way to think about "dropping the noise floor" is more generically -- that anything that adds noise, distorts, adds jitter, or adds anything reduces the clarity with which we hear the music. Agreed that it has nothing to do with measured noise floor of the signal & more to do with the dynamic stability of the reproduced audio. Definition 4: The following article purports to explain noise floor, but as far as I see really just refers to other audiophile terms. I didn't find it helpful myself in pinning down the meaning of noise floor: http://tweekgeek.blogspot.com/2016/06/what-is-sound-of-low-noise-floor.html Step 2 We can now consider the various definitons/descriptions above. If audiophile noise floor includes additional noise generated when signal is present, the total could be measured. However it would arguably be redundant as a measurement, as THD already measures extraneous signals. We seem to be faced with a degree of uncertainty with the definitions/descriptions so let's simply proceed to Step 3. Step 3 Without as listeners understanding exactly what the term (audiophile) "noise floor" specifically means to some audiophiles, it may still be possible to have it demonstrated to us. It should be possible to download files that audiophiles or academics have identified as exemplifying poor or good audiophile noise floor. We as listeners, provided our own equipment had a reasonably low noise floor, could listen to the demonstration files and be enlightened! I await anyone being able to direct me to one or more such demonstration files! * * * I note that demonstration files do exist for a range of other audio parameters. I'll give just three examples currently on YouTube:- Harmonic distortion:- High, mid, and low frequency ranges: A description and demonstration of classic background noise (not of audiophile noise floor):
  2. This I find is often the case when I listen with headphones. You tend to hear the recording warts and all, whereas with sound coming from speakers there is enough colouration and distortion produced by the speakers, and enough reverberation in the listening room, to give a warmth that makes blemishes less noticeable, or at least more palatable. In live performances vocalists will often have electronic reverberation added to the microphone signal. Without it, their voices can sound thin and exposed.
  3. Typically I assign a large percentage to the speakers (and room acoustics). [I find my Sennheisser HD800 phones will reveal detail my speakers won't. And I find my speakers colour the sound.] With chamber music there are many different recording techniques possible. I've recently sampled about 20 different recordings of the Trout quintet available on the net. More often than not the audio bitrate and codec were good enough not to get in the way too obviously. In some cases though the microphone placement and mix favoured some of the performers over the others so much that it became hard to hear some of the playing. One of the recordings really stood out for me, in terms of its great clarity. This clarity was evident for of all instruments (except the cello). It involved a performance in Russia. I'll attach it below Another recording stood out for me because of the individual fame of the performers (Daniel Barenboim, Itzhak Perlman, Pinchas Zukerman, Jacqueline du Pré, and Zubin Mehta). Pretty horrible recording quality unfortunately! I'll attach it too. The actual recording I used for my tests was intermediate in quality between these two. Not as well miked as the Russian group, and not as distorted as the Barenboim et al version. It's hard to be precise, but I'd ascribe about a 30% impairment to the recording, a 60% impairment to the speakers and room, and about a 10% impairment to the amplifier, if using the old amplifier. I happen to be an (amateur) string player myself, and am very much interested in how clearly a chamber music performance is captured in a recording.
  4. The speakers were not sold as matched pairs. Given that published loudspeaker system frequency response graphs are typically very jagged (despite smoothing in the measuring/graphing process) it would be fortuitous if the peaks and troughs coincided for two loudspeaker systems taken from a warehouse, despite bearing the same model number. I would emphasize that I'm not conscious of any difference between the PSB main speakers in day to day use as front Left and Right speakers 2 or 3 metres apart. But once we specifically start listening for small differences, fun begins! Placed side by side and just fed a plain 1000Hz sine wave they didn't sound exactly the same. They were of slightly different apparent sensitivity. And one had a different edge to its sound than the other. Differences remained noticeable with music. I couldn't just assume that both channels of one amplifier were capable of delivering the same signal. So at one point I connected both speakers to the left channel only of the old amplifier (using the separate speaker A and speaker B terminals provided ). Using a button on the amplifier I could then play speaker A, speaker B, or both together. In that way I satisfied myself that the speakers did definitely sound different to each other. I have a matched pair of large diameter Rode condenser microphones, and an unmatched pair of different model Rode large diameter condenser microphones. One day I might try to listen for differences and see whether the matched pair really sound more alike than the unmatched pair! I abandoned any idea of listening to stereo signals once it became apparent that the speakers differed so greatly as to be distracting for precise comparisons. I ended up providing both speakers with pure Left, pure Right, or with mono (L + R). I used the Audacity software to solo one speaker or the other, and occasionally to allow both speakers to be driven.
  5. It wasn't my intention to give an evaluation of a $20k power amplifier relative to a $2k power amplifier. What I was suggesting was that if an individual bought a $20k amplifier as opposed to a $2k amplifier [thinking they "should"] it would be possible that the particular individual might not actually be able to tell them apart in a blind test [if they ever agreed to doing a level-matched blind test!]. That's not to say other individuals might be able to tell them apart in a blind test. For individuals who could hear a difference, I'd be interested in how big the difference was for them, and how it compared with other variables in the reproduction chain (such as the sound quality of the recording, and the sound quality of the speakers and listening room).. I think I should mention something well known, that in the audiophile world there is not necessarily a good correlation between retail price and performance. So the fact an amplifier for home use retailed for $20k rather than $10k would not of itself be a guarantee of superior performance over a $10k amplifier. And it's possible a speaker system presenting an unusual load could interact badly with some amplifiers (an example of poor "synergy"). Practical comparisons For some time I've been planning to do comparison tests at home between various low to mid-range power amplifiers. I've purchased resistors to make up dummy loads to help with that exercise, and for making recordings of the amplifier outputs. However I don't have the dummy loads available yet. I plan to be able to switch between speakers for immediate A B testing. The testing may still be a few months away. [It may involve using relays to do the switching.] Today I did some simple tests, without special equipment, with somewhat inclusive results. Speakers: PSB Imagine T Amplifiers: 1. Pioneer VSX-1131. This AVR uses a Class D output stage. It is in current regular use as the main amplifier for listening to music,. 2. Yamaha HTR-5750. This AVR would use a conventional output stage. This AVR predates HDMI and was last in regular use about 10 years ago. (I thought it might be good to take it out of the cupboard today and try to contrast its performance with the much more recent vintage Pioneer AVR.) Sources: I tried using a CD player but that wasn't all that convenient for changing channels and changing levels. In the end I used a pc and the software Audacity. This enabled me to generate test tones and to switch readily between Left channel , Right channel and stereo; and to match levels. (The main music I used was the Andante movement of Schubert's "Trout" piano and strings quintet.) Although I'd normally connect the audio from the pc with HDMI or S/PDIF, today I used RCA connectors. The testing: Initially I had hoped to compare the amplifiers simply by placing the PSB speakers next to each other and connecting one speaker to one amplifier and the other speaker to the other amplifier. Unfortunately the speakers although the same model and purchased together from a retailer (a few years ago) differed somewhat in their sound. This would not be unusual I expect. Although not noticeable with day to day listening in stereo with the speakers some distance apart it was quite a stark difference today with the speakers placed side by side and being fed the same test signals. (I didn't try other, older, speakers to see whether they have been better as a "matched pair".) Tentative conclusion: I persevered with the relatively poorly matched PSB speakers. My tentative conclusion was : The late model amplifier seemed to produce a "tighter", "cleaner" sound. The earlier model amplifier in comparison seemed to produce a somewhat "woolly" sound. I felt I could hear those differences going on in the background for each speaker system, even though the speaker systems differed quite noticeably from each other. How would I assess the impact of the different amplifiers on the overall listening experience? I think closer to 10% than 5%. However I'd really like to do the test again using just one of the PSB speakers, switched without delay between two amps.
  6. The best thing would be if you and I were in the same listening room and a level matched switch was made between two power amps feeding the same speakers. If you heard a distinct difference there's every chance I would too. The thing I might tend to do then might be to quickly in my mind assess the percentage impact on the sound of: colourations/imperfections in the source recording colourations/imperfections in the two amplifiers under comparison colourations/imperfections in the particular speaker system (and the room). Depending on where microphones were located and other recording conditions there might happen to be to my mind a roughly 30% impact from the source recording, a 5 or 10% impact from the amplifier, and a roughly 60% or so impact from the speakers and room. Some people would focus on possible influences on sound quality attributable to the CD transport, an external DAC, an interconnect from a DAC to a preamp, the preamp itself, and interconnects from the preamp to the amp. Then there would be the possible influence of speaker leads (e.g. if long and thin). I think it's really important to distinguish between being able to discern a difference, and putting that discerned difference into the perspective of the overall experience of listening to a performance. I attend a lot of live performances of classical music and I find I can hear very noticeable differences in the clarity of the sound arising from only small differences in seating location. The human ear has to adjust to such differences as best it can! In comparison I just don't hear much effect at all on reproduced sound if I switch power amplifiers, or if using headphones I listen first using the signal before the power amp, and then using the power amp headphone socket. I don't use state of the art monoblock amps, just integrated amps, but even with an integrated amp the effect on sound quality strikes me as pretty minor for the purpose of appreciating a musical performance on CD. If I were to choose to play a 33 1⁄3 rpm vinyl disc of a full orchestra playing a symphony, I'd prepare myself for a lot of distortion in the loud passages; and rather reduced bass at times, compared with a CD. And if I fished out a 1 7⁄8 inches per sec commercially released compact audio cassette dubbed at high speed in the factory with a recording of a piano sonata, I'd just hope that the flutter, and the hiss, wouldn't be too noticeable. (Actually, thinking about it, I haven't tried to play an audio cassette for many years!)
  7. I'm by nature an optimist myself [and a lover of Cadbury chocolate if it comes to that]. And I guess a lot of the posters in this thread would be old enough to remember the prof.. I used to enjoy watching Prof Julius Sumner Miller's practical demonstrations of science in action and his clear explanations of why it was "so". I can remember the programs being broadcast in black and white, so they may have been first shown in Australia in the late 1960s or early 1970s. I can't recall exactly. Anyway, back on topic...
  8. That's an interesting report of a breach of advertising standards in the UK that you've linked to. I've found similar details for that case reported at: https://hifiwigwam.com/forum/topic/11684-russ-andrews-investigated-by-advertising-standards-authority/ I think it would be good to see proceedings of that kind in Australia, in relation to unsubstantiated claims by commercial vendors, of benefits of expensive tweaks they sell.
  9. That's always been my understanding. For me, and I think for most people, even quite expensive loudspeakers systems sound different from each other (with different strengths and weaknesses, distortion levels, and colourations). When auditioning speakers I've always had to compromise. Nothing has ever sounded close to "transparent" for my ears. On the other hand, except going back some decades, I've found audible differences between power amplifiers to be much smaller, to the point of not even being noticeable. These days I can plug my Sennheiser HD800 phones into the output of a preamplifier, or the output of a power amplifier (via attenuation pad) and enjoy the music perfectly well either way. [I keep promising to make comparative recordings between the analogue waveform going into a power amp and analogue waveform coming out of it. One of these days I'll get around to that and upload the recordings.]
  10. Can you please assume that a good quality circa $20,000 amplifier is in use to drive various speaker systems? Under that assumption, how big is the discernible difference in the sound as between different upmarket loudspeaker systems, in your experience?
  11. It's of course a successful level-matched blind test that would provide the more credible evidence, rather than a reported sighted perception of difference. If two amplifiers are both so good that they impart no colouration or sound signature, but amplify the sound transparently, for a particular listener, it would I suggest be unwise to jump to the conclusion that that same listener would not be able to distinguish entry level speakers (a sound bar) from mid or high end speakers. [Edit: I now see @rantan has deleted the post I've quoted above, except for its first line.]
  12. My questions would then be, how significant was that difference for you? Did the more expensive amplifier sound more realistic? Or just "different"? Did it reveal detail you couldn't otherwise hear? And with what types of recordings/music? For you, how did the size of the audible difference compare with the size of the audible differences with different upmarket speaker systems?
  13. Spending $20,000 instead of $2,000 for a difference a particular audiophile would be unable to hear (themselves) in a blind comparison, but which results in a different audio output as measured with sensitive test instruments is indeed different to: Spending $18,000 on a power cord that makes no measurable difference to the audible output even with sensitive test instruments. This in turn is, arguably, different to: Spending $18,000 on a doll crafted by an artisan to resemble a particular audiophile, and enchanted by a mystic to imbue that audiophile with a better listening experience if the doll is under the same roof as the audiophile. The degree of apparent waste of money and the degree of possible deceptive vendor conduct are questions that that may lie on a continuum, though there may be no provable deception in a court of law, and individual audiophiles may feel they have spent their money wisely in any of the three scenarios. In the case of the doll, I am not sure a prosecution of a retailer for deceptive conduct would succeed if a group of audiophiles testified that they had heard an improved sound stage, a lower noise floor, and a better dynamic range whenever their personal hand-crafted sound dolls were under the same roof as themselves. I presume any believer in sound dolls would refuse to participate in a blind test. It's the way the more outlandish tweaks can survive "scrutiny", i.e. by avoiding it! The dolls could easily provide a placebo benefit, but that would of course only work if the audiophile were made aware that the doll was under the same room as him or her.
  14. The problem as I see it is that various parts of the audio reproduction chain have improved to such an extent that differences are minor if audible at all. However a small hard core of individuals refuse to accept that. They feel a need to spend huge sums on a CD transport, external DAC, preamplifier and on monoblock power amplifiers. They may pay $20,000 rather than $2,000 because they feel they ought to to get the "best" quality. There's a certain amount of peer pressure to spend up big. Some manufacturers cater for that hard core. And many review magazines do. If the hard core audiophile is into vinyl as well, then there's a bottomless pit into which to drop dollars. Perfection can never be achieved because grooves in vinyl tracked mechanically will inevitably result in audible harmonic and intermodulation distortion. And yet for true believers in vinyl, the quest must continue. The more expensive arm, the more expensive cartridge, the more expensive phono preamplifier, the more expensive disc cleaner. There is no end to the elusive search for "vinyl perfection"! Edit: And to be true to the thread topic I should also mention "tweaks". There are audiophiles who cannot accept that a basic power cord or a basic audio interconnect could possibly be good enough. They will insist on expensive alternatives. And review magazines, and advertiser blurb, will readily encourage them in that direction. As for legal action to prevent fraud, there are many witnesses prepared to say they hear a difference. Do we prosecute fortune tellers in Australia?
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