Bits, ghosts, and metaphysics...

[sandyk]

given that ‘frozen jitter’/‘media surface variations’/‘switching click-clacks' may affect audio playback, would it follow that such things may also potentially affect photo and video files as well?

I think that one member may have already reported that improvements in the USB output area has resulted in a superior video picture ? It could be interesting to save a high quality video in 1080 (or 2160 if the TV /Monitor is capable) to a USB memory stick then play it through the Player/TV's USB input with a Regen in line, as well as without the Regen.

[goldsdad]

given that ‘frozen jitter’/‘media surface variations’/‘switching click-clacks' may affect audio playback, would it follow that such things may also potentially affect photo and video files as well?

 

I seem to remember sandyk/Alex telling us that the esteemed Martin Colloms has found that bit-identical still image files look different when compared to each other, if different power supplies were in use when the files were written to storage. Is that right, Alex?

[Don Hills]

Don, as others have already said, a wonderful explanation.

 

My quibble, again as others have mentioned, is your reference to DACs that are "unaffected." If you change that to "less affected," we're in agreement. Perhaps this is what you were saying when you spoke of "close enough for rock 'n' roll" in a following post.

 

I'll accept "less affected". And for me, "close enough for rock'n'roll" is accurate - I have almost no classical / jazz / acoustic music in my collection. I mainly listen to various forms of rock and metal, from Apocalyptica to Zappa. The finer details of imaging and soundstage, for example, are irrelevant to me because in most cases there is none in the recording. But I am sensitive to distortion in general, and I hate hypercompression - low dynamic range - with a passion. I'd rather have an 80s vintage CD of an album, with all it's "digititus", rather than a heavily compressed hi-res remaster. I can tame the highs and add a little body to cardboard drums, but there's no way to properly restore lost dynamic range.

[Don Hills]

I suspect that the reason "it keeps coming up" is that folks want an explanation for what they believe they are hearing. There seems to be a basic "analogue/digital" confusion, or a tendency to try to understand digital in a way that does not make sense to me. I appreciate the good explanation of what a "digital signature" is, yet it seems like (yet another) tangent - I see no explanation of how it gets "converted" or "encoded" into digital information that results in two identical files being "heard" differently (assuming they are being delivered to the DAC in the same way - which with asynchronous buffers is the case)

 

 

There's a perfectly good explanation for what they believe they hear, but most people don't want to accept it.

 

"Digital signature" was a poor phrase to use. Perhaps "noise signature" might be better?

When you turn a light switch on or off, it makes a characteristic sound. Different model switches generate different sounds - their "noise signature". You can tell one model from another just by listening to the noise they make, and you can tell if they are being switched at a regular rate or irregularly, and how hard they are being pressed.

 

In theory, two bit-identical bitstreams should sound identical - The output of the DAC should depend only on the content of the digital bitstream. But there's a lot of circuitry operating to create this output, and a byproduct of this activity is electrical noise - even electronic switches make noise when they are operated. You can hear this in the video clips showing noise being generated by computers. So when the bits get delivered to the DAC and placed in the "asynchronous buffer", any noise that came along the transmission path such as variations in the signal voltage, or variation in timing (jitter) can directly or indirectly get into the DAC's circuitry and be carried to the DAC clock or the analogue output stage. Remember, the noise is analogue, just like the fluctuation in the mains voltage that causes your lights to flicker, and your digital clock radio time to tick over slightly early or late (jitter) and/or a crackle to appear in the audio output. So if the two bit-idemtical streams are each accompanied by a different amount and type of noise, then it is possible for the resulting audio output to differ. It's surprisngly hard to design a DAC to be as far as possible unaffected by such noise.

[esldude]

I seem to remember sandyk/Alex telling us that the esteemed Martin Colloms has found that bit-identical still image files look different when compared to each other, if different power supplies were in use when the files were written to storage. Is that right, Alex?

 

Don't know if MC was involved in the images. Alex did send me images like that once. I got two bit identical 1920x1080 images displayed them on 1920x1080 monitors (three different ones). I used software that allowed me to swap images instantly at a button push. No differences at all. In the case of a still image there is no frozen jitter possible. Very curious stuff some people perceive.

[sandyk]

I seem to remember sandyk/Alex telling us that the esteemed Martin Colloms has found that bit-identical still image files look different when compared to each other, if different power supplies were in use when the files were written to storage. Is that right, Alex?

 

Yes, that is correct. The suggestion was made by DIY Audio member Erin from Melbourne. Several people saw differences ,even when the images were reversed. Others such as Dennis didn't. It is a fact though, that rectifier switching noise in the high voltage area of a SMPS in a DVD player can result in similar with video. Replacing the 4 x bridge rectifiers with fast, slow recovery types, combined with an added byass capacitor across the main HV electrolytic capacitor can result in a less noisy and more glossy picture.

The same MAY apply to using a Regen when playing videos from a USB source ?

 

And of course, additional software couldn't possibly have degraded the images, just as it can with Digital Room EQ ?