Comment by Mediterraneo10 | Hacker News Reader

Comment by Mediterraneo10 | Hacker News Reader

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> Of course, it's not only the compression that's at stake-- it's also the mastering quality.

HN threads on lossless music so often descend into "well, you couldn’t hear the difference". But historically a key reason for people to prefer e.g. SACD releases of recordings is not because one can hear the extra frequencies of this format, but because the SACD release – being targeted at people with a good stereo and silent listening environment – is mastered with more dynamic range. The mainstream release of the same music, on the other hand, often features a different mastering with levels pushed up, because they assume that ordinary people will be listening to music in noisy environments, like through earbuds in the metro. This is often a problem for re-releases of 1960s recordings of jazz where the producer and engineer really exploited dynamic range, but that is lost in the most recent of the digital-era re-releases.

(Another reason to prefer SACDs and Blu-ray releases of recordings is for the possibility of 5.0 surround sound, because of course CD and mainstream downloads or streaming are limited to mono or stereo only.)

Absolutely agreed. People spend so much time arguing about whether we're "past the limits of human perception" on sound or video. They want to quote Nyquist and check frequencies.

Spend a million dollars on audio equipment. Turn on your speakers, play some chamber music in insane multi-channel high-res audio, and invite a friend over.

Your friend does not think you hired a string quartet. Your friend thinks you have nice speakers.

If your friend is naive and easily fooled, do an A/B test by actually hiring a quartet and alternating with the speakers.

There are a thousand compromises between the source of music and your ear. What is worth paying for is a recording where those compromises were made well. The compression level is a very small part of the picture.

I have been surprised in both directions where what I thought was live music was prerecorded and what I thought was prerecorded turned out to be live music. Which shouldn’t be that surprising, audio equipment has gotten really good and audio standards are based around what people notice.

The more realistic scenario where it might actually make a difference is DJs playing on huge high-end club soundsystems where compression artefacts might not only effect what you can hear, but the reverberations you can physically feel, and where there might be post-processing effects applied to the source material that show up the compression artifacts.

Yep, it was a sad day when they switched from vinyl 45 singles to digital.

> A/B test by actually hiring a quartet

That's easy. The one with room echos, washed out highs, and missing bass is the live.

This may be true about popular music, because this is how we came to know this style of music - live performances (without proper sound engineering) sound worse. It is completely the opposite for classical music. There's still no way to replicate the sound quality of being close to an orchestra.

>There's still no way to replicate the sound quality of being close to an orchestra.

That's why I always tend to bail out of audiophile discussion but I'll bite: why?

What's so special about the soundwaves going into your ears when you sit close to an orchestra that couldn't be reproduced with good audio equipment?

If you're talking about the experience itself of siting next to performers then I wholeheartedly agree, but that's the problem, it's no longer something that can be measured and objectivized.

And that's entirely fine, but I think there's a trend among some people (and especially the type of people who frequent this forum) that deem that if a feeling or emotion can't be objectivized then it's effectively worthless or irrational or something like that, so you see people grasping at straws to justify their emotions with a pseudo-scientific explanation. I find that frankly sad and quite toxic in a way.

Music is art, the enjoyment we derive from it can't be measured in kilobits per second. That doesn't mean that we need to make up pseudo-facts about acoustics to justify our preferences.

If you've never heard an orchestra in an auditorium with proper sound design you're in for a treat. Two or four speakers are simply a poor alternative to dozens of live performers around you.

> That's why I always tend to bail out of audiophile discussion but I'll bite: why?

Disclaimer: I am definitely not an audiophile.

The low frequencies that we feel with/through our bodies feel entirely different at a non-electric live concert as compared to what we feel through speakers. No headphones can reproduce such effects. For sure, there are speakers that can reproduce such sounds faithfully, but how often do the audio production guys use such speakers, and how often do they try to control for the feeling in their bodies? Not often, I imagine.

> but how often do the audio production guys use such speakers, and how often do they try to control for the feeling in their bodies? Not often, I imagine.

Yes, but we're talking about 5 digit and up audio equipment and listening to the top operas of the world, which definitely do have guys that know how to record. Your 10$ (or 250$) headphones combined with a CD from a smaller producer will not get you all the way there, I agree, but once you're in the insane high-price audiophile world, this becomes possible.

Maybe if you move your head just a little bit with a live orchestra, the change is different from what happens with a few speakers (and often in a different room)

To start replicating the sound of an orchestra, you'll at a minimum need one speaker at each location where a player is, playing a single channel (the instrument).

But even this is simplifying things, because each instrument has a different body shape, different sound projection, which would need to be replicated by specialized speakers. Also, the room has an important effect on how the sound waves travel and hit you from different directions. At the end it is probably cheaper and easier to pay a ticket to have this live experience.

Of course not, what you need is model the way your ear handles sound coming from various locations then model this and reproduce it. It's like VR, but for your ears. That's how ASMR effectively works. If you want full immersion you can add head tracking so that the sound "rotates" around you when you move your head. I know that Apple offers that with their latest headphones.

Admittedly in order to do this you need to have post-processing specific for every person since we don't process sound exactly the same depending on our physiology. I know that Sony attempted something like that with its "3D audio". I think it's a bit of a gimmick myself, but it's technically doable.

> Of course not [you just need individual head related transfer functions for everyone and a fast DSP]

I agree that it is probably possible in theory, but aren't we talking about actual equipment and recordings that people can buy?

You can buy it; the keyword is 'binaural' recording/headphones.

https://en.wikipedia.org/wiki/Binaural_recording

Except this is a long way yet from what the GP was describing, although it is an attempt in that direction.

What if you only want to replicate the sound of an orchestra as heard by an observer at a specified point? Why wouldn't two microphones be sufficient? That's how it's perceived, after all.

You can get really nice sound that way, but to get the full effect you need to take into account the shape of the head and ears of the listener. After all, these are important factors that help us place sound in space.

https://en.wikipedia.org/wiki/Head-related_transfer_function

Your ears are highly directional devices and an orchestra in a concert hall creates a highly complex soundscape that is impossible to replicate with 2 channels. Location awareness (i.e. 2 mics where your ears are) is just a small part of the problem.

So it sounds like the experience can be fully captured with two microphones mounted in the ears of an acoustic dummy head, as long as you're willing to accept a single position and orientation for the observer. Personally, that would be more than good enough fidelity.

I suppose then you would need to have the transfer function of that specific observer's head and ears at that specific point. Perhaps some time in the future there will be personalization of the transfer function so that you can hear the sounds as you would hear it at that spot.

I also thought the same, then I went to listen some orchestral performance at the Rome Auditorium.

During an interval I was sitting in a shitty corner up on some balcony, pretty far; but I could hear the voice and discern the words of a girl chatting down in the platea next to an entrance.

A single mouth, chatting, among hundreds other voices.

During the concert you could hear the individual performers’ instruments, the strings rubbing, the valves clicking. I was blown away

A critical factor in this experience was the actual room. Anyone dealing with audio and hifi will confirm how much great acoustics depend on a well treated room.

While most of us can't live in such a purpose-optimized room I think OP's point was that a bunch of high quality speakers in that very same auditorium might have yielded very similar results to your experience.

There is a scientific reason reggae dub shows feature massive woofer stacks built out of specific types of wood…

> What's so special about the soundwaves going into your ears when you sit close to an orchestra that couldn't be reproduced with good audio equipment?

An orchestra is a large number of instruments spread across a wide stage. Each of those instruments is its own sound source. The audio cortex in the brain is highly tuned to understand things like the 3D location of sounds from cues generated by factors like the individual shape of our ears and how sounds bounce around and down into the ear canal.

Now I'm sure you'd agree that sitting in front of two speakers X metres apart, or with headphones on, no matter how good those speakers / headphones are is a different set of sound waves.

Some people are absolutely able to determine the difference between those sound sources. They're likely to have listened to a lot of music. I think these discussions get derailed by the blanket "people can" or "people can't" statements rather than thinking about who might be able to make those distinctions. It might be that the majority of people can't make that distinction. But that doesn't mean that no-one can.

It's like folks are talking past each other here. There appear to be a substantial number of (I assume younger)posters that have never been to something like a symphony orchestra and don't see the point when they can geek out with FLAC at home. Maybe the orchestras should advertise "Come see our array of 120 separate high end speakers" and the kidz would respond.

"Why go to a museum when I can look it up on Google?"

> What's so special about the soundwaves going into your ears

tongue in cheek answer: nothing. It's your ears that are special.

Less tongue in cheek, while we have got pretty good at making microphones, they don't behave anything like human audio system; this makes it really difficult to reproduce what we experience when generated a different way (e.g. multichannel playback).

There is nothing "special" about classical music here either, it's just got a lot of complexity (from multiple instruments, and room dynamics) and dynamic range.

I see your point: if we could a) design microphones that capture everything going by them in a neutral way and b) design speakers that precisely reproduce everything they are sent in a neutral way, and c) set up a room to reproduce things in a neutral way for your particular position ... then this would work. We can't actually do any of those things.

First time I had been to an actual classical concert I thought the walls need more dampening, mics placement is terrible and couple sliders on the right side of equalizer could be turned down a bit.

By the time It was over I completely "got" it though. I was internally complaining that an actual fishing port at 5AM don't look like a Monet copy, not watered down, skewed, or idealized.

Good point, my exact experience of live concerts

Meanwhile I'm listening the output of an amplifier playing a distorted guitar. I might listen to an acoustic guitar, and there might be a small horn section. Of course there's going to be drums. So it's super-simple to tell if it's live or a recording - the volume levels are going to be insanely different!

> Your friend does not think you hired a string quartet. Your friend thinks you have nice speakers.

When I first got nice high end speakers (TY Craigslist) I did this with an acoustic guitar CD.

The amount of detail I could hear, and by detail I mean "close my eyes and hear every details of the musican's fingers moving across the strings" detail, was incredible.

That is also the day that I learned MP3 encoders of the time (~8 years ago) still had bad encoding artifacts even at 256kbps.

After hearing enough clicks and pops, I ended up having to re-rip my CDs as FLAC, or in some cases buy the CDs so I could rip them.

Now days encoders are a LOT better. You don't get clicks and hisses except at 128kbps.

Also 90% of my listening is done through a wireless headset (...) through spotify (...) so quality has taken a serious nose dive anyway.

That said if I want to listen to music as an all immersive activity, yeah, lossless through high end speakers. But I do that maybe once every other month for half an hour.

Theoretica Applied Physics and BACCH Labs audition this exact demo -- A/B test by actually hiring a quartet and alternating the musicians playing with the speakers silent and the musicians silently air-playing and with the speakers playing. With a perfect image you literally cannot hear the difference.

https://www.theoretica.us/ https://bacch.com/

Unless you have bad hearing everyone would be able to hear the difference on speakers and live unless live is defined as someone playing far away on a scene or something, no matter how expensive equipment you have. It is impossible to have it sound like musicians playing in the same room. To even come close you would need several speakers per instrument playing in multiple directions and some playing sounds of the people moving, breathing and talking too. Not even a simple snare drum being hit at intervals can be reproduced by a normal stereo setup to sound as if it were in the same room unless it's at distance. Remember, we play music at home so the definition should be an orchestra two to three meters away, not an orchestra ten to twenty meters away up at a scene.

Someone with something to sell is a very unreliable source btw.

I found a video in one of those links from Princeton. It's a narrative of this guy developing 3D sound that works in normal 2 channel laptop speakers.

It's quite impressive when they demo it. There is a moment around 1:20 that plays flies circling around and my cat next to me didnt care about the normal recording but he stood up with his ears out when the 3d version played.

https://www.youtube.com/watch?v=SQmQD27uCt0&t=3s

I know it's probably old hat by now (the video is ~10yrs old, yes 2010 was over a decade ago) but it still blows my mind.

This is pretty old hat now. IRCAM was experimenting with spatialized sound on a stereo medium already back in the 1990s. The software they came up with was used e.g. for the Deutsche Grammophon recording of Pierre Boulez’s piece Répons where sound is moved around the hall.

> Your friend does not think you hired a string quartet.

To be fair to the audio system, a significant reason why they'd sound different is because of room acoustics—and we rarely listen to string quartets playing in residential living rooms.

What you said is totally true but it's not relevant here.

Apple already have all the lossless files on their server. Just that before they converted them to lossy format before sending to the user, and now they serve the original.

There is no new master / new re-release involved in all these.

> Apple already have all the lossless files on their server. Just that before they converted them to lossy format before sending to the user, and now they serve the original.

Do you happen to have a citation for when this changed? According to the "Apple Digital Masters" Technology Brief[1], the masters delivered to Apple have historically been AAC files.

[1] https://www.apple.com/itunes/docs/apple-digital-masters.pdf

I might be misunderstanding, but I think that PDF is about how to master your music such that it will sound good after they convert it to AAC. It doesn't actually speak to the audio that's sent to them.

Can't source anything except our own deliveries to Apple, but we've been delivering PCM since ~2018. Likely earlier, that's just when the code got moved into source control. That actually predates the copyright on that PDF.

In general, of the maybe 150-odd DSPs we deliver to, as far as I know all but a handful have us deliver PCM. The remainder have us delivering flac.

> Can't source anything except our own deliveries to Apple, but we've been delivering PCM since ~2018.

Cool, I take your word for it. Thanks!

The referenced document only talks about AAC masters, and the tools at https://www.apple.com/itunes/mastered-for-itunes/ only create AAC masters. The simplest explanation is that the public materials and tools are just sadly out of date.

I'm pretty sure nucleardog is correct and that Apple wants 24/96KHz minimum sent to them; the PDF you linked to actually says that under "Best Practices" -- "To take best advantage of our latest encoders, use only 24-bit sources and send us the highest-resolution master file possible, appropriate to the medium and the project." Then Apple encodes their AACs using the tools and methods described in that document. If I understand it correctly, they're basically trying to ensure that the downsampling from 24/96 to 16/44 preserves as much information as possible. (Does it really make a difference? No idea. But it does mean that Apple has a whole lot of music they can re-encode at varying quality levels.)

It's odd because I've read that before and made an assumption that it was talking about AAC mastering, but it only implies that. There's nothing that comes out and says what they want! There are some parts where they suggest higher fidelity sources, but mostly it comes down to:

    Apple Digital Masters Droplet 
    You can use the Apple Digital Masters Droplet to automate the creation of 256 kbps

AAC encodes.

There isn't actually anything about what you're supposed to send them, only the recommendation to use their tooling which seems geared to produce 256k AAC files.

Ah, that makes sense, thanks!

For anyone bored and looking to explore: https://dr.loudness-war.info/

Note that all entries that have the format Vinyl on that site can be ignored, as the dynamic range calculations don't work well on audio recorded from vinyl records.

Well, I'm glad I've been using it to pick out which pressings to target haha.

I agree. For me the limiting factor is not necessarily whether it is poodles high quality encoded or lossless. For "normal" music the bottleneck is often the recording. With good headphones it is easy to differantiate good from not so good recordings. I For me a lot of recordings on Tidal/qobuz did not sound better than HQ on Spotify

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