nyquist-shannon means that you only need to sample at 192khz if you need to encode signals up to 96khz.
humans can’t hear above 20khz. adult humans can’t hear above 16khz or so, we lose the top end before age 20. this means that the standard 48khz sampling rate covers the entire human hearing range and then some (0-24khz). any sampling rate over 48khz for sound intended for human hearing is a total waste.
Why do 96 or 128khz sampled audio files sound better than 48khz ones? I blind tested and could always tell the difference between them, but not between 128 and 192
Typically, high sampling rate files are part of a different mastering process than what is published as a 44.1kHz cd audio or 48kHz dvd audio.
Also, you might possibly be sensitive to resampling artifacts if your output device runs at 44.1kHz and your file is 48kHz or vice versa.
Audio testing is hard, and testing on yourself is tricky... But if you have a sample that you're convinced sounds better at high rates than lower rates, I would urge you to put it through a tool to resample it down to lower rates and see if/when you can tell the difference. If the rate isn't an even multiple, it's worth using a tool that can dither; dithered resampling artifacts are less abrasive than undithered... I had some voice recordings to play over the phone, and everything needed to be 8kHz u-law; the 48kHz original recordings sounded better than 44.1kHz original recordings because one is even multiple and the other isn't, but either way, the waveforms looked worse than it sounded.
> If the rate isn't an even multiple, it's worth using a tool that can dither; dithered resampling artifacts are less abrasive than undithered...
This seems to be mixing up two things; proper interpolation and dithering.
If you have limited bit depth (in practice, 16 bits or worse), you should pretty much always dither, ideally also noise shape. This is independent of the interpolation you're using; having a rational relationship between the original and downsampled signal makes some of the implementation a bit easier, but even for something like 48000 -> 24000, you'll end up with effectively a float signal that you need to convert to your chosen bit depth somehow, and that should be done better than just truncating/rounding.
And even for interpolating between two prime rates, or even variable-rate interpolation, you can and should get great interpolation (typically by picking out polyphase filtering coefficients from a windowed sinc of some sort).
Oh come on. I have handheld recorders that do 192khz.
"Headroom"
And the idea that humans can't hear over 20khz is like "humans taste 'sweet' on the tip of the tongue, and 'bitter' on the sides"
As we get older the hairs in out ears break or whatever and our perception decreases, but I could hear the fly backs in my old monitors, I used to be able to see the flicker in 3khz pwm LEDs, and my induction hob drives my kids crazy but it's merely midly annoying to me.
Get a real soundcard and some young people and play square(pwm) and sine tones starting at 16khz and find out where they can't hear it anymore. I find studio monitors with tweeters that are not paper are the best.
If you think you can hear ultrasound, it's nearly always due to nonlinearities in your system producing non-ultrasound when you try to play it. Seriously. (You can sometimes hear above-20 if it's very loud and/or you are pressing the source against your skull. Above-40 would be completely insane.)
The extra headroom can indeed be useful for some kinds of processing, but you can safely discard it for actual listening.
ime 48/96/128kHz 16/24bit through a modern DAC and well warmed Class AB amp and barely more than okay headphones can be told apart in a double blind test
but you do need phile-enough gears(minus the gilded pebbles hot glued onto circuit breakers)
sampling theorem only applies to sine waves. the rate is bit like the order of (fourier)series expansion and so approximations deviate as rate reduces. how many orders is enough depends and is situational
I was also diagnosed with a duodenal ulcer when I was 10. In my case, it was the late 1980's and the H. pylori cause of ulcers wasn't accepted or widely known.
I spent a week in bed in excruciating pain, throwing up blood regularly. The doctor visited a couple of times, I'm not sure what he told my mother, but it was a week before he agreed I should go to hospital.
At that stage I was severely anemic and had peritonitis. I ended up in surgery to have a third of my stomach and some of my small intestine removed. A couple of weeks in intensive care and another few weeks in the children's ward before I was strong enough to go home.
When I left, I was told that I shouldn't eat acidic or spicy foods, and that I had an ulcer because of stress. I was 10, and I can tell you, while we didn't have a whole lot, I was far from being stressed.
Nearly 40 years later that surgery still impacts on my life. I still have some digestion issues, but knowing that Warren's & Marshall's work has prevented others from repeating my experiences has been some comfort.
Good on your doctor for trying something experimental which had such a great outcome.
The issue isn't that the grid can't handle large amount of renewables, it's that renewables aren't consistent.
Large thermal plants provide inertia that renewables simply can't provide. A lot of the work around incorporating renewables into grids is around the provision of synthetic inertia and how to manage sudden drops in supply.
Battery storage is one solution. Better demand response solutions backed by energy markets that incentivise the participation of large numbers of energy users is another.
Grids that have a high level of interconnection with other grids also reduces the impact of inconsistent supply, but not every grid has enough inter-connections for that to be a viable full solution. (See ERCOT in Texas, AEMO in Australia, Eirgrid in Ireland for examples)
Here in Ireland, we frequently run the grid up to 80% renewables, but the grid operator only does that because they have the mechanisms in places to handle sudden drops in supply.
Dermot Morgan died just after making the third series. Before Ted, he was best known for Scrap Saturday, a radio show that parodied and mocked the Irish politicians of the day.
Scrap Saturday was arguably a watershed in Irish culture. It was broadcast on the national broadcaster (RTE) that even today is criticised for being too close to the government. By making fun of powerful figures, it opened peoples eyes to how ridiculous and corrupt Irish politics could be.
Ironically, Fr. Ted was commissioned and broadcast on Channel 4 on UK TV. At the time, the talk was about how RTE refused to commission the series because they didn't want to mock the Church, although this has been refuted by the writers.
Over the course of two series, Dermot Morgan mocked both the political and religious establishment and brought both closer to the common person. Whether this reflected the changes that were happening in modern Ireland, or lead the way can be debated. But we're certainly poorer for his loss.
They're short series, and with very few arcs, there's not much to differentiate between series. And it's easy to binge watch the entire box series!
My favourite part of my job is naming internal tools and applications after characters and quotes... it helps that the owner of the company is a huge Ted fan.
The company I work for provides Demand Response to the Irish grid operator.
In cases like this, our systems would detect the frequency deviation, and shut off loads within 100 milliseonds to reduce the demand on the grid. This helps in cases where demand is greater than supply.
The entire system is automated - the required time frames are so quick that you don't have time for humans to be involved. By the time we're aware that an event has occurred, we've already reduced demand on the grid.
Handling high frequency events where supply is greater than demand is tricker. Sites that have long running generation can be instructed to shut down their generation, but large-scale batteries are probably the best solution in these cases. They can be switched quickly to start charging (if they have spare capacity).
As you've identified, one potential issue is that you can end up over-responding to the event and move from a low frequency event to a high frequency event.
The way we do in in Ireland is that our response is proportional to the frequency nadir. Not everything is tripped off at the same time.
As other posters have noted, the actual frequency deviations that occurred are not that big. 49.7 Hz is not that low compared to normal grid frequency. In fact, some of our systems wouldn't even activate at this level. They would see it, but wouldn't trip off any loads.
I’m curious about this. What kinds of load is your company is running? How do you take them offline and online so quickly without affecting production or leading to long restart cycles?
We control a mixture of loads, but for Fast Frequency Response (FFR), it's mainly compressor/ motors, with the occassional mains breaker thrown in. Large cement factories, refrigeration companies etc.
As for how we control them so quickly, it's usually via a direct connection to a breaker of some description, or where there's a SCADA system that can trip out the loads in the required time frames. Before the site can participate in these services, we perform extensive testing to ensure they meet the required time constraints.
Our system monitors the grid voltage and current at 8 kHz, and we down sample that to 50 Hz (average grid frequency). We can detect a frequency event across 3 phases within 60 milliseconds. (We check all three phases for multiple cycles to reduce any false positives.)
When we trip out the loads, production stops. We'll notify the client why their loads have been turned off, but the SMS message will usually arrive a few seconds after the trip.
The clients that participate in these services get paid quite well to make their loads available and they're aware of the process. They agree to turn off demand without notice when there's a frequency event.
It's not suitable for every site. We work quite a lot with pharma companies for "regular" demand response, but very few can do FFR. Shutting down a pharma plant with no notice can cost a lot of money in wasted product and down time as they clear the wasted product off the production lines.
