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Title: The Distortion of Sound
Post by: Jonathan Goodall on August 25, 2014, 01:37:44 AM
Might have already seen this and it states what most of us already feel, but it's an interesting watch.
https://www.youtube.com/watch?v=mDZcz-V29_M#t=138
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 25, 2014, 07:50:01 AM
it states what most of us already feel,

No it's just more of the same misleading propaganda. Music file compression DOES NOT remove dynamics and high frequency content.. or at least it doesn't have to. You can go get your favorite CD or vinyl album and rip it to MP3 on your personal computer and hear for yourself, you can look at the resulting waveform in software and it won't look any different than what came off the original source. The dynamically compressed-all-to-hell music currently being released is a deliberate action by major record labels to degrade the product, they lost the file sharing war and have stated many times in the past that they don't want the public having pristine copies of studio masters because they know they will just share them with everybody else and cut the labels out of the profits they had become accustomed to. So they are giving the public a product that is just barely acceptable as music for the average listener... your typical ear bud wearing under 30, and I'm sure what the labels feel is equivalent quality for what the consumer is paying.
Title: Re: The Distortion of Sound
Post by: Lee Buckalew on August 25, 2014, 08:48:53 AM
No it's just more of the same misleading propaganda. Music file compression DOES NOT remove dynamics and high frequency content.. or at least it doesn't have to. You can go get your favorite CD or vinyl album and rip it to MP3 on your personal computer and hear for yourself, you can look at the resulting waveform in software and it won't look any different than what came off the original source. The dynamically compressed-all-to-hell music currently being released is a deliberate action by major record labels to degrade the product, they lost the file sharing war and have stated many times in the past that they don't want the public having pristine copies of studio masters because they know they will just share them with everybody else and cut the labels out of all that profit. So they are giving the public a product that is just barely acceptable as music for the average listener... your typical ear bud wearing under 30.

This is two different types of compression, audio vs. data.
Various codecs for data compression of audio files do exactly what they are designed to do. Throw away what was perceived in the testing of that codec information that was not needed.  It may not be needed for an anticipated use due to limited frequency response of anticipated playback devices, etc., or it may be that the data delivery system required smaller files. 
All of the data compression codecs change the original content.  Some remain closer to the original than do others. 
In recording for an internationally recognized symphony orchestra we provide the orchestra members with online MP3 copies of each concert for their review.  We also provide a lower quality MP3 conversion for any guest artists or conductors.  This streamlines their download and saves storage on the FTP server.  There is a significant difference between these two codecs in terms of audio quality.  We also provide CD copies of special concerts for their listening committee to review.  The balance of the orchestra as well as the frequency response and stereo imaging are changed when converting to MP3.  All conversions are produced from original source files.
The original file source for these conversions is stereo BWAV, 24 bit, 96kHz from our archival 2 track masters.

Lee
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 25, 2014, 09:35:40 AM
This is two different types of compression, audio vs. data.

Yes. Just to be clear I'm not suggesting that MP3 conversion doesn't degrade sound quality, I'm just pointing out the all too common tactic of these special interest groups to suggest that audio compression is an unavoidable byproduct of digital audio conversions and the reason why we have so many bad sounding recordings in circulation.
Title: Re: The Distortion of Sound
Post by: Hayden J. Nebus on August 25, 2014, 01:53:25 PM
No it's just more of the same misleading propaganda. Music file compression DOES NOT remove dynamics and high frequency content.. or at least it doesn't have to. You can go get your favorite CD or vinyl album and rip it to MP3 on your personal computer and hear for yourself, you can look at the resulting waveform in software and it won't look any different than what came off the original source. The dynamically compressed-all-to-hell music currently being released is a deliberate action by major record labels to degrade the product, they lost the file sharing war and have stated many times in the past that they don't want the public having pristine copies of studio masters because they know they will just share them with everybody else and cut the labels out of the profits they had become accustomed to. So they are giving the public a product that is just barely acceptable as music for the average listener... your typical ear bud wearing under 30, and I'm sure what the labels feel is equivalent quality for what the consumer is paying.

I'm sure the idea of allocating 2x-5x the bandwidth for lossless music downloads isn't very attractive to the likes of Apple or any of our ISPs, who also have to deliver petabytes of movies and apps daily. If you've used netflix on the big 2 U.S. ISPs , you've probably experienced the forced scarcity that peering agreements can create.   

This is why I try and use alternate services like Murfie (no affiliation, just my current favorite). For a price that's comparable to an itunes download, you get to own a pre-loved physical CD, which you can have if you want, or they will hold onto it for you, rip it to FLAC (or your choice of codec)  and send you a link. 


Title: Re: The Distortion of Sound
Post by: Keith Broughton on August 25, 2014, 03:19:18 PM
I'm just pointing out the all too common tactic of these special interest groups to suggest that audio compression is an unavoidable byproduct of digital audio conversions and the reason why we have so many bad sounding recordings in circulation.
I'm not sure if we watched the same video.
There was no mention of of audio compression as an "unavoidable by product of digital audio conversion"
I also did not see any "special interest group"
This is a  POV for the broad  acceptance of sub standard audio quality for the distribution and listening "convenience" factor.
I thought it was well done and not biased to a product or company.
Title: Re: The Distortion of Sound
Post by: Tommy Peel on August 25, 2014, 04:10:17 PM
My current "poison" for music is Spotify Premium. For $10 a month I can listen to just about anything I want and keep some playlists downloaded to my phone & computer so I can listen offline. Being that I listen to a pretty wide variety of music buying all of it wouldn't be feasible and Spotify has a great recommendation system for finding new music. I find that the sound quality is acceptable for most of my listening(mainly in the car and with cheap ear buds) and for music I really like I have some vinyl records at home. I also buy the occasional album on iTunes if it's one of my favorite bands and I want to support them.
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 25, 2014, 08:42:37 PM
I'm not sure if we watched the same video.
There was no mention of of audio compression as an "unavoidable by product of digital audio conversion"
Yeah you need to go back and have another look, in the section where they show music waveforms they illustrate the MP3 file as having a compressed and clipped waveform compared to the original and the speaker explains that when a track is converted it loses dynamic range and frequency response. These assertions are just wrong or misleading at best, it is only the lowest bitrate MP3 conversion that would exhibit any of these traits, any decent codec and higher bitrate conversion will produce results that are indistinguishable from the original in all aspects on everything but the most high end sound system. 

I also did not see any "special interest group"
Well like it or not the recording artists and producers appearing in the video represent a special interest group, so it is what it is.

This is a POV for the broad acceptance of sub standard audio quality for the distribution and listening "convenience" factor.
That I can agree with and the video was well done, it's just that I don't agree with what they blame as the reason why we have so many substandard audio recordings these days.
Title: Re: The Distortion of Sound
Post by: Corey Scogin on August 25, 2014, 10:23:24 PM
I'll say there certainly is a huge amount of false information there.  Take a look at 11:30.  Nearly everything said around that point is BS. 

It's ironic that at 11:30 they cycle between "compressed" music and "uncompressed" music yet, when listening on YouTube, all of the audio is compressed more than the typical mp3 or aac from any major music store so in theory, we should not notice a difference during their "comparison" if compressed audio (YouTube) is that bad.

From the video: "[mp3] is not what is faithful to the original recording".  I dare say that in the transition from 24-bit / 96kHz master tracks to 16-bit / 44.1kHz CD tracks more is lost than in the transition from CD audio to mp3 when encoded at a high bitrate.

That said, I would love for a lossless compression codec to become popular.  I don't think the mobile bandwidth limits would allow that right now though.  I do a little project studio recording on the side and recently I discovered one track that had serious artifacts when encoded to mp3 due to low level, high frequency noise at the beginning.  The song was tracked live and started out with a very soft vocal part so there was a little ambient room noise.  For some reason, no matter how I encoded it with LAME, those artifacts remained.  Apple's AAC handled it better in this instance though I've heard that sometimes the opposite is true.  This was the first time I have ever noticed any difference between a 16-bit/44.1kHz lossless track and a lossy one. 
Title: Re: The Distortion of Sound
Post by: Lee Buckalew on August 25, 2014, 10:31:45 PM
Yeah you need to go back and have another look, in the section where they show music waveforms they illustrate the MP3 file as having a compressed and clipped waveform compared to the original and the speaker explains that when a track is converted it loses dynamic range and frequency response. These assertions are just wrong or misleading at best, it is only the lowest bitrate MP3 conversion that would exhibit any of these traits, any decent codec and higher bitrate conversion will produce results that are indistinguishable from the original in all aspects on everything but the most high end sound system. 

Incorrect.  All MP3 codecs create frequency response changes and loss of dynamic range (lower bit depth) capability.  The reduction in bit depth may not be noticed depending upon the actual source but the frequency response shift is noticeable on all but the worst systems or earbuds/headphones.  There is also a shift in stereo imaging and tonal balance that is very noticeable and measurable compared to an original high resolution master.

Lee
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 26, 2014, 07:28:58 PM
Incorrect.  All MP3 codecs create frequency response changes and loss of dynamic range (lower bit depth) capability.  The reduction in bit depth may not be noticed depending upon the actual source but the frequency response shift is noticeable on all but the worst systems or earbuds/headphones. 


Reduction in bit depth is irrelevant consider how much dynamic range current popular recording use, and I hear(nor see with Adobe Audition) any difference in freq response between a CD and an MP3 conversion done at 320kb/s or higher.
Title: Re: The Distortion of Sound
Post by: Lee Buckalew on August 26, 2014, 08:01:33 PM


Reduction in bit depth is irrelevant consider how much dynamic range current popular recording use, and I hear(nor see with Adobe Audition) any difference in freq response between a CD and an MP3 conversion done at 320kb/s or higher.

Notice that I said the reduction in bit depth may not be noticed depending upon the original.  It is most definitely noticeable on some recordings.  It is very easy to hear the shift of MP3 in music that has response below 40Hz or so and to hear the shift in balance as long as you are using reasonable accurate equipment.

Lee
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 26, 2014, 09:08:04 PM
It is very easy to hear the shift of MP3 in music that has response below 40Hz or so and to hear the shift in balance as long as you are using reasonable accurate equipment.

In a double blind test? Look, my argument here is not that there isn't some degradation in sound with compressed music formats, it's that the video totally overstates how much MP3 formats are to blame for the bad sound people are being exposed to. Yes there are all kinds of really bad MP3 files floating around in cyber space, but if a completely computer illiterate were to make an MP3 copy from a current top100 artist's CD with the default setting in windows media player(for example), that copy would be indistinguishable from the original on your average home audio system or portable listening device. The reason I'm confident in making that statement is because the recording on that CD is already far more compromised than it would have been even 10yrs ago and nowhere close to being hi-fi.. IMO. The big problem with todays music is not with portable music formats it's a lot further back up the food chain in a place where the consumer and probably the artists have no control over.
Title: Re: The Distortion of Sound
Post by: Tommy Peel on August 26, 2014, 09:24:23 PM
Here's a thought that might make for some interesting discussion. One of the things iTunes promotes are "Mastered for iTunes" versions of songs/albums. It sounds as if the tracks with that label are mastered with the intention to put them in the iTunes file format(256 kbps AAC). Any thoughts on this? Are there things that can be done in the mastering process to make a track Mastered for iTunes better than one ripped from the CD into the same format? I've never done a A-B comparison of these tracks with "normal" CD versions, but I'd be interested to see the difference.

Sent from my Moto X (XT1053) using Tapatalk

Title: Re: The Distortion of Sound
Post by: Lee Buckalew on August 26, 2014, 10:22:08 PM
Here's a thought that might make for some interesting discussion. One of the things iTunes promotes are "Mastered for iTunes" versions of songs/albums. It sounds as if the tracks with that label are mastered with the intention to put them in the iTunes file format(256 kbps AAC). Any thoughts on this? Are there things that can be done in the mastering process to make a track Mastered for iTunes better than one ripped from the CD into the same format? I've never done a A-B comparison of these tracks with "normal" CD versions, but I'd be interested to see the difference.

Sent from my Moto X (XT1053) using Tapatalk

This is absolutely necessary if you want the same mix.  Each codec actually requires a different mix in order to have the same blend of parts.  Our classical musicians have asked this to be done whenever there are multiple download formats available or if a mix is available on CD but also on a compressed download.

Lee
Title: Re: The Distortion of Sound
Post by: Lee Buckalew on August 26, 2014, 10:39:51 PM
In a double blind test? Look, my argument here is not that there isn't some degradation in sound with compressed music formats, it's that the video totally overstates how much MP3 formats are to blame for the bad sound people are being exposed to. Yes there are all kinds of really bad MP3 files floating around in cyber space, but if a completely computer illiterate were to make an MP3 copy from a current top100 artist's CD with the default setting in windows media player(for example), that copy would be indistinguishable from the original on your average home audio system or portable listening device. The reason I'm confident in making that statement is because the recording on that CD is already far more compromised than it would have been even 10yrs ago and nowhere close to being hi-fi.. IMO. The big problem with todays music is not with portable music formats it's a lot further back up the food chain in a place where the consumer and probably the artists have no control over.

Arguing that because current pop production techniques often mix/master to the lowest common denominator of is not the point here.  If I do have a poorly produced pop tune that has limited frequency response and limited dynamic range, and that's all I ever listen to, then your argument would make sense.  If however I listen to music that has good frequency response from 20Hz or below up to the highest that I can still hear (17kHz or so) and I also care that the mix translates (I may or may not) then the distortions matter.  Aside from the frequency response limitations there is significant artifacting created.  This is easily heard by taking a CDA and ripping it into a good phase coherent DAW as two track BWAV and ripping the same CDA in as an MP3 to the same session.  Now polarity invert the left and right track of either the BWAV or the MP3.  What you now hear is the difference between the data compressed tracks and the uncompressed tracks.  It is worse at lower rates but even a 320kbps MP3 creates significant amounts of artifacting and I can hear it not only double blind but on tracks that I have never heard before.  I can, more than 90% of the time, tell you if I am hearing an MP3 even on a cheaper system with no reference comparison.  With a reference in AB, nearly 100% of the time.

Unless I am never going to use an image except as a thumbnail I don't take a picture at low resolution, I take it at as high a resolution as I practically can.  Then, when I want to use it in a situation where low resolution is preferred, I convert a copy.  The same thing goes with digital audio formats for me.all of my files are at CD quality minimum.  If I need to down convert something for a particular device or other need I can but my main files are all full resolution.

There is a large difference between, there is no (noticeable) difference and in certain situations or with certain base material those differences don't matter.

Lee
Title: Re: The Distortion of Sound
Post by: Keith Broughton on August 27, 2014, 06:32:24 AM
it's that the video totally overstates how much MP3 formats are to blame for the bad sound people are being exposed to.
I have to agree with you on that point. They do not distinguish the difference betweem low and high bit rate.
As for the listening "demo" it was all BS for sure.
My hope is that even if a bit poorly "proven"  the basic point of the idea that we need to listen to better sound will be taken.
Title: Re: The Distortion of Sound
Post by: Paul G. OBrien on August 30, 2014, 07:18:45 PM
Arguing that because current pop production techniques often mix/master to the lowest common denominator is not the point here.

But it is the point, at least it's the point I'm trying to make. The fact that the source material that the general public listens to is of such poor quality completely negates any negative impact MP3 conversion may have on it, and means that the conclusions stated in the video are totally misdirected.
Title: Re: The Distortion of Sound
Post by: Luke Geis on August 31, 2014, 01:42:10 AM
Here is the basic run down. Anything with 44.1khz and above is totally transparent as far as our ears can tell. Which means that anything below that bit depth will have degraded quality that can be heard. The way music is compressed and decompressed is another story. You are no longer looking at bit depth, you are looking at the amount of key data that will be re-constructed later. The codec takes the data and " decides " what is valuable or not and then rebuilds the information back into something that resembles the original. If the information is missing and or scarce, the codec will create aliasing effects that we can hear. 128kbps is considered to be the lowest compression that is " acceptable " to most people. For many 320kbps is the only option if one must go to MP3. I am one such person who believes that 320kbps is the floor that we should aim for. Any lower and it is not truly good enough.

The way the music is produced can have a huge impact on the way the codec compresses. The codec has an algorithm that " looks " for information within a certain range and threshold. Anything not in that range or threshold is eliminated. When the codec rebuilds the information, those missing pieces are made up to fill in the blanks. Songs that are really loud and " not " dynamic are consistently outside of the codec threshold and will tend to sound overly compressed and crunchy. The codec negates important parts of the music that when put back together reduces dynamic range and it clips the peaks in order to " fit " within it's criteria.

Bad dithering is another huge contributor to bad MP3 exchanges. There are several dithering options and not all are created equal. Anytime you change the songs bit depth, you are introducing noise and aliasing artifacts. If these songs are then tuned into MP3 the bad information is made even worse as the codec further reduces it's lack of information.

Streaming music is hard. Imagine streaming fully uncompressed data for hours on end. A regular CD in wave format is around the ballpark of 70-80 min worth of music. Each minute of music is roughly 10mb, with a full cd capable of safely holding about 737mb of data with error correction. That would work out to several gigs a day if you listen to music regularly on your phone. The current data streaming for pandora is 192kbps if you choose that rate and have a premium account. I am lucky to have been grandfathered into truly unlimited data usage because I listen to a lot of pandora at the highest available speed. My emailing and other data usage done on my phone nearly places me as a data abuser!!!!! I have used 3.07gigs in this billing cycle and I still have another week to go. Over 1/3rd of that is Pandora!!!! I'm not usually over 5 gigs, which is the current cap for most carriers. Point being that with full data transfer of music that is streamed would add up very quickly. That being said, I can hear aliasing even with 192kbps.

The reason most people are happy with MP3 even in it's lowest form is because who doesn't want 128 songs on a CD, or 500 songs on a 2 gig ipod? It's nice to have the numbers even if the quality is low. I myself have 162 gigs worth of high end MP3 music and that is about 30,000 files!!!!  Those same files in wave would take 10X the amount of space to hold. More recent codecs are better at compressing music and maintaining space. 20 years ago HDD space was small and so the compression also had to be aggressive. Now a 500+gb HDD costs very little and space is not an issue. I could get most almost all of my music in wave format on a single drive these days if I wanted! Within the next five years we will see full data streaming capability for sure! 44.1khz CD quality music streamed hot right to your computer or phone! Europe is starting to do it already! MP3 compression of music will be a thing of the past soon!

The next thing that will improve music will not be elimination of the compressed data, but the elimination of compression period....... The mastering process where music is squeezed into the lifeless, dynamic-less loud music that it has become, will hopefully be dropped to a level where the music sounds the way it does as it comes off the channel tracks and onto the master track. If you have ever heard a song before and after mastering you are usually amazed! The un-mastered song is quieter and sounds bigger, dynamic and open. The current standard of mastering does as much damage as the MP3 compression. Mastered music is compressed ( highly ) and has a bit of it's sonic content reduced, sometimes drastically. It is true that music that is louder gets attention easier, but if everyone is doing it, then no one wins. We need to change the game from loudest and most produced, to simply best produced.
Title: Re: The Distortion of Sound
Post by: Jonathan Goodall on August 31, 2014, 01:46:14 AM
But it is the point, at least it's the point I'm trying to make. The fact that the source material that the general public listens to is of such poor quality completely negates any negative impact MP3 conversion may have on it, and means that the conclusions stated in the video are totally misdirected.

So would you agree with, Poor source material + MP3 (or what ever) conversion + rubbish speakers/head phones = Totally unacceptable  :)
Title: Re: The Distortion of Sound
Post by: Corey Scogin on August 31, 2014, 02:06:22 PM

Here is the basic run down. Anything with 44.1khz and above is totally transparent as far as our ears can tell. Which means that anything below that bit depth will have degraded quality that can be heard

44.1kHz is the sample rate, not bit depth.  16-bit is the bit depth for CD audio.

44.1kHz was chosen because Nyquist theorem states that digital sampling must occur at twice the highest frequency of interest in order to accurately capture and reproduce the sampled signal. Humans typically can't hear much higher than 20kHz.

It has been argued, though, that harmonic content above the normal range of hearing affects our perception of the sound.
Title: Re: The Distortion of Sound
Post by: Art Welter on August 31, 2014, 03:00:27 PM
It has been argued, though, that harmonic content above the normal range of hearing affects our perception of the sound.
Corey,

Having heard the arguments, finally decided to test the theory, you can see (and hear) the results in post #179 here:

 http://www.diyaudio.com/forums/multi-way/210914-what-benefits-adding-hf-driver-7khz-up-18.html

Though the recordings prove that the beat frequencies of ultrasonic harmonics can be clearly audible, in actual practice they wouldn't be, my test required listening in one specific location using a pair of very directional HF horns focused at that point. Another responder to the thread found his "normal" speakers did not have enough VHF output and directivity to have audible or recordable results.

Art
Title: Re: The Distortion of Sound
Post by: Keith Broughton on August 31, 2014, 04:25:09 PM
The big problem with todays music is not with portable music formats it's a lot further back up the food chain in a place where the consumer and probably the artists have no control over.
That statement certainly clarifies what you are trying to say and I have to agree. However, the fact that questionable quality sources are being crushed down to 128 MP3s isn't helping the matter.
In the video, the artists are saying that they feel their creative intent is being compromised and blaming it just on data compression alone is not the whole truth. Let's not give the punters too much technical info at once or their eyes will glaze over and we'll loose them forever ;)
As you suggested, artists may not have any control over the mastering of their material and that is where the problem starts.
So what if they focus on  data compressing as a major culprit? At least, if people start at that end to correct the problem, they might eventually find their way to the mastering process.
I still think it's a great video and perhaps to the the "choir" that we are, the message they are preaching seems a bit obvious and incomplete.
However, if this video can get people thinking about audio quality, then the quest for better sound may follow.
I'm not holding out much hope as most people just don't give a rat's a$$ !
I'm setting up shows with crew around me listening to rap music on a smart phone stuck in their pocket and they think it's juuuuust fine. ARRRRRG!!

Title: Re: The Distortion of Sound
Post by: Luke Geis on September 04, 2014, 09:51:01 PM
44.1kHz is the sample rate, not bit depth.  16-bit is the bit depth for CD audio.

44.1kHz was chosen because Nyquist theorem states that digital sampling must occur at twice the highest frequency of interest in order to accurately capture and reproduce the sampled signal. Humans typically can't hear much higher than 20kHz.

It has been argued, though, that harmonic content above the normal range of hearing affects our perception of the sound.

Truth...... My point is basically that there is nothing below 44.1khz 16 bit as a standard. I.E. we don't have a 22khz 8 bit format. I should have just stuck to sample rate, since 192kbps is not a bit depth, but more or less a sample rate. In either case you're correct. Good catch.

Title: Re: The Distortion of Sound
Post by: Scott Holtzman on September 05, 2014, 02:25:29 AM
Truth...... My point is basically that there is nothing below 44.1khz 16 bit as a standard. I.E. we don't have a 22khz 8 bit format. I should have just stuck to sample rate, since 192kbps is not a bit depth, but more or less a sample rate. In either case you're correct. Good catch.

Agree that Nyquist would dictate a sample rate of greater than 44khz however the actual selection of 44.1khz came from the early redbook CD standards group.  North American Phillips was deeply involved in the standard.  They also made TV's so they had 44.1khz colorburst crystals readily available.  The rest is history.

On this note Bob did you ever meet Claude Shannon and (I think it was Carl) Nyquist in Murray Hill?