The impossibility of sound quality difference whatever the medium

[sleger]

optical cables are unlikely to contribute to sound quality on the Phantom since the data is reclocked and processed by the DSP.  I would attribute it to day to day variation rather than cable differences.  If you have a PS Audio Noise Harvester, you can see the day to day variation in AC line quality.

Yes, totally agree with that.
But people saying bits are bits need to learn about jitter. Yes 0 stay 0 and do not become 1 but a jittered source will produce different sound output which can AND has been measured already, so OP is totally wrong.

[dvx]

My 2c on the effect of jitter on the optical inputs, because I just can't resist:

Old CD players generated their clock from the disc data itself. So, if the master was recorded with jitter, jitter had an effect on reproduced signal on the player as well.

Today most devices are "reclocking" input signals, that means they use an internal master clock to drive the DAC, so there's no jitter correlated to the jitter of the input signal anymore. So yes, for modern devices, bits are bits!

So many generalisations in those two sentences that anybody could find a proper reason to disagree.... Oh well

[AlanD]

Right. The jitter that affects the sound is the jitter in the Phantom itself which can only be manipulated with the AC cable and/or quality of AC power.

What makes the Phantom less "tweakable" is that source data, jitter and all, is transmitted to the Phantom in an asychronous manner where there is a reclocking and processing (160 ms). Because the Phantom reprocesses the data, the jitter is corrected because of the processing.

http://www.stereophile.com/content/jitte...528Ce1s.97

https://m.youtube.com/watch?v=JYjHKv2_OqQ

https://help.devialet.com/hc/en-us/artic...a-Devialet

[AlanD]

Also...

http://en.devialet.com/assets/Uploads/D-...Munich.pdf
emphasizes the concept of asynchronous music playback

http://devialetchat.com/showthread.php?tid=1790
Air1 and Phantom/Spark

http://devialetchat.com/showthread.php?tid=1884
Confirms with packet analysis that the whole file is transmitted to the Phantom

-----------
So, the amount of jitter you alter from the optical cable is down to the jitter of the optical receiver.  The dialog then transports the LPCM data to the phantom in chunks as if it is a digital file.  This is in contrast to a traditional transport/DAC.

Therefore, the only jitter is what's introduced inside the physical phantom itself and the only modification that exists would be the power cable itself...

[JohnnySix]

That is an interesting post about Phantom downloading the whole file... and therefore external data-jitter is irrelevant. It's perhaps worth pointing out that this could only happen via SPARK, which has access to the whole file from the beginning. When playing from an external source into Optical, this cannot possibly happen, except in small packets maybe.

People do tend to over-simplify digital theory; e.g. it is thought that any extra processing needed upon "imperfect" data by the electronics (i.e. timing or CRC) causes a ripple on the PSU, which could theoretically affect the analogue parts.

Having said that, I do agree that by the nature of the Phantoms whole signal infrastructure, they should indeed be more immune to jitter effects than traditional DACs.

By the way... Paul Miller, Editor of HiFi News, can easily measure the multiple types of jitter surrounding any digital audio equipment (data or PSU-induced). He posts the graphs online for every review.

[iamwappie]

The good old cables influence topic. I used to be in the camp of people stating exactly the same as the topic starter. Having an electrical engineering background I always thought that in the digital world anything below a certain voltage level is a 0 and above a 1 and if in the example of interlinks (max length maybe 1m) there would be such differences how poorly designs must that be to not being able to tranfer a digital signal properly over 1 meter?

I was wrong and really was one of those always taking a strong position.

Some things to consider:
1. The digital interlink mechanism does not incorporate any error correction
2. A block wave representing a digital signal does not exist in the physical signal path world. The block wave will be more rounded. Quality depending on cable and materials used
3. If I'm correct the receiving device must sync its clock based on the provided signal. This introduces errors in recreating the signal

I contribute the above to explain why I hear a difference. Most shocking to me was that replacing the digital interlink by a Crystal Cable one made the biggest improvement. I would have imagined analog cables would provide more improvements. Regarding the position of the poster that cables don't matter; why is a Crystal Cable provided with a D400 setup and not a 50 cent 'shoe lace' cable? It really matters.

I learned the hardway; Do an A - B comparison between cables and then judge but do not so based on theory. Ofcourse there are people that do not hear the difference as we are talking about the last percentages of sound improvements here.

[f1eng]

Don't forget the placebo effect.
The placebo effect is real and works.
In the case of curing a real illness only some illnesses can be cured by placebo cures in many, but not all, individuals. Surprisingly (to me anyway) this is the case even when the subject knows they are receiving a placebo. It is a sufficiently well known phenomenon that in some countries placebos are a permitted medicine for some ailments.

If the subject believes the placebo to be expensive it is more effective.

My personal opinion is that whilst many people hear an improvement due to cables there is absolutely no reason why a real one should actually exist between adequate cables and the difference heard is real to the listener but is simply a manifestation of the placebo effect.

[Womaz]

My personal opinion is that whilst many people hear an improvement due to cables there is absolutely no reason why a real one should actually exist between adequate cables and the difference heard is real to the listener but is simply a manifestation of the placebo effect.

An interesting view on the subject. When I get some time I will take my USB cable out and compare it with my printer USB cable. See if I can hear a difference. I paid £190 for it so I better ?

[iamwappie]

Don't forget the placebo effect.
The placebo effect is real and works.
In the case of curing a real illness only some illnesses can be cured by placebo cures in many, but not all, individuals. Surprisingly (to me anyway) this is the case even when the subject knows they are receiving a placebo. It is a sufficiently well known phenomenon that in some countries placebos are a permitted medicine for some ailments.

If the subject believes the placebo to be expensive it is more effective.

My personal opinion is that whilst many people hear an improvement due to cables there is absolutely no reason why a real one should actually exist between adequate cables and the difference heard is real to the listener but is simply a manifestation of the placebo effect.

To rule out a placebo effect there are blind tests.

[f1eng]

Don't forget the placebo effect.
The placebo effect is real and works.
In the case of curing a real illness only some illnesses can be cured by placebo cures in many, but not all, individuals. Surprisingly (to me anyway) this is the case even when the subject knows they are receiving a placebo. It is a sufficiently well known phenomenon that in some countries placebos are a permitted medicine for some ailments.

If the subject believes the placebo to be expensive it is more effective.

My personal opinion is that whilst many people hear an improvement due to cables there is absolutely no reason why a real one should actually exist between adequate cables and the difference heard is real to the listener but is simply a manifestation of the placebo effect.

To rule out a placebo effect there are blind tests.

Indeed there are, and I have yet to hear about a single valid blind test in which cable differences were heard and seen dozens, maybe over 100 over the last 30 years, where the apparent sound differences were unable to be confirmed in a controlled blind test.

I have been a practicing engineer for 45 years, starting out in noise and vibration research, with racing car engineering as a paid part timer but eventually designing and running mainly formula 1 cars as a full time job.
During the whole of my career I never found a phenomenon which was not explained by physics, even if it was difficult to analyse initially.
I do not believe in magic, and all the sales BS about jitter, insulation dielectric, conductor material and so forth are demonstrably simple marketing bollox. At audio frequencies cables are trivial bits of engineering and as long as the LCR is appropriate and the connections well engineered they will all do the same audio job, digital, interconnect or speaker cable.

The whole hifi cable difference issue can only be satisfactorily scientifically explained by the placebo effect, no other explanation that I have heard, and there have been lots, holds water.
The placebo effect allows differences to be perceived where there are none and few things fit the placebo effect explanation more neatly than cable sound differences.

I absolutely believe that some people hear differences between cables and are happy to spend their money on expensive ones.
I have made the mistake myself in the past and still use some of the expensive cables I bought when I thought I could hear the difference since I own them already but my latest speaker cables we <£20 and I use standard cat 6 ethernet and standard optical leads.