Axiom Home Page Forums General Discussion Advice from Axiom Owners Odyssey amp with m80s

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As example, I listen to some pretty old jazz and lots of live recordings and boy, those have sometimes lots of noise at the bottom (over 70dB almost everything recorded before late 80's has a distince noise bottom) but nevertheless I love lots of those dearly compared to many clinically black-canvas engineered HDCD.

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Ah... The noise introduced by recording equipment/technology is, of course, a totally differnt beast than the performing or human noise -- the former is always "bad" thing. Just to make sure that our thoughts are in sync on this...

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That all maybe true scientifically, but why did I hear a discernible difference when running my gear of a 541i vs. a Audiotron over toslink. Both put out a digital stream.

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prz, see my post in this thread above on 2/13/03 (response to Saturn). Have you already "scientifically" eliminated the possibility (3) described in that post?

The point still stands.
Audible differences may not be due to the electronics. If it is, then it is measurable, and using the graphs of the TacT software, it might be possible to test that.

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That all maybe true scientifically, but why did I hear a discernible difference when running my gear of a 541i vs. a Audiotron over toslink.

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Having not been in your experiment, I can only offer a possibility. You were expecting a difference, you knew which source you were listening to, so you heard one. Psychology plays a major role in these which is why those of us that demand proof require blind listening.

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DAC, clock jitter?

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My company produces the best timing silicon in the world. Unparalleled. As such, I'm pretty familiar with timing schemes. In a digital music stream from identical CD players, there is absolutely no difference in the raw data received unless one of the players is of such a poor caliber that it can't provide the digital information to the amp. Having had a few decades to play with CD's, no one designs that poorly. Clock jitter is the average difference between one cycle of the clock signal and the next. While it can be measured, it would have no effect on the system unless it was so massive as to cause the DAC to actually be mistimed. The result of that would definitely be audible in that the entire piece of music would be garbage as the bitstream wouldn't even resemble the final piece. But more importantly, CD's are designed with parity, and the players have a large buffer in which the final bitstream is compared to itself to make sure no bits have been lost in transmission long before it's actually played through your speakers.

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The best explanation I have is right now digital 'clock jitter' so maybe I'll try to follow it up.

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Only because it doesn't appear you understand the circuit involved. It is FAR from a good explanation.

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the wave form, when restored at wrong time, may get warped significantly enough to matter?

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Remember: you're talking about a digital bitstream, not an analogue wave form. If the bitstream is screwed up, the result isn't an output that's a little off like an analogue wave that gets distorted. It's an entirely different piece of information. That's the beauty of digital. It's either 1 or 0. Screw that up, and there's only one place it can go.

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Why not clock sync the CD player and the preamp, can't be bad, except some money wasted ;-)

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I'm not sure exactly what you mean here. Are you saying we should opperate the CD player and the preamp at the same frequency? What possible purpose would that serve?

Regards,
Semi

ok, semi,

1) I understand the 'psychology' effect, I don't have the equipment for double-blind. So I _believe_ to hear a significant difference. Good enough. Funny enough, when
running the CD transport via toslink or 75Ohm (it has both) I don't _believe_ to hear a difference.
2) Trust me, I'm a bit believer in digital, I went from EE 20 years ago to software for that reason, 1 is 1 and 0 is 0. I started to build everything digital, only TacT. I realized that digital amps have their problems though ;-) and no digital speakers are around. And right now, 96kHz analog oversample sounds better ;-)
3) ok, on a technical level I admit I don't understand why jitter should be such a big problem. First, I hope you got my setup. I run digital CD transport feeding a TacT preamp and the preamp ADCs the wave to an analog amp. So, the digital stream with the clock comes from the CD and it should be digitial-wise perfect as you say, even if the clock jitters. Fine. Now, it shows up at the pre-amp digital input. Now, the preamp sucks up the bits (which cannot have bit-skipping like you said) and puts them into its
DSPs and then on the DAC which all run of its internal clock which is very high quality (maybe your companies ;-). Now, if the DAC has jitter, I see clearly how that can screw up the resulting wave. So the whole clock-sync between CD and TacT doesn't seem to affect stuff. But lots
of people with a sound clue say that clock-syncing the TacT
and the CD transport improves the sound significantly (including the guys that developed tact ;-). And funny enough, I _believe_ to hear the effect they describe as digital jitter effect. So why should that be if not digital clock jitter from the CD transport somehow affecting the DAC or DSPs in the preamp ?

And last, in all respect, It would hurt my ears tad less if you didn't try to go into offensive that quickly on your posts.
I'm sure I know much stuff you don't know and vice versa. This forum is to have some fun, learn and discuss, not to prove who's bigger ?

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Now, the preamp sucks up the bits (which cannot have bit-skipping like you said) and puts them into its
DSPs and then on the DAC which all run of its internal clock which is very high quality (maybe your companies ;-).

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Not likely. When I say the best, I'm talking about 12GHz clock distribution chips with jitter below 200 femto-seconds... I doubt they have a need for anything remotely that precise.

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Now, if the DAC has jitter, I see clearly how that can screw up the resulting wave.

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The clock merely tells the DAC at what pace to perform its activity. The DAC is not operating very fast so you'd have to have jitter at such a proportion to matter to that device as to make the chip misstep. A high bit rate 24bit 96kHz DAC is representing a piece of data in steps of 1 point per 10 micro seconds. Your everyday standard, and very cheap Silicon based clock generator has jitter in the nano-second scale.

You're at least 1000 significant figures away from a timing problem...

Incidentally, this is also why jitter isn't much of a concern to digitial designers until they get into the >500MHz range at the very least and really not more than 1GHz.

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But lots
of people with a sound clue say that clock-syncing the TacT
and the CD transport improves the sound significantly (including the guys that developed tact ;-). And funny enough, I _believe_ to hear the effect they describe as digital jitter effect. So why should that be if not digital clock jitter from the CD transport somehow affecting the DAC or DSPs in the preamp ?

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Lots of people who are considered experts claim you can improve your sound with $2000 digital interconnects. That doesn't mean its true. Our brain is FAR more complicated than we give it credit for. It's ability to affect our perception of the world is phenomenal and shoudl always be taken into consideration when discussing such things.

That said, if you're happy with the results and are perceiving an improvement, that sounds good to me. All that really matters in the end is whether you enjoy the results. It seems clear to me that you do.

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And last, in all respect, It would hurt my ears tad less if you didn't try to go into offensive that quickly on your posts.
I'm sure I know much stuff you don't know and vice versa. This forum is to have some fun, learn and discuss, not to prove who's bigger ?

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This is brought to my attention fairly often on this site. I really don't understand the nature of it. I'm not intending to be abrasive and I've actually been trying to pad my posts with hugs and kisses in order to temper the problem some here have with them. I certainly don't mean for you to interpret what I say as offensive or hurtful. Can you point out specifically what gave you this impression? By my eye, I'm just direct and perhaps lack a little warmth in computer correspondence due largely to the fact that I'm staring at a cold piece of machinery.

Regards,
Semi

prz,
I would have to say that Semi does have an indirect style of writing but usually does not mean anything offensive by it.
The hardest part about responding to ideas and questions sometimes on forums is not knowing the level of intelligence (or the technical background) of the individuals doing the reading or the posting.
Often a poster can get a little too technical or the reverse, too condescending in their explanation. Writing at a computer easily puts a poster at the face of an unemotional beast widely known for headaches (the windows operating system for most ppl). Combine these two together and you get blunt, forward postings that lack any sense of emotion.

However, i believe Semi felt you did not understand how clock jitter works and with respect to your background, has tried to give you information at a level of understanding that is useful.
I certainly feel like i have a better explanation and understanding about clock jitter now and i also have a science background, although a biological one more than electrical.

Semi's point about negligbile jitter effect makes sense.
A clock working at microseconds with a 'variation' in the nanasecond range is very negligible indeed. If any human can hear the off-timing of a musical note by nanoseconds, they would have to be a god.

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Now, the preamp sucks up the bits (which cannot have bit-skipping like you said) and puts them into its
DSPs and then on the DAC which all run of its internal clock which is very high quality (maybe your companies ;-).


Not likely. When I say the best, I'm talking about 12GHz clock distribution chips with jitter below 200 femto-seconds... I doubt they have a need for anything remotely that precise.

nope, I was told that good ears hear waveform differences caused by patterns of couple of pico-seconds deviations
but femto, I pull my hat off, that's what, fractions of inches for light in this time ;-) You guys must have fun, sounds
bleeding edge.



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Now, if the DAC has jitter, I see clearly how that can screw up the resulting wave.


The clock merely tells the DAC at what pace to perform its activity. The DAC is not operating very fast so you'd have to have jitter at such a proportion to matter to that device as to make the chip misstep. A high bit rate 24bit 96kHz DAC is representing a piece of data in steps of 1 point per 10 micro seconds. Your everyday standard, and very cheap Silicon based clock generator has jitter in the nano-second scale.

You're at least 1000 significant figures away from a timing problem...

Incidentally, this is also why jitter isn't much of a concern to digitial designers until they get into the >500MHz range at the very least and really not more than 1GHz.

so, not sure I follow here, so if you say that I reconstruct something around 10kHz with 10 microsec clock (that's 1e-6 if I'm correct) (which means I'll need at least 20kHz samples to do it anyway decent, that's 1/20*1e3 = 0.5 msec = 500 micro seconds so 1 microsecond clock jitter could be already 0.2% difference on the timescale). Could we hear that one ? My experience with image processing (was a hobby long time ago) suggests to me that just couple of those are surely not to be heard but if such difference happens in a predictable pattern like jitter on another pattern (like music material) I can easily imagine we are able to tell recognize it's going on in an incredibly exact fashion
(analogous to e.g. human eye being pretty
weak with colors, we only see couple thousands if I remember correctly but once we put them close to each other, we can differentiate millions of hues demonstrably). If you think I'm off the charts, read
the reports of NASA that for I think 10+ years thought that astronauts lied their teeth off when they were saying they can see single cars from orbit (it's _way_ beyond the resolution of human retina). They found the explanation, it
makes you shake the head in disbelief as to the accuracy of human senses.

But the core of the problem you didn't mention. What you talk about here is to just make the clock on the DAC very precise, I understand the benefit that it may or
may not bring. I don't understand why there is a claim around that sync'ing the clocks between the transport and the pre-amp should buy me anything. The clocks are
independent and there is a buffer inbetween so the effect should be zero, is that what you say ?


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But lots
of people with a sound clue say that clock-syncing the TacT
and the CD transport improves the sound significantly (including the guys that developed tact ;-). And funny enough, I _believe_ to hear the effect they describe as digital jitter effect. So why should that be if not digital clock jitter from the CD transport somehow affecting the DAC or DSPs in the preamp ?


Lots of people who are considered experts claim you can improve your sound with $2000 digital interconnects. ;-)

I just bought 190$ silver interconnects. Just for the kicks ;-)

That doesn't mean its true. Our brain is FAR more complicated than we give it credit for.

agreed.

It's ability to affect our perception of the world is phenomenal and shoudl always be taken into consideration when discussing such things.

agreed even more. If you want to see something in the audio-visual space that makes your jaw _drop_ look up the work that's going on in
language acquisition. There is a video done in canada or US (some woman I forgot the name off, she's a big shot in children language
development world, Patricia something) where a face is saying a sound [one of the anchor sounds of english language, like 'ka'] and the sound playing does
another key sound like 'ba'. When you close you eyes you hear 'ba', when you open them and see the face you hear yet a completely different
anchor sound, 'fa' or something like
that. It's below conciousness, you can't influence it and the effect is very distinct. As to why, they don't know ;-), obviously the sound we hear
is being modified in the brain by the visual circuitry before it even goes to the cerebreum. So yes, we warp reality unbelievably.


That said, if you're happy with the results and are perceiving an improvement, that sounds good to me. All that really matters in the end is whether you enjoy the results. It seems clear to me that you do.

yepp, I wish I would do double-blind-testing but frankly, I'm too lazy for that and probably rather spend $1K on clock sync to see whether I _believe_ it improved the sound.
Much more fun that way, I'm dealing with commercial, analytical, exact, unforgiving science every day at my job, this is a hobby and it should be a little voodo ;-)


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And last, in all respect, It would hurt my ears tad less if you didn't try to go into offensive that quickly on your posts.
I'm sure I know much stuff you don't know and vice versa. This forum is to have some fun, learn and discuss, not to prove who's bigger ?


This is brought to my attention fairly often on this site. I really don't understand the nature of it. I'm not intending to be abrasive and I've actually been trying to pad my posts with hugs and kisses in order to temper the problem some here have with them. I certainly don't mean for you to interpret what I say as offensive or hurtful. Can you point out specifically what gave you this impression? By my eye, I'm just direct and perhaps lack a little warmth in computer correspondence due largely to the fact that I'm staring at a cold piece of machinery.

Having fought that problem for a long time in my life (and still doing so) I extrapolate that you're a very knowledgable individual who cares very deeply
about his work or area of expertise and who considers 'truth' as
seen by you overriding any social norms which are of course just 'agreements' and not hard axioms (albeit going into greeks I realized
that moral and ethics are basically axioms that allow society and therefore not different from axioms that hold math together. Even deeper here,
I assume you are familiar with Goedel and Wittgenstein and the conclusion I had to draw from their work [one mathematical, the other philosophical]
that math is as arbitrary and unprovable system as society with contradictions being the nature of the beast in the deepest meaning of its sense ;-).
On more tactical terms, telling people straight on they have no clue what they talk about seldom furthers your cause as isn't lack of modesty as isn't
the claim to be the bearer of the truth. I tend to either patiently explain over and over or walk away from forums like that when I tense up and feel
that 'there are too many nuts' or when I feel the competitive edge coming up. And yes, electronic mediums warp things to the worse also often ;-)

Anyway, thanks for good input here

-- tony

Great reply Tony. The problem we have here is that some "experts" in this forum have a god complex. Unless you don't share the same views as them you will get chastised. You will always have to prove yourself. Instead of being enlightened in this forum I leave with a bitter taste in my mouth.

Saturn

I totally agree with Saturn! I manytimes refrain from posting on this forum for this very reason. I do however read this forum daily. I actively participate (read & post) in other audio forums where various ideas are welcomed and you dont get beat up for it.

I for one beleive that I can here a substantial sonic improvement from things like speaker wires, caps, resistors, binding posts, and electrical feed componets. Maybe there is no hard techinical scientific explanation to it but none-the-less I can hear it. It is like love, I know when im in love but science can not prove it.

I do have a question for Tony:

I am curious as to why you bought Axiom M80 speakers given the fact that you spent a lot of money to spring for your high end and very well built pre amp & monoblocks?