First, if you do not have any idea of what 64-bit float means, then you need some introduction. When you are recording/tracking digitally, you are converting analog audio to digital audio data which are processed and stored in your computer.
Then if you are using a 24-bit audio interface (which is a standard in professional music productions), it will convert these analog data into 24-bit data (binary data in the series of 1 and 0) streams which are communicated via your Firewire or USB cable (depending on whether you are using a Firewire or USB audio interface).
64-bit float and 32-bit float
The actual resolution of your audio when saved into your hard disk drive is actually using 24-bits. However when processed by your DAW, it can either process the 24-bit audio data as:
a.) 32-bit float
b.) 64-bit float
Even though your DAW processes audio at any of these floating point systems, the source audio is still 24-bit and nothing is changed. The reason why they are processing it as a floating point is for convenience in the computation and representation of very large /very small numbers and efficiency. This makes it possible to retain resolution while doing complex computation thus benefiting audio quality during the mix. After all, your DAW would perform a lot of arithmetic calculations during the mixing process that includes:
a.) Implementation of plug-in effect settings.
b.) Setting levels.
c.) Digital summing of the mix (mix down or rendering the project)
The format of 64-bit float is similar to 32-bit float except that it accepts a wider range of bits. This is the 32-bit float format:
32 bit floating structure
Errors occurring during Digital Calculations in the Audio Mix
When you are mixing using a 32-bit float DAW, you would be applying effects or any digital manipulations to the audio. One downside of doing these digital calculations is not they cannot exactly represent all resulting numbers in the computation.
If you are confused why they cannot represent all resulting numbers, let’s start with decimal number system in which you are very familiar. Let say you are performing arithmetic calculations like dividing a number; if you divide 1 to 4 that is equal to 0.25. So it’s represented exactly. Another example is that if you divide 4 to 5, this is equal to 0.8. Again the result is an exact representation of the number.
However, if you divide 1/3 the result is 0.33333…. repeating infinitely. Thus you would need to round off say the first 3 digits of the result which is 0.333. This rounding off results it is not an exact representation of the actual results and this would introduce some errors.
The same if you divide 1/9 or 1/27 and there are many numbers. Going back to floating point arithmetic in binary, same concept applies. It cannot represent numbers such as 0.1 because of the same explanation/limitations as in decimal system. Converting the decimal 0.1 to binary will result to:
0.00011001100110011001100110011001…
The dots in the end signifying that the number is repeating infinitely; thus when this number occurs in your DAW calculation it is approximated or rounded off.
Why 64-bit float DAW is an advantage compared to using 32-bit float system?
Based on the analogy presented on the previous section, it is simply because “processing” and “calculation” of binary numbers in 64-bit float format results to less rounding error which would translate a much “realistic” audio that is closer to its analog sound.
For example, let’s go back to the decimal number system since most of you are not familiar with binary arithmetic; supposing the DAW would add 1/3 + 1/3; in decimal number system computation (supposing you are using 3-digit resolution):
0.333 + 0.333 = 0.666
But if you are using a high resolution in the computation, the results would be “closer” to the exact number, for example:
0.333333333333333333333333333 + 0.333333333333333333333333333 = 0.66666666666666666666666666
If your DAW is still using 32-bit float, then it cannot represent all numbers in its calculation as accurate as using 64-bit float computation. Using 64-bits minimizes these rounding errors to a minimum in such a way it would not be obvious to the ear or the resolution of your audio interface converters.
Why this is very important?
1.) If you are processing audio internally during the mix, it is crucial your DAW would perform a very accurate calculation because an inaccurate arithmetic can have an effect on the audio quality.
2.) Aside from many advantages in digital music production; summing in digital (as compared to rendering a mix in analog) has always been considered inferior to professional mixing engineers because of this limitation. Summing digital audio in 64-bit float increases the accuracy of the mix that would stand out which would now be comparable to the mix done using analog.
So if you asked? With all the advantages of 64-bit DAW, what are the disadvantages?
1.) Since your CPU and computer will now be dealing with long series of bits during the calculation; it demands more CPU and memory power than using 32-bit float.
2.) Even using 64-bits, remember that it still cannot exactly represent certain numbers in the results. There would still be rounding errors but at a minimum compared when using 32-bit float DAW.
Finally, Reaper DAW is using 64-bit in its internal engine and these are one of the reasons (aside from low licensing cost) I use this DAW in my projects.
Content last updated on July 13, 2012