Lossless? Really?

I appreciate that we have some REAL experts writing here and that the conversation has got very technical!

Apologies for bringing it back to the simplistic but what I am hearing is this:

It makes a difference what you use to rip CDs to minimise errors but the file will be the same as the original as long as it is not compressed (although I detect some criticism of the "lossless" process)

The difference between streaming and CD is a matter of preference (with many people preferring streaming)

Does that sum it up? 

Bill

Thanks for making me feel cheap...

There's a real skill to making this stuff readable and comprehensible and I salute you on both counts.

G

Big Bill - ok lets beg to differ on some of those points - any way i hope i am right or my job as a professional voice/network design engineer will disappear on Tuesday  and i would have wasted the last 20 years.. but at least my customers have paid me well for it 

PS if you are really interested I can point to you texts on data transmission/encoding and entropy which is of course a grounding principle in ICT. Ok I haven't gone into the deep theory and mathematics since being an undergraduate but it was one of my favourite areas of study, and i certainly use the principles now. You are questioning the words I am using to try and describe the basics in a non technical way - and it is beyond my capability clearly to explain it to you via this forum - perhaps if we had a white board - I usually find it helps.

Of course Morse was quite inefficient in information rate, but it was a digital or even a quantised mapping of the alphabet/numbers and certain special codes, and indeed in use you would / do send sentences/messages and seek positive confirmation.. or resend.

Data comms that use TCP use dropping algorithms to regulate data flow, so data is deliberately lost in transmission and needs to be resent. WRED is an example of this in class of service managed networks. Of course lower layers such as link frames are discarded if checksums fail due to data transmission error - and the above transport/session mechanism will manage the resend or the data is lost.

UDP is connectionless or often fire and forget - and so if corrupted it is lost for ever - which is why in class of service managed networks with give special consideration to UDP when carry realtime info such as encoded voice datagrams - as we know networks which manage class of service across a layer 3 boundary will some times need to deliberately drop traffic.

Interestingly UDP uses sequence numbers and can arrive out of order - from a data transmission point of view the datagram is digitally received 100% - however if used in realtime - its position and relationship to other datagrams is important with respect to time, therefore an application might chose to discard the successfully received data - as its information has become invalid.

Therefore one needs to look at the combination of the information and not just rely on the data transmission,  and this is my point - as effectively digital information transmission is not simply a case of sending digital data.

In the same way the data transmission can be unreliable and lost but the information recovered using transport methods  - and of course this was the basis of the development of the OSI 7 layer model that data/info comms has been largely based on over the 40 years.

PPS - being an engineer I like to design optimum efficient systems, and wasteful inefficient data consumption for no benefit niggles me - you could argue it is sloppy lazy design and it is a lot easier to  be inefficient in data transmission rather than be efficient.

PPPS Graeme - no salutes necessary please 

Ah, the magic of digital transmission and storage. As has been evinced elsewhere in life, size itself does not guarantee satisfaction, though a Statement owner might disagree. In my very humble opinion the storage and transmission of data, musical or otherwise, is a reasonably settled science. Can both be done consistently and efficiently, well let me turn on my Samsung TV and watch a programme. My God, it works, as does this iPad astonishingly enough. Both are heavily reliant on successful transmission and decoding of digital bits.

Again, in my humble opinion, the game changer is in the success or otherwise of the presentation layer, how these digital bits are translated from digital to analogue, the timing, accuracy and lack of electrical interference. The quality of the output medium; the DAC, the amplifier and the speakers all play a part. How? I have no idea, but they do. Play your music through a crap system and it will sound crap even though it has all the bits of information to literally play with. Will a valve amp colour your music? You bet. Will a pair of chap desktops stand up agains some Focal Grandes? Doubtful, but I bet the initiating bits were the same.

Why not just keep it simple? Can you hear a difference? If not then it doesn't matter. If you can, then go with what appeals the most. Conversion is simple, anything can be tagged and storage is cheap and getting cheaper.

I agree about the digital stream is a digital stream and completely accurate. Is it accurate version of the music though?

The digital stream cannot be a completely accurate sample unless the analogue waves are read by an infinite number of samples, no quantisation distortion.

You could ensure that the music only produces notes that can be exactly measured in your scanning frequency/sample rate I suppose.

I agree with Harry - its all about the sound an what sounds best. One shouldn't really cling onto terms or concepts in lieu of your ears and brain.

Technically things are not always what they seem anyway - and reality, from an engineer's point of view, is usually far more interesting that simplified marketing terms / concepts. And in my view many of these marketing terms are used to convince you that something should be better irrespective of whether it is... as is said trust your ears.

Simon

Trouble is there are so many permutations and combinations in the ripped arena not to mention post-conversion to analogue (including the layout of the listening room) that some guidance would really help...

Trusting our ears, yeah, trusting what our brains make of what the ears hear? Risky.

When someone tells me that digital music reproduction in my home is analogous to my bank atm machine taking the money from the proper account, I tend to stop reading . . .

I have played with my own set-up, aided by 'blinded' listening from my wife, to know that all 1's and 0's are not the same.  Yet, I am comfortably with online banking and using the ATM machine. Go figure!

 Will you fly in a plane though...?

I have tried to delineate what my ears hear from what my brain makes of what my ears hear, but to no avail.  Is there a "trick" to decoupling one's ears from one's brain?

Simon I think we are going to have to agree to disagree.  But I find it hard to believe that someone who works wtih networks (data and voice over IP) does not believe that digital messages will be sent 100%.

I used to work for a manufacturer of hubs, switches etc and was involved with the low-level programming of these devices. So my knowledge of networks (or notworks as you might say) is I believe extensive.

But so be it.

Bart do you honestly believe that not all 0s & 1s are the same, or was that a joke.

Good point Jota.  When people with so called 'Golden Ears' have taken part in blind listening tests then over the years they haven't covered themselves in glory.  I remember some years back auditioning a piece of kit (can't remember what) and I said to my missus that it sounded much better than our current component.  "No it doesn't," she replied, "it just sounds different!"  What a lesson that was and when I listened again I could hear that she was right.  Mind you she is now saying that our Naim UnitiLite through Kef R700s sounds really good.  Progress!

Good point Jota.  When people with so called 'Golden Ears' have taken part in blind listening tests then over the years they haven't covered themselves in glory.  I remember some years back auditioning a piece of kit (can't remember what) and I said to my missus that it sounded much better than our current component.  "No it doesn't," she replied, "it just sounds different!"  What a lesson that was and when I listened again I could hear that she was right.  Mind you she is now saying that our Naim UnitiLite through Kef R700s sounds really good.  Progress!

BigH47 you hit the nail on the head!  It seems to me that when referring to word length (16 or 24 of course) people just mention the dynamic range and forget quantisation errors.  24bits will give lower quantisation errors that 16.  Just think if you are listening to a low passage in a piece of 16bit classical then it could easily be at -36db (ref to the loudest part), now assuming that the engineer was able to use all 16 bits for the loudest part, then at -36db we are looking at a 10bit word length  Now work out the quantisation error on that.  Is that why 24bit classical recordings have a delicacy of sound that 16bit just doesn't have?  If the engineer wasn't so skilled/keen then it will be even worse.  I believe many earlier analog LPs were remastered to CD and were recorded low, which is what they would have done on analog tape.  It's all about headroom here.

Simon I wasn't putting forward the idea of using Morse, I was simply using it as an illustration of what digital data flow is about.  ie message not electrical signal.  Sorry but I thought that was obvious.

Big Bill, I don't mean to be a protagonist on this but

>Bart do you honestly believe that not all 0s & 1s are the same, or was that a joke.

! and 0 are logical abstractions used for boolean algebra - in the real world voltage/current/light values need to be mapped and be sampled at specific times with respect to change to derive a digital boolean value. Digital communication is usually encoded using analogue signals - and as a consequence care is needed  in its interpretation and is statisitically not fool proof in all circumstances, especially when bandwidth and damping limitations are introduced or noise is introduced into the analogue signal carrying the digital values. Elementary digital/electronic hardware design texts such as from Horrowitz and Hill are a good introduction to understanding the challenges of interpreting digital boolean values from analogue logic level signals, but if you were involved with digital hardware design then I am sure you would be fluent in this.

Furthermore PCM values with respect to describing a discrete sampled analogue signal are  only valid relative to time - so an identical series of numeric integer sample values can convert different meanings or convey different information  by the nature of relative  timing of the sample values.

Simon

Simon what on earth has that got to do with the question: do you believe that not all 0s and 1s are the same.  Your answer is basically a load of techno babble, it contains no information.

You are babbling on about what the wave forms look like, I am surprised you haven't gone into the different methods of triggering.  But all this, although not irrelevant, is not really required in this discussion, it's enough to assume it just works.  Yes if you are interested in the details go on and read it up.  But nothing you say suggests that digital transmission do not work 100%.

The programming on a switch for example is not worried about the shape of digital waveforms, in fact the ones I worked with could function perfectly well with different shaped/triggering waveforms.  This was all done in hardware, my software was never concerned with this because it was never needed.  In the same way when someone writes a piece of javaScript to sit inside a web page, that script is also not worried about what the waveforms look like.  It's all about levels of abstraction.

I will tell you a story.  I did my first degree in Chemistry and my PhD in biochemistry - not perhaps the background you might of imagined.  But during my second year of my 1st degree I was chatting to a new flat member who was studying computer science (or whatever they called it then).  So I was interested, computers were very new in 1970 and a thing of great mystery to me.  So I asked the obvious question: "How does a computer work?" and I was absolutely appalled when he said "I dunno, I don't need to know".  This to a chemist was an anathema, not having your basics in chemistry meant going forward to more advanced stuff very difficult, if not impossible.  But during my PhD I spent as much time with the prehistoric computers (PDP8 and Dec10 mainframe) as I did in the lab.  But after a very short while I realised my ex-flatmate was correct.  ABSTRACTION ABSTRACTION ABSTRACTION it's all the rage in networks, why not read about the ISO 7 layer model.

So if you really believe that not all 0s and 1s are the same, when we are in the digital domain, then please go ahead and explain it.  I am still waiting for the evidence and sources of what you said earlier about noise floors.

Long time since I saw those two mentioned!  Bill, whether Simon has explained it adequately or not he is correct. i no longer work in the sphere of Electronic Engineering, but when I did the care required in managing digital signals was just as important as the analogue ones, especially when bandwidth is limited and you only get one 'go' at reading, interpreting and storing data ie Black Boxes.

Everything degrades. Nothing stays exactly the same. Digital errors happen all the time but with simple data computers can 'reconstruct' the degraded parts but not necessarily perfectly and not necessarily 'in time' . Digital data is part of the real world, it and the computers that use it are all slowly degrading. Just like everything else. They are not 'magic'

Andy

This thread is becoming rather surreal.

Andy Pat, you will certainly know when your data has 'degraded' whether at CD level or on your PC or even in RL.

Do I understand from this that a bit-perfect copy of a bit-perfect rip is not actually identical, and bit-perfect?

ATB from George

Yep, the bit fairies will have a munch at them! 

I am going to have a very close look at my on-line bank statement, primarily in the hope that it will have been up sampled and not down. Anyone want to bet against it being as the real transactions would anticipate? Or is banking, as opposed to bankers, simply a subjective exercise?