16/44 FLAC vs. AAC 256

[ElviaCaprice]

Sorry Sandy and forum for being mean. Merry Christmas and a Happy New Year to all including Sandy!!!

 

Jaynyc, I like to use IZotope RX4 for analysis and mastering.

[sandyk]

Sorry Sandy and forum for being mean. Merry Christmas and a Happy New Year to all including Sandy!!!

 

Jaynyc, I like to use IZotope RX4 for analysis and mastering.

 

Apologies from me , for being mean too, with my replies to you in this thread.

One of the great things that I treasure, was with another forum, being able to meet up with a couple of U.K. members when they visited Australia. One member is a Virgin pilot, and several members of the forum from Sydney and myself, were able to catch up with him on quite a few occasions, and enjoy drinks and meals at several different Sydney locations.

 

BTW, I use Sound Forge 9 for these types of comparisons.

 

P.S.

In a little over 5 hours time, it will be Xmas Day "Downunder."

[kumakuma]

Elvia-- I used Spek (Spek – Free Acoustic Spectrum Analyzer / Spectrogram Viewer). What is better (or best) software to use to do this type of visual confirmation analysis?

 

I use MusicScope:

 

https://www.xivero.com/musicscope/

[mansr]

Legit to them in that this was provided to them as is to be sold, doesn't mean it's legit redbook. From the graph I'm still in the camp that it is not. Could also be a poor recording. How does it sound to you?

 

It appears to have been filtered slightly below the theoretical cutoff of 22.05 kHz. That doesn't mean it's lossy in the usual sense or that it doesn't sound good.

[JSWolf]

Looks to me they are both lossy and identical. Just because they say it's flac doen't mean it is.

 

They are in no way the same.Just compare the two images and you'll see the AAC track has some loss to it vs the FLAC track.

[semente]

Don't feel bad. I recently bought a track on Pono and it was also obviously lossy rewrapped flac. You can tell when it's cut off below 22hz, a telling sign of lossy.

 

Why do you say that the FLAC is lossy?

 

It looks to me like a 16/44.1 file that has been low-passed, but that is not lossy, only lower-res when compared to the original master file (assuming that it was mastered at a higher resolution).

 

R

 

 

 

P.S.: I've just realised that many before me have made a similar comment...

[teruhata]

Has anybody compare the sound quality from Apple to an actual CD? I've done the comparison on a song between Apple Music format and MP3 format; and seems to me that the sound quality from Apple Music is better than MP3. Well, this is just my opinion..feel free to comments.

[mansr]

Has anybody compare the sound quality from Apple to an actual CD? I've done the comparison on a song between Apple Music format and MP3 format; and seems to me that the sound quality from Apple Music is better than MP3. Well, this is just my opinion..feel free to comments.

 

By Apple Music, do you mean ALAC or AAC? ALAC is lossless so should be exactly the same as the CD (if made from the same master). AAC is lossy but generally of better quality than MP3 at the same bitrate, and 256 kbps or higher AAC is probably better than MP3 can ever be.

[Ice]

Nice thread

 

Clear point of discussion but unformtunately no comment about how the files sound.

 

well, the physical CD arrived and I ripped the track to WAV (just to make it easier to see in graph comparison, there's no diff between FLAC and WAV)

 

[ATTACH=CONFIG]22922[/ATTACH]

 

Looks to me like the download FLAC from 7Digital is identical to the ripped WAV, which means 7Digital is selling legit lossless music. The AAC from iTunes is different. Thanks to everyone here who helped with this analysis.

 

Just that i understand the plots: Green indicates a recording level between -60 and -70 dB, right?

So from about 16KHz up to the top of about 22KHz i see a colour indicating a level from -70 dB towards -100dB.

 

How can i hear fequencies above 16KHz if i listen to this track with a peak-level e.g. 80 - 90 dB (not damaging my hearingsense and https://en.wikipedia.org/wiki/ReplayGain)? These frequencies would have a level of 10 - 20 dB. Concerning that a ground level of 20-30 dB in a listening room is normal to good and the loudness-contour (https://en.wikipedia.org/wiki/Loudness) and the age of the listener.

 

Is there more than subtracting some dB-Levels?

 

PS: The horizontal Line is clear below 16KHz, https://en.wikipedia.org/wiki/Audio_frequency explains:

 

[TABLE=class: wikitable]

[TR]

[TD]16744 Hz[/TD]

[TD]Approximately the tone that a typical CRT television emits while running.[/TD]

[/TR]

[/TABLE]

[mansr]

Just that i understand the plots: Green indicates a recording level between -60 and -70 dB, right?

So from about 16KHz up to the top of about 22KHz i see a colour indicating a level from -70 dB towards -100dB.

 

How can i hear fequencies above 16KHz if i listen to this track with a peak-level e.g. 80 - 90 dB (not damaging my hearingsense and https://en.wikipedia.org/wiki/ReplayGain)? These frequencies would have a level of 10 - 20 dB. Concerning that a ground level of 20-30 dB in a listening room is normal to good and the loudness-contour (https://en.wikipedia.org/wiki/Loudness) and the age of the listener.

 

Is there more than subtracting some dB-Levels?

 

The total sound level is the dB/Hz value integrated over the entire frequency range, and dB values are logarithmic, so there's a little more to it than simple subtraction. Looking at the spectrogram, we can approximate the distribution as -60 dB/Hz up to 15 kHz, then -80 dB/Hz (if we're generous) up to 20 kHz. A 20 dB difference is a factor of 100, and the low band is 3x wider than the top part. In other words, the energy contributed by frequencies above 15 kHz is only a fraction of a percent of the total. You probably can't hear (much of) those high frequencies under these conditions (masking by much louder low frequencies), which is why the AAC compression has eliminated some of them entirely (the black spots). That's not to say that there can't be moments where the high frequencies make an audible difference, but you'll have to listen rather carefully to notice.

 

PS: The horizontal Line is clear below 16KHz, https://en.wikipedia.org/wiki/Audio_frequency explains:

 

[TABLE=class: wikitable]

[TR]

[TD]16744 Hz[/TD]

[TD]Approximately the tone that a typical CRT television emits while running.[/TD]

[/TR]

[/TABLE]

 

European (PAL) TVs run at 15.625 kHz.

[sandyk]

European (PAL) TVs run at 15.625 kHz.

 

Surely you don't still use Analogue TV broadcasting and watch TV via CRT's ?

[mansr]

Surely you don't still use Analogue TV broadcasting and watch TV via CRT's ?

 

No, we don't. Most European countries discontinued analogue broadcasts a few years ago.

[Rexp]

well, the physical CD arrived and I ripped the track to WAV (just to make it easier to see in graph comparison, there's no diff between FLAC and WAV)

 

[ATTACH=CONFIG]22922[/ATTACH]

 

Looks to me like the download FLAC from 7Digital is identical to the ripped WAV, which means 7Digital is selling legit lossless music. The AAC from iTunes is different. Thanks to everyone here who helped with this analysis.

Thanks for posting, how about posting a FLAC v ALAC analysis?

[JSWolf]

Thanks for posting, how about posting a FLAC v ALAC analysis?

 

The same audio file in FLAC or ALAC will sound the same.

[Ice]

That's not to say that there can't be moments where the high frequencies make an audible difference, but you'll have to listen rather carefully to notice.

 

Very very loud playback may make these high frequencies audible: That's what you point out, isn't it?

This lossy files (with masked parts of the sound) are good in cars or as background sound at a homeparty or in mobile playback with earphones in noisy envirnoment like subways or downtown cities... It's all a matter of how loud we play our music. I think that's all the magic.

[mansr]

Very very loud playback may make these high frequencies audible: That's what you point out, isn't it?

 

Then the low frequencies will be even louder. I was more thinking that there could be brief moments where the high frequencies actually dominate, and there you might notice the difference. Or not, due to temporal masking.

 

This lossy files (with masked parts of the sound) are good in cars or as background sound at a homeparty or in mobile playback with earphones in noisy envirnoment like subways or downtown cities... It's all a matter of how loud we play our music. I think that's all the magic.

 

The main reason I avoid lossy compression is that once in a while the encoder messes up badly (it's a hard problem, after all). It's rare but annoying when it happens, and avoiding it entirely costs nothing (storage is cheap).

[JSWolf]

AAC 256 is not as good as 16/44.1. If you want lossy that's better than AAC, use Ogg Vorbis. Ogg Vorbis sounds better than AAC or MP3. Still not as good as 16/44.1.

[mansr]

AAC 256 is not as good as 16/44.1. If you want lossy that's better than AAC, use Ogg Vorbis. Ogg Vorbis sounds better than AAC or MP3. Still not as good as 16/44.1.

 

AAC and Vorbis have roughly the same potential in theory. The actual quality achieved depends largely on the encoder implementation. Lossless is obviously preferable unless precluded by bandwidth constraints.

[Ice]

The main reason I avoid lossy compression is that once in a while the encoder messes up badly (it's a hard problem, after all). It's rare but annoying when it happens, and avoiding it entirely costs nothing (storage is cheap).

...and you are shure this might not happen with FLAC or ALAC? I am not aware if i recognized such an event ever, theoretically possible and interesting issue...

[mansr]

...and you are shure this might not happen with FLAC or ALAC? I am not aware if i recognized such an event ever, theoretically possible and interesting issue...

 

Both are lossless, so it's theoretically impossible.

[kaufenpreis]

Looks to me they are both lossy and identical.

[JSWolf]

It is actually an interesting question: How to assess whether a compression method such as aac has actually destroyed data?

 

AAC by it's very nature is lossy, so yes it DOES destroy data. How much it destroys depends on the settings used.

[JSWolf]

Looks to me they are both lossy and identical.

 

The AAC is lossy. The FLAC does have more information than the AAC. So no, they are no way identical. As to both being lossy, there's no way to know about the FLAC based on that one photo.

[wgscott]

Both are lossless, so it's theoretically impossible.

 

But you have to be sure to use a mega-expensive linear power supply on the computer during the transcoding, and only transfer the data on a silicon chip under liquid argon via DHL surface courier, to avoid cosmic ray exposure. Otherwise, several guys in Sidney will be able to hear the difference, as long as there are no witnesses in the room.

[sandyk]

Next Issue of HiFi Critic magazine (Vol 10 no2) will carry a well researched 8 page article on how WAV differs from FLAC ,

 

.......how the files are made up and how they sound different.