Optical digital interconnects

[Vaughan Odendaa]

Apparently, if cables are slightly longer than another run of cable it will cause a phase shift. Whatever. Sometimes I wonder if these people actually believe the things they claim.

--Sincerely,

 

[mtrycrafts]

Apparently, if cables are slightly longer than another run of cable it will cause a phase shift. Whatever. Sometimes I wonder if these people actually believe the things they claim.

--Sincerely,

Well, each foot of length difference means that the electric signal will arrive in that speaker 1 nanoseconds sooner. How far does the sound waves travel in air in that time period? Remember, it travels 1 ft in 1 millisecond., that is 1x10to the -3 power and the nano is 10-9. So, that would be 1ft x 10-6?

Better get a super caliper and a head clamp

Well, now you see the type of desperation they are in. Good thing you didn't ask questions You still have a job.

 

[jonnythan]

A one meter difference in cable length by 3 meters will give you about a 0.000000009 second difference in phase.

Compare this with the actual length of even a high-frequency sound wave - .00005 seconds.

That's a 0.018% difference in phase.

If you graphed two identical sound waves .000000009 seconds out of phase, you wouldn't even be able to see it without zooming in so you only see about 1/1000 of a single cycle.

 

[Jack Hammer]

A one meter difference in cable length by 3 meters will give you about a 0.000000009 second difference in phase.

Compare this with the actual length of even a high-frequency sound wave - .00005 seconds.

That's a 0.018% difference in phase.

If you graphed two identical sound waves .000000009 seconds out of phase, you wouldn't even be able to see it without zooming in so you only see about 1/1000 of a single cycle.

I'm starting to get a headache from the phase difference from just reading about it.

 

[markw]

I'm starting to get a headache from this thread in general.

I'm starting to get a headache from the phase difference from just reading about it.

What's everyone fighting about anyway?

Did someone say they could hear a difference?

 

[mtrycrafts]

If you graphed two identical sound waves .000000009 seconds out of phase, you wouldn't even be able to see it without zooming in so you only see about 1/1000 of a single cycle.

That Much? I better get a precision tape on that next cut
I don't know if I can handle that much drift. LOL

 

[Nick250]

I've been in this industry for going on 8 years. I have dissected, tested, used, and compared more cables than you can count. Someone who's only interested in finding the cheapest thing available that he considers functional should not be giving other people advice as to what performs better, which is what this thread was about.

I agree about getting the thread back on track in regards to performance. Given your years of experience in the industry, could you summarize the performance differences the readers of this forum might expect using different types of cables and interconnects. You need only comment where there are audible differences. An explanation of what the factors that contribute to the differences would be appreciated.

Nick

 

[Rayn129]

I really appreaciate all the info. Getting a little heated in here, but informational non-the-less. I have an additional question to add. The instructions for my DVD/CD player state that SACD signals will not output through the digital jack. Why?

 

[MDS]

I really appreaciate all the info. Getting a little heated in here, but informational non-the-less. I have an additional question to add. The instructions for my DVD/CD player state that SACD signals will not output through the digital jack. Why?

The bandwidth of the s/pdif interface is not sufficient to pass multi-channel high-resolution audio from sacd or dvd-audio.

There are proprietary digital interfaces; eg., Denon D-Link, but you need both the receiver and dvd player to utilize it.

 

[JAD2]

Has anyone used DVE for calibrating their displays ? Has there been a big improvement in the picture ? Anyone used the PAL version ?

Sorry to change the topic of discussion. Optical cable is inferior to coaxial in terms of build quality. And I think that is all. Sound quality wise, both are identical, in my opinion.

--Sincerely,

I'd like to chime in here for a few points.

Calibrating video of discs is another scam of sorts and I'll tell you why.

DVD players are not made all the same, if you look at benchmarks of DVD players you'll see that all machines have some sort of black level problems and so on.
Your TV could be absolutely fine in something that your DVD player lacks and your just adjusting the TV for your DVD players lack.You've corrected the player input, but have ruined your TV's setting that was fine.Then alot of people will change all there inputs used to the setting they got using the DVD calibration ruining the rest.

Audio calibration is also along these lines when using those discs and their pink noises etc. Pink noises arent full spectrum frequency tones and while you've it up for those, when listening to music etc that have the full spectrum it doesnt balance out the same.

I had the TV calibrated professionally and costed just about the same as my own attempts with different discs, which the patterns were not all created equally, probably in the creation of the disc. I used 3 different discs, Washer, DVE and another, their patterns of simple grey scales per each disc needed different level set.

For audio and friend of mine that sets up audio stuff as a side hobby has a disc with different tones from 20-20,000 and when I used it I found that since the speakers arent all the same exact models, but within a brand thats suppose to match, each has strong areas and weak ones making it difficult to get equal readings, so I averaged them. I ended up throwing the meter out and using my ears!!

Optical over digital coax??? Well on paper optical wins, but on my system optical won on my CD player but lost out on my HD Cable box to digital coax. Optical had drop outs you could easily hear on the HD box and the CD player had noises using the digital cable which I assume was a electrical noise issue which optical wont have!!
Its not a simple game of XXXXX's and OOOO's once you've read all this crap and start to believe you could get better. Like I said earlier, you best choice would have been was to " Just Walk Away".

 

[Vaughan Odendaa]

Does anyone have similar thoughts (or experiences) with video calibration disks ? Everything I've read about DVE is that it's brilliant for video calibration and sound calibration. No big problems have been noted.

I just ordered DVE PAL btw.

And JAD2, why do you claim that optical is better than coaxial on paper ? Don't you have it the other way around ? I thought, in theory, that coaxial was better.

--Sincerely,

 

[JAD2]

Depends on whom you read and what you want to believe.
Both will carry the same amount of data, but thats camp divisions that say otherwise.
Next optical is completely immune to interference and coax is not. Coax can be shielded, but shielding is never 100%. But since optical is a fiber and transmits thru light, everything goes right thru the light without distorting it. Now even this has its camps also, but the theory behind it and science says this.

 

[JAD2]

Does anyone have similar thoughts (or experiences) with video calibration disks ? Everything I've read about DVE is that it's brilliant for video calibration and sound calibration. No big problems have been noted.

Every disc when it came out was the next best thing since sliced bread and people will not question stuff like this because of the so-called results it gives.

I still have both the disc washer one and a avia disc, both get different settings and I couldnt figure out why that was, then common sense prevailed!!

I also have 2 DVD players, one and older progressive and a new oppo, again different settings per player, again common sense prevailed.

 

[Vaughan Odendaa]

So then what is your verdict on the calibration disks ? Are they worth the money ? No improvements ?

People over at AVSforum and numerous other sites have sworn by these dvd's. So I just want more opinions on the software.

Thanks.

--Sincerely,

 

[JAD2]

So then what is your verdict on the calibration disks ? Are they worth the money ? No improvements ?

People over at AVSforum and numerous other sites have sworn by these dvd's. So I just want more opinions on the software.

Thanks.

--Sincerely,

Verdict??? More gimmick than anything else.
Improvements, as I said, you'll maybe correct the deficiencies that the DVD player you have, has.
As far as the TV connection, you could uses home shopping channels which have vivid colors, also blocks in the prices from colors to black and whites to get some improvement there. Dont use the levels you use and set with the disc on other inputs, as I said, your setting it to the DVD player, not the TV.

Those other sites also SWEAR,
This speaker is better than the other
Cables make wild differences you can hear and see.
One receiver brand is better than the other
One TV is better than the other
And so on, all opinions and personal preferences its based upon.
So is this Disc stuff any different?? NO!!!

You want your TV and audio set up as close to perfect as possible and there is no 100% perfect, but 98% is possible, PROFESSIONAL CALIBRATION. Few hundred bucks and its there, no ifs, ands or buts!!! You could easily be spending that doing it yourself and doing it again and again and again!!
If you dont like the results with your naked eyes and ears as is, with different abilities free within your realm, you think a disc will be any different?? Its all within the mind!!!!

 

[tbewick]

I'm sort of blowing my own trumpet here, but a while ago I had a helpful discussion with mtrycrafts and Chris on jitter:

http://forums.audioholics.com/forums/showthread.php?t=20397

I don't think many companies make factually wrong statements but it's more a case of over-emphasising the importance of cables. Earlier on someone suggested 10% of your system budget to spend on cables which I think is sensible. Probably video cables are the most important ones.

There is an additional step in converting from electrical to optical signals, so this could possibly add jitter. If you really want to know how good the Toslink and electrical digital S/P-DIF's interfaces perform, you should run some objective tests on them. You could run test tones through them and analyse the results on a good quality sound card. Probably there's an AES paper out there you can refer to to guide you in setting up a good test. Arny Krueger's site does jitter tests:

http://www.pcavtech.com/

Jitter tests on DVD players are conducted at www.homecinemachoice.com. Jitter levels at almost 1 ns is a fairly typical result.

Here's a link to a paper which did jitter audibility tests:

http://forums.audioholics.com/forums/showthread.php?t=4547

I've found the Video Essentials test disc useful.

 

[MDS]

But since optical is a fiber and transmits thru light, everything goes right thru the light without distorting it. Now even this has its camps also, but the theory behind it and science says this.

"Everything goes right thru the light without distorting it"?????

Sorry JAD2 but you don't understand digital transmission in general or optical in particular.

 

[JAD2]

"Everything goes right thru the light without distorting it"?????

Sorry JAD2 but you don't understand digital transmission in general or optical in particular.

Its a generic answer. The distortion of the light signal sent down the optical fibers isnt as great as the signal sent over a digital coax line with added electrical distortion factors also in play, so they say. Sorry I didnt technical geeky, freaky the answer and word it to your liking!!!!

 

[Vaughan Odendaa]

MDS, I know this thread has nothing to do with video calibration and I apologize for straying off the topic of discussion, but can you please offer your views on calibration disks for displays ? Like DVE. Are they really "essential" for calibrating displays or are they gimmicks like JAD2 said ?

Thanks. End rant on calibration software.

--Sincerely,

 

[JAD2]

Ask yourself this question.
If the TV does have a wild skew in something it shows or doesnt show, do you think those DYI controls you have access to will fix the problem????