Comment by jovial_cavalier | Hacker News Reader

Comment by jovial_cavalier | Hacker News Reader

Parent Full thread

jovial_cavalier

I will defend the coffee people.

Distribution tools are for espresso, not pour over or immersion brewed coffee. In espresso, you have extremely high pressure, so if there is a density differential in the coffee cake, you will get most of the water flowing through the spot that has the lowest density, and the rest of the cake will not be visited, making for a weaker drink.

Also, the "recipes" are usually just a ratio of coffee grounds to boiling water by mass, a rough idea of how fine to grind, and a brew time. If you take these parameters and vary them by any reasonable amount, you will definitely taste the difference.

Overall, it's not an apt analogy. There is no "fidelity" for coffee like there is for audio. There is a quantitative loss function you can define for audio quality - just the sound you're trying to replicate versus the sound that your system actually ends up generating. For example, no human ear can hear frequencies above ~22kHz, meaning anything over the normal ~44kHz sample rate provably makes no difference.

> No human ear can hear frequencies above ~22kHz, meaning anything over the normal ~44kHz sample rate provably makes no difference.

The real fun is when "audiophiles" give you music with high sample rate (e.g. 384kHz) and it sounds objectively worse on a standard playback device because the playback device only supports e.g. 48kHz natively and has to resample internally, with a resampling algorithm that's worse than what you would get if the audio was resampled with a high quality resampling algorithm and directly stored as e.g. 48kHz.

Agreeing with this, and likewise I wanna suggest for some coffee drinkers who are skeptical on "coffee nerds" to try a coffee cupping (basically a form of coffee tasting, like wine tasting, where different beans are prepared identically in a particular method good for producing a very strong and flavour-filled coffee).

When you have different beans, especially from different climates, regions, and preparation methods, and taste them side-by-side. You'll notice characteristics that you would not otherwise notice drinking from day-to-day; and the ability to taste and emphasize those characteristics is why coffee nerds use different techniques and forms of equipment.

It's easy enough to make a quality coffee that is tasty (a sub-$10 of supermarket ground coffee, a sub-$10 french press, and a pot of boiling water can produce a good coffee). But to emphasize things like fruity and floral notes requires extracting coffee in particular ways to bring them to the forefront; like ensuring that coffee is constantly exposed to fresh unsaturated water, for particular amount of time, with a certain surface-area, within a narrow temperature range.

> No human ear can hear frequencies above ~22kHz

Many human ear can hear pure ~28kHz tone under ideal condition [1]. Some can hear higher.

[1] Ashihara, Kaoru (2007-09-01). "Hearing thresholds for pure tones above 16kHz". The Journal of the Acoustical Society of America. 122 (3): EL52–EL57

Interesting

I can hear bats, which I have been told is impossible.

The electrical whine from a crt used to really about me...

I can't hear much at all in a noisy room and sometimes miss whole conversations, which can be bad for one's relationships. I was recently diagnosed with 'auditory processing disorder'. With my 'perfect' sonogram (is that the right word?) in hand, a hearing therapist suggested that I may have lost a tiny bit of my exceptional hearing and that may have triggered my brains confusion with sound.

CRT whine is at a much lower frequency, though. It's within (average, young) human hearing range.

I once debugged a switchmode power supply this way. I was in my late 20's-early 30's and walked into a room where an engineer in his 50's was testing a power supply. First thing I said, was "what's that annoying noise? Oh, it's coming from your test bench." He blinked at me, but immediately realized that I could hear a high frequency noise he couldn't and that it was related to the problem he was troubleshooting.

IIRC, the problem was that his oscillator was running at a lower than expected frequency: it should have been well outside hearing range but was actually just barely within mine.

Reply on news.ycombinator.com