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  1. #21
    Tech Guru mostapha's Avatar
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    You're still not understanding it.

    Intersample peaks come from 2 samples loud enough so that the smooth curve drawn between them rises over 0dB. It doesn't require any processing. It just happens with all DACs.

    The digital connection is just transferring numbers, not an analog waveform. So, two adjacent samples at 0dB (assuming they're not clipped themselves and were actually at exactly 0dB in the origianl signal) or otherwise loud enough to casue an intersample peak won't clip the DAC....because there is no DAC.

    If you run that same signal through the DAC on the CDJ, it'll clip that peak.

    The processing they do (MT, tempo shift) is a separate issue. And part of the reason they use floating point math is so that the processing can't clip the signal. The only time it will is if they do something dumb when converting back to a 16 or 24-bit PCM to output either to the DAC or to S/PDIF. And that should be both predictable and dealt with appropriately.

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    Quote Originally Posted by mostapha View Post
    You're still not understanding it.

    Intersample peaks come from 2 samples loud enough so that the smooth curve drawn between them rises over 0dB. It doesn't require any processing. It just happens with all DACs.

    The digital connection is just transferring numbers, not an analog waveform. So, two adjacent samples at 0dB (assuming they're not clipped themselves and were actually at exactly 0dB in the origianl signal) or otherwise loud enough to casue an intersample peak won't clip the DAC....because there is no DAC.

    If you run that same signal through the DAC on the CDJ, it'll clip that peak.

    The processing they do (MT, tempo shift) is a separate issue. And part of the reason they use floating point math is so that the processing can't clip the signal. The only time it will is if they do something dumb when converting back to a 16 or 24-bit PCM to output either to the DAC or to S/PDIF. And that should be both predictable and dealt with appropriately.
    My understanding was that's a myth that it's some analog thing, rather it was a post processing artifact as a result of overs that get clamped back down to 0dBFS.
    Last edited by Reticuli; 01-31-2018 at 04:58 PM.

  3. #23
    Tech Guru mostapha's Avatar
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    Quote Originally Posted by Reticuli View Post
    My understanding was that's a myth that it's some analog thing, rather it was a post processing artifact as a result of overs that get clamped back down to 0dBFS.
    We might be talking about different things.

    Digital clipping comes from a sample that should be over 0dBFS but can't be because digital won't allow it.

    Intersample Modulation Distortion comes from things like this:



    That's a ridiculously simple diagram, but the idea is sound. And that only happens when actually running through a DAC, where the electronics do a lot of advnaced math that boils down to drawing a smooth curve through the sample points.

    That's what I'm talking about. You're talking about something different, whic is also a conern, but which isn't avoidable based on user controls or setup as far as I'm aware. So, you just have to deal with it.

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    Quote Originally Posted by mostapha View Post
    We might be talking about different things.

    Digital clipping comes from a sample that should be over 0dBFS but can't be because digital won't allow it.

    Intersample Modulation Distortion comes from things like this:



    That's a ridiculously simple diagram, but the idea is sound. And that only happens when actually running through a DAC, where the electronics do a lot of advnaced math that boils down to drawing a smooth curve through the sample points.

    That's what I'm talking about. You're talking about something different, whic is also a conern, but which isn't avoidable based on user controls or setup as far as I'm aware. So, you just have to deal with it.
    Interesting. I wonder if the analog distortion you point out is still at all related to the processing die portion of a DAC, though, because I've heard of goofy audiophile companies who don't like the voodoo some of these Delta Sigmas do actually remove that portion of the chip section and then bypass the "integration" low pass filter. They get shit tons of ultrasonic grunge and boast that they have the analog headroom now to not only deal with the new grunge but any other problem that could occur on it... hoping your preamp or amplifier or at the very least tweeters are going to roll that junk off. Can't say I've agreed with that seeing as what many amps do when they get fed too much over 20khz. Thanks for being patient. While it would be a long shot, maybe I can put in a request to Pioneer to add a -6dB processing mode to clear that up. They don't ever do anything else I ask them too, but not going to hurt.

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    Tech Guru mostapha's Avatar
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    Quote Originally Posted by Reticuli View Post
    Interesting. I wonder if the analog distortion you point out is still at all related to the processing die portion of a DAC, though, because I've heard of goofy audiophile companies who don't like the voodoo some of these Delta Sigmas do actually remove that portion of the chip section and then bypass the "integration" low pass filter. They get shit tons of ultrasonic grunge and boast that they have the analog headroom now to not only deal with the new grunge but any other problem that could occur on it... hoping your preamp or amplifier or at the very least tweeters are going to roll that junk off. Can't say I've agreed with that seeing as what many amps do when they get fed too much over 20khz. Thanks for being patient. While it would be a long shot, maybe I can put in a request to Pioneer to add a -6dB processing mode to clear that up. They don't ever do anything else I ask them too, but not going to hurt.
    Yeah....I wouldn't put too much stock in what self-professed audiophiles say.

    The difference between Delta-Sigma and R2R DACs is so infintesimal....if there even is enough of a difference for a preference, people who listen to insanely expensive speakers in untreated living rooms with all parallel walls are [i]never[i] going to hear it. On top of that, the low-pass filter is essential to how DACs work. It's already supersonic and theoretically can't cause problems. On cheaper converters, higher sample rates (that move that filter even higher) actually can cause more problems. There are sound tests you can find online to see if yours is succeptible. But, as far as the results I've seen...they all are, except a few high-end recording/mastering interfaces....they literally cause more distortion at 96k than 48k.

    The joke is that audiophiles claim to hear the difference between different power cables but can't hear that one of their speakers is out of phase. I think that's a little ridiculous, but after some of the claims I've heard...I wouldn't actually be all that surprised if it happened.

    A couple months ago, I decided I wanted to play my vinyl just to listen to and was asking about discrete phono preamps...the preamp I bought on a whim off amazon was clipping the shit out of my audio interface...which is obviously a gain issue.

    On another forum, asking for recoomendations, I got into a huge debate with some guy who was saying that literally eveyrthing in my signal chain was causing a problem and that I needed $800 cartridges (i have m-447s right now), better cables (wired to the board of my 1200), a new tonearm (stock), a power conditioner (it's actually plugged into a UPS because it was convenient), a cork slipmat (dskreet), and that all still might not stop the problem if the reords were just too hot, which was his ultimate conclusion...that the records I've had for a decade or so all of a sudden were too loud to be played.

    Yeah...there was a "hi/low gain" switch on the board of the preamp. I eventually found and switched that, and eveything sounds fine, though I still haven't figured out what the hell the high setting is for. The exact fix doesn't matter....but when someone says "This thing is outputting about 40dBu hotter than it's supposed to" and your response is to list a who's who of a whole bunch of high end shit that has nothing to do with that problem....it means you're an audiophile in the worst sense of the word.

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    Quote Originally Posted by mostapha View Post
    Yeah....I wouldn't put too much stock in what self-professed audiophiles say.

    The difference between Delta-Sigma and R2R DACs is so infintesimal....if there even is enough of a difference for a preference, people who listen to insanely expensive speakers in untreated living rooms with all parallel walls are [i]never[i] going to hear it. On top of that, the low-pass filter is essential to how DACs work. It's already supersonic and theoretically can't cause problems. On cheaper converters, higher sample rates (that move that filter even higher) actually can cause more problems. There are sound tests you can find online to see if yours is succeptible. But, as far as the results I've seen...they all are, except a few high-end recording/mastering interfaces....they literally cause more distortion at 96k than 48k.

    The joke is that audiophiles claim to hear the difference between different power cables but can't hear that one of their speakers is out of phase. I think that's a little ridiculous, but after some of the claims I've heard...I wouldn't actually be all that surprised if it happened.

    A couple months ago, I decided I wanted to play my vinyl just to listen to and was asking about discrete phono preamps...the preamp I bought on a whim off amazon was clipping the shit out of my audio interface...which is obviously a gain issue.

    On another forum, asking for recoomendations, I got into a huge debate with some guy who was saying that literally eveyrthing in my signal chain was causing a problem and that I needed $800 cartridges (i have m-447s right now), better cables (wired to the board of my 1200), a new tonearm (stock), a power conditioner (it's actually plugged into a UPS because it was convenient), a cork slipmat (dskreet), and that all still might not stop the problem if the reords were just too hot, which was his ultimate conclusion...that the records I've had for a decade or so all of a sudden were too loud to be played.

    Yeah...there was a "hi/low gain" switch on the board of the preamp. I eventually found and switched that, and eveything sounds fine, though I still haven't figured out what the hell the high setting is for. The exact fix doesn't matter....but when someone says "This thing is outputting about 40dBu hotter than it's supposed to" and your response is to list a who's who of a whole bunch of high end shit that has nothing to do with that problem....it means you're an audiophile in the worst sense of the word.
    At one time I could hear exotic stuff. At Alexis Park during CES I would go to the special test demo things off in side rooms, and I was usually the only one who could repeatedly hear freaky small blind changes in our test groups. I think my most notable ones that really freaked the engineers out was Bermester's new (at the time) upsampling system and Theil's crazy powered-dialectric single ended cable. The latter was a cable like a fire hose and a power supply for each cable the size of a car battery. I think it may have been for the Navy or something not available for us to buy. Now I'm moderately hearing impaired from years of DJing, plugging headphones into ports that haven't been turned down, and the random ear infections.

  7. #27
    Tech Guru mostapha's Avatar
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    Quote Originally Posted by Reticuli View Post
    At one time I could hear exotic stuff. At Alexis Park during CES I would go to the special test demo things off in side rooms, and I was usually the only one who could repeatedly hear freaky small blind changes in our test groups. I think my most notable ones that really freaked the engineers out was Bermester's new (at the time) upsampling system and Theil's crazy powered-dialectric single ended cable. The latter was a cable like a fire hose and a power supply for each cable the size of a car battery. I think it may have been for the Navy or something not available for us to buy. Now I'm moderately hearing impaired from years of DJing, plugging headphones into ports that haven't been turned down, and the random ear infections.
    I've heard some interesting tests of audio interfaces. The guys on gearslutz are kind of crazy. There's a lot of unicorn tears style tomfoolery, but people occasionally do loopback tests...basically running outputs to inputs over and over agand and recording it to try and make differences between converters sound more obvious.

    I can hear those. But, the takeaway for me was that it's largely irrelevant unless you're trying to impress people. Once you get past the crap, they're all pretty good unless something is unsable or something has some feature you really like.

    If I were running a pro masterng studio, I'd drop the money on Dangerous or Prism or whatever to impress clients or look cool on an equipment list. But as far as actually hearing it....I'm not completely convinced. It matters a lot less than moving speakers a few inches.

    In a DJ context, it's totally and completely irrelevant given the sound systems and volume levels in most clubs.

    Frankly, even ISM distortion is far from the biggest issue in a DJ context. It just bugs me because it's so easy to avoid.

  8. #28
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    This pissing contest has been entertaining, but has so much TLDR that my brain hurts. Y'all just need to agree to disagree.
    - Equipment - 2X Technics 1200, 2X Audio Technica ATLP1240, 2X XDJ700, 2X XDJ1000 MK2, Denon DNX-1100, Mixars DUO, DJM750 MK2, NI Audio 10, NI Aduio 4, Serato SL3, 4X Shure M44-7, 2X Ortofon Pro S, 2X Numark Groove Tool, Maschine MK3, Samson Carbon 49, Roland SE-02, Novation Launchcontrol, TouchOSC, Nocation Peak, Arturia MiniBrute, Korg Volca Kick, MicroKorg (Classic), NI Komplete Audio 6

  9. #29
    Tech Guru mostapha's Avatar
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    Quote Originally Posted by the_bastet View Post
    This pissing contest has been entertaining, but has so much TLDR that my brain hurts. Y'all just need to agree to disagree.
    We actually don't. We were talking about different things. It took a bit to realize that.

  10. #30
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    I asked for a -6dB internal digital pad option on the CDJs. Pulse says that the CDJ analog out already has some type of (I presume digital) headroom prior to the DAC stage to prevent intersample distortion on their DACs. Could possibly be the case, though as I've mentioned, the CDJs are bit-perfect from the SPDIF at zero pitch, so it'd have to be specific to the bit stream going to the DAC. When I'm over the flu and this week's school work, I'll try and do some of the tests from the reddit thread on intersample distortion I found last night. Some guy on there named Arve has come up with a novel means to simply figure out if a device has the issue or not. Might not be an issue on the CDJs, but it also wouldn't be the first time Pioneer pretends everything is fine. I agree it's a minor issue, but no harm checking, especially since this solution in the CDJ line firmware would be so easy.

    https://www.reddit.com/r/audiophile/...ctual_problem/
    Last edited by Reticuli; 02-01-2018 at 04:35 PM.

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