[audioengr]

Agreed.  The guys were talking about a new USB technology as if it represents a jitter-free a paradigm shift and its not....I believe what they are referring to is an asynchronous DAC such as Wavelength....

It's not necessary to use asynch to get low jitter from USB.  I have essentially the same USB protocol as Benchmark DAC-1, and my latest offering has jitter almost as low as my Pace-Car reclocker.  They are difficult to tell apart.  This is so low that there is not much incentive to pursue async.  Besides, even with asynch there are no guarantees that you will be insensitive to incoming jitter.

Steve N.

[BrianM]

Only works for SPDIF. Which is the only application that jitter needs to be addressed. (I already showed in the other thread that jitter in a stand-alone player is not much of a problem. Stop worrying about it unless you have lots of time and money. Mostly the latter.)

I probably missed it somewhere, but to what extent do you feel the SPDIF problem is ameliorated by a so-called optimized digital cable length?

It certainly helps.  Read this white-paper:
http://www.positive-feedback.com/Issue14/spdif.htm

Hi Steve,
I'd read that paper before, and my memory of it was kinda why I brought up the issue here.  Looking over it again, unless I'm missing something, you don't go into specific optimal lengths other than that 1-meter isn't as good as 1.5 meters.  Are your findings such that longer is always better, i.e. if 1.5 meters is better than 1, then 2 meters should be better than 1.5?  (And up to what point? the Audio Research SPDIF cable is apparently 16 feet long.)  Should I just go by a 16-foot Belden coax?  Thanks for any input.

[audioengr]

Only works for SPDIF. Which is the only application that jitter needs to be addressed. (I already showed in the other thread that jitter in a stand-alone player is not much of a problem. Stop worrying about it unless you have lots of time and money. Mostly the latter.)

I probably missed it somewhere, but to what extent do you feel the SPDIF problem is ameliorated by a so-called optimized digital cable length?

It certainly helps.  Read this white-paper:
http://www.positive-feedback.com/Issue14/spdif.htm

Hi Steve,
I'd read that paper before, and my memory of it was kinda why I brought up the issue here.  Looking over it again, unless I'm missing something, you don't go into specific optimal lengths other than that 1-meter isn't as good as 1.5 meters.  Are your findings such that longer is always better, i.e. if 1.5 meters is better than 1, then 2 meters should be better than 1.5?  (And up to what point? the Audio Research SPDIF cable is apparently 16 feet long.)  Should I just go by a 16-foot Belden coax?  Thanks for any input.

Brian - There is a point of diminishing returns.  Like all interconnects, shorter is better because you minimize losses and dispersion.  In the digital cable case though, you need to be long enough so that the reflections are damped-out completely by the time the destination device samples the signal edge.  This makes the optimal length between 1.5m and probably 2m for most transports.  More than 2m starts to add a lot of dispersion and losses unless it is an extremely low loss cable.  These are rare.

Steve N.

[art]

  More than 2m starts to add a lot of dispersion and losses unless it is an extremely low loss cable.  These are rare.

Steve N.

Oh, you are going to tell me that there is that much more dispersion at 5 m than 2 m. Sorry, not buying it.

Maybe our cable is rare........better raise the price.

And why is loss bad? No, don't ask me, 'cuz I ain't sayin'.

Pat

[audioengr]

  More than 2m starts to add a lot of dispersion and losses unless it is an extremely low loss cable.  These are rare.

Steve N.

Oh, you are going to tell me that there is that much more dispersion at 5 m than 2 m. Sorry, not buying it.

Maybe our cable is rare........better raise the price.

And why is loss bad? No, don't ask me, 'cuz I ain't sayin'.

Pat

How about 2.5X more.  It is a linear phenomena.

Loss is bad because combined with the cable capacitance and dielectric absorption it adds pattern-related jitter, AKA ISI or inter-symbol interference.

Steve N.

[BrianM]

So it's a linear measurable phenomenon; I guess the question is when your ears pick up on it.  The ICs between my components (excluding the SPDIF cable) are 2 feet length.  Should I replace them with 1-foot ICs?  That's half the dispersion!  Would I hear it?

[art]

Yes, but that may not be a good thing.

Pat

[art]

Loss is bad because combined with the cable capacitance and dielectric absorption it adds pattern-related jitter, AKA ISI or inter-symbol interference.

Steve N.

It is a free country. Believe anything that you want, even when you don't know all the facts.

Pat

[audioengr]

So it's a linear measurable phenomenon; I guess the question is when your ears pick up on it.  The ICs between my components (excluding the SPDIF cable) are 2 feet length.  Should I replace them with 1-foot ICs?  That's half the dispersion!  Would I hear it?

Depends on your entire system electrical noise.  Most systems are too noisy and sibialant to hear things like this.  I recommend 0.5m analog IC's if they will reach.  Most of my customers buy 1m, but only because 1m is generally easier to resell.

Steve N.

[doug s.]

i recently demo'd one of my modded art di/o's, (now maxwalrath's!   ), driven by a stock modwright transporter against a few other digital sources, including an EA modded Northstar 192 DAC/EA SB3/Pace-car set-up.  three of us found pretty-much no difference whatsoever between these sources.  one guy thought the mw transporter/modded di/o was better!?!  no, i was not that guy, lol!

i get excellent results at home w/a modded di/o fed from a denon dcm560 5-disc changer, which cost me all of $80, instead of a modwright transporter.  i will soon be trying an audio alchemy acd pro as transport in my home rig, which features the pioneer stable platter - it cost me $248.  mebbe it will give me an improvement, if so i suspect it will be tiny.  i use separate isolation transformers for dac & transport, which makes a difference - quieting noise floor & increasing detail.  (in the demo above, only the di/o had a separate isolation transformer, not the transporter.)

imo, the law of diminishing returns w/digital playback starts at an extremely low price point, but as always -

ymmv,

doug s.

[jimdgoulding]

This is very interesting to me.  The word “halo” as a description of a distortion grabbed my attention.  Sometimes on closely miked female vocals I get what sounds like a blunting to their projection rather than clean articulation.  I thought I may be overloading my room at certain frequencies or the singer’s voice was too much pressure on the mike’s filament cause of the way it sounds when this happens.   Room treatment has not helped this so far.  “Halo” describes this to a point.   Anybody get this?  It’s a drag, for sure.  Singer’s not so closely miked fare better.  I’m ready to try a 2 meter length cable.  So what cable with RCA’s qualifies as TRUE 75 ohm?   My transport is a cheaper Sony DVD player out to a Bel Canto DAC2.  Any more information as to what might be causing this and/or suggestions are greatly appreciated.

[Geardaddy]

imo, the law of diminishing returns w/digital playback starts at an extremely low price point, but as always -

ymmv,

doug s.

Doug, that has not been my experience.  I guess it depends to some degree on the system as Steve opined above.  When we recently compared an Arcam DIVA79 to a tricked out Shanling tube CDP from Exemplar Audio, it was like night and day.  The monitors used (Intuitive Design Summits) are very transparent and the room itself was also tricked out in terms of sonic treatments....

[Daygloworange]

  Sometimes on closely miked female vocals I get what sounds like a blunting to their projection rather than clean articulation.  I thought I may be overloading my room at certain frequencies or the singer’s voice was too much pressure on the mike’s filament cause of the way it sounds when this happens.   Room treatment has not helped this so far. 

Room treatments won't help. The problem is most likely embedded on the recording. Most female vocalist would be mic'd with a large diaphram condenser mic. They capture subtle nuances very well, but at the expense of being subsceptible to overloading and windnoise. A vocalist expells a lot of air when they sing, which is why windscreens are used, to diffuse and dampen the onrush of air coming from a vocalist, and prevent mic "popping" from "plosives" from hard consonants like "P's" and "T's".

Large diaphram mics can get a little "sloppy" due to the slower response of the large diaphram and it's tendancy to oscillate at times. They are not perfect. But their general sonic attributes favour them being used on feature vocals.

Other possible distortions can be mic pre-amp overloading, tape oversaturation, or a compressor's envelope tracking (attack and release) controls not being properly set.

The logical question would be "why didn't they just re-do the vocal"? 

The answer could be (and usually is) that, while the sonics weren't the best, the performance captured was the best one, and they decided to leave well enough alone.

Kinda like "the money shot" in photography, they don't come around often, and sometimes you'll never consciously be able to do it over, better.

Cheers

[BrianM]

I’m ready to try a 2 meter length cable.  So what cable with RCA’s qualifies as TRUE 75 ohm?   My transport is a cheaper Sony DVD player out to a Bel Canto DAC2.  Any more information as to what might be causing this and/or suggestions are greatly appreciated.

I use a cheap transport, too, and recently got a 6-foot Belden 1694a coaxial cable to connect to my DAC.  There is no true 75 ohm RCA connector but Belden says the Canare model they use is the best impedance match available ("by far" I believe are their words).  Anyway mine seems to work great, and only cost like $15.  Sold off the much more expensive one I'd been trying out.

[BrianM]

A vocalist expells a lot of air when they sing, which is why windscreens are used, to diffuse and dampen the onrush of air coming from a vocalist, and prevent mic "popping" from "plosives" from hard consonants like "P's" and "T's".

The exception would be opera singers, who actually don't expel a lot of air (very little actually, plosives aside).  But then they're not usually close-miked either. Using a very efficient flow of air is the only way to make as much sound as they do (and of course is how they're able to sustain long phrases without stopping).  Thanks for the input DGO, very interesting.

[jimdgoulding]

Dayglo-  That occurred to me but it’s good to hear it from someone like yourself.   Thought it might be the problem.  Or, at least, a problem.  And I thank you for your clear comprehensive reply.   Brian- I got a meter of Belden that I’ve had for years.  Thank you, too.

Fellas-  I’m listening to some records this afternoon.  Female vocals to be exact.  It’s been several months since I’ve put my TT back into the system.  I had forgotten what a solid bottom I get.  The weight of drums, baritone saxes, stuff like that, and sweet highs.  Just finished listening to Tracy Nelson, Doin It My Way, a direct to disc on Audio Directions.  Man, you ought to hear this girl sing Down So Low.  Janis was getting all the headlines during the day while this little mama languished away cross the bay.  God this girl can sing.

[Daygloworange]

The exception would be opera singers, who actually don't expel a lot of air (very little actually, plosives aside).  But then they're not usually close-miked either. Using a very efficient flow of air is the only way to make as much sound as they do (and of course is how they're able to sustain long phrases without stopping).  Thanks for the input DGO, very interesting.

You're right, Brian. Opera singers have very highly developed vocal chords. Their vocal chords are stronger and allow less air to "blow" by. They also learn to resonate their resonant cavities (nasal, vocal tract, chest) and project more volume than a typical pop singer, who sing more through their throats than anything else.

Listen to Mariah Carey, she has a tremendous amount of "blow" by, probably due to vocal chords that have been damaged and don't seal properly anymore (which is not uncommon among singers).

Cheers

[BrianM]

The exception would be opera singers, who actually don't expel a lot of air (very little actually, plosives aside).  But then they're not usually close-miked either. Using a very efficient flow of air is the only way to make as much sound as they do (and of course is how they're able to sustain long phrases without stopping).  Thanks for the input DGO, very interesting.

You're right, Brian. Opera singers have very highly developed vocal chords. Their vocal chords are stronger and allow less air to "blow" by. They also learn to resonate their resonant cavities (nasal, vocal tract, chest) and project more volume than a typical pop singer, who sing more through their throats than anything else.

Listen to Mariah Carey, she has a tremendous amount of "blow" bye, probably due to vocal chords that have been damaged and don't seal properly anymore (which is not uncommon among singers).

Cheers

So I guess to answer Jim's concern about jittery vocalists, listen to more opera!

Yes indeed, too much air in the sound is the kiss of death, dries out the cords, which become calloused, which leads to nodes, which leads to surgery, etc.  Madonna had 'em removed more than once, I believe.

[jimdgoulding]

Believe I'll listen to some tonite.  Just now finished listening to Kate and Anna McGarrigle- self titled (Warner Bros).  I had a beer I'd be cryin in it.  Everything about this album is note perfect forkin beautiful. 

[Daygloworange]

So I guess to answer Jim's concern about jittery vocalists, listen to more opera!

One of my favorite female vocalists. No jitter here.

http://www.youtube.com/watch?v=6Hg3DNNrH1M

Cheers