[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
Andrew L.Weekes said the following on 02/01/2006 00:16: Interesting. What is the equations that describe this? If it is too long to post, got an URL? SNR (DBC)=#8211;20 LOG10(2#960;.FIN.TJITTER), WHERE FIN IS THE ANALOG-INPUT FREQUENCY, TJITTER IS THE TOTAL SYSTEM JITTER IN SECONDS. Immediately it should be clear that the fIN factor gives result dependant upon the sampled frequency, using the figures mentioned, 20,000ps gives, assuming no other system errors, 98dB dynamic range (non-dithered CD spec) at 20Hz, but only 51dB at 20kHz. 100pS would meet the 20kHz non-dithered spec, but what about dithered input signals? Factor in a 15dB additional dynamic range from a properly dithered input signal, or a 24bit system (or worse still, a wide-bandwidth system) and you can see things rapidly becoming much harder. It's one reason why the newer, hi-res formats fail to live up to my expectations, they make the engineering, which is already bloody difficult, MUCH harder. It really isn't as easy as many so called 'experts' make out, jitter isn't that easy to measure (to the man in the street) and even when one can, it's not as simple as a headline figure. The recent volume rounding error problem of the Squeezebox gave rise to an error at the 16bit of the audio data - so many experts would tell you this is inaudible, yet people here (without knowledge of any change) found it wasn't. The human ear / brain interface is a really astonishingly complex thing, that can at one and the same time be both amazingly sensitive, yet easily fooled. What it isn't is measurable, in any quantitative manner. No-one, anywhere, with any experiment or test, can 'prove' the absolute audibility or inaudibility of anything when it comes to music. Realising that is crucial to avoiding the often prolonged debates that happen around these subject areas. Whilst the maths above, for example, explains a mechanism for audibility, it tells you nothing at all about an individual's ability to hear the effects, there are few absolutes of 'audiblity'. Amen. Andy has articulated my thoughts on this matter much more clearly than I could ever be bothered to write down! R. ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
FlyFishAndGolf Wrote: The studies published by the Audio Engineering Society demonstrated that jitter isn't audible until around 20,000 ps. I am also of the opinion that the entire jitter problem was overhyped by marketers. Figure 9 of http://www.nanophon.com/audio/jitter92.pdf (also an AES paper) suggests audibility of jitter goes much lower than 20ns... -- Triode Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
Interesting. What is the equations that describe this? If it is too long to post, got an URL? SNR (DBC)=#8211;20 LOG10(2#960;.FIN.TJITTER), WHERE FIN IS THE ANALOG-INPUT FREQUENCY, TJITTER IS THE TOTAL SYSTEM JITTER IN SECONDS. Immediately it should be clear that the fIN factor gives result dependant upon the sampled frequency, using the figures mentioned, 20,000ps gives, assuming no other system errors, 98dB dynamic range (non-dithered CD spec) at 20Hz, but only 51dB at 20kHz. 100pS would meet the 20kHz non-dithered spec, but what about dithered input signals? Factor in a 15dB additional dynamic range from a properly dithered input signal, or a 24bit system (or worse still, a wide-bandwidth system) and you can see things rapidly becoming much harder. It's one reason why the newer, hi-res formats fail to live up to my expectations, they make the engineering, which is already bloody difficult, MUCH harder. It really isn't as easy as many so called 'experts' make out, jitter isn't that easy to measure (to the man in the street) and even when one can, it's not as simple as a headline figure. The recent volume rounding error problem of the Squeezebox gave rise to an error at the 16bit of the audio data - so many experts would tell you this is inaudible, yet people here (without knowledge of any change) found it wasn't. The human ear / brain interface is a really astonishingly complex thing, that can at one and the same time be both amazingly sensitive, yet easily fooled. What it isn't is measurable, in any quantitative manner. No-one, anywhere, with any experiment or test, can 'prove' the absolute audibility or inaudibility of anything when it comes to music. Realising that is crucial to avoiding the often prolonged debates that happen around these subject areas. Whilst the maths above, for example, explains a mechanism for audibility, it tells you nothing at all about an individual's ability to hear the effects, there are few absolutes of 'audiblity'. Andy. -- Andrew L. Weekes Andrew L. Weekes's Profile: http://forums.slimdevices.com/member.php?userid=573 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
davehg Wrote: in the January 1993 volume of Stereophile. The author, recording engineer and now absolute sound editor Robert Harley, first explored the scientific measurements of Ed Meitner, who first discovered a means of measuring jitter. Meitner presented his findings to the 91st AES convention, in a paper called Time Distortions within Digital Audio Equipment due to Integrated Circuit Logic induced Modulation. Harley references the following scientific journal article: Is the AES EBU/S/PDIF Digital Audio interface Flawed? by Chris Dunn and Malcolm Hawksford. Dunn and Hawskford calculate that for 16bit converters, a measurement of less than 100 picoseconds of jitter is not likely audible, whereas a 20 bit conversion accuracy on the order of 8 picoseconds in order not to induce audible (and measurable) differences. This also assumes that the jitter is random; in many cases, it appears consistently at the same frequency as the audio signal. Also, in 1993, these engineers did not have access to 24 bit converters, whose jitter measurements would need to be well below 8ps given the mathmatical formula developed. Pat, I appreciate your healthy skepticism of the hi end, but as others have noted here, jitter has a discernible and measurable impact on audio frequencies, which is also easily heard. Less clear is at what point the lowest measured jitter becomes relevant when all such devices display incredibly low measured jitter. In the case of the SB3, its 55 ps of jitter is one aspect of its sonic improvement when comparing against typical transports which measure 200ps, especially when both are using 24 bit or even 16 bit conversion. The studies published by the Audio Engineering Society demonstrated that jitter isn't audible until around 20,000 ps. I am also of the opinion that the entire jitter problem was overhyped by marketers. They basically created a problem were there was none. If you are aware of any scientifically valid tests that prooves me wrong, please share it. Theoretical and Audible Effects of Jitter on Digital Audio Quality Benjamin, Eric; Gannon, Benjamin AES Preprint: 4826 Most audiophiles can't even articulate what jitter sounds like. That should be the biggest clue. -- FlyFishAndGolf FlyFishAndGolf's Profile: http://forums.slimdevices.com/member.php?userid=287 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
pfarrell Wrote: :[color=blue] Humans have evolved for a long time to pay critical attention to phase and frequency. It meant telling where the lion was. But audiophiles also love tube gear, which any engineer knows has bad bandwidth (aka rolloff, aka warmth) and all sorts of intermodulation distortions. I'd love a cite to some science or engineering about the meaning of jitter at audio frequencies or redbook data rates. -- Pat Farrell http://www.pfarrell.com Tube preamps can have flat frequency response when properly engineered. Tubes are inherently superior to transistors in some respects. See this series of interviews with the great (and slightly odd) Tim de Paravicini: http://www.ear-usa.com/timdeparavicini.htm YOU USE VACUUM TUBES IN MANY OF YOUR DESIGNS. SOME PEOPLE HAVE SAID THAT TUBES HAVE EUPHONIC EVEN-ORDER HARMONIC DISTORTION. DO YOU RELY ON THIS TUBE NONLINEARITY TO ACHIEVE THE SOUND OF YOUR MODS, OR DO YOU ALWAYS RUN THE TUBES IN THEIR LINEAR REGION? I do not rely on tube nonlinearity. I don't want a sound in my machines. What comes out must sound the same as what went in. The warmth in a lot of tube electronics is due to their dismal top end, the bad transformers they use, and the loading down of their high-impedance outputs. Because of the output transformer and the feedback used, many tube circuits have a partial bass instability that gives a bloated bass. Any warmth in the tube sound is a defect, but listeners don't want to know that. I don't have to use tubes in my designs; I only do it for marketing reasons. I've got an exact equivalent in solid state. I can make either type do the same job, and I have no preference. People can't pick which is which. And electrons have no memory of where they've been! The end result is what counts. Most transistor-circuit architecture was different from tube-circuit architecture, and that's what people were hearing, more than the device itself. The main advantage of tubes is that an average tube has more gain than an average transistor. Second, tubes don't have the enormous storage times of transistors, so they are very fast. Tubes go to 100 MHz without trying. Andrew -- Andrew B. = SB3- Benchmark DAC1 - EAR864 valve pre - ATC SCM50ASL active speakers... nice! Andrew B.'s Profile: http://forums.slimdevices.com/member.php?userid=2619 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
On Fri, 2005-12-16 at 09:59 -0800, Andrew B. wrote: pfarrell Wrote: Humans have evolved for a long time to pay critical attention to phase and frequency. It meant telling where the lion was. But audiophiles also love tube gear, which any engineer knows has bad bandwidth (aka rolloff, aka warmth) and all sorts of intermodulation distortions. Tube preamps can have flat frequency response when properly engineered. Tubes are inherently superior to transistors in some respects. No argument about how good tube amps can sound from me. The preamps can have flat response a lot easier than power amps. Because of the output transformer and the feedback used, many tube circuits have a partial bass instability that gives a bloated bass. Any warmth in the tube sound is a defect, but listeners don't want to know that. Isn't that what I said :-) But, it does sound good. I don't have to use tubes in my designs; I only do it for marketing reasons. When you are selling a product, you have to provide what people want. Many Audiophiles love tubes. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
I'm open to being educated on it, but I'm not convinced by this message or year of reading the high end rags. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html If you're happy with the sound you're getting from the SB, then don't worry about jitter levels. Perhaps you've never heard a low jitter hiend system. What system(s)are your SBs connect to? -- mauidan mauidan's Profile: http://forums.slimdevices.com/member.php?userid=1679 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
pfarrell Wrote: Could be, but I have not seen a credible definition of what jitter is, how jitter is caused, what fixes it, or how jitter effects sound. The first three are well defined and understood. Jitter is critical in high speed logic circuits and communication systems, and there are many books explaining the phenomenon and how to manage and reduce jitter. There are also plenty of instruments offering different ways of analyzing jitter. Audibility (at the picosecond level) is nebulous, but I am no longer surprised at the things some trained ears can pick up on a good system. -- seanadams seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
in the January 1993 volume of Stereophile. The author, recording engineer and now absolute sound editor Robert Harley, first explored the scientific measurements of Ed Meitner, who first discovered a means of measuring jitter. Meitner presented his findings to the 91st AES convention, in a paper called Time Distortions within Digital Audio Equipment due to Integrated Circuit Logic induced Modulation. Harley references the following scientific journal article: Is the AES EBU/S/PDIF Digital Audio interface Flawed? by Chris Dunn and Malcolm Hawksford. Dunn and Hawskford calculate that for 16bit converters, a measurement of less than 100 picoseconds of jitter is not likely audible, whereas a 20 bit conversion accuracy on the order of 8 picoseconds in order not to induce audible (and measurable) differences. This also assumes that the jitter is random; in many cases, it appears consistently at the same frequency as the audio signal. Also, in 1993, these engineers did not have access to 24 bit converters, whose jitter measurements would need to be well below 8ps given the mathmatical formula developed. Pat, I appreciate your healthy skepticism of the hi end, but as others have noted here, jitter has a discernible and measurable impact on audio frequencies, which is also easily heard. Less clear is at what point the lowest measured jitter becomes relevant when all such devices display incredibly low measured jitter. In the case of the SB3, its 55 ps of jitter is audible using a 24 bit conversion, and comparing against typical transports which measure in excesss of 100ps. -- davehg davehg's Profile: http://forums.slimdevices.com/member.php?userid=2269 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
pfarrell Wrote: On Tue, 2005-12-13 at 19:01 -0800, mauidan wrote: If you're happy with the sound you're getting from the SB, then don't worry about jitter levels. Perhaps you've never heard a low jitter hiend system. What system(s)are your SBs connect to? I'm not worried about it now. My serious SB is connected to a Benchmark DAC-1. If you care about the rest, its in the archives. -- Pat Farrell http://www.pfarrell.com I don't need to search the archives for the rest. I've tested the DAC-1 in my system. Be well. Mele Kalikimaka -- mauidan mauidan's Profile: http://forums.slimdevices.com/member.php?userid=1679 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
Here's an excellent article on jitter basics, in five parts: http://www.tnt-audio.com/clinica/diginterf1_e.html -- JohnnyLightOn JohnnyLightOn's Profile: http://forums.slimdevices.com/member.php?userid=28 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
I think this really depends on your dac. I can tell the difference between different transports. But then my dac has a simple spdif input receiver [very common crystal 8412] with standard loopfilter - this only attenuates jitter above 25Khz. Adding a new clock to an old cd transport was noticable with this. More complex dacs attenuate jitter much more (in the digital domain using async resampling or by secondary plls with much tighter loop filters). With these any jitter on the spdif line should be much less noticable... -- Triode Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
pfarrell Wrote: On Sat, 2005-12-10 at 18:26 -0800, scan80269 wrote:[color=blue] I believe that most of the focus on jitter is hype to separate audiophiles from their money. I could be wrong. YMMV and all that. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html Yes, you are wrong. -- mauidan mauidan's Profile: http://forums.slimdevices.com/member.php?userid=1679 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
Your first assumption may be wrong; there is a potentially relevant diference between the SB2 and SB3 hardware. To quote Bolder CAble Co: It contains all the same circuitry of the SB2 with one small difference. The internal power supply for the digital buffer chips is now powered by a linear regulator. -- Neil kronos [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] ok, given that SB2 and SB3 feature the same hardware; my real question is : is there a difference between the DIGITAL out of the SB1 and the DIGITAL out of the SB2 ? ...i'm planning on using an external DAC, so i thank you all in advance for feedback that will help me decide which SQUEEZEBOX i am going to buy. =) -- kronos kronos's Profile: http://forums.slimdevices.com/member.php?userid=728 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
I just purchased a brand new SB3, and a colleague subjected the digital outputs to a quick jitter measurement using Audio Precision equipment. Results: SB3 digital coax out jitter: ~99ps SB3 digital optical out jitter: ~892ps My colleague's own SB1 is supposed to have digital optical out jitter measured in the range of 1400ps. Thus, we believe that SB2/3 digital output is superior to SB1 based on lower jitter levels. My colleague also managed to improve his SB1 optical out sound quality by soldering an additional bypass cap directly across the power ground pins of the Toslink optical module. He believed that the cap is specified as a requirement for the Toslink optical module design guide, but was not used by the SB1 design. -- scan80269 scan80269's Profile: http://forums.slimdevices.com/member.php?userid=2739 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
On Sat, 2005-12-10 at 18:26 -0800, scan80269 wrote: Thus, we believe that SB2/3 digital output is superior to SB1 based on lower jitter levels. Well, you've measured superior jitter levels. No need to believe for the measured units. I believe that most of the focus on jitter is hype to separate audiophiles from their money. I could be wrong. YMMV and all that. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
kronos, the sb2 has a better digital output than the sb1 - i have both and an audio synthesis dax decade. this dac has 2 'lock' methods one for low quality high jitter signals and one for high quality low jitter signals. the lock method is shown on the display as either lock (low quality) or x-lock (high quality) the sb1 (even with various reclockers and jitter busters) always showed 'lock' on the display. the sb2 always shows 'x-lock'. i'd say this is pretty conclusive proof that the sb2 has a better digital output than the sb1. of course dacs vary in their sensitivity to jitter but i've often found that dacs that are less sensitive to transports don;t produce a sound that i enjoy, i suspect because they are desinged from an engineering first perspective rather than a music first one which means only 'good enough' psus and components but then i'm a audiophile nutter, so i'm happy to live with my current solution - an sb2 and a sensitive a/s dax decade. cheers julian. -- julian2002 julian2002's Profile: http://forums.slimdevices.com/member.php?userid=113 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
From that description it sounds like a relatively simple input circuit (nothing wrong with that). I would expect it will work fine with SB1 or SB2/3, but as it does not include any internal jitter rejection, the SB2/3 will potentially sound better. -- Triode Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
SB2 SPDIF output is much better than SB1. -- JayNYC JayNYC's Profile: http://forums.slimdevices.com/member.php?userid=121 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
I think this depends on your dac, what it does to reduce jitter and if it is fussy about the frequency of the digital signal. SB1 used an integrated chip to do the dsp functions and produce the spdif output. This had a known limitation that the exact frequency it produced could be slightly off 44.1 KHz and given that the chip vendor was unwilling to fix it, slim had no control over it. This is no cause for concern for the vast majority of dac users, but did impact some as their external dac was unable to lock onto the signal. There were also some reports of channels swapping over in SB1 due to the operation of the dsp chip. The dsp chip in SB1 also used a PLL to derive the clock used for the digital out. This means that the jitter on this clock is higher than that which would be obtained with a direct crystal based oscillator. SB2/3 should have all of this solved - the spdif output is generated directly from a crystal oscillator with no PLL. There are two separate crystals for 44.1 and 48 KHz sampling. So what does this mean, I would suggest: 1) If you dac is not fussy about the exact frequency of the digital input (does not experience 'lock' problems) and has internal circitry to reduce jitter, then you may not hear any benefit from SB2/3. 2) If however your dac is fussy about locking or does not have strong jitter rejection, then the SB2/3 is likely give better performance. The one hardware change between SB3 and SB2 will also be beneficial as it should further reduce the jitter on the digital output. In short SB3 (and 2) is definately technically better for the digital output than SB1. Whether you can hear this depends on how well your external dac hides the influence of jitter from the transport. -- Triode Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SB1 digital out compared to SB2 and SB3
THANKS a lot guys, now i'm out there looking for info about frequency of digital input and internal circuitry to reduce jitter for my soon to be delivered : Triode Wrote: DAC-AH Dac special DIYCLUB version (Red PCB) using CS8414 as digital input reciver, 8 pcs of TDA1543 in parallel (matched). EL2044 OPAMP, On board with three seperate rectifier and regulators provide power to digital and analog circuit. Optical and Coaxial input selectable (Ready plug in and play) available for 135$ + shipping here : http://tinyurl.com/cfnrc Not being a techie i don't really understand if the answer to my question is already included in the DAC elements description... =P anyway, if you are interested too just click on the link; if you have one and feel like dropping a line, it will certainly help me decide whether to go SB1 or later. Triode Wrote: 1) If you dac is not fussy about the exact frequency of the digital input (does not experience 'lock' problems) and has internal circitry to reduce jitter, then you may not hear any benefit from SB2/3. THANKS ! -- kronos kronos's Profile: http://forums.slimdevices.com/member.php?userid=728 View this thread: http://forums.slimdevices.com/showthread.php?t=18116 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
