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ADCs, what is important?

Discussion in 'Pro Audio Equipment' started by kmetal, Jan 17, 2013.

  1. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    i was talking shop w/ a co-worker about converters, and he was saying that there are only a few chips out there being made, and what your actually ing when you buy better converters is superior clocking. is this true? thanx.
     
  2. DonnyThompson

    DonnyThompson Distinguished Member

    I've heard the same thing, K. Don't know the answer, but yeah, I've talked to cats who said the same thing to me.
     
  3. Boswell

    Boswell Moderator Distinguished Member

    The answer is to be found one step back from that. What you have to compare is the overall design of the equipment. It's no good saying that a well-regarded piece of gear uses the same chip as a cheap far-eastern import and therefore must sound the same. Every bit of an equipment's design has an effect on its performance, however small, and top designers go to great lengths to get as many as they can of these small effects working in the same direction within the product budget. In the right hands, standard chips can sound stellar; in the wrong hands the same chips can sound like mud.

    I have done contract designs for a number of medium to high-end companies, and it's very surprising how different the attitudes are to the concept of overall design. I have been asked why I bothered about a particular detail when it would be cheaper to leave it out, and sometimes I have had to say "I can't demonstrate it to you, but I know it makes a difference." The companies that then remove that detail in manufacture to save the pennies I do not accept work from again.
     
  4. DonnyThompson

    DonnyThompson Distinguished Member

    So then, what you're saying is in support of the old saying that a chain is only as strong as its weakest link.
     
  5. Boswell

    Boswell Moderator Distinguished Member

    I don't think that applies directly in this case. A good design can often tolerate some weaker links that may be in there for cost purposes ("value engineering") without greatly compromising their performance or specifications. However, the very top designs have no discernible weak links, and, often as a consequence, have no price limit.
     
  6. Davedog

    Davedog Distinguished Member

    I'm gonna chime in here for just a moment because I experienced this recently.

    Of course the build quality throughout the device will be the key to it sounding better than a bag of the very same components assembled in a cave by blind monkeys...

    To the 'clocking' thing.

    I just finished a record that was recorded and mixed here at The DroolinDogg Ranch. Usually i go outside and mix at another facility with 'more stuff'. Not this time. Understand that my conversion isnt up to par with most of you. Really, it has been the last point on my list to upgrade because things simply sounded 'good enough' to my ear for release and playback on most earbud and iPod systems as well as computer stations and car stereos......isnt that where we deliver most of the goods too??
    Anyway, I had a younger fellow come in and edit some tracks for me. (This IS a skill I ABSOLUTELY MUST HAVE!!!!) He was fast and accurate and actually graduated from a well known recording school....His take was all about the clocking at mix. I have a Digi 003 factory that I use for my fingers-on automation primarily and thus am stuck with the Digi converters and clock........but not anymore. I also have an Alesis HD24 that I use as my ADAT conversion when I'm running a lot of tracks at tracking. In doing this it makes the HD24 the master clock and I used it almost exclusively throughout the tracking stages so the only analog through the Digi converters happened at basic tracks BUT ALWAYS with the HD24 as the clock.

    So he tells me that simply having the ADAT pipe hooked up at mixdown and selecting the ADAt as my external clock makes this the master clock no matter what I'm doing in PT. The difference is audible immediately. It happens that the clock in the HD24 is 'better' in some way that my aged mind can't conceive but is willing to acknowledge.


    So next is a clock. Before conversion. Black Lion maybe? Others I know will swear by the really really cheap ADA8000 conversions this company does to that coverter and I'm starting to believe. Its true that only a few companies make chips used by the companies building conversion these days.And of these only a small number take this past a certain level of development.

    I dont know why......but I do know that the clocking makes a big difference....especially when you are using cheap crap like I have here.

    well.....its not ALL cheap.+
     
  7. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    hmmm intersting stuff as always fellas. even before i read dave's post, which re-inforced my next thought. lol, i think every few days.

    very very hypothetically this would be a question of what makes more a drastic effect, given all other parameters the same. conversion or clocking.?

    like if say there was a 1-5 scale for both, say a new design employed a level 4 all-round, but the suits said hey we need to save some money, lets go w/ a level 3 converter, or clocking (thing) (i'm very rudimentary in my understanding of circuits pretty much noob level so thanx for bearing w/ me). which level drop would preserve the overall quality level if it was between only those two components.?

    interested in more depth of the topic. more than just yes or no, some basic explanation of why would really help me start wrapping my head around. also as sample rates and bit rates are becoming higher, how does that relate to conversion/clocking?

    cheap, lol, what about audio is? lol i wish i was genius enough to be able to sell chunks of mahogany for 2500. ya know ber-copy-inger really does get it rite once in a while, def a try before ya buy company, but i don't don't their ability to get by patent issues. cheers all!
     
  8. Boswell

    Boswell Moderator Distinguished Member

    They are both important. The most expensive ADC in the world will sound bad if you force it to run on a rubbish clock. Looked at from the other side, the highest quality, most stable clock you can generate will allow a poor ADC to run to the best of its ability, but it won't turn it into a good ADC.

    I don't think you can judge them by levels 1 - 5, as you have to look at the wider picture, including the purpose of the recording. Deficiencies introduced by lower quality clocking may be deemed acceptable for recording MP3s for YouTube, but might sound horrible in the studio.

    There is a qualification to all this. Some of the higher-quality interfaces have clock flywheel circuits that can straighten out shortcomings in external clocks. Even boxes like the RME FireFace800 have sophisticated clock-regeneration circuits that result in there being little difference between moderate and high-quality external clocks. So I suppose one answer to your question is that if you go for the right type of ADC and DAC unit, you do not have to spend huge amounts on high-quality external clocks, and a simple box that keeps everything in sync could be all that is needed until the next spending round.
     
  9. MrEase

    MrEase Active Member

    I covered a lot of stuff regarding clocks in the "What is clock jitter?" thread in the DIY pro audio forum which is relevant here. Particularly where external clocks are used or soundcards are slaved to others. In that thread I mentioned that for a given A-D chip, we know, from the datasheet, what the best possible performance is going to be. Once we start putting this chip on a soundcard PCB all we can do is detract from this optimum. We certainly can't improve on it as the chip makers spend a small fortune on getting the last drop of performance for their datasheets!

    I am firmly with Boswell here, yes the clock is important but so too are the input conditioning amplifier/buffer (we cannot just connect a line input straight to the chip), internally generated power supplies etc. Poor design of any one item can throw away performance hand over fist and no circuit element should be the weakest link. This is all down to the design, both electrical and mechanical (good PCB layout is crucial).

    In the past, some clock circuits have not received the attention they deserved in the design process (my gear included) and we end up with cautionary tales about clocks such as that given by Davedog. Certainly it is important to understand how clocks can affect our converters but, even if we may witness some stellar improvement on a particular set up by switching clocks around, this wisdom may well not hold true with other equipment.

    This formed a large part of what I tried to suggest in the other thread as I believe a good understanding is more important than anecdotal evidence which may not hold up to closer scrutiny. Anecdotal evidence also has a nasty habit of "going viral" and being taken as gospel.

    So yes, we can all probably come up with some surprises (as I did with my own set up in the other thread) and this should not cloud the facts but be used wisely within the set up that created the surprise.
     
  10. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    interesting. i'm not in the market right now, was just kinda trying to expand my knowledge. good some good starting places. thanx!!!!
     
  11. RemyRAD

    RemyRAD Guest

    Dave, I hope you realize that the clock in the ALESIS HD 24 is only good at 48 kHz/96 kHz. It's not accurate at 44.1 kHz as it is a fudge, a kludge. And so the HD 24 needs an external clock for accuracy at 44.1 kHz and throws everything out of tune on other systems. Oy vey. And so, I can clock my HD 24 and 44.1 kHz using my MOTU 2408 as the master clock for 44.1 kHz. I have no budget currently for a better clock. In a similar but unrelated scenario... we all know that George Massenburg's ITI/SONTEC/GML, is some of the finest equipment available in the world today. And on his compressor/limiters, he was using DBX VCA's. And we all know that VCA's mush up sound. But his stuff is crystal clear overall and where the VCA doesn't do undue damage but it's still a VCA. And nobody in their right minds should want a VCA in their signal path unless they are George Massenburg, Bob Clearmountain, Elliott Scheiner and all the rest that they too use them. And that just craps up your sound unless you like that crappy sound which everybody likes. And where folks like Chris might prefer his optical tube limiter folks like George are going the VCA route. And that's not a good route. So what's that tell ya? That grunge is good... that's what.
    I think I need a shower?
    Mx. Remy Ann David
     
  12. Davedog

    Davedog Distinguished Member

    I actually knew that. All my tracks with it are at 24/48. My POINT being that clocking, is an important part of relative clarity in digital no matter the chipset or the quality of the converter build. My example, using less than normally desirable devices and achieving quality results, is proof to me. I will add a quality clock next and then converters. If I can afford it, it will be Burl.
     
  13. Davedog

    Davedog Distinguished Member

    May I assume that these tales will include the ones pointing at the differences in performance for a certain LE based converter set when used with a quality external clocking device? I've known guys with studios that still swear by a BigBen on a Digi LE system despite other limitations etc etc.....

    I , myself, while not trying to be anecdotal or viral, nor does spreading anything unsubstantiated thrill me in the least, have simply discovered another segment to my digital education, whether this is true in a technical sense or not. Something is definately a difference maker here and when turning it on and off in side by side comparisons lend images perfectly audible, I gotta say, okay then....on we go.
     
  14. MrEase

    MrEase Active Member

    Hi Davedog,

    I do not have any direct experience with the Digi LE and BigBen but from what I have heard from those with experience of them, it certainly does make a notable improvement. This indicates to me that the internal clocks on the Digi LE are poor although I cannot verify that.

    I think the general point I am making is that any older equipment (that many of us have no immediate prospect of upgrading) will be far more likely to be improved by a good clock. From my experience, older gear is more likely to have had inadequate attention to the clocks. Hence we see so many aftermarket mods being offered.

    The current trend is for new gear to herald their wonderful new and improved clocks. This is great marketing as so many have had bad experiences previously. Once bitten, twice shy as they say. I would certainly say that well designed modern gear should not show the same marked (if any) differences when used with external clocks.

    P.S. My comments about anecdotal evidence were not directed at you per se but were meant as a general comment on the nature of the internet. This is why I did not and would not question your very real experience. I'm sure we all get frustrated when we see total rubbish presented as "fact" on various sites. I don't bother responding on such sites as all you can expect is a load of vitriolic bunkum in return. That's why I like it here and am happy to try and contribute.
     
  15. audiokid

    audiokid Staff

    I researched this to death between my update from Apple/ Pro Tools 24/888 to PC and RME converters.

    One of many reasons I choose RME HDSP PCIe 32 interfaces is because of the "Steady Clock". I don't need a Big Ben for even 4 racks of 8 > 32 ADDA channels ( I think). Newer designs like this don't have the old Digi issues back in the day.

    I'm with MrEase 100% but then still wonder. when I read stuff like below..

    PS.

    I have no idea about computer parts but, I've often wondered if all the Avid trade stuff isn't recycled... All they're interested in for trade is what? What do they do with it all?
     
  16. audiokid

    audiokid Staff

    MrEase,

    Interestingly enough,

    What are you thoughts on this: Orion32 Multi-Channel AD/DA Converter | Antelope Audio
    I have one coming next month. Trying it for my 24 channel Neos hybrid rig. Its a 32 channel ADC with USB or MADI interface. USB is where I'll try.
    Just thinking out loud, I don't expect it to outperform my ADI-8 QS / PCIe combo for latency but this going one way at a time > DA to the Neos might be pretty cool. I'm monitoring OTB so latency isn't an issue for me.

    But, like the dog, an area I'm most curious about is the 10M clock on these. I'm told its outstanding, their best yet. I'm clueless on this technical stuff and how do you know until you use something like this. Can you elaborate on their claims, what this means? Its been suggested I try this as my master clock now. But, RME is working great, how would it improve, I wonder?
    Maybe they are talking more about this: http://www.antelopeaudio.com/en/products/10M-atomic-clock in combination. But the specs on the Orion say 10M
    http://www.antelopeaudio.com/en/products/Orion32-Multi-Channel-AD-DA-converter

    And then there thread where guys I know are claiming this and the Big Ben are amazing, but the 10M is unbelievable:
    http://www.gearslutz.com/board/high-end/443209-antelope-audio-10m-atomic-clock-getting-sold-off-owners.html

    And then there are these guys saying its hype:
    http://www.gearslutz.com/board/high-end/622491-antelope-trinity-10m-vs-internal-clock-comparison-2.html
     
  17. Davedog

    Davedog Distinguished Member

    At some point, Chris, ones mans hype is another mans truth in practice while being another mans hearsay.

    That thing sounds like something they use to time things during the shuttle missions!

    The deeper I go into digital work the more I see and hear what some folks have been talking about for ages. I still dont really care that much about having it technically perfect if it sounds good, but having gear that allows the 'sounding good' to be easily heard is certainly a powerful inducement for perfecting ones signal chains.

    Having said that, I still get goosebumps when listening to well made vinyl recorded with great big headroom and large power supplies on large format equipment from the 70's golden age. The depth of field from the late 60's to early 80's recordings is still unmatched.
     
  18. RemyRAD

    RemyRAD Guest

    WTF don't know what is going on? My connection has gone screwy.
     
  19. RemyRAD

    RemyRAD Guest

    And I think as generally Dave, from all the analog stuff being in lockstep at the speed of light. I don't care what the digital coders and programmers say, I hear otherwise from all digitally based recording and mixing. And probably why Chris has gone so crazy over the hybrid stuff? This is nothing new to us old-school, old-timers. Nevertheless, we are basically now living in the digital age, where 24-bit, 96 kHz has become the norm. But transcoding down to 44.1 kHz is not mathematically precise and introduces artifacting. So why aren't people recording at 88.2 kHz? Because 96 kHz sounds better? With no regard to what happens later? But what does 96 kHz sound like after it is trans-coded down to 44.1 kHz? The answer: not pristine anymore.

    I mean we all heard the difference between 7.5, 15 & 30 IPS yet, not everyone recorded at 30 IPS. Was this a budgetary concern back in the days of 30-$50,000 recording budgets from the record labels? I think not. It was a decision the engineer and producer made to produce at 15 IPS. Does this make their recordings less professional than those who were recording at 30 IPS? I don't think so. We all do things for a reason sonically or otherwise. So while it's nice that George Massenburg tells us we should all be recording a 24-bit, 96 kHz, because you can definitely hear the difference... I could definitely hear the difference between 15 IPS and 30 IPS. And we still recorded at 15 IPS for various reasons. And this all translates over to the digital side as well. How big is the budget? How much are you getting paid? How many hard disk drives does the client want to purchase? It's a lot cheaper than 2 inch for sure. And again, probably why George tells everybody we should be recording at 24-bit, 96 kHz? And yet, maybe actually mixes down to 1/2 inch, Ampex, ATR 102, 1/2 inch, 30 IPS machines? Maybe not? And where 96 kHz would work out just fine for the multitrack recordings. But he doesn't say anything about that. That in fact might be his secret ingredient?? These guys are all getting paid to endorse some product by some manufacturer. And maybe George is no longer recording and producing because perhaps he has blown his hearing out over the years? Which I'm sure he would never tell anybody about. So you really have to read between all of the lines when you hear this stuff. Recording at 24-bit, 96 kHz, won't make anyone a better engineer without the technique to back it up. And I'm an ardent firm believer in technique. That's where it's at.

    Of course you'll get goosebumps. Those guys knew how to record stuff. And the limited technology wasn't even a factor. And that's what I teach. These guys created great sounds simply through a finely polished technique. And they didn't use entry-level equipment most obviously. Only the stuff with high headroom. Whatever it was at the time? API, Neve, Electro-Dyne, Quad-Eight, Olive, Sphere, MCI, Flickinger, Helios, EMI, Phillips, Neumann, which were the consoles of the day. A couple of 1176's, LA-2/3 and that's about all. A PulTEC, API 550, Neve 1073/1081 et al., EMT plate, AKG BX 20. And no plug-ins. And then they had those noisy tube microphones and noisy KM-84's, 87's. So how the heck did they make such beautiful sounding pristine recordings? Answer: they knew what they were doing. And they didn't have much to do it with. Today, everybody has a $1 million control room in their bundled software yet they still can't make good recordings because they keep playing with stuff that doesn't need to be played with. It's the microphones. It's the room. It's the placement of the microphones within the room. These older rooms were not the lavish looking studios you see today. Yet they still made these incredible recordings on noisy analog tape. And does it sound noisy to you? Rarely do I hear any. So this tells you something doesn't it? LOL. They didn't have the finely honed artistically and acoustically designed facilities that everybody thinks is so absolutely necessary today. On location, mobile recordings have taught me otherwise. Well it really didn't teach me anything that I didn't already know. It just reinforced everything I had already learned. And another reason why really don't care about the acoustic environment unless I'm dealing with a Symphony Orchestra or an operatic recording and/or broadcast. Yet it still must be perfectly professional and perfectly listenable regardless of the acoustic environment. And you only learn how to do that when you have a thorough knowledge of the equivalent available or what you simply have. And it's really amazing how beautiful an orchestra can sound with a pair of Electro-Voice RE 10's into a tube microphone mixer and nothing else. Where's the condenser microphones? I didn't have any. Yet with a simple XY and a pair of out Rigger's and through beautiful custom tube preamps, it sounded wonderful. Of course I would've liked to have had some condenser microphones but I didn't have any when I was 16. Just that other stuff. And people really don't realize how fine dynamic microphones actually sound only because, " Studio" is written on most condenser microphone boxes. So all of the lemmings flock and are a bunch of Flockers because they just don't know any better.

    I mean, I know that DSD is in fact the finest digital format ever conceived. Where the hell is it!? People are running around like the monkeys at monkey Island at the zoo going off about 24-bit and 96 kHz, 192 kHz, it's all crap PCM. I just happened to hear it differently than others do than George even does. George doesn't even know how to record a Baroque harpsichord for Christ's sake. He only does rock 'n roll as that's all he really knows how to do. And he's very good at that quite obviously. I'm better at recording Baroque music, operas, Symphony Orchestra's and so I know the real art behind the science. Art comes first science comes later. Science is simply encroached upon the performing arts and is utilized as such. It's not a replacement for the art of recording. And people are getting this very confused. Remember, some of those great sounding and most memorable hits, were all recorded with very rudimentary equipment. You have to learn how to print before you can learn how to write in longhand. And that's what I preach.


    And that's the name of that tune
    Mx. Remy Ann David
     
  20. audiokid

    audiokid Staff

    get this, I sold my DSD and mix into the second DAW at the destination SR ( usually 16/44.1 ). Why did I sell the DSD. What good is it when it still has to be converted anyway. But, the coolest thing about DSD is archiving, that I get.
    And, there will be a day when what we have now, can be made better, so by having your gem archived on DSD, well, you have the best archive imaginable. But, here's the joke. Its still only as good as the source so , does that even make scene. I mean, you have a perfect archive of 2013 in 2020.

    The ultimate reason to have DSD would be to track directly to that. Like using your finest micpre and mic and recording direct into the DSD ( 2 track) . Otherwise, I didn't need it. Tracking into the second DAW rocks.

    Check this out now...

    An LA mastering engineer sent me two tracks last night. One that he used a 10M clock on and one without. All I can say is I was totally blown away. The detail and center imaging was exactly how I wanted it to sound.

    This meeting between him and I started while we were chatting about hybrid summing. I asked him for an example of his work. He gave me two versions and I had to ask him What the ^%$$^&, he did to the second mix. Because the first Mix, I knew I could do better. Then that second Mix came and OMG. He asked me to not play it. I wish I could for all. And, it could sound this good online.

    So, I've contacted the company and I hope they send me one to try. I want to believe it. Its hard to believe that there is something that has this much impact on a mix. I'm hoping its not BS. Or, I'm hoping that it will make this much difference to my converter setup. I don't know his configuration in detail but I've read that AES EBU clocked internally is more stable with some systems and others.
    Like MrEase say's, older converters had poor clocks and since then, things are improved to a point, its not an issue. And this could be why we see the odd Big Ben for sale now. But, this guy is no little league and no reason to BS me.

    To Add, over the years Fletcher has not been my most favorite guy around here. I can't stand gear pimps on forums. But I've always trusted his choices on high end. He said this thing is amazing and I haven't heard him use that term to many times. If he could afford it, he would keep it. The people that all liked this thing, all relayed hearing the same thing I noticed in the recording last night. The guys that said they heard no difference, maybe their systems are running great like mine right now, or, maybe what...

    Hopefully I report back with incredible news on this.

    So there is my story from last night relevant to this OP.
     

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