I think I finally noticed the difference between compressed and non compressed

[price.pittsburgh]

Okay, I may be wrong. First off I don't have an expensive system. I listen to my music on a retail stereo system, my computer speakers or my iPhone or Ipod. However, I also listen to burned discs in my car. Given, my cd system isn't high tech either, but I honestly think because of the small space of my vehicle with the windows up, that I picked up on something. I've compared lossy and lossless of the same tracks before on my iPod and living room stereo before but with not much success in noticing a difference. Nevertheless, today I was playing an older disc that I burned from 256 kbpm. I hadn't chosen that one in a while because I had recently purchased the actual cds and imported them in lossless format, then re burned them. The new lossless ones are the one's I had been using recently in the car. However, today I had the older lossy one playing and I swear I knew something was different. So I started comparing them back to back using the same tracks. I couldn't tell a difference on al the songs but on certain ones, there is no doubt that the lossless burned cds seemed to make the music feel like it was around me more. On the same tracks on the lossy, it felt like it was coming straight out of the dashboard and into my ears but not going anywhere else. Am I imagining things, since it's just a cd player in a SUV? I honestly don't think so. I re did it a few times with the same songs that I noticed the difference in. I've heard the terms flat used before to describe lossy. I guess it would make sense if it's feels like it's coming flat out at you. The songs that I noticed the difference on was Over the Hills and Far a way, with the acoustic at the start and the bass once the song picks up, as well on D'yer Mak'er and Custard Pie.

[lcondo123]

Well, for one, a heavily compressed song sounds very "crappy" sounding, for a lack of a better word. Allow an amateur (me) to help clear things up for you

Higher quality digital music has more bits to it that add clarity and ambiance that compression removes. It also removes a lot of the "air" that analogue music is known for. There's a lot of separation between different instruments and vocals; but with compression, it all gets compressed together to make it take up less memory. Take, for example, these two versions of Kashmir:

^This video of Kashmir was posted in 2009, when YouTube videos were much more compressed then today's. Do you hear how the drums sound choppy and digital? And how all the instruments sound more like one instrument than drums/guitar/bass/vocals/orchestra? That's from the compression of the audio.

^This was posted on February 23 of this year. It's the new remastered audio on a HD YT video. You can hear how there's much more separation between instruments and how there's much more ambiance in the song than the first video.

Listen to the two with a pair of headphones/speakers and there's a good chance you'll hear some difference. Hope I helped in some way

[mknopfler]

The top and bottom of the audio spectrum are chopped off for lossy media. I can hear the difference and that's one reason I stick with EAC verified Flac rips.

[ksgemini]

Respectfully I ask r there just some people whose brains are wired to not hear a difference I concede for most the remasters must b better but do all people notice the difference? Also I have burned Apple lossless cd and they do not play in my car...flac does not seem to be option on wife's iMac

[mknopfler]

Respectfully I ask r there just some people whose brains are wired to not hear a difference I concede for most the remasters must b better but do all people notice the difference? Also I have burned Apple lossless cd and they do not play in my car...flac does not seem to be option on wife's iMac

If you are burning a CD just use the original wave files. For your wife's Imac use the apple lossless format, problem solved.

[ksgemini]

The cd's burned with Apple lossless wil not play in car. I ended up just loading 2300 songs on phone and plugging into aux port in car so really I phone in car and on small ue speaker r the only ways I listen to music. Also concerts I have been to and age have given me hi frequency 40 db loss in one ear which may affect why I don't hear differences other can

[sixpense]

Listen to the drums from Queen's first lp. The producer compressed the hell out of them.

[ksgemini]

Ivan not hear what u r talking about that's my whole issue... I can't tell the difference so 'compressed' is a concept I can't grasp although I now realize it's me could be because I never owned a home stereo...

[ksgemini]

I can not hear what u r talking about that's my whole issue... I can't tell the difference so 'compressed' is a concept I can't grasp although I now realize it's me could be because I never owned a home stereo...my ? Is is there a website that explains all this I have looked at Steve Hoffman forum and seems like people there r just as passionate that the Diament 80's cd's r the best ever I am not an audiophile and know nothing about audiophile things

[Sue Dounim]

I can tell the difference between lossy and lossless but I still cant hear the difference between 44.1kHz audio and 96kHz audio

[chef free]

I'm surprised that most "music lovers" don't have a half decent stereo/5.1 rig in their homes these days. In the seventies it was the FIRST thing you bought for your pad. I couldn't live without a good quality amp and some accurate speakers.

[woz70]

Man.... there's a whole kettle of fish in this here topic. The amount of misinformation and downright ignorance about 'compression' is unbelievable. I'll start at the top and try to help you all understand some of the why's and how's.

Firstly:

Am I imagining things, since it's just a cd player in a SUV?

I know it's counterintuitive, but a music system in a vehicle - especially a newer one - is actually one of the best places to be able to hear the difference between lossless and lossy formats. Car manufacturers spend a lot of money on making sure that stereos in cars sound good, and you end up with a listening environment that is far more conducive to hearing small detail in recordings than most domestic situations. In the car you have lots of sound insulation and damping, speakers that have been placed so that you don't get bass traps, standing waves etc... and many other acoustic treatments to make the newer car actually a very good place to listen to music.

Well, for one, a heavily compressed song sounds very "crappy" sounding, for a lack of a better word. Allow an amateur (me) to help clear things up for you

Higher quality digital music has more bits to it that add clarity and ambiance that compression removes. It also removes a lot of the "air" that analogue music is known for. There's a lot of separation between different instruments and vocals; but with compression, it all gets compressed together to make it take up less memory.

To start with 'very crappy sounding' is not very helpful. I understand what you're trying to get across, but listening is such a subjective thing that blanket statements don't help much.
The rest of what you've written here has a smattering of truth (higher quality digital music has more bits to it..), but the rest is complete and utter rubbish I'm afraid. I'll explain why after I've covered a few more points....

The top and bottom of the audio spectrum are chopped off for lossy media. I can hear the difference and that's one reason I stick with EAC verified Flac rips.

This is absolute rubbish. You are describing narrow bandwidth, not data compression. Listening to lossy media does NOT sound the same as a listening to music on a telephone or through a megaphone for example - both of which have restricted bandwidth e.g. the top & bottom of the audio spectrum chopped off.

Listen to the drums from Queen's first lp. The producer compressed the hell out of them.

You have made the classic mistake of not understanding the difference between audio, or dynamic compression and data compression.

The sort of compression that the producer applies to a sound during recording, mixdown or mastering is called dynamic compression. The simplest way to look at this is to think of the compressor as an automatic volume control. The automatic volume control (or 'compressor') looks at the loudness of the sound, and automatically turns down the loud bits so that they are closer in volume to the quiet bits. So it basically 'squashes' - or compresses - the loud bits to make them less loud compared to everything else.
Why do this? Well, recorded sound has a thing called its 'dynamic range', which is the difference between the loudest and quietest noises that can be captured. If you want to record something very quiet that has unexpected loud moments then you may want to set the recording level quite high to capture the detail in the quiet bits. But when the sudden loud bit comes along it may then exceed the dynamic range of your recording medium, and sound distorted. The compressor stops the distortion from happening by automatically turning down the loud signal to an acceptable level. This is a very simplistic example, but the general principle is there.

This wiki article gives quite a good explanation of the process if you want to find out some more:
http://en.wikipedia.org/wiki/Dynamic_range_compression

This sort of compression - dynamic compression - has absolutely nothing to do with data compression.

Data compression covers a BIG area, but as far as sound or music goes we are talking about 'Lossy' data formats, such as .mp3, .wma etc., and 'Lossless' formats such as .flac etc.

The 'lossless' formats aren't of much importance here since they don't really change what's going on in the recorded sound.

'Lossy' data compression works on the principles of an area of science called 'psychoacoustics'. Put simply, it has been found that the brain does quite a bit of manipulation to the sound that is encoded by your ears. One of the things that it does is a process called 'masking', which is where your brain will tend to ignore a quiet sound if there is a loud sound going on at the same time. Another thing that the brain does is concentrate more time and effort on understanding detail in only certain frequency ranges - generally the range where speech lies. If we go back to the megaphone/telephone example from above - both of these methods of reproducing the voice have thrown away a vast amount of information by severely limiting the frequency range they are able to reproduce, but you can still understand somebody who is communicating via one of these methods. Basically psychoacoustics works on the principle that our perceptions do not exactly mirror events in the outside world, but rather reflect and accentuate certain properties of those events.
These findings were taken and applied to the way we listen to and perceive music, and it was found that you can actually throw quite a lot of information away without too much detriment to the actual perception of the music, which was great for the people who wanted to manufacture affordable portable music players with a playback resolution that was approximately the same as, or slightly better than the compact cassette. Of course this was when data storage was a hell of a lot more expensive than it is now, so smaller file sizes meant more music.
Look at an mp3 file encoded at 320bps (the highest bitrate, and for most people difficult to discern from 44.1kHz/16bit, or 'cd quality'). One minute of audio takes up 2.4MB. Compare this to 'cd quality' which comes in at nearly 5.3MB per minute. The mp3 is less than half the size, but the majority of people wouldn't hear the difference between that and a CD.
Higher bit-rate encoding of .mp3 throws away less information and therefore sounds better. The lower the bit-rate, the more information is thrown away and the more obvious the detriment in sound quality. To be clear, lossy encoding does not 'compress the instruments together' or change the separation between instruments in a recording. The amount of 'air' in a recording is dependent on the environment it was recorded in (and is generally added with artificial reverberation anyway......).

I can tell the difference between lossy and lossless but I still cant hear the difference between 44.1kHz audio and 96kHz audio

There are very few people who genuinely can if you put them in a double blind situation, and it's rarely the change in bit rate/sample rate that is audible - it's the bit depth. You're more likely to hear the difference between 16 bit and 24 bit recordings. And even then, it all depends on what you're listening to and how it's been mastered. You're far more likely to be able to hear the difference in a recording of an orchestra, with a huge dynamic range, than that of a rock band which has a comparatively narrow dynamic range.

I'm surprised that most "music lovers" don't have a half decent stereo/5.1 rig in their homes these days. In the seventies it was the FIRST thing you bought for your pad. I couldn't live without a good quality amp and some accurate speakers.

Most of the people I have met who spend enormous amounts of money on high end speakers, snake oil oxygen-free super-expensive speaker cables, top-of the range amps and DAC's put their lovely equipment into untreated square rooms with nasty resonant furniture and then put their speakers on the floor against the wall in the corner of the room. Which, of course, renders their listening environment deeply compromised due to flutter reflections, standing waves, comb filtering, inaccurate bass response etc. etc. and the money they've spent largely wasted. And then they spout off about all the detail they can hear....

[Patrycja]

woz, just wanted to say that you write very well. These are tricky concepts to grasp for the lay person, but you communicate them clearly so thanks for the explanation.

[price.pittsburgh]

I'm the OP and just realized that after all of my rambling, that the original sources weren't really the same. Burned CD 1 was from the 94 Marino remasters and cd 2 was the new Davis. (Although the Marino was in 256 kbps on the burned disc and Davis in 901 lossless) So basically, I was may have only been noticing the difference in the 2 remasters. Not sure now.

However, I have read on here by a member that HTWWW was already highly compressed on cd. Which I think I did pick up on before reading that. Or maybe not. Who knows. I'm probably over thinking things.

[mknopfler]

You type well but are wrong Woz70. Lossy media absolutely chops off the music past a certain point in the spectrum as clearly seen in the photo. So unload your rubbish on somebody else.

[chef free]

Most of the people I have met who spend enormous amounts of money on high end speakers, snake oil oxygen-free super-expensive speaker cables, top-of the range amps and DAC's put their lovely equipment into untreated square rooms with nasty resonant furniture and then put their speakers on the floor against the wall in the corner of the room. Which, of course, renders their listening environment deeply compromised due to flutter reflections, standing waves, comb filtering, inaccurate bass response etc. etc. and the money they've spent largely wasted. And then they spout off about all the detail they can hear....

This is totally true! As soon as the volume gets "good" you are essentially listening to the room as much as the recording, speakers, source or amp.

I have carefully treated my "listening palace" (garage) with floor to ceiling bass traps in the corners, a thick padded rug, a 6' x 6', 6" thick acoustic panel on the ceiling, 2' x 4', 2" thick panels at the first reflection points and sound diffusers on the wall behind me. I have spent hours adjusting the speaker placement both by ear, with help from several friends, and with acoustic measuring equipment.

I would rate the most important factors in sound quality in order of importance like this:

1. Original recording and mastering; you can't shine shit no matter how much you spend on equipment.

2. Transducers. The moving mechanical parts which produce sound, they are the hardest part to manufacture; speakers, and turntable parts like the needle, cartridge, tone arm, and how well they are set up.

3. Room set up; speaker placement and acoustic treatments. Moving your speakers is the cheapest (and most effective) upgrade ever!

4. DAC; good digital to analogue conversion is a key to a natural sound if you go modern.

5. Pre amp; I'm amazed how much the quality of the pre affects the overall sound of a stereo.

6. Amp,; way down the list but all amps have a different sound, best to get 1-5 right before you spend a bunch of $ on amps!

[woz70]

You type well but are wrong Woz70. Lossy media absolutely chops off the music past a certain point in the spectrum as clearly seen in the photo. So unload your rubbish on somebody else.

Riiiight.

Lets explain this again for you.

Firstly - how to read a spectrum analysis graph, examples of which you have given above. The x-axis is time, running from left to right. The y-axis is frequency, from 0 to just above 22050Hz (the 'Nysquist Frequency' for 44.1kHz encoded audio if you are a nerd, like me). The colours of the graph range from white (loud) through yellow and red (getting quieter) to purples etc (quiet).

Let's look at the top graph first. You'll see there's a lot of loud low frequency stuff going on up to about 4000Hz - especially at the 2:00-2:20 mark. You'll also see that, whilst there is a lot of information above about 11.5kHz, it's mostly in the darker colours. There's quite a bit of orange/red going on, but it tables off at about 11.5kHz.

Now let's recall what I said about the concept of 'masking'. The brain ignores quieter sounds when there are louder sounds going on, and this principle is carried over to the way mp3's are encoded. So - we've got lots of loud stuff up to about 4000Hz, lots of moderately loud stuff happening up to about 11.5kHz, and above that there's quieter stuff. Got that?

Now let's recall what I said about mp3 bitrates - the higher the bitrate, the less stuff gets thrown away, yes?

Therefore the lower the bitrate, the more stuff gets thrown away.

I would struggle to call an mp3 encoded at 96kbps 'music'. You'd probably understand the spoken word, but music would be a mush. An mp3 encoded at 96kbps is what the lower spectrum analysis you have so kindly supplied shows. An mp3 encoded at 96kbps throws away over 90% of the original data - of course it's going to sound like crap. (Again, for the nerds out there I made a mistake in my previous post - CD quality is actually about 10.6MB per minute. I calculated for mono and forgot to multiply by two to make it stereo. D'oh!)

Remember - low bitrates = throw more stuff away.

Psychoacoustics says - if it's quiet with loud stuff going on at the same time = throw it away.

Have you cottoned on yet?

So on the examples you have given we have represented a piece of music where there's lots of louder sound happening below 11.5kHz, and much quieter sound above 11.5kHz encoded at 96kbps. SO, OF COURSE IT'S GOING TO LOSE ALMOST EVERYTHING ABOVE 11.5kHz - in the case of the piece of music shown here, which some numbnuts moron has picked because he was trying to make the 'but mp'3 slice off bandwidth' point, and you have picked on because you haven't bothered to actually research what this is all about in a constructive way. You will also notice that there is still some information left above 11.5kHz - there are still some coloured bars. This means that there is still sound being reproduced in that frequency band, so it hasn't, as you have stated, been totally removed, or 'chopped off'.

The frequency analysis for a piece of music that consisted only of the singing of a female voice would have lots of colour from about 165Hz to about 3500Hz, with whites/yellows from about 165Hz to about 350Hz . a 96kbps mp3 of this would look like a coloured band in the middle of the picture, with black below and above it - THE SPECTRUM ANALYSIS ALL DEPENDS ON THE SOURCE MATERIAL. Similarly the spectrum analysis of an mp3 will be totally dependent on the frequency range, and the loudness of each frequency band within the original material.

You CANNOT make the point you are trying to make with ONE example, and certainly not comparing CD quality with a 96kbps mp3.

With respect, the 'rubbish' I have 'unloaded' on you is based on knowledge obtained during a 3 year degree and 20 years of subsequent work in the world of audio. You got your shit off the internet in a few minutes without even making the effort to understand what it is you're talking about. Your argument is the equivalent of 'I have a car. My car is green. Therefore all cars are green'.

I'm trying to pass on my knowledge in a way that other people can hopefully understand. Poo-poo it if you like, but at least find out about what it is you're trying to argue about before you start spouting horseshit.

This is totally true! As soon as the volume gets "good" you are essentially listening to the room as much as the recording, speakers, source or amp.

I have carefully treated my "listening palace" (garage) with floor to ceiling bass traps in the corners, a thick padded rug, a 6' x 6', 6" thick acoustic panel on the ceiling, 2' x 4', 2" thick panels at the first reflection points and sound diffusers on the wall behind me. I have spent hours adjusting the speaker placement both by ear, with help from several friends, and with acoustic measuring equipment.

I would rate the most important factors in sound quality in order of importance like this:

1. Original recording and mastering; you can't shine shit no matter how much you spend on equipment.

2. Transducers. The moving mechanical parts which produce sound, they are the hardest part to manufacture; speakers, and turntable parts like the needle, cartridge, tone arm, and how well they are set up.

3. Room set up; speaker placement and acoustic treatments. Moving your speakers is the cheapest (and most effective) upgrade ever!

4. DAC; good digital to analogue conversion is a key to a natural sound if you go modern.

5. Pre amp; I'm amazed how much the quality of the pre affects the overall sound of a stereo.

6. Amp,; way down the list but all amps have a different sound, best to get 1-5 right before you spend a bunch of $ on amps!

And this, dear readers, is an example of a GOOD POST!

I would only add to no.3 - move speakers off the floor and onto decent high-mass stands at the correct height for your listening position, although from the sound of it I'm telling you how to suck eggs.

Nice one chef.

[woz70]

woz, just wanted to say that you write very well. These are tricky concepts to grasp for the lay person, but you communicate them clearly so thanks for the explanation.

Thank you Patrycja. I'm glad that you appreciated my explanations!

[Stairway is NOT stolen]

I've always compared uncompressed and compressed to a sandwich.

Uncompressed is you making a tuna sandwich, and placing it on a plate. Someone then reaches over and eats the sandwich.

Compressed is you making the same tuna sandwich, and placing it on a plate. Someone then places the sandwich down and starts to squish the sandwich. They then eat the sandwich.

The compressed sandwich is still the same sandwich, using the same ingredients and prepared the same way, but it doesn't taste as nice, nor does it look as good.

[woz70]

I've always compared uncompressed and compressed to a sandwich.

Uncompressed is you making a tuna sandwich, and placing it on a plate. Someone then reaches over and eats the sandwich.

Compressed is you making the same tuna sandwich, and placing it on a plate. Someone then places the sandwich down and starts to squish the sandwich. They then eat the sandwich.

The compressed sandwich is still the same sandwich, using the same ingredients and prepared the same way, but it doesn't taste as nice, nor does it look as good.

That's almost a good analogy for dynamic compression, but not for data compression.

For data compression, take away the parts of the original sandwich that you can't taste in one bite, or alternatively that you can't see on first glance - like the insides......

Basically you end up with the same sandwich visually, but it weighs half as much.

[Sathington Willoughby]

Are there really people out there listening to 96kbps mp3's?

[woz70]

Are there really people out there listening to 96kbps mp3's?

I shouldn't think so. That's partly the point I was making. It's a crap example leading to an erroneous conclusion.

[price.pittsburgh]

I think I now realize that cd 1, regardless of system, was going to sound not as good, because it was a Marino remaster, which was already dynamically compressed on the original cd, then lossy compressed to the computer and burned cd as well. Cd 2 was from Davis 2014, and it wasn't compressed dynamically compressed on the original cd or to lossy on the computer.

[ScarletMacaw]

I don't even know what any of this means. I grasp the "compressed" concept but how to translate that into choosing music, I don't get. I buy Amazon digital music, are you saying it's crap? Still don't understand what "lossy" and "lossless" mean.

I will say that I have wall-mounted speakers and I have determined that if I sit at my desk, I am at exactly the right distance from them. I hear the music far better than if I sit somewhere else, either closer or farther, so I would add, where you are physically located when listening, in relation to your speakers, assuming you just have two speakers as I do, is crucial.

[Sathington Willoughby]

I don't even know what any of this means. I grasp the "compressed" concept but how to translate that into choosing music, I don't get. I buy Amazon digital music, are you saying it's crap? Still don't understand what "lossy" and "lossless" mean.

I will say that I have wall-mounted speakers and I have determined that if I sit at my desk, I am at exactly the right distance from them. I hear the music far better than if I sit somewhere else, either closer or farther, so I would add, where you are physically located when listening, in relation to your speakers, assuming you just have two speakers as I do, is crucial.

Audio data compression, as distinguished from dynamic range compression, has the potential to reduce the transmission bandwidth and storage requirements of audio data. Audio compression algorithms are implemented in software as audio codecs. Lossy audio compression algorithms provide higher compression at the cost of fidelity and are used in numerous audio applications. These algorithms almost all rely on psychoacoustics to eliminate less audible or meaningful sounds, thereby reducing the space required to store or transmit them.^[2]

In both lossy and lossless compression, information redundancy is reduced, using methods such as coding, pattern recognition, and linear prediction to reduce the amount of information used to represent the uncompressed data.

The acceptable trade-off between loss of audio quality and transmission or storage size depends upon the application. For example, one 640MB compact disc (CD) holds approximately one hour of uncompressed high fidelity music, less than 2 hours of music compressed losslessly, or 7 hours of music compressed in the MP3format at a medium bit rate. A digital sound recorder can typically store around 200 hours of clearly intelligible speech in 640MB.^[14]

Lossless audio compression produces a representation of digital data that decompress to an exact digital duplicate of the original audio stream, unlike playback from lossy compression techniques such as Vorbis and MP3. Compression ratios are around 50–60% of original size,^[15] which is similar to those for generic lossless data compression. Lossless compression is unable to attain high compression ratios due to the complexity of waveforms and the rapid changes in sound forms. Codecs like FLAC, Shorten and TTA use linear prediction to estimate the spectrum of the signal. Many of these algorithms use convolution with the filter [-1 1] to slightly whiten or flatten the spectrum, thereby allowing traditional lossless compression to work more efficiently. The process is reversed upon decompression.

When audio files are to be processed, either by further compression or for editing, it is desirable to work from an unchanged original (uncompressed or losslessly compressed). Processing of a lossily compressed file for some purpose usually produces a final result inferior to the creation of the same compressed file from an uncompressed original. In addition to sound editing or mixing, lossless audio compression is often used for archival storage, or as master copies.

A number of lossless audio compression formats exist. Shorten was an early lossless format. Newer ones include Free Lossless Audio Codec (FLAC), Apple's Apple Lossless (ALAC), MPEG-4 ALS, Microsoft's Windows Media Audio 9 Lossless (WMA Lossless), Monkey's Audio, TTA, and WavPack. See list of lossless codecs for a complete listing.

Some audio formats feature a combination of a lossy format and a lossless correction; this allows stripping the correction to easily obtain a lossy file. Such formats include MPEG-4 SLS (Scalable to Lossless), WavPack, and OptimFROG DualStream.

Lossy audio compression

Lossy audio compression is used in a wide range of applications. In addition to the direct applications (mp3 players or computers), digitally compressed audio streams are used in most video DVDs, digital television, streaming media on theinternet, satellite and cable radio, and increasingly in terrestrial radio broadcasts. Lossy compression typically achieves far greater compression than lossless compression (data of 5 percent to 20 percent of the original stream, rather than 50 percent to 60 percent), by discarding less-critical data.^[16]

The innovation of lossy audio compression was to use psychoacoustics to recognize that not all data in an audio stream can be perceived by the human auditory system. Most lossy compression reduces perceptual redundancy by first identifying perceptually irrelevant sounds, that is, sounds that are very hard to hear. Typical examples include high frequencies or sounds that occur at the same time as louder sounds. Those sounds are coded with decreased accuracy or not at all.

Due to the nature of lossy algorithms, audio quality suffers when a file is decompressed and recompressed (digital generation loss). This makes lossy compression unsuitable for storing the intermediate results in professional audio engineering applications, such as sound editing and multitrack recording. However, they are very popular with end users (particularly MP3) as a megabyte can store about a minute's worth of music at adequate quality.

https://en.wikipedia.org/wiki/Data_compression#Audio

https://en.wikipedia.org/wiki/Lossless_compression#Audio

https://en.wikipedia.org/wiki/Lossy_compression#Audio