Re: The Audiophoolery Thread.
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Ah - got it. It was EEG and PET scanning. Oohashi again...
Craig |
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Steve. |
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It's not unusual though for people who don't 'get' modern hi-fi, well, not to get it, and for people who do get it to be prepared to make significant sacrifices in pursuit of their hobby ;D. Cheers, GJ |
Re: The Audiophoolery Thread.
I have seen claims that no-one else has been able to replicate Oohashi's findings and also that the effects are down to distortion in the high frequency drivers that he uses which produce artefacts below 20kHz. If the effect were real I would have expected other people to have written papers about it.
Unfortunately I can't find any really authoritative sources that disagree with him. |
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There is plenty of audio being radiated in the region above 20kHz.... all those parking sensors on cars for example. Some SMPS are rather good emitters, too at a wider variety of frequencies. And then there's very high power from ultrasonic cleaning baths. So if people really were sensitive to these things, even if just a small section of the population, it would have been noticed.
I agree with James, maybe some intermodulation effect creating mixing products at normal audible frequencies is at work, due to some non-linearity? Or maybe it's all just wishful thinking, deliberate or innocent? One thing is for sure, we have microphones and spectrum analysers that go into those frequency regions. A more interesting paper would be a survey of the >20kHz content in various live performances... acoustic ones, so we stick to original sound and don't get mislead into trying to reproduce the spurious oscillation or ringing of a bad stage amplifier. I'd expect cymbals and rimshots to have some content, maybe squeaks from wound strings. There are two questions: 1) Is there any stuff to be heard? 2) Can anyone hear it? David |
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I take 20 kHz to be a rough approximation of the absolute highest frequency a human can hear (in my high school physics text it was 16 kHz) but in practice it can be much lower, depending on age, sex, hearing loss, wax and dirt in the ear canal, etc.
I worked for a time in the hearing aid industry which is mostly geared towards helping people understand speech. We tested peoples' hearing often to no higher than 8 kHz. Many of the school audiometers I calibrated in the summer holidays could test no higher than 6 kHz. Many older clients had a severe drop in response above 1 kHz. If we could help them restore some clarity from above 1 kHz to 3 kHz it made a huge difference to their lives especially in conversations. The range from about 300 Hz to 3 kHz is where much of the action is. When I see people arguing over whether this speaker is better than that because it goes out to 23.5 kHz as against the other's 18 kHz, I wonder if they have had their own hearing tested lately. What can they actually hear? |
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I have a hearing aid, two in fact, but only really need it for speech. It really helps with that, but maybe surprisingly it doesn't make anywhere near as much difference to music. I put it down to music having a "flywheel" effect, I subconsciously fill in and don't really notice. Speech is different, it's all too easy to lose sync!
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Steve. |
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The hearing mechanism is in a constant state of flux. It has numerous mechanisms (Malleus, Stapedius, Cilia etc) that can attenuate levels, which vary by tiredness, nutrition, mental state and other factors. Even if you have perfect hearing, it will never the *exactly* the same from hour to hour, particularly if you've come into work on the Tube and had a lot of coffee (for example). One could argue that the whole concept of publishing subjective listening evaluation to be so unscientific, it verges on the pointless (approaching immoral, if you consider that livelihoods depend on reviews in a competitive marketplace). |
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In the end though, as has been said many times already, there's nothing like hearing equipment yourself, ideally in your own listening room. Cheers, GJ |
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We have a saying, "Nowt so queer as folk"
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How can he tell absolute phase has been flipped on a rare piece of vinyl made in Uganda in 1973 with nothing to compare it against? Secondly, the preamp is a non-inverting design...(it has minimal phase shift, and uses 0.1% Rs and 1% Cs). I was going to call him to discuss this, as it isn't good for my rep. But I didn't, as I'm wondering if he is so deeply into phool ideology that I'm probably banging my head against a brick wall... This reminds me of 2 occasions about 25 yrs back when I was engineering in studios. Separate clients saw that the cables connecting the DAT player looked cheap and refused to listen through them. I whipped out a couple of nicer looking XLR cables, plugged them into redundant sockets and put the music back on, but with about a dB increase. 'Thank you, that sounds much better'... |
Re: The Audiophoolery Thread.
NB - I hope you snuck around to the bins and rescued the SP10 :-)
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Good day Gentlemen,
Thank You ! for a great education about the topic, i've read all 92 pages over the last 6 months. I hope you enjoy the review about this 350K$ class A Amp using an RF power tube. Nice construction though, and at +/- 800lb weight, probably better to live on the ground floor. https://www.stereophile.com/tubepowe...vac/index.html Best Regards jhalphen Paris/France |
Re: The Audiophoolery Thread.
Thank you, jhalphen! That is truly in the spirit of the audiophoolery thread.
What seems to be missing in that review, after pouring so much praise over that amplifier, is any announcement that he had bought a pair. How can he now live without them having had such an experience? But if that amplifier is so wonderful, so transparent, then maybe what he was reviewing was not the sound of the amplifier, but the acoustic signature of his power provider and all the cabling and transformers en-route to his home? The specification section of the review alone is worth a good laugh. The dimensions and weights are given quite comprehensively, but the output power is specified without mentioning the distortion level at which it applies, similarly the frequency response values do not state at what level of roll-off they apply. So the figures relating to it being an amplifier are just guff. I also think this sort of review could only be written by someone blissfully unaware of how unfashionable was the gear the recordings were made with. What it has done is made me realise that the amplifier in my lounge was installed and set-up by its designer in person. All these years I've listened to something with such an advantage and I'd never noticed it! I must be deaf. David |
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So, what about the SH-833's output capability power? Those 550 lbs and that humongous transmitter tube promise a lot of power, not to mention the specified "effective" output of 150W. As you can see from figs.5 and 6, which plot the percentage of distortion and noise in the Wavac's output against power from the 8 and 4 ohm taps, respectively, that promise is not kept. At our usual definition of clipping—1% THD+noise—the Wavac gives out just 2W or less into loads ranging from twice the nominal tap impedance to one quarter that nominal value. The highest power is obtained when the load is half the nominal tap—ie, from the 8 ohm tap into 4 ohms—but even then, the definition of clipping has to be relaxed from 1% to 10% for the amplifier to approach its specified power. Looking at the waveform on an oscilloscope during these tests, the point in these graphs when the waveform clips is actually the sharp notch in the traces. At 10% THD, the amplifier is putting out a pretty good squarewave! and in conclusion So, that's that for the Wavac SH-833. I can't explain why Michael found its sound so seductive; all I can do is point to the measurable problems or audible idiosyncrasies that must be listened through to hear what it does right. Good man. Cheers, GJ |
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