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External Clocking - is it all that?

  • 27-05-2009 5:36pm
    #1
    Registered Users, Registered Users 2 Posts: 352 ✭✭


    woodsdenis wrote: »
    If I was to give a piece of advice as to how to improve your the sound of your DAW I would say get an external clock first.
    I've heard a few different schools of thought on this. Dan Lavry (who makes some amazing converters) says:

    "As a rule Internal clock yields less jitter, so use the internal clock when ever possible. There are times when one must use external clocks (such as the case of many channels) When doing so, the jitter goes up and the sound quality suffers a bit. That is a compromise we have to live with. Just do not fall into the false hype claiming that external clock improves your sound."

    He also talked on Gearslutz (I'm trying to find the exact quote) about how the clocking part of the audio device is the simplest part to get right, and the actual converters are the more complicated and expensive part, and if you buy a great converter it should already have a decent clock in it.

    This would seem to suggest that instead of buying an external world clock, a person wanting to improve the sound when working ITB should just get a better converter.

    That said, I've heard other people say that when they use the Apogee Big Ben to clock their Pro Tools converters that it improves the sound.

    I'm an amateur home producer myself (who spends more money than is sensible on audio equipment) and if I had the choice I'd get a proper converter before going for an external clock. However more research should be done into each choice.

    As for the ITB vs OTB argument, that's one of those "vinyl vs CDs" ones that will rage to the end of time. I own a Mackie 1402 and a Motu 828 MKII (yes, this converter is currently the weakest link in my studio!) and when I stick everything into the Mackie it sounds a bit better than the Motu. They're both low end pieces of gear though.


«134

Comments

  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    splitrmx wrote: »
    if you buy a great converter it should already have a decent clock in it.

    That's true, it should. However some don't.

    Also most pro-setups would be multi chan so a distributed master clock would be the norm. Some outboard equipment also needs word-clock - so NOT distributing clock isn't an option, even if it is desirable in other aspects.

    Of all the things in a studio guys don't want to buy a €1400 box that doesn't make any sound is one!

    However, on plugging them up and making them go in a clients studio they rarely return to me.


  • Registered Users, Registered Users 2 Posts: 352 ✭✭splitrmx


    PaulBrewer wrote: »
    That's true, it should. However some don't.

    Also most pro-setups would be multi chan so a distributed master clock would be the norm. Some outboard equipment also needs word-clock - so NOT distributing clock isn't an option, even if it is desirable in other aspects
    Wouldn't most good converters output world clock that could be chained to multiple devices that needed it using those bnc splitter connectors?


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    splitrmx wrote: »
    Wouldn't most good converters output world clock that could be chained to multiple devices that needed it using those bnc splitter connectors?

    Looping word clock is considered a no-no. A master clock will have multiple outs i.e. one for each unit.


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Here we go again... all current converters use a PLL (Phase Locked Loop), which basically means that they re clock, so an external clock makes no difference whatsoever. Also sometimes referred to as "jitter immune". The PT HD boxes have a PLL, for example.

    Apogee are trying to sell you a Big Ben, so they go on about how important clocking is, Dan Lavry's info just makes one more aware of what to look for, and is not based on trying to sell you something (his advice applies to all converters).

    Five years or so ago, external clocking made sense, but not now.

    As for looping clock, it will work perfectly as long as you know where the termination is, and you're using 75ohm cable. Problem is most boxes have the termination built in, so unless you open them up and do a little surgery, you'll have feedback all over the shop.


  • Registered Users, Registered Users 2 Posts: 6,401 ✭✭✭jtsuited


    epic clocking war begins here.


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  • Hosted Moderators Posts: 8,344 ✭✭✭fitz


    Split this off from the "Analogue Desks" thread so a proper clocking discussion can rage on in its own little space. Have at it gentlemen.


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    splitrmx wrote: »
    I've heard a few different schools of thought on this. Dan Lavry (who makes some amazing converters) says:

    "As a rule Internal clock yields less jitter, so use the internal clock when ever possible. There are times when one must use external clocks (such as the case of many channels) When doing so, the jitter goes up and the sound quality suffers a bit. That is a compromise we have to live with. Just do not fall into the false hype claiming that external clock improves your sound."

    He also talked on Gearslutz (I'm trying to find the exact quote) about how the clocking part of the audio device is the simplest part to get right, and the actual converters are the more complicated and expensive part, and if you buy a great converter it should already have a decent clock in it.

    This would seem to suggest that instead of buying an external world clock, a person wanting to improve the sound when working ITB should just get a better converter.

    That said, I've heard other people say that when they use the Apogee Big Ben to clock their Pro Tools converters that it improves the sound.

    I'm an amateur home producer myself (who spends more money than is sensible on audio equipment) and if I had the choice I'd get a proper converter before going for an external clock. However more research should be done into each choice.

    As for the ITB vs OTB argument, that's one of those "vinyl vs CDs" ones that will rage to the end of time. I own a Mackie 1402 and a Motu 828 MKII (yes, this converter is currently the weakest link in my studio!) and when I stick everything into the Mackie it sounds a bit better than the Motu. They're both low end pieces of gear though.

    My 2 cents on this. Using an External clock on any Protools system I have heard improves the sound, no question. Do Protools/MOTU interfaces have Lavry grade converters? NO. There is the answer. Dan Lavry is probably right in that if you have his converters there is no need. Do you know how much they cost?

    More importantly though is that if you are running multiple Digital devices
    you definitely need a Master Word Clock clocking/running everything. This does not apply to PT HD systems where they loop through. I am talking about DAW/Digital Desk/FX Units/Video/Analogue Tape sync etc.

    My comments were based on whether an External Clock or a Summing box
    should be your first purchase if you had a choice.. I would still go for the External clock.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    woodsdenis wrote: »
    Using an External clock on any Protools system I have heard improves the sound, no question.

    That has been my and my customer's experience.

    If anyone wants to try a Big Ben for themselves let me know.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Here we go again... all current converters use a PLL (Phase Locked Loop), which basically means that they re clock, so an external clock makes no difference whatsoever. Also sometimes referred to as "jitter immune". The PT HD boxes have a PLL, for example.

    Apogee are trying to sell you a Big Ben, so they go on about how important clocking is, Dan Lavry's info just makes one more aware of what to look for, and is not based on trying to sell you something (his advice applies to all converters).

    Five years or so ago, external clocking made sense, but not now.

    As for looping clock, it will work perfectly as long as you know where the termination is, and you're using 75ohm cable. Problem is most boxes have the termination built in, so unless you open them up and do a little surgery, you'll have feedback all over the shop.

    If it had ' no difference whatsoever' it would sound the same ? That clearly isn't the case.


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Has anyone done a blind AB test in a treated room, and decided that the external clock is better? If the answer is yes, then I'd have to agree. However, all I've ever read is conjecture, or non blind testing. Fact is, the way the converter works means that external clock ends up being synchronised to the internal clock with 100% accuracy, because it's a Phase locked loop. So the difference heard with the external clock is caused by subjectivity.

    I contend that if the subjective element is removed, as with a blind AB test, then no difference will be heard.

    Actually Paul, I'm tempted to borrow a Big Ben from you to set up my own blind AB test. I might get a few other guys on board, a friend has a super room with a HD2 rig. Would you be willing?


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  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Has anyone done a blind AB test in a treated room, and decided that the external clock is better? If the answer is yes, then I'd have to agree. However, all I've ever read is conjecture, or non blind testing. Fact is, the way the converter works means that external clock ends up being synchronised to the internal clock with 100% accuracy, because it's a Phase locked loop. So the difference heard with the external clock is caused by subjectivity.

    I contend that if the subjective element is removed, as with a blind AB test, then no difference will be heard.

    Actually Paul, I'm tempted to borrow a Big Ben from you to set up my own blind AB test. I might get a few other guys on board, a friend has a super room with a HD2 rig. Would you be willing?



    Of course! You're welcome to a unit.

    What room and what converters?

    Woodsdenis' background would be at the Highest End of recording for quite a while too so his is one opinion I would listen to. (if not always agree!)

    I only have a very slight understanding of the science behind it.

    Most of the guys who have purchased them would be more experienced chaps who -
    1. Are looking for incremental improvement
    2. Have no particular interest in the science behind it.... merely that it's 'better' in their opinion.

    The Digi 192 seems to be one unit that raises it's game with the Big Ben as does the SSL Alpha.

    Of note to is the fact one must record AND mix to gain maximum benefit (A2D + D2A) of using a clock.


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Cool, I just emailed a few of the guys around here, we might set up a test. The room is here, it's 192s:
    http://www.soundsound.ie/index.php?article=gear
    PS that's an old pic, it actually sounds better now :)

    For me, opinion is not science... but that's just my opinion ;)
    PaulBrewer wrote: »
    The Digi 192 seems to be one unit that raises it's game with the Big Ben.

    Of note to is the fact one must record AND mix to gain maximum benefit (A2D + D2A) of using a clock.
    RE the 192: is that at 44.1k, or 192kHz?

    Your second point has me concerned. If you have a jittery clock, then the difference becomes more apparent with each conversion! Maybe jitter sounds like "better" to some ears? A bit like harmonic distortion does?


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    madtheory wrote: »
    Has anyone done a blind AB test in a treated room, and decided that the external clock is better? If the answer is yes, then I'd have to agree. However, all I've ever read is conjecture, or non blind testing. Fact is, the way the converter works means that external clock ends up being synchronised to the internal clock with 100% accuracy, because it's a Phase locked loop. So the difference heard with the external clock is caused by subjectivity.

    I contend that if the subjective element is removed, as with a blind AB test, then no difference will be heard.

    Actually Paul, I'm tempted to borrow a Big Ben from you to set up my own blind AB test. I might get a few other guys on board, a friend has a super room with a HD2 rig. Would you be willing?

    Even try using a Digi Sync IO and you will hear the difference. Yes I have heard the difference in a treated control room.

    I think you are getting confused with the way that digi syncs more than one of its interfaces. If you are using an external clock to clock a 192 using word clock where is the loop ? There is only one master. We are not talking about Digi loop sync we are talking about Word clock.

    Word Clock
    Many professional digital audio products—including
    open-reel multitrack tape recorders, digital
    mixing consoles, and the Tascam DA-88
    modular digital multitrack—have Word Clock
    (1x sample rate) connectors.
    Word Clock allows the DA-88 (and other Word
    Clock-compatible devices) to send or receive external
    clock information which controls the
    sample rate, which in turn (where applicable)
    controls the play and record speed.
    Using just Word Clock, it is possible to create a
    “chain” of digital devices in your studio by picking
    one source as the Word Clock master, and
    configuring other sources as Word Clock slaves

    This is from the Digi Sync IO manual. Granted what we are doing here is
    for example controlling the sample rate of external devices from a master.
    There is no loop here, one master clock controlling the sample rate/speed
    of Protools against an analogue tape machine for example.

    What we are discussing is the benifits of having a Master Word Clock for one or all of your digital devices. When using it on a Protools HD3 rig only there is a difference. There are many different brands Apogee/Nanosync/Aardvark. Try it out, if you dont notice a difference ignore this.:D


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    woodsdenis wrote: »
    If you are using an external clock to clock a 192 using word clock where is the loop ?
    It's not that sort of loop, it's a PLL. This is a way of ensuring that the master oscillator (the one controlling the sampling rate) never drifts. It's inside the converter, part of the circuit. I'm not talking about Digi's way of syncing. PLL is a very common clock design for digital circuits, a.k.a. jitter immune. I think Benchmark were the first to trumpet it, although the concept itself is probably thirty years old.

    And yes, I am going to try out the Big Ben :)


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Cool, I just emailed a few of the guys around here, we might set up a test.

    RE the 192: is that at 44.1k, or 192kHz?

    Your second point has me concerned. If you have a jittery clock, then the difference becomes more apparent with each conversion! Maybe jitter sounds like "better" to some ears? A bit like harmonic distortion does?

    Across various sample frequencies as I recall.

    Well, as I say I'm no expert.

    If the unit's own clock has more jitter that being clocked externally (even though there may be issues with that process as has been suggested) then my thinking was that if you're recording with less overall jitter with clocking externally (if indeed that is the case) so too are you playing back with less jitter.

    That, of course, is presuming that Less Jitter does , in fact, sound better!

    What room are you suggesting? I know very few 'good' rooms around.


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    PaulBrewer wrote: »
    What room are you suggesting? I know very few 'good' rooms around.
    I edited my post, while you were editing, see previously for link...


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    madtheory wrote: »
    It's not that sort of loop, it's a PLL. This is a way of ensuring that the master oscillator (the one controlling the sampling rate) never drifts. It's inside the converter, part of the circuit. I'm not talking about Digi's way of syncing. PLL is a very common clock design for digital circuits, a.k.a. jitter immune. I think Benchmark were the first to trumpet it, although the concept itself is probably thirty years old.

    And yes, I am going to try out the Big Ben :)

    Fair enough madtheory but in the real world I am using an interface which isn't jitter immune therefore using a reliable clock improves this.

    What audio interfaces for DAWs us this PLL system ?


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    Ah DanDan's room ...... ex of this Parish! Very ex ;)

    Cool, just let me know when you need it. Our demo one is out at the moment but should be back in a week or two.

    To reiterate the point I think the fairest way is to record AND play back using the clock.

    I know in one instance we played back a mix that was done on 192s with a Big Ben and everyone agreed that it now sounded like there was a bunch of frequencies around the 5k area quite prominent.

    The mix engineer (Ciaran Byrne in Cauldron) then piped up that that's what he'd been adding to his 'clockless' mix ! Had he not been around that info might have gone unnoticed skewing the outcome.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    woodsdenis wrote: »
    Fair enough madtheory but in the real world I am using an interface which isn't jitter immune therefore using a reliable clock improves this.

    What audio interfaces for DAWs us this PLL system ?

    I think it's a very interesting area and as Madtheory has alluded to perhaps it's the making more jitter that sounds better !

    I personally don't know - however I'd say we've sold maybe a dozen Big Bens and of that dozen about 8 of those are pure music guys i.e. non techy in anyway so it does seem to be a very music driven decision.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    I've just dropped a line to Apogee and SSL to see have they any thoughts on the subject for us.


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  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    I dont know of anyone who thinks that jitter is a good thing.

    However, intrigued by madtheorys post I googled PLL audio and the only thing that came up in about a minute of searching was a section from the Bob Katz book on mastering, who had been externally clocking all his equipment, until he bought a PLL convertor. I am sure they sound fantastic and don't need to be externally clocked but I suspect they cost a great deal more than what the majority of us are using.

    Bob Katz's opinion is that all Firewire interfaces should use external clocks.
    "Let Firewire carry the Audio not the clock"

    I still would like to know what brands of Audio interfaces use this type of PPL converter.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    woodsdenis wrote: »
    I dont know of anyone who thinks that jitter is a good thing.

    However, intrigued by madtheorys post I googled PLL audio and the only thing that came up in about a minute of searching was a section from the Bob Katz book on mastering, who had been externally clocking all his equipment, until he bought a PLL convertor. I am sure they sound fantastic and don't need to be externally clocked but I suspect they cost a great deal more than what the majority of us are using.

    Bob Katz's opinion is that all Firewire interfaces should use external clocks.
    "Let Firewire carry the Audio not the clock"

    I still would like to know what brands of Audio interfaces use this type of PPL converter.

    Phase Locked Loop it stands for as I recall. It's not a new thing, used in radio tuners etc I believe.

    http://en.wikipedia.org/wiki/Phase-locked_loop


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    Actually reading the PLL wiki the implication is that it references to a 'clock standard' i.e. a wordclock master in our case.

    Isn't the implication then that the more stable and accurate the reference so to the PLL circuit and hence Jitter?

    This would imply jitter is directly related to the master clock's accuracy or am I missing something?


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Ya, but the master is always the internal oscillator.
    woodsdenis wrote: »
    What audio interfaces for DAWs us this PLL system ?
    All the Digi HD stuff :) And pretty much any converter built since around 2004, give or take.

    I can't keep up with the rate of posting and editing! :)

    Bob Katz's book is a little out of date on the issue, I haven't seen the revised edition so I dunno what he says about it in that. Given the omnipresence of PLLs, I'd say that no current firewire box takes its clock ref off the firewire bus.

    Note that Dan Lavry has had some very heated arguments with Apogee folk online, about their claims for their cables and their clocks. Funnily enough, it was always Mr.Lavry that had the science argument, and Apogee the subjective line...


  • Registered Users, Registered Users 2 Posts: 440 ✭✭teamdresch


    Hehe, clocky/jittery topics are always fun.

    I finally picked up a wordclock cable to hook up two pieces of gear instead of clocking them across ADAT.
    I'm expecting to convince myself that I can hear a difference :D


  • Registered Users, Registered Users 2 Posts: 352 ✭✭splitrmx


    PaulBrewer wrote: »
    I've just dropped a line to Apogee and SSL to see have they any thoughts on the subject for us.
    Gee I wonder what Apogee will have to say about the subject of whether external clocks improve things or not! :)


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Ya, but the master is always the internal oscillator.


    So it doesn't ever reference to an external one? So does that imply in our situation that PLL isn't in use if one uses an external clock source?


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Re: what Apogee think- see my previous edited post, Lavry v Apogee.
    PaulBrewer wrote: »
    So it doesn't ever reference to an external one? So does that imply in our situation that PLL isn't in use if one uses an external clock source?
    The PLL effectively re clocks whatever you send in.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    splitrmx wrote: »
    Gee I wonder what Apogee will have to say about the subject of whether external clocks improve things or not! :)

    Indeed, I hear ya barking Big Dog !

    Obviously they may be 'pro' clocking however it's the science behind it they make have points to make on.


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  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    PaulBrewer wrote: »
    Indeed, I hear ya barking Big Dog !

    Obviously they may be 'pro' clocking however it's the science behind it they make have points to make on.
    Note that Dan Lavry has had some very heated arguments with Apogee folk online, about their claims for their cables and their clocks. Funnily enough, it was always Mr.Lavry that had the science argument, and Apogee the subjective line...

    I think it's also worth noting that jitter distortion is at least as quiet, and probably quieter than, 16 bit dither. So in most studios, there are much bigger issues than clocking...


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Re: what Apogee think- see my previous edited post, Lavry v Apogee.

    The PLL effectively re clocks whatever you send in.

    But if the clock it re-clocks to has less jitter does that get lost in the process? Is that the central point of your argument?


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    madtheory wrote: »
    Ya, but the master is always the internal oscillator.


    All the Digi HD stuff :) And pretty much any converter built since around 2004, give or take.

    I can't keep up with the rate of posting and editing! :)

    Bob Katz's book is a little out of date on the issue, I haven't seen the revised edition so I dunno what he says about it in that. Given the omnipresence of PLLs, I'd say that no current firewire box takes its clock ref off the firewire bus.

    Note that Dan Lavry has had some very heated arguments with Apogee folk online, about their claims for their cables and their clocks. Funnily enough, it was always Mr.Lavry that had the science argument, and Apogee the subjective line...

    Jesus we are posting at a ridiculous rate:D. If you are correct and that all HD stuff has these converters, then you will have an interesting day when you hook up an external clock to this. According to your theory there should be no difference, correct? We'll wait and see, for you to post back with your opinions.

    I agree the Bob Katz book is probably outdated now with the rate of technology.

    I am not a techie but your opinion seems to suggest that all converters in audio equipment these days more or less is jitter free. I'd love if that was the case.:p

    Could you post a link to the Dan Lavry/Apogee debate


  • Registered Users, Registered Users 2 Posts: 440 ✭✭teamdresch


    woodsdenis wrote: »
    I am not a techie but your opinion seems to suggest that all converters in audio equipment these days more or less is jitter free. I'd love if that was the case.:p

    I believe the line is that a converter should have less jitter when clocked internally than when an external clock is used, not that PLL means no jitter.


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    teamdresch wrote: »
    I believe the line is that a converter should have less jitter when clocked internally than when an external clock is used, not that PLL means no jitter.

    Good point. I still hold to my own experience of Protools HD, which according
    to madtheory has PLL converters, It sounds markedly better when clocked to an external clock.

    All of this depends on the quality of your clock source and that if the external one is more solid than the internal one it surely must be better.

    We await madtheory's test.:eek:


  • Registered Users, Registered Users 2 Posts: 440 ✭✭teamdresch


    teamdresch wrote: »
    I believe the line is that a converter should have less jitter when clocked internally than when an external clock is used, not that PLL means no jitter.

    The Dan Lavry line, that is.
    I have no real opinion on the subject :)


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  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    Christ! The posting rate is phenomenal.
    PaulBrewer wrote: »
    But if the clock it re-clocks to has less jitter does that get lost in the process? Is that the central point of your argument?
    Pretty much, but with PLL the rule is, internal is always better. I'll dig out links to Lavry's white paper, and the Apogee debacle...

    Paul, can you email me when your demo Big Ben is back in the shop?


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    woodsdenis wrote: »
    Could you post a link to the Dan Lavry/Apogee debate
    I think it's inside this epic thread:
    http://recforums.prosoundweb.com/index.php/t/14324/0/

    Bob Katz and Lavry both make basically the same point I'm making, but with more technical know how :)

    Lavry actually designed the first Apogee product, upon which they made their name- the filter upgrades for the Mitsubishi 20 bit recorders. He also worked for Nasa, and designed the converters for the NED Synclavier.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Christ! The posting rate is phenomenal.

    Pretty much, but with PLL the rule is, internal is always better. I'll dig out links to Lavry's white paper, and the Apogee debacle...

    Paul, can you email me when your demo Big Ben is back in the shop?

    Interesting.

    If my understanding of the science presented here is correct, as WD says there should be NO perceivable sonic difference with or without an external wordclock.

    Can we agree that if there's an perceivable repeatable difference in sound then the science itself isn't explaining what is happening?


    Is that what we're talking about?

    We'll leave the 'Better' argument for another day !


  • Registered Users, Registered Users 2 Posts: 535 ✭✭✭woodsdenis


    madtheory wrote: »
    I think it's inside this epic thread:
    http://recforums.prosoundweb.com/index.php/t/14324/0/

    Bob Katz and Lavry both make basically the same point I'm making, but with more technical know how :)

    Lavry actually designed the first Apogee product, upon which they made their name- the filter upgrades for the Mitsubishi 20 bit recorders. He also worked for Nasa, and designed the converters for the NED Synclavier.

    I think I read this over a couple of days. As Paul says my opinion is that in PT HD it sounds better/different with an external clock. Other systems will differ of course.

    As Bob Katz says in the thread

    If you hear differences when you change clocks "controlling" your converters, then you have a defective converter design! A well-designed converter should contain internal phase locked loops whose performance reduces any incoming jitter artifacts to inaudibility. An external clock is a bandaid for a "cure" which can only be done properly within a good converter design. In fact, any converter which does not perform equally as good or BETTER on internal clock than external is also defective.

    I am totally prepared to accept aswell that the converters in PTHD are not up to scratch.:o

    Thanks for the info madtheory.


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    woodsdenis wrote: »

    I am totally prepared to accept aswell that the converters in PTHD are not up to scratch.:o
    Ya, that's a distinct possibility :) Blind AB test with a few heads will sort this out I think...


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  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    Ya, that's a distinct possibility :) Blind AB test with a few heads will sort this out I think...

    We already have :pac:


  • Registered Users, Registered Users 2 Posts: 1,892 ✭✭✭madtheory


    SO it seems that a genuine blind AB test is impossible, which is why this is always a contentious point. Dandan has come up with an interesting workaround, so we'll try it and see what the result is.

    Emailing the other lads, they're all of the view that external clock is BS :D


  • Registered Users, Registered Users 2 Posts: 352 ✭✭splitrmx


    woodsdenis wrote: »
    Dan Lavry is probably right in that if you have his converters there is no need. Do you know how much they cost?
    Found some EU prices here: http://www.truetrackrec.de/LavryOnlineEU.htm
    You can get an 8 channel AD for 3600 Euro. Apogee's AD-16X gives you 16 channels of AD for 3199 so yes, the Lavry is more expensive for what you get!

    I'm not trying to debase Apogee at all, they make amazing converters, I was just posting up the Lavry quotes as an interesting debating point. I was actually considering getting some an Apogee converter as this Motu 828 I have has got to go! :o

    (P.S. I don't work for any music company or retailer, I'm just a gear nerd with access to the internet in work!)


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    madtheory wrote: »
    SO it seems that a genuine blind AB test is impossible, which is why this is always a contentious point. Dandan has come up with an interesting workaround, so we'll try it and see what the result is.

    Emailing the other lads, they're all of the view that external clock is BS :D

    Who are the other lads?


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    splitrmx wrote: »
    Found some EU prices here: http://www.truetrackrec.de/LavryOnlineEU.htm
    You can get an 8 channel AD for 3600 Euro. Apogee's AD-16X gives you 16 channels of AD for 3199 so yes, the Lavry is more expensive for what you get!

    I'm not trying to debase Apogee at all, they make amazing converters, I was just posting up the Lavry quotes as an interesting debating point. I was actually considering getting some an Apogee converter as this Motu 828 I have has got to go! :o

    (P.S. I don't work for any music company or retailer, I'm just a gear nerd with access to the internet in work!)

    Lavry always had a great name.

    Cenzo Townshend, who makes great sounding mixes to my ears, was running the output of the SSL in Olympic into a Lavry for his Master mix.

    http://www.recordproduction.com/townhouse_studios_cenzo_townshen.htm


  • Registered Users, Registered Users 2 Posts: 1,472 ✭✭✭Rockshamrover


    Why would professionals buy a product if it's not needed or doesn't add something to your product? Especially given the cost.

    I'd be very surprised if the test results proved the pros wrong.

    But it will be interesting to see the results none the less.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    Why would professionals buy a product if it's not needed or doesn't add something to your product? Especially given the cost.

    I'd be very surprised if the test results proved the pros wrong.

    But it will be interesting to see the results none the less.

    Well you may ask - however the fact they do doesn't mean , by itself, that it's better.

    Anyways, MadTheory has put himself under pressure to prove his point now .... if anyone of his party can hear any difference with the Big Ben he owes me big time. ;)


  • Registered Users, Registered Users 2 Posts: 1,472 ✭✭✭Rockshamrover


    PaulBrewer wrote: »
    Well you may ask - however the fact they do doesn't mean , by itself, that it's better.

    Anyways, MadTheory has put himself under pressure to prove his point now .... if anyone of his party can hear any difference with the Big Ben he owes me big time. ;)

    Very true, Flies and Sh1t3, suddenly springs to mind.


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    A quote from Dan Lavry from Denis' forum above ....


    " It is true that the PLL does better when fed a less jittery clock "


  • Registered Users, Registered Users 2 Posts: 7,790 ✭✭✭PaulBrewer


    .... but he also says

    "I am no fan of distribution amplifiers either. You can not beat:
    Driver to point A (with a BNC T), than to point B (with BNC T)… at the end the BNC T is terminated with the proper line impedance (if the cable is 75Ohm, so is the termination). It is a cost effective solution that yields the best results."


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