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32-bit floating point

Discussion in 'Recording' started by audiokid, Oct 18, 2010.

  1. audiokid

    audiokid Staff

  2. TheJackAttack

    TheJackAttack Distinguished Member

    The floating point portion has to do with variable processing. The DAW program has recorded (or imported) your audio in whatever it's source format was-either 16 bit or 24 bit. Now, while the audio is being processed in regards summing or VST plugs, the DAW may decide to process those segments at 32 bit to better handle the procedure in question. Just like 24 bit increases headroom and processing power of 24 bit, 32 bit is incrementally better than 24 bit. Why then don't we just work from A-Z with 32 bit? Because the size of the files. These files would be quite a bit larger.

    Someone else will have a better explanation I'm sure.
     
  3. JohnTodd

    JohnTodd Well-Known Member

    Mathematically, 32-bit float increases the number pool available to describe the audio waveform. The more numbers, the more subtlety can be encoded in the output.

    IOW, more detail in the sound, like the subtle pluck of an acoustic guitar or a quiver in a voice. Not the best examples, but sufficient here.

    A single 24-bit track on it's own can sound great, but when, for example, 24 tracks are mixed together in 24 bit, some numbers may have to be "thrown out", thus omitting parts of the sound. With 32-bit float, there are more numbers and more decimal places available to counteract that. Add in plug-ins and it gets even more complicated.

    Someday it will all be 256-bit float from A-Z! And "real life" will have an undo function, as well. :)

    Simple explanation, anybody want to elaborate?
     
  4. djmukilteo

    djmukilteo Well-Known Member

    32 bit math in audio algorithms also creates better dynamic range something on the order of 140-150db and that's probably with truncation.
    I've read that 32 bits can actually produce somewhere around 300db of dynamic range...and if the engine is using 64 bit processing that number can grow exponentially to over a 1000....of course not sure how practical that would be...that is strictly binary math being done within the CPU and software routines and then converted back to 24bit....I suppose if you had converters and amplifiers that could faithfully reproduce those kinds of ranges it might be pretty interesting...in fact it's very possible that will be the direction in the future...but the weak link and limiting factors would be the D/A conversion and then the actual amplifiers and speakers....
    Dynamic range tends to be the thing that most peoples ears detect as "better" sounding....dynamic range has always been the primary factor in sound improvement over the years, most older people here will remember how different 70-80db sounded compared to 90-100db...which is almost common today...even 16bit CD players are around 90db and if you grew up listening to records or cassette's you know how astounding that changed things!
    Doing digital math in 32bit FLOP just gives you way more precision than 24...the permutations of 24 bits is 16777216 and 16 bit is 65536 and 32 is 8 bits longer than 24 so the math there is well beyond what is needed or can be used...technologically were at the mercy of the analog converter chip guys to come up with faster more precise converters...when that moves to the next level of cheap viable processes...the current 110-115db should move up a notch!
     
  5. audiokid

    audiokid Staff

    Excellent thread!

    I so remember Vinyl, 8 track, Cassette, CD, DAT, Beta and to date ... All those stages have been incredible level improvements and you are right, a big part of how I have measured gear in the past has been by the SNR specs.

    Do you all have a 32-bit floating point option with your DAW and do you have it active?
     
  6. hueseph

    hueseph Well-Known Member

    I see school is back in session. This is why I love this site so much. Always something new to learn.
     
  7. TheJackAttack

    TheJackAttack Distinguished Member

    Most modern DAW's are already floating 32bit whether they tell you that or not. Maybe some of the LE versions or other restricted versions are not but I would be surprised any full featured DAW was NOT 32 bit float or even the option (Audition does) of working completely in 32 bit.
     
  8. TheJackAttack

    TheJackAttack Distinguished Member

    Oh, and expect floating 64 bit in the not distant future.
     
  9. hueseph

    hueseph Well-Known Member

    Sonar Producer 8.5 already has 64 bit float as an option.
     
  10. djmukilteo

    djmukilteo Well-Known Member

    I'm still using Cubase 4.5.2 set at 24bit in the project setup with my meager WinXP AMD FX-60 and the RME FF800 at 44.1 sample rate and to me that sounds pretty amazing to my old ears...I did try a test of piano recorded at 192khz with the 32bit selected in Cubase. Of course listening to that back through the headphone output of the RME with ATH-M50's....it was better....very open and airy, but it was a very subtle difference to me....that was the only test I've done.....to me it was the two extremes to see if there was a discernible difference.
    I usually listen to MP3's these days with WMP which sounds as good as CD (well maybe not quite as good as my Pioneer) but pretty darn good...I tend to compare sound quality to music I know very well with all the little ambiance and nuances etc...so these days that's how I judge my electronics and setup...and I tend to pick up the headphones a lot.
    I think we all strive to get better and better sound from the electronics which is where it's at....always....I'm still able to hear a difference today and then I'm happy with that new quality....the next time the electronics changes something in audio I hope I can (will) still be able to hear that improvement....BTW to all you younger children of sound out there....always protect your hearing...I always did over the years but still had a couple serious level blasts to my eardrums....so always think before your ears start ringing...or if you find yourself screaming to be heard in a concert or club...that's a sign.....always plug your ears and always be careful with your controls.....
     
  11. apstrong

    apstrong Active Member

    I had heard that 1 bit recording was actually the next big thing. At extremely high sample rates, it's supposed to be able to capture up to 100KHz. Or something like that. Must be massive files? How exactly it works is a mystery to me.
     
  12. JohnTodd

    JohnTodd Well-Known Member

    @apstrong:
    The 1 bit is basically this: The digital "wave" starts at zero. A 1 determines if the wave should go up, and a 0 means it should go down. So, 100,000 times per second it's either going up from the previous value or down from it. So it isn't 1 bit as in quantization like we are used too, it's a totally "new" way of using bits; it is driving an analog-like output section. It's reminiscent of SACD.

    @audiokid:
    I'm using Cubase LE 4.something, and a PreSonus Firepod. The 'pod does 96K@24bit, but Cubase does 32bit float internally for mixing/FX. I render mixdowns at 96Khz@32bit-float and master that file in Wavelab 6.
     
  13. Boswell

    Boswell Moderator Distinguished Member

    Leaving 1-bit DSD aside for the moment (since we have covered it in previous threads), many of these posts are confusing 32-bit fixed point with 32-bit floating-point.

    With 32-bit fixed point you can sum 256 24-bit fixed point numbers and not lose accuracy or risk overflow.

    With 32-bit floating-point, you still have only 24 bits of precision (the mantissa), but the remaining 8 bits form an exponent that says where the 24 bits sit in the whole representable range. This is fine until you start to sum floating-point values that have different exponents. One of the two operands has to be shifted until its exponent matches the other, and then 24-bit summation can happen. It means that for every operation, precision is irretrievably lost by the bits being shifted out.

    Many high-quality digital mixing desks use 32,40 or 48 bit fixed point arithmetic, as the summation process is always accurate. Least significant bits may be discarded in the sum signal when converting and rounding back to 24-bits for output.

    The higher-quality DAW packages use either 64-bit fixed point or 64-bit floating point to minimize the effects due to data loss when summing channels. 64-bit (double precision) floating point uses 53 bits in the mantissa.
     
  14. audiokid

    audiokid Staff

    ah...

    So the next question is, why do they give us the option to activate it or not? when would you say... ah, time to select 32-bit floating point?
     
  15. audiokid

    audiokid Staff

    In Sequoia 11 it says this:
     
  16. audiokid

    audiokid Staff

    Ah, found this from Benjamin Maas.

    So there are debates whether to use it or not in a mix down or final project to 32bit float for mastering and/or with vst plugins?

    And then whether the AD DA can actually deal with this anyway.

    I'm thinking, when in doubt, stay at 24 bit .
     
  17. Boswell

    Boswell Moderator Distinguished Member

    It all depends on the DAW and your computer. Under all conditions, 64-bit representation of data takes twice the space of 32-bit representation, so you either need more addressable memory, or you put up with fitting less data at a time in the memory you have. Arithmetic on 64-bit data takes longer to compute than 32-bit, although usually not twice the time in a 64-bit program environment. However, if you are running a 32-bit version of the DAW, using 64-bit data can take more than twice the time, as the double data fetch and store times become the dominant part of the time to operate on the data.

    If you are running a 32-bit DAW under either a 32-bit or 64-bit operating environment, it's probably not worth selecting 64-bit data representation for a particular job, unless you have only a few tracks with huge dynamic range. In a genuine 64-bit OS and DAW environment, there is no point in selecting 32-bit data representation unless you are really short of memory (in which case, fit some more).

    Regarding Sequoia, Magix are particularly coy about whether the version that runs under a 64-bit OS is a 32-bit or 64-bit build. They spec it as needing twice the amount of installed memory when running under Vista64, and that might indicate that it is a 64-bit build, but I have my doubts. They may be simply indicating that the 64-bit OS consumes so much memory that there is little left for user programs.
     
  18. audiokid

    audiokid Staff

    Bos, I wish you lived next door to me:) but this is definitely the next best thing isn't it!
     
  19. studioshaman

    studioshaman Guest

    32 bit floats & beyond

    Hey ya'll, great info....I am a firm believer in using 32 bit float 1st-ly, as a 1TB HDD is (higher end) about $120-150 so drive space shouldn't an issue. I'm using Cubase 5.5 & even "True Tape" 32 bit feature in VST 5.0, was created with good reasons according to Steinberg's Mr Warner... & as I use Cubase 5.5 now, I still always select 32. The headroom gained in audio will be captured for all-time & may have even greater advantages, as ad/da units go in that direction. Despite obvious comparison issues....the taking more density of frames per second on film, is pretty much self-evident example of why it's the best choice.

    Yes, we have to re-convert back to 24 bit & once it's captured, 32 bit is still a good choice, whether or not new standards will bring sound converter ad/da's to better use this extra "frames". I'm not a math expert by far but an increase in bit rates from 12 to 16 were hailed as revolutionary; the move forward is ongoing & once you've recorded at 16 or 24, you stuck with this into the future, should you wish to re-work a track with higher bit hardware. 64 bit is already here, & elsewhere on it's way....

    My Delta 1010, employs a 36 bit float...though it's 24/96. I will bet, in 2 years, this debate will be over. I'm more than happy to hear what the math experts have to say about extra headroom, but it is recommended by some of the best mix & mastering engineers. Trevor Horn's advice & MO is good enough for moi!

    This is a truly great forum....thx to those who greater understand algorithms, though in the end, it's my ears I listen to....awesome explanations pro & con...
     
  20. studioshaman

    studioshaman Guest

    Ditto....audiokid...
     

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