5 ms·

Jitter – Does It Matter? (2011)

37 points by PascLeRasc 7y ago

pickdenis 7y ago
NwAvGuy was a true beacon of light in the sea of bullshit that the audiophile community can sometimes be. It's sad he's not around anymore. I had a lot of fun building his Objective2 amplifier.
- ch_sm 7y ago
  It’s true that audiophiles can be some of the worst pseudoscientists around. But still, without the input of some good journalists (like NwAvGuy) I honestly wouldn‘t have found the bliss that is a good-quality and nicely set-up stereo system. I find that this topic is gettig far too little attention compared to visual media (4k, 8k, etc)
- bscphil 7y ago
  It's true. One of the few blogs I've read from end to end. In fact I've even scraped it and keep it saved just to make sure that nothing ever happens to it. I own his DAC design, which is great as well.
- corey_moncure 7y ago
  I bought the assembled O2/ODAC from JDS labs, and then the black edition a few years later. It's essentially a perfect product and I fully believe that any claims of superior transparency in audio reproduction over it from any other manufacturer are 'outside the realm of human perception' (i.e. snake oil). There might be a few nice utility bells and whistles on other products but that's it. Probably someone in the industry made him a hush money deal he couldn't refuse and that was that. Good for him.
deleted 7y ago
[deleted]
samstave 7y ago
Jitter was a HUGE issue in ~2004 for Lucas/ILM wrt rendering speeds... but due to how long ago that was, I dont exactly recall why... They were the first Foundry customer, for these reasons... They had render farms that were sensitive to jitter... Raleigh Mann later went on to run netops for google... thought he has left there and now runs williams sonoma - but he was super jitter allergic...
new_realist 7y ago
Love NwAvGuy’s DAC and amp. I own two of each and attempted to upgrade to expensive alternatives only to be disappointed.
ldoughty 7y ago
So the article is in reference to audio... Jitter in regards to sending data/requests to a 3rd party, such as a cloud provider of a service... definitely a good thing.. it helps differentiate your requests from a DDOS. Skimmed the article to see the subject, saw it was audio, but still wanted to make this comment.
Animats 7y ago
"Cables can “smear” digital signals by attenuating the highest frequencies." Yeah, right. If you get "smeared" digital signals beyond the sampling threshold, you'll get so many data errors that nothing will work. The only thing that matters is whether whatever is clocking the DAC has a constant clock rate and that you don't get a buffer underrun on whatever feeds it data. If this were a real problem, it would have shown up on analog VGA monitors as a wobbly image. Those are also an analog signal from a DAC coming from a clocked data stream. Several orders of magnitude faster than for audio. There have been VGA devices with jitter problems, and it's really obvious - vertical lines aren't straight. That was pretty much fixed by the time VGA went away. (There was once a $13,500 HDMI cable. Really[1]. It was laughed at on Amazon.[2]) [1] https://www.forbes.com/sites/ianmorris/2015/01/02/please-dont-buy-a-13500-hdmi-cable/#588ce29639b6 https://www.forbes.com/sites/ianmorris/2015/01/02/please-don... [2] https://www.amazon.com/WireWorld-Platinum-Starlight-Cable-Meter/dp/B00KY2NKCO https://www.amazon.com/WireWorld-Platinum-Starlight-Cable-Me...
- Doxin 7y ago
  For a real laugh you can go look around for gold plated toslink cables. There's at least a dozen brands out there. Somehow I doubt gold plating optical cables will improve signal quality...
  - hatsunearu 7y ago
    I mean, you can file that one under "looks cool". Absolutely doesn't improve anything else though.
    - Doxin 7y ago
      They sure seem to imply it improves things in the product descriptions though. I just found it interesting how that trick works even for selling non-electric interconnects.
      - hatsunearu 7y ago
        I mean for certain things making whatever its plating not rust is a nice thing. For electrical connections that's a great idea; for other things it might be for looks. Looks is important, and I'm not being ironic.
rurban 7y ago
It does for realtime. This article only cares for audio, but with realtime jitter is the worst problem of all. Comparable to memory failures, segv, out of bounds, ... Usually caused by a HW problem, but sometimes SW is at fault also.
GregoryPerry 7y ago
Jitter is always introduced by non-RTOS operating systems that don't have a guarantee for preemptive realtime scheduling. The kernel scheduler introduces jitter, supervisory processes introduce jitter, etc. And an easy test to see the effects of this is to try to control a servo motor with a GPIO pin without RT_PREEMPT or comparable RTOS. Simple fix would be an RT_PREEMPT-linked Linux sound player.
- Fice 7y ago
  Scheduling jitter does not cause jitter in audio, because audio is buffered and the buffer is consumed by audio device using it's own clock. Yet OS has to fill the buffer in time or underrun will happen, which will be audible as crackling and stutter. For some applications input and output audio buffers need to be very small to avoid introducing noticeable delay in audio processing, and in this case real-time capabilities are required to prevent buffer overruns and underruns.

37 points by PascLeRasc 7y ago

NwAvGuy was a true beacon of light in the sea of bullshit that the audiophile community can sometimes be. It's sad he's not around anymore. I had a lot of fun building his Objective2 amplifier.

ch_sm 7y ago
It’s true that audiophiles can be some of the worst pseudoscientists around. But still, without the input of some good journalists (like NwAvGuy) I honestly wouldn‘t have found the bliss that is a good-quality and nicely set-up stereo system. I find that this topic is gettig far too little attention compared to visual media (4k, 8k, etc)
bscphil 7y ago
It's true. One of the few blogs I've read from end to end. In fact I've even scraped it and keep it saved just to make sure that nothing ever happens to it. I own his DAC design, which is great as well.
corey_moncure 7y ago
I bought the assembled O2/ODAC from JDS labs, and then the black edition a few years later. It's essentially a perfect product and I fully believe that any claims of superior transparency in audio reproduction over it from any other manufacturer are 'outside the realm of human perception' (i.e. snake oil). There might be a few nice utility bells and whistles on other products but that's it. Probably someone in the industry made him a hush money deal he couldn't refuse and that was that. Good for him.

deleted 7y ago

[deleted]

samstave 7y ago

Jitter was a HUGE issue in ~2004 for Lucas/ILM wrt rendering speeds... but due to how long ago that was, I dont exactly recall why... They were the first Foundry customer, for these reasons... They had render farms that were sensitive to jitter... Raleigh Mann later went on to run netops for google... thought he has left there and now runs williams sonoma - but he was super jitter allergic...

new_realist 7y ago

Love NwAvGuy’s DAC and amp. I own two of each and attempted to upgrade to expensive alternatives only to be disappointed.

ldoughty 7y ago

So the article is in reference to audio... Jitter in regards to sending data/requests to a 3rd party, such as a cloud provider of a service... definitely a good thing.. it helps differentiate your requests from a DDOS. Skimmed the article to see the subject, saw it was audio, but still wanted to make this comment.

Animats 7y ago

"Cables can “smear” digital signals by attenuating the highest frequencies." Yeah, right. If you get "smeared" digital signals beyond the sampling threshold, you'll get so many data errors that nothing will work. The only thing that matters is whether whatever is clocking the DAC has a constant clock rate and that you don't get a buffer underrun on whatever feeds it data. If this were a real problem, it would have shown up on analog VGA monitors as a wobbly image. Those are also an analog signal from a DAC coming from a clocked data stream. Several orders of magnitude faster than for audio. There have been VGA devices with jitter problems, and it's really obvious - vertical lines aren't straight. That was pretty much fixed by the time VGA went away. (There was once a $13,500 HDMI cable. Really[1]. It was laughed at on Amazon.[2]) [1] https://www.forbes.com/sites/ianmorris/2015/01/02/please-dont-buy-a-13500-hdmi-cable/#588ce29639b6 https://www.forbes.com/sites/ianmorris/2015/01/02/please-don... [2] https://www.amazon.com/WireWorld-Platinum-Starlight-Cable-Meter/dp/B00KY2NKCO https://www.amazon.com/WireWorld-Platinum-Starlight-Cable-Me...

Doxin 7y ago
For a real laugh you can go look around for gold plated toslink cables. There's at least a dozen brands out there. Somehow I doubt gold plating optical cables will improve signal quality...
- hatsunearu 7y ago
  I mean, you can file that one under "looks cool". Absolutely doesn't improve anything else though.
  - Doxin 7y ago
    They sure seem to imply it improves things in the product descriptions though. I just found it interesting how that trick works even for selling non-electric interconnects.
    - hatsunearu 7y ago
      I mean for certain things making whatever its plating not rust is a nice thing. For electrical connections that's a great idea; for other things it might be for looks. Looks is important, and I'm not being ironic.

rurban 7y ago

It does for realtime. This article only cares for audio, but with realtime jitter is the worst problem of all. Comparable to memory failures, segv, out of bounds, ... Usually caused by a HW problem, but sometimes SW is at fault also.

GregoryPerry 7y ago

Jitter is always introduced by non-RTOS operating systems that don't have a guarantee for preemptive realtime scheduling. The kernel scheduler introduces jitter, supervisory processes introduce jitter, etc. And an easy test to see the effects of this is to try to control a servo motor with a GPIO pin without RT_PREEMPT or comparable RTOS. Simple fix would be an RT_PREEMPT-linked Linux sound player.

Fice 7y ago
Scheduling jitter does not cause jitter in audio, because audio is buffered and the buffer is consumed by audio device using it's own clock. Yet OS has to fill the buffer in time or underrun will happen, which will be audible as crackling and stutter. For some applications input and output audio buffers need to be very small to avoid introducing noticeable delay in audio processing, and in this case real-time capabilities are required to prevent buffer overruns and underruns.