[bigshot]

Some MP3 encoders boost the gain slightly when they encode. I've seen tracks that were riding the line on CD start to clip on MP3. But if you normalize them down a hair before encoding they work fine. It may be true of streaming servers too.

Of course, clipping is easily audible and quite easy to generate, while jitter as it occurs in home audio is not.

 

[dvw]

Quote:

Amazing ! Cyrus electrical Engineers --digital engineers --analog electronic engineers . Design engineers -all with a whole string of  letters after their names are WRONG??? All qualified at major UK universities. Must write to Cyrus and tell them they are "not up to scratch" That will be a revelation to the MD.

I have no idea what you are talking about. Are you saying the Cyrus has published a paper on how noise induce jitter at an ANALOG output driver? Or are you saying the clocks are embedded in the data stream inside the box? If indeed that's what you're saying, then yes they need to review their design methodology. You are probably old enough to remember transistor radio. One of the marketing ploy is to advertise how many transistors the radio has. The more transistors, the radio quality must be better. Manufacturers started stuffing transistors in their product that do nothing just so they can claim they have more transistors than others. Early in my career, the company I worked for made ignition modules. Lots of customers complained about the quality and its build. This is because the solid state design was light. We put sand in the module to get more weight. All of a sudden, we get rave review for the same design with its magic sand. Sometimes companies do thing for marketing hype and not for any technical merit.
 
Don't you ever wonder how a cable company has so many different grades of cable? How do they grade them if there is no measurement? How do they justify different price points?

 

[Don Hills]

Quote:

 
 
In some pathological cases the differences can be audible. I have a pair of WD HDTV music streamers which fed an Entech 203.2 and one day listening to a pretty saturated MP3 track (Crowded House) I heard an annoying distortion that was not apparent on the source CD, nor was it readily apparent on the MP3 played back via a computer. I took recordings from the digital outputs and found they were different. On an already saturated track the WD was actually increasing the digital signal output and causing clipping which was visible when captured and analyzed in Audacity, the digital output from the PC did not clip though it was hitting maximum a lot. I am at a loss to explain this but this was what I measured. My only wild guess is that the WD native sample rate was 48K and so the 44.1 track already right on the limit was being resampled badly and thus clipping. In context this was a $130 movie played that also did music after a fashion. I then did some DBTs of the wav file vs the MP3 and found I actually could hear the difference, the mp3 was slightly distorted.

 
You might be interested in this:
 
http://archimago.blogspot.com/2013/08/measurements-wd-tv-live-look-at-and.html

 

[Don Hills]

Quote:

...Also, be careful you don't accidently clean off the green sharpie markings on your CD that make it play better. If you do, you'll have to redraw them. Don't use a regular black sharpie either---it has to be green for best results.
 
This is a joke. Please use common sense! It's pretty difficult to get digital audio to sound only slightly different by random flipping of a bit stream. The analog section is the only real place where things can get slightly botched and any competently designed section its effectively transparent
Cheers!

 
The real joke is that many permanent marker inks are transparent to infrared light. It's simple to test - colour in both sides of a piece of clear plastic with the pen. Place it over the IR emitter of a remote control. Operate the control and see if the controlled equipment responds.

 

[Don Hills]

Quote:

 here is an example of an SPDIF -> analog DAC. Please help me understand where nanosecond-scale jitter on the digital transmission can find it's way into the analog output signal?
 
here's the data sheet for the SPDIF reciever CS8414
here's the data sheet for the DAC converter CS4334
 
Given this simple DAC, please help me understand how an advanced DAC on any competently designed device since 1995 can have jitter influence the output.
 
Cheers

 
I think you might have mistaken me for someone who disagrees with your understanding.

 

[ab initio]

Quote:

 
I think you might have mistaken me for someone who disagrees with your understanding.

It was not directed towards you in particular. It's an open offer to initiate a dialog with anybody interested. Those parts serve as the basis for a case study to determine how much jitter can actually affect the system where the problem at hand is well defined.
 
Cheers!

 

[bigshot]

This forum is a little different than the others on HeadFi. There are a lot of lurkers here who are reading to find out the truth, but don't want to be challenged on it like the few who post. We are often addressing them in our comments, not just replying to the others in the thread.

 

[dvw]

Actually, I'm surprised that more questions aren't being asked. For example; I always wondered if there is a difference between a heavily fragmented file and a non-fragmented file under heavy CPU load. Some how I think there is a difference, but I could be wrong. I think I heard some pops in some specific file sometimes. It doesn't bother me too much. And after I got a new drive, it went away. Oh yes, this is not one of those mega buck audiophile HDD, just a simple WD 2TB drive.

 

[bigshot]

Try opening a 1 GB photoshop file while an MP3 file is playing in iTunes. You'll get stalls in the music for sure. It isn't CPU, it's HD access.

 

[blueangel2323]

Not a problem with SSDs Unless you have huge collections of 1GB Photoshop files, then it gets expensive fast.

 

[blueangel2323]

.

 

[xnor]

Even with a slow, old HDD this should only be a problem if the application doesn't set its I/O priority properly, other applications with equal/higher priority are running (Photoshop should clearly have a lower one than an audio player), or the operating system doesn't support I/O priorities or fails implementing them properly. Phew..

 

[dvw]

My understanding is access jitter could cause double reading or missing a byte. Sometimes I thought I heard some clicks but when I go back and look, it's not there. Occasionally, I found the click in the original CD. I used an editor to edit it out. With my latest computer upgrade, I haven't had similar experience. Maybe I should try to put all the music in one drive and avoid accessing the drive simultaneously with other apps. I think HDD performance is the worst with simultaneous read/write. It could also be my set up is not optimized. How do you set priority for the apps?

 

[duncan1]

Quote- As tested independently by a UK well known hi-fi mag using the latest electronic test equipment costing £100000-or more. on the Cyrus XTSE[not the plus which I have]=Signal related jitter in the digital stream can be seen in our analysis where the residual from a 1 KHZ--minus 60DB tone can be seen with a level of 45  PS at 1KHZ and other related components remain below-10PS .The jitter residual from the -60DB [minus] tone is about as low as it gets so the Cyrus transport is as clean as can be reasonably expected.Random jitter from hum and clock noise etc was very low, lower than 5PS on peaks. Checks were made of sample rate and to ensure linearity wasnt compromised by factors such as noise. Band width extended to 21 KHZ a sweep into our Rohde+ Schwarz UPV digital analyser. fixed tones giving a perfectly flat result with measured distortion at 0.019--as low as it gets. The Cyrus CD XTSE transport gives a fine set of results as a transport and works very well.end quote.  

 

[bigshot]

duncan1, that means there is no audible jitter or distortion by a long shot. But you could end up with the same summary with just about any properly functioning piece of equipment.