About noise and de-noizing... from Eroc

Discussion in 'Music Corner' started by Claus, Jan 9, 2003.

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  1. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    My question is *why* could that not occur naturally?

    As I've said before, think of it this way: you make two digital copies of an analog tape, one with (analog) EQ, the other without. You compare the two digitally and find out what the differences are. You then design something that will re-create that difference. You apply that to the non-EQ'd version. So you've got two identical files, one with EQ done in the analog domain, one done in the digital domain.

    Again, if the ends are the same, what does it matter what the means were?

    I'm not saying that *all* digital reverb will sound exactly like analog reverb. But there's no reason to believe that digital processing *can't* replicate "natural" processing
     
  2. Claus

    Claus Senior Member Thread Starter

    Location:
    Germany
    Maybe digital cracks like Ed Meitner can answer this question...
     
  3. Mal

    Mal Phorum Physicist

    Well, if you're saying you take the digital copy of the un-EQ'd analogue waveform and change it so it is now identical to a digital copy of the analogue EQ'd waveform, then of course you will be able to replicate the analogue EQ'd waveform accurately on D/A conversion.

    What your suggesting is a simple fact - take a set of samples, take another set of samples, compare the two and work out what you need to add or subtract to each sample in one set to make the two sets identical. Of course you may as well just replace one set with the other to obtain the same result!

    All you've succeeded in demonstrating is that it is trivial to generate digital clones of a digitally encoded signal.

    In fact, your example backs up my assertion that the only way to produce a natural sounding analogue waveform from a digital signal is for that digital signal to represent the unprocessed sampling of an input analogue waveform!

    :)
     
  4. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    No, I'm saying that digital processing *can* give you the exact same result as analog processing; that there's nothing inherently flawed with digital processing itself. Sure, some digital processing sounds bad, but then again, so does some analog processing.
     
  5. Claus

    Claus Senior Member Thread Starter

    Location:
    Germany
    Really fun reading the postings between lukpac and Malc S... ;) perhaps you understand you... sometime ;) :cool: :rolleyes:
     
  6. Mal

    Mal Phorum Physicist

    Right, but only in the special case where you have a pure, unprocessed digitally sampled analogue waveform and you create a clone of this by "processing" some other set of samples. Like I said, this a case where you're not really processing anything, you're really just cloning a pure, unprocessed, digitally encoded analogue waveform.


    Aside from the special case described above, where you end up with a clone of an unprocessed digital signal, I think there is something "inherently flawed with digital processing" as far as producing the most natural sounding audio is concerned.
     
  7. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    No, it doesn't have to be in this special case. Why would it? Why would it be impossible to get the same result without having the analog EQ reference? Hint - it wouldn't. That makes it *easy*, but not necessary.
     
  8. Ken_McAlinden

    Ken_McAlinden MichiGort Staff

    Location:
    Livonia, MI
    I still maintain it is no more "unnatural" than a waveform manipulated via analog tools to achieve a waveform that did not occur naturally. Heck, active filters use operational amplifiers which are composed of these crazy non-linear devices called "transistors" to achieve their "unnatural" results.

    As a matter of fact, a lot of the IIR algorithms used for digital filtering are merely mathematical constructs of analog filters that will give you comparable (but sometimes better and always more predictable) results than what you would get in the analog domain. The only place the Nyquist rate really comes into play is that if you try to implement filters that are operating mostly at or around the highest frequencies sampled, you can run into trouble with your filter's performance. It also affects the paramters of your filter to get the equivalent performance of the desired analog filter.

    There are certainly some things that analog does better than digital, and your example of reverb is a good one. You could knock yourself out trying to get a digital reverb that has the character of a particular echo chamber and maybe come close if you are very good, but that is analagous to trying to introduce errors and hesitations into a drum machine track, and probably a waste of your time. If you want the Capitol reverb, get in your car and go there.

    When it comes to things like filtering and eq, though, judiciously applied digital processing is hardly a recipe for disaster. Some of the stuff that goes wrong with digital processing has to do with trying to do things you would never do with analog processing just because you can. You know, like, "Wow! I could implement a 10th order Butterworth filter" without thinking "Wow! That would really create some screwy transient effects around the cut-off frequency - just like it would in the analog domain".

    Regards,
     
  9. softtech

    softtech Forum Resident

    Location:
    LA, CA
    I believe that this supposition is false. Malc talks about the "special case" in which you merely replace one set of digital data with another, but that is not what you are suggesting.

    You are suggesting that it is possible to take an analog signal, apply some sort of analog process to it, convert it to digital and end up with the same result as that same analog signal converted to digital that has a digital process applied to it.

    When you understand the complexities involved in how the data changes when analog processes are applied to it before it is converted to a digital stream you will see that we certainly are not there yet and, as Malc believes, along with me, we never will get there.

    If you disbelieve us, try it yourself. Use an analog equalizer to modify the signal and see how close you can come to matching it when you use the digital equalizer. I would be shocked if you got very close at all.

    Steve, if you are reading any of this, I would assume that you eschew the use of products that manipulate the digital stream in favor of modifying a signal (to the extent that you modify it at all) before it is converted to the digital domain. Is this in fact correct?

    Emery
     
  10. Ken_McAlinden

    Ken_McAlinden MichiGort Staff

    Location:
    Livonia, MI
    I actually believe this to be true, but for the reason that the analog device will never give you the same exact result twice. In a way, the analog processes are more of a distortion since they are not behaving predictably. On a case by case basis, depending on the effect you are trying to achieve via processing, this could be considered a "bug" or a "feature".

    Regards,
     
  11. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    First of all, what analog EQ are you using? What digital EQ? Sure, the results will be different, just as they will between different analog EQs. However, saying they *don't* sound alike and they *can't* sound alike are two different things.
     
  12. Bob Lovely

    Bob Lovely Super Gort In Memoriam

    Malc & Luke,

    I am not an Engineer or a Math guy. All I know is sound and how to listen intently with passion.

    So, I will share some listening experiences that may explain some of the perceived and eventual real outcomes in this digital v. analog debut.

    Clearly, I see Malc's point on this because I follow the logic and historically, my ears follow the thinking of his logic.

    Recently, I purchased an Oldies comp released by a label that has been releasing oldies comps for many years. The disc contains releases from the early to mid 60's. A number of the tracks have been remixed from the multi-tracks for Stereo. And, to my ears they have been mixed in a digital domain (Pro Tools?). They are clean as a whistle, well-balanced, pristinely mastered and yet, I do not find them compelling at all. Why? They are too clean, they do not sound as I remember them sounding in the 60's, they are cold to my ears and they are missing the warm analog artifacts of the original recordings/mixes. In other words, for as clean as they sound they are missing the aesthetically pleasing analog qualities of their era. Those are "musical" qualities that were "burned" into my sonic memory.

    Now, that being said, people without the sonic memory of these aesthetically pleasing warm artifacts may find these new digitally processed mixes to sound wonderful and very pleasing!

    I would rather have the original master, re-mastered on circa vintage analog equipment by an Engineer that has an affection for getting the most out of the vintage master tapes and keep all the processing in analog right up until the point where the digital master is made by that same competent and sympathetic Engineer. Mastered in this way, I am more likely to hear the sound I want to hear musically!

    Bob:)
     
  13. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    Again, Bob, I think they key issue is less what equipment was used, but *how* it was used. To get down to a very basic level, let's talk about EQ - the exact same equipment, in two different hands, can yield two vastly different results. Jon Astley could walk into Steve's studio, master something, and it wouldn't sound anything like what Steve does.

    The same applies to digital. Sure, a ProTools mix can be very "clean". But it doesn't have to be that way. An analog mix could be just as "clean" - for all we know, the mixes you speak of *are* analog mixes.
     
  14. Bob Lovely

    Bob Lovely Super Gort In Memoriam

    Luke,

    Yeah, your point is logical, as presented. How is that equipment used!

    The mixes that I am referring to could be analog mixes but, I doubt it, in this case. They can be heard on Varese Sarabande, Then - Oldies, Vol #4.

    Take a listen to:

    The Lion Sleeps Tonight - Tokens
    He's So Fine - Chiffons
    Hang On Sloopy - McCoys

    Certainly, I would trust your ears on the technology deployed on these mixes. To my ears, they sound digitally mixed and processed and, sadly less musical as a result. They are pristine but, they are aesthetically wrong. Actually, this may prove the "use" point in you post.

    Unfortunately, these are the versions of these classic hits that are being released today....

    Bob
     
  15. John B

    John B Once Blue Gort,<br>now just blue.

    Location:
    Toronto, Canada
    If I understand Ken, Emery and Malc correctly, you are all saying that analog is superior to digital when it comes to processing the sound with say reverb or EQ. The end result simply sounds better.
    Also, a top quality digital copy of the finished analog work will sound very good.
    This sounds reasonable to me and I have not seen any evidence to the contrary. It actually explains many of my own observations. Thanks guys.
    John
     
  16. Ed Bishop

    Ed Bishop Incredibly, I'm still here

    Glad you've figured it out, John. This whole thread has me dazed:p and confused:confused: .

    ED:cool:
     
  17. Ken_McAlinden

    Ken_McAlinden MichiGort Staff

    Location:
    Livonia, MI
    That's not quite what I am saying. I actually am more in line with Luke and Grant's thinking, although my main point is that they both have their strengths and weaknessess. Reverb is one area where I think analog has a big advantage because slight variations are your friend. Since you are trying to create a "fake" room ambience, the accuracy of digital seems to work against you. Digital eq can be implemented very effectively, on the other hand.

    Regards,
     
  18. Grant

    Grant Life is a rock, but the radio rolled me!

    You have summed up my exact feelings on remixing. But, I also say that digital can reproduce what is on the original tapes to an exact degree.

    Yes, I understand where Malc is coming from, but you can't blame the sound of someone's work on the technology.
     
  19. Bob Lovely

    Bob Lovely Super Gort In Memoriam

    Grant,

    Then you and I agree that it is the use of that technology, correct?

    Certainly, I can stipulate that in this discussion. Ultimately, it comes down to that use that we discuss here with such fervor!

    Bob:)
     
  20. Grant

    Grant Life is a rock, but the radio rolled me!

    Bob, I have that CD, and those songs actually sound less processed than the 45s. Why? because the 45s were in mono and compressed, where the digital remixes weren't. It has nothing to do with digital.
     
  21. Grant

    Grant Life is a rock, but the radio rolled me!

    But there are clearly those who are confusing the use of that technology with the technology itself. If someone does a bad analog production, they don't blame analog.

    Digital is unfairly used as a scapegoat for everything an engineer does wrong.
     
  22. John B

    John B Once Blue Gort,<br>now just blue.

    Location:
    Toronto, Canada
    Thanks for clarifying Ken. I'm trying to get a handle on this because I have never properly understood the whole digital versus analog issue. I reread your posts with interest. I still wonder if you too might be saying you prefer the end result in the analog domain - given that reverb is such a crucial part of the sound. Do you?
    John
     
  23. Ken_McAlinden

    Ken_McAlinden MichiGort Staff

    Location:
    Livonia, MI
    I like good work no matter how it was accomplished. :)

    The real end result is always in the analog domain via my ears.

    Regards,
     
  24. Bob Lovely

    Bob Lovely Super Gort In Memoriam

    Grant,

    I don't know, they sound "Pro Tools'ed" to me - they are just too clean, pristine and perfectly balanced. I have many other versions of these tracks on other CD's that do not sound like these versions do and those other versions more accurately reflect the "original" sound, yet with the full dynamic range of the recorded works on tape as afforded by the digital format. In this case, I am not comparing the sound of the tracks on the referenced disc to the 45's. If I were, clearly, I would agree with your point. This is most evident on "The Lion Sleeps Tonight". Compare the version on Then - Oldies, Vol. #4 to the RCA/BMG version. The RCA/BMG version has all the original odd analog artifacts present in the original recording. For me, these artifacts are a part of the musicality of the recorded work. Cleaned-up, the track loses it's aesthetic, historically accurate appeal.

    But, hey!, that is just my opinion!

    Bob:)
     
  25. John B

    John B Once Blue Gort,<br>now just blue.

    Location:
    Toronto, Canada
    Thanks again Ken,

    I'm trying to come to my own conclusion without the resources to compare for myself. From what I have heard here, it looks like analog is the way to go from a strictly sonic POV.
     
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