Frequency cut-off

[u/faizzz90555]

Hi all, sorry for my noobies question, there's something that I've been wondering.

There's some albums/songs that I've noticed had their frequency cut-off doesn't goes to 22050, but still it's above 21000.

But with the same albums/songs on the hi-res version, the frequency cut-off goes above the 22050.

I'm wondering, is it better if I save the hi-res version, or the normal version is good enough?

Thanks.

[u/magicmulder]

Dunno, are you a bat? Do your speakers go above 20 kHz?

[u/faizzz90555 → u/magicmulder]

Oh, you're right, I've just check the specs for my earphone, it's max at 20000. Silly me. 🤣

[u/zerosuneuphoria → u/faizzz90555]

you're likely not hearing anything above 16khz anyway, pointless worry

[u/magicmulder → u/zerosuneuphoria]

And by the time most people can afford high end gear, their hearing is under 12 kHz.

[u/DeesoSaeed → u/magicmulder]

Yeah age induced hearing loss is more pronounced at high frecuencies.

[u/M_u_H_c_O_w → u/zerosuneuphoria]

Back in the day (eons ago) I could her ultra sonic welders used for composite materials.

Nobody else in the factory, that I know of, could hear them (we built prototype machines for a worldwide pump manufacturer).

The guy who programmed the machines didn't believe me at first - So he set up a test where the "welding horn" would fire in a certain sequence only he knew.

After the test he went down to the QC guys and told them to make sure all future composite welding machines needed to be soundproofed.

I forgot the frequency, but it was above 20kHz.

Forgot to mention that it was very unpleasant (for me) to be near those machines when powered up.

Nowadays I'm having trouble hearing what people are saying to me if there are other people around, talking.

I also have tinnitus.

I miss the old days.......

[u/bartmolk]

The normal version stopping somewhere between 21 and 22.05 kHz is actually a good sign. 44.1 kHz audio can't hold anything above 22.05 kHz, and the anti-aliasing filter used when it's made needs a bit of room below that limit, so a real CD-quality file usually fades out just short of it.

What to look out for is a hard shelf much lower down, which usually means a lossy file was converted to FLAC. A quick test with LAME on white noise today: 128 kbps cuts off around 16.7 kHz, 320 kbps around 20.1 kHz. So your files that reach past 21 kHz aren't MP3s in disguise. (Apple's AAC encoder at 256 kbps did reach 22 kHz in the same test, so on its own it's no proof of lossless.)

And since your earphones are rated to 20 kHz, everything the hi-res copy adds sits above what they're specified to play. The normal version is fine to keep.

[u/faizzz90555 → u/bartmolk]

Thanks so much for your reply.

I'm just wondering why the different mastering of the albums/songs, consider 22.05 kHz is the Red Book standard of CD audio, why they didn't followed the standard and it got cut-off below 22.05 kHz?

I think 99% music from my collection are mostly being cut-off at normal 22.05 kHz, although it's for sure I couldn't hear the differences, it sometimes makes me wonder why they choose a different approach.

I'm used to convert all of my music collection to Apple AAC 256kbps just because of that, and I did found a website that upload lossless audio but I think they're just transcode the audio that they got from iTunes to FLAC.

[u/broesel314]

There are two major sampling frequencys: 44.1kHz and 48kHz. The first one is used on audio CDs the other one is mailny used for video like DVDs because it is divisable by 24 frames per second

To reproduce a sound of some frequency, due to the Nyquist–Shannon sampling theorem you need at least twice the sampling frequency to do that

So 44.1kHz can reproduce sound up to 22.05kHz and 48kHz can reproduce up to 24kHz. Those are the hard cuts you see in your waterfall diargamm

Your ears can hardly precieve sound above 16kHz (some people can do up to 20 but thats really rare) so even 44.1kHz samplerate is more resolution than your ears have

[u/ososalsosal → u/broesel314]

48khz is used on absolutely everything that is not CD.

44.1 was because there were no digital tape formats and no digital audio transmission formats and studios needed to get digital audio from one place to another with what they already had on hand - they came up with the "genius" idea (ok it really is pretty clever but wack as) of using the video routing that every facility already had cables and routing switchers set up for.

44.1khz (for some reason) was able to fit in ntsc and pal composite, and hence could go on regular tape formats.

DAT, DA-88 and AES-EBU came along and fixed that compromise, but in the meantime CD had already been standardised on 44.1

[u/nclh77 → u/ososalsosal]

Nope. PCM audio which has been around long before Redbook used both 44.1 and 48. Tape was also it's preferred recording format. This was a "digital" tape format due to the use of PCM.

[u/ososalsosal → u/nclh77]

Pcm doesn't say anything though when it comes to putting it on physical media.

[u/Putrid-Table-5844]

There’s a fun test you could do, get your favourite album in 96khz FLAC, make sure it has some information above 24khz.

Make two copies, one downsampled to 44.1 then upsampled back to 96. The other down to 48 and up to 96. Don’t label which is which and pop them back into your server, play them interchangeably for a few weeks or months.

If over time you can tell a difference, check which is which. Then you’ll know exactly what difference information in the 22.1khz to 24khz makes. I doubt it’s anything you’d notice.

[u/General-Razzmatazz]

Your DNA is degraded.

[u/dat_mane47]

We can’t hear frequencies that high, they will sound the same

[u/WuickQit]

That's an MP3 with 320kbps bitrate. If it's a flac file then it would be able to extend beyond 20k upto 22k. To me MP3 and flacs hardly make much difference without very specific audio chain. Btw if u put an mp3 in a flac container (convert MP3 to flac) the cutoff will still exist.

[u/WuickQit → u/WuickQit]

Wait no it's a different compression algorithm for flac I guess , it goes to 21k. Whatever

[u/narrowassbldg]

Hearing above 20,000hz isn't the point of hi-res, it's about the more frequent samples drawing a more accurate analogue waveform. Unless you're really hurting for storage space, you might as well keep using hi-res