Sound quality - what is this?, page 1

A few words about the sound quality.

The popular radio shows:
John Digweed’s Transitions and Carl Cox’s Global – on Kiss100 – signal bandwidth 16 kHz
Tiesto’s Club Live – on Radio 538 - signal bandwidth 15.5 kHz
David Guetta’s Dansin – on Radio FG - signal bandwidth 15.3 kHz

All these shows are shared as mp3 @192 kbps. Knowing that an mp3 @192 kbps can preserve a signal bandwidth up to 18.5 kHz why the above shows have a narrower bandwidth?
The answer is: because the FM radio broadcast is band limited up to the values shown above.

Knowing that an mp3 @128 can preserve a signal with a bandwidth of 16 kHz (my experiments show 15.5 kHz) it follows that the music broadcasted through FM radio cannel has a sound quality as an mp3 @128 kbps no matter if the  file container been used can preserve better quality.

About XM Radio (not again).
The radio uses a compression technology (ACC+) that can reconstruct the whole audio CD sound spectrum (22.05 kHz) with the drawback of reducing the middle and high frequency ranges. This drawback should can be corrected using a player’s tone controls or equalizer to boost these frequency ranges.
(As to me, I am going to write a small digital filter program to try to correct this drawback by boosting these frequency ranges.)

If we do not consider the live recorded music shared on the tracker and other sources that use ACC+ coding technology, from all mp3s @192 kbps, the only real 192 kbps quality show is the Armin’s ASOT streamed on DI.fm as 192 kbps mp3. (Their platinum service) P.S. I need to add DI.fm is licensed first to broadcast the show.

P.S. After having read slash' post:
Yes, you are right slash.
I should have said “live and studio recorded music”

i would love to mention here, that author is talking mostly about "popular shows", recorded off fm-air, satellite or i-streams.

on the contrary i wanted to mention, that all mp3s marked to be a part of the Tribalmixes Radio, are shared and passed to the members of tribalmixes.com as unchanged MASTER recordings, thus representing the original music and encoding quality produced by djs's decks, software, or whatever sources applicable here. and again i cannot say "all", because i'm not sure what each dj uses to make their sounds...

oh.. after i read this, i can't understand it myself... to sum it all up: Tribalmixes Radio music shared as torrents is presented in the best possible quality as intended/produced by the dj/software..

obviously there are some more DAB recordings which are 192kbps or above original quality than ASOT

Surprisingly, not.
I have not found spectrum bandwidth more than 15.5 kHz in all mp3s @192 kbps I have checked out and that have been announced as having a source DAB (Digital Audio Broadcast Radio).

Here is some information as an example:
02-dave_clarke-white_noise-dab-02-03-2007.mp3 - 15.2 kHz
01-sven_vath-live_at_groove_city_2006-dab-11-18-2006.mp3 - 15.2 kHz
01-dave_vega_-_ministry_of_sound_session-12-15-dab-2006-xds.mp3 - 15.5 kHz
01-big_nite_in-steve_angello_and_sebastian_ingrosso_live-dab-18-08-2006-1real.mp3 - 15.5 kHz

Sound quality, what is this - an empty word maybe.

What about this?
There are two torrents still alive:
"Deep Dish (Ali Dubfire) - guestmix on Matt Darey Nocturnal 84 on DI.fm - 17-Mar-2007" –announced sound quality of 224 kbps and 344 downloads
"Matt Darey - Nocturnal 084 On Di.Fm - 17-Mar-2007" – announced sound quality of 192 kbps and 405 downloads
It is clear – Ali Dubfire is one of the best House DJ in the world – the interest is enormous.

But what is true about the sound quality – nothing.
• First of all DI.fm best service (Premium – paid service) is 192 kbps mp3. So, 224 kbps cannot be true. It is really 192 kbps with a spectrum bandwidth of 18.7 kHz. But I can understand the uploader because another torrent is fake 192 kbps quality.
• The second torrent is simply 128 kbps quality because the spectrum bandwidth is 15.4 kHz and it is obviously the free DI.fm service.

Maybe 344 users preferred better sound quality and they had it. But what about another 405 if they knew the file they were going to download is not a 192 kbps sound but 128 kbps and another file was a real 192 kbps sound?

the world would definitely turn upside down!

ps  that is, if people always knew what they were getting before actually getting it...

I agree with you guys for those who are making the difference I'm sure it is important to get this better quality

but what if most of those about 700 people just wanted to hear the music Dubfire(or whoever is the DJ they want to hear)  plays and if the quality is good they don't care if it is 192 or 224 or whatever what if they listen to the music not to the khz or bitrates or whtever and don't want to read a manuals how to become sound engineers  

P.S. this is applying of course only if the quality is good (that means the sound is clear) And of course that if I can choose from the 2 options I'll get the better quality

I have already posted a reference I am going to post here but I think this is the place for it.
I really try to use sources of information which could seem more abstract but they are proven scientific texts.
Here is the source: THE DIGITAL SIGNAL PROCESSING HANDBOOK
Edited by VIJAY K. MADISETTI, DOUGLAS B. WILLIAMS.
both editors:
Center for Signal and Image Processing
School of Electrical and Computer Engineering
Georgia Institue of Technology
Atlanta, Georgia

Nikil Jayant
Bell Laboratories, Lucent Technologies

says in chapter IX - Digital Audio Communications:

"The three parameters of digital audio quality are: signal bandwidth, fidelity and spatial realism".
The spatial realism is provided by increasing the number of spatial channels. The common formats are:
1-channel (mono), 2-channel (stereo), 5-channel, 5.1 channel, 8-channel.
The fidelity refers to the level of perceptibility of quantization or reconstruction noise. It is evaluated by formal listening tests.

It is clear we cannot talk strictly about digital audio quality not using the signal bandwidth or in other words without using a spectral analysis tool.

And more:
"Compact-disk (CD) signals have bandwidth of 20-20,000 Hz, while traditional telephone speech has a bandwidth of 200-3400 Hz. Intermediate bandwidths characterize various grades of wideband speech and audio, including roughly defined ranges of quality referred to as AM radio and FM radio quality (bandwidth on the order or 7-10 kHz and 12-15 kHz, respectively)."

Is the sound quality an empty word?
For many, yes.

I saw three releases of the Tiesto’s  Club Life 010 (Radio538 broadcast) recently.
• a TALiON’s release – 44.1 kHz VBR avg 171 kbps
• a Monse’s  release – 48 kHz mp3 VBR avg 213 kbps
• a Monse’s  release – 48 kHz mp2 @192 kHz (the same release is shared at TM also)
(Monse is an TBM uploader and TM user also)

Obviously Monse rips his music using some mp2 stream which was the reason for
Ojay – a Resident of TMB - to say about the Monse’s release of ASOT 302:
“This is not one of the usual 192kbps DI.fm versions!!
This release was obtained from a source with a bitrate of up to 384kbps!
It was converted by Monse to … - roughly the same quality as 320kbps CBR MP3.
This is the highest quality ASOT version on the entire Internet!!!”

The quality of the ASOT 302 as well as the quality of the above Monse’s releases of the Tiesto’s Club Live 010 is 128 kbps and the reason for that obviously is the source of the mp2 streamer (in spite of its  bitrate of up to 384kbps). In the case with the Club Life the source is Radio538 broadcast which is band limited to 16 kHz (an FM radio station).
This is obvious but here I am showing the spectra that prove this also.
(All spectra have been calculated over the whole length of the files.)
• First, these are two spectra: Tiesto010-MoN.wav and Copy of 01_-_Tiesto_-_Club_Life_010_MoN.mp3. The file Tiesto010-MoN.wav is result of conversion of the file Tiesto010-MoN.mp2. This conversion is lossless and I needed it because the Sony Sound Forge 8.0 does not work with mp2 files. The second file is copy of … because … (if someone wants to know why I would explain but it has nothing in common with the topic).

Both spectra are the same, with a shift in Y axis, which is not surprising because the spectra are determined by the source – the radio broadcast – not by the encoders. These two files can hold sound with better quality than this and the source spectrum is not intact.
So, as it is seen the spectrum bandwidth of the both files (mp2 @192 kbps and mp3 VBR 213 kbps) is the same – around 16 kHz.



• Second, here are spectra to compare Club Life - 010 versions: mp2 @192 kbps, mp3 VBR 213kbps, and two mp3s @128kbps and to show they are essentially the same.
How the 128 kbps files have been generated?
I think the idea is clear. I used the file Tiesto010-MoN.wav (a conversion from Tiesto010-MoN.mp2) as a source and compressed it to mp3@128 kbps using two different encoders: Lame 3.97 and Blaze Media Pro. The same software (Blaze Media Pro) I used to convert Tiesto010-MoN.mp2 to Tiesto010-MoN.wav.
(all mp3 files have a sampling frequency of 48 kHz – same as the Monse’s source files)

These spectra are shown relatively -112 dB because this level is the level of the quantization noise and it makes no sense to consider spectral components that are lower than the noise for now.
The red line is at the level of -92 dB to show the spectral components that are at least 20 dB higher than the noise. I prefer to determine the spectrum bandwidth based on the level -92 dB.


mp2@192 kbps (Tiesto010-MoN.wav) vs mp3@128 kbps (k128_lame.mp3)



And
mp3 VBR avg 213 kbps (Copy of 01_-_Tiesto_-_Club_Life_010-MoN.mp3) vs mp3@128 kbps




As it is seen the four spectra are essentially the same (the differences are of the magnitude of the quantization noise) hence the Monse’s files are 128 kbps quality and it is determined by the Radio538 broadcast channel. (Of course, the same is true for the TALiON’s release as well.)
(What determines for a sound to be of a 128 kbps quality? If the original sound spectrum and its bandwidth specifically can be preserved with an mp3@128 kbps compression then the sound is at most 128 kbps quality. But it could be worse quality also.)

I am not showing the TALiON’s files spectra because with the same source (Radio538 broadcast) and mp3 VBR avg 171 kbps they should be the same.

To put a bottom line for now:
A 128 kbps sound offered as:
mp3 VBR avg 171 kbps
mp3 VBR avg 213 kbps
mp2 @192 kbps.

Isn’t it funny? No, it is not.

sure its notnow thats funny

What do you think, is there something in common between bit rate and the quality of the digital sound?
If there is, then …

A three hours set of 15.5 kHz bandwidth sound in an mp3 @320 kbps!
(After all an mp3 @320 can hold a sound of 20 kHz bandwidth.)

The file Sasha & Digweed - Live @ Bonnaroo 17-06-2007.mp3 has a size of 516,416 KB and its content is a 15.5 kHz bandwidth sound.
The size can be safety reduced without loosing the quality:
• First, decode it to a wav file. Using (command line application) LAME: lame –decode Sasha&Digweed-Live@Bonnaroo17-06-2007.mp3  Sasha&Digweed-Live@Bonnaroo17-06-2007.wav (or rename the files)
• Then, encode: lame -v --lowpass 16 Sasha&Digweed-Live@Bonnaroo17-06-2007.wav  @new_bitrate.mp3
(No spaces in the file names.)

The result will be a 156 kbps file of size 251,375 KB and a sound of the same quality.

You can download this result here: https://www.megaupload.com/?d=83O6FIYI

yes, i know all this SpasV, and i said in the description that this is not the real sound quality, just the bitrate of the file. Now, i didnt decoded it because this was what i found, its not mine, so for later request/reseed/use there will be the original file, as about the decode, i think who wants can do it himself as you did

I remember you were the first to tell me the file size does matter even when the quality is considered.
After then I always try to find some balance between the quality and the size. I often recode some improperly encoded files to cut the needless size.
In this case the unnecessary, needless file size is 105.4%. The file size is more than doubled!
It took me more than three hours to download the file.
And even with my relatively fast computer it took me long time for recoding it to the proper bit rate.
I do not understand why haven’t you done the recoding?
Anyway, thanks.
I have uploaded a proper encoded version of the file and the megaupload link works.
(again the download link: https://www.megaupload.com/?d=83O6FIYI)

as i said, its not mine recording, thats why i've puted up what i was found and its the one which will be available in all the www as it was posted in 1st place, as about the unnecessary size, i have another copy made by myself for my creative, and you have yours as well. cheers SpasV, i know you do your best as i do