Originally Posted by leeperry
Well, Wolfson are IC makers and the companies using WM8804(Little Dot put it between the inputs and the DAC chip in their DAC's for instance, and so did Neko Audio. Also, all the newest A-GD units use it as well on their S/PDIF inputs) don't seem too interested in making studies either. Audiophile gear is very much a nice market, I surely don't want the prices to go up because of some huge studies taking place in order to make the skeptics peeps at the back of the bus happy(or unhappy, depending on the results ).
Where are the DBTs that show that this technology makes an audible difference ? - this is a very simple question and one that you dodge again and again !
Coz I've got nothing to sell nor to prove...
Actually you are the one who insists that jitter is a problem when the prevailing empirical evidence is that it simply is not, therefore you are the one with the radical position that needs proof ! or alternatively you could accept that there is no proof and it is all audiophile flummery ?
EDIT: I just looked at the Firestone Bravo web page - you do know that they are not measuring jitter here that they are showing noise levels via a FR analysis , exactly what I have been talking about ! - So in fact while their device does show a lowering of noise you have no way of knowing how much of that was jitter to start with !
Nick, sometimes you guys at the back of the bus don't seem as technically savvy as I would have though. First you test cables by doing SRN/THD/FR measurements, and call them all identical....when obviously, this could be apparented to eating soup w/ a fork.
Lee, as I have repeatedly said, I am most interested in FR as that is the single most defining audio quality, it is the underlying tone of an item, surely you agree with this ?
You'd need at worst an analog oscilloscope and at best a serious measurements package such as the AP in order to actually measure those differences:
No, not at all, anything that captures the FR will suffice, an ADC can do this very nicely ! - it does not need to be sophisticated to capture the FR
Then you offer to capture the analog outputs of your DAC on a cheap USB soundcard(your Roland thingie?) in order to prove that jitter doesn't exist? Did I get this right?
Of course not and you know it, of course jitter exists, how big it is and how audible it is are the questions - jitter shows up in deviations to the FR - we know this to be true, it has been shown again and again.
A signal with one level of jitter will look different from a signal with a different level of jitter, this is not rocket science you can prove this using audacity - feed the two signals in chart the spectra and you can mathematically measure the differences - this is easy, I've done this.
Your thesis that my capture device will not adequately capture the differences boils down to the fact that these night and day differences in jitter when reclocking are so insignificant as to be underneath the threshold of a 16 bit system - i.e the differences are smaller than 1/2 of an LSB of a 16 bit system i.e they are below the quantization error, do you really contend that deviations this low will be audible, you are talking about differences between the stimulae below -96db - really night and day stuff !
Say a nominal full scale signal is 2V , divvy that up by 16 bits and you get 0.000030517578125V per step - that is the difference adding 1 to the value makes so going from 0 to 1 goes from 0V to 0.000030517578125V , however our quantization error is half that so the difference due to jitter must be below 0.015millivolts in orer to not be detected. This is the night and day difference you are talking about ?
any recent DAC's use ASRC because resampling lowers jitter drastically....this is exactly what you intend to do. This is nicht gonna work, and you will tell me that they all sound the same to you...yada yada
Lee, first you say this Bravo device will radically lower jitter by reclocking and thus make the sound much much better, now you say that this difference cannot be measured, that makes no sense, which is it - can the massive difference be measured or not - if it cannot be measured how do you even know it is working ?
Anyway, you guys seem pretty happy w/ the gear you own, and all the cables sound the same too...how is that not a good thing?
And to get back to jitter audibility: http://www.avguide.com/forums/jitter-audibility-robert-harley-and-keith-johnson-comment
Robert Harley - seriously ?, the man whose understanding of jitter is so bad that he was routinely corrected and even incited Peter Aczel to get Bob Adams (Analog Devices) , someone who actually knows what he is talking about re jitter not some audio hack who got his job writing an essay , to write a proper article explaining jitter
"Quote from the text linked above "Experiments were carried out in the listening booth or studio that each listener had offered. The examiner only brought there a personal computer with a digital audio interface and a mouse and each listener provided his or her favorite DAC, amplifiers and loudspeakers."
Knowing what we know about USB DACs and interfaces between portable computers and DACs, it's no wonder that jitter differences were masked by this inferior and highly variable interface methodology. Also these tests were done in 2005 when the quality of USB DACs was far inferior to today."
This is from , er an audio hack isn't it ? - and his evidence is ......? well it is just speculation as usual. Where is the evidence, that jitter was masked by whatever not anecdotes ?
Do the same studies w/ the 46ps spec'ed $189 TC Konnekt 6, and I'll be more willing to take their results into serious consideration.
I have nothing to prove, others have provided good evidence, if you want to prove them wrong .....