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Does pono's 24-bit audio matter? Hear for yourself.

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11–20 of 77 posts

Re: Does pono's 24-bit audio matter? Hear for yourself.

#11
This test is flawed in a few ways. The and the error lies in the source material. The why would there be a perciveable difference between the same inferior input shown to both encoding formats. Changing between encoding formats is a topic of its own but the problem here is similar to getting a 640x480 compressed jpeg and putting it into a 1920x1080 lossless format and the same source into a 1280x720 lossless file and saying. What's the difference? They both look crappy! Many people have an opinion on high res audio formats but they are so many places to go wrong. Audio should be given a little more credit for it immersive ability. When done right it can take you places. Something to consider is that our eyes can only see 1 octave of information our ears can hear 10 octaves. Whilst these high res formats aren't needed for every application they do make a big difference when the source material can take advantage of it. I feel in 2014 music should be released in the best format available from the studio and if u want a crappier version so u can shove 5000 songs on your iWhatever that's your choice.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#12
post #6

Newborns can hear a SNR of about 120dB which is around 21-bit. So 24-bit seems useless for playing back audio. But I always wonder how much of the sound we hear by feeling (skin, hair vibrations). Because maybe I can't hear 1Hz, but I can very well feel it.

> Newborns can hear a SNR of about 120dB which is around 21-bit. So 24-bit seems useless for playing back audio.

21-bit would make for an awkward file format. If we can hear 17 bits of range that's enough to justify storing music as 24-bit.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#13
post #8

Weird that the author uses a 'ordinary MP3' as source for the test. Garbage in, garbage out. Right? Would be a better test with a very high rez audio file.

I suspect it's heavily compressed audio. His argument is that you'll have a hard time hearing it at all, so if anything's going to help you hear it in the first place, it's garbage in. garbage recordings are the only ones which will survive this test.

Anyway, nobody here is both qualified and willing at the same time to tell you what you need to know about this topic. The article referred to, written by Monty at Xiph, should give you a very good overview of how this works .

http://people.xiph.org/~xiphmont/demo/neil-young.html

Re: Does pono's 24-bit audio matter? Hear for yourself.

#14
post #5

One thing that is alluded to but perhaps not explored fully is the use of noise-shaping dither techniques which rely on pushing the noise out into the ultrasonic region. Xiph mentions it in the context of 16 bit resolution, but I believe it interacts with the discussion of 192 kHz sampling. Significant noise power at ultrasonic frequencies (or even a skewing towards higher audible frequencies) represents a problem fo…

> Significant noise power at ultrasonic frequencies (or even a skewing towards higher audible frequencies) represents a problem for tweeters & amplifiers both in terms of the intermodulation distortion mentioned in the article and in terms of power dissipation at the business end. IIRC Dell and VLC are having a falling-out because VLC's soft clipping is damaging the speakers in certain Dell laptops.

Dell probably didn't bother putting an analog reconstruction filter on their DACs, assuming they used an average Realtek codec the digital filter in the DAC has a minimum cutoff point around 28khz but could be higher when operating with higher sampling rates. They probably also sent the signal into a filterless class D amp to drive the output. Those two things together add up to a lot of ultrasonic crap in the signal.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#15
The methodology might be flawed, but the point stands: We can't use the full dynamic range of a 24 bit signal for audio. Great converters have 20-21 bits of range and if we fully use this range, hearing damage will start at maximum volume levels. If the volume is kept the same between the two files, there is a 48dB drop in level - not inaudible, but there are very few source materials that will actually use the extra dynamic range. On top of that due to fletcher munson curves we will only hear content in the 1-4kHz range at that low volume level.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#16
It would take highly dynamic music to really hear more bits. The quiet passages is where it makes the difference. Most music is compressed beyond the need for anything other than 40db of dynamic range.

I barely can tell the difference between high sample rate 8 or 12 bit audio and 16 bit audio. In some circles I hear people talk about that "gritty" 12 bit sound, but its usually not properly dithered, heavily filtered, 20khz or less sample rate and generally destroyed on purpose.

Audio is generally the best arena for snake oil since subjectivity is so high. I cannot believe that Focal Grande Utopia EM loudspeakers(180,000 usd MSRP) exist in quantity, but I know two people who own a set in their (comparatively) modest living room. I have heard them in action, they sound great, but Im not sure that I heard anything in any of the music that I hadnt heard with good headphones or speakers. At what point is it "good enough"? I own plenty of recordings that no amount of hifi audiophilia will help.(many that I recorded myself ;) )

Re: Does pono's 24-bit audio matter? Hear for yourself.

#17
post #6

Newborns can hear a SNR of about 120dB which is around 21-bit. So 24-bit seems useless for playing back audio. But I always wonder how much of the sound we hear by feeling (skin, hair vibrations). Because maybe I can't hear 1Hz, but I can very well feel it.

You can definitely "experience" the sub-audio range, but you don't need 24 bits to do that.

I have very sensitive hearing, I hear things most others cannot. I can detect 192kbps vs 320kbps mp3 encoding. I cannot have any switch-mode AC/DC transformers in my bedroom because the switching noise actually keeps me awake (I charge my phone in the kitchen, most people think I'm mad when I complain about the "noise" :)

Still, I've never been able to detect frequencies above 20Khz or hear the difference between 16 and 24 bit. I think anyone claiming to is full of crap.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#18
post #11

This test is flawed in a few ways. The and the error lies in the source material. The why would there be a perciveable difference between the same inferior input shown to both encoding formats. Changing between encoding formats is a topic of its own but the problem here is similar to getting a 640x480 compressed jpeg and putting it into a 1920x1080 lossless format and the same source into a 1280x720 lossless file and…

It's not the same as the same inferiour source material.

When you apply negative gain to the 16-bit signal, it has less amplitude in absolute terms, but it should have all the resolution of a whole 16-bit sample in that space.

The point is that whether that 16-bit signal is represented with the lower 4 bits of a 16-bit sample, or the lower 12 bits of a 24-bit sample, you can scarcely hear anything at all, let alone a qualitative difference between the signals.

192KHz is not a higher quality format, it is a production format. The purpose is to reduce the cost and finality of anti-aliasing filters when sampling the signal, it is just cheaper to manufacture. There's a good reason for this being the standard in professional audio, they need to buy a LOT of audio interfaces, many studios will have thousands of such inputs.

Thanks to the basic laws governing signals, we know with near certainty that not only is 192KHz overkill, but so is 48KHz, and so is 44.1. Without significant new evidence showing humans hearing signals with frequencies greater than 24KHz, you will not make any convincing argument as to why we should go with any sample rate higher than 48KHz for human listening.

As for 24-bit, it is another production interchange format. It's there so that you don't need to stand around adjusting gain knobs on audio interfaces so that you get decent fidelity but also don't clip. With 24-bit you can just sample your audio once, and assuming it's within a reasonable range, you can adjust the gain in the discrete signal. There is some indication that 16-bit sampling is less than completely ideal. The very best ears in humanity(newborn ears) distinguish about 21 bits in the safe ranges of amplitude, 24-bit may make sense in an audio system for newborn babies.

I feel that in 2014, music should be released in the best format available from the studio, and if you want a crappier version so that you can shove only 100 songs on your iWhatever, that's your choice.

Re: Does pono's 24-bit audio matter? Hear for yourself.

#19
post #10

This test is pretty uninteresting, but I'm glad the author linked to the Xiph article because it's one of the best articles on the subject I've read. http://people.xiph.org/~xiphmont/demo/neil-young.html

The author admits that "16 bits does not quite cover the entire theoretical dynamic range of the human ear in ideal conditions". But then the author concludes "let's not use 24 bits anyway because it doesn't really help anyway, and it wastes space"

Wastes space? In an age where we stream gigabyte movies? Do we need to remind the author that we're no longer in 1982 and that we have evolved beyond floppy disks?

Re: Does pono's 24-bit audio matter? Hear for yourself.

#20
post #5

One thing that is alluded to but perhaps not explored fully is the use of noise-shaping dither techniques which rely on pushing the noise out into the ultrasonic region. Xiph mentions it in the context of 16 bit resolution, but I believe it interacts with the discussion of 192 kHz sampling. Significant noise power at ultrasonic frequencies (or even a skewing towards higher audible frequencies) represents a problem fo…

VLC doesn't soft-clip to my knowledge.
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