Okay - by 64 and 32 bits you probably 64 and 32 bit processor (CPU) and software. This is just about the internal workings of your of how your CPU crunches bits, with 64-bit systems generally being a bit faster and able to address more memory than 32-bit systems. Note that 64-bit CPU's are capable of running either 32 or 64 bit software...
...
a different thing is the bit-depth of your audio.
Audio can be encoded so that each sample uses more or
fewer bits. The most common is 16 bits (normal CD audio),
other values frequently used are 8,12, 24 and 32 bits.
8 will sound decidedly lo-fi, 12 bits was used for many
early samplers and some people love the sound. These
days anything less than 16bits is uncommon. (The bit
depth of your audio is independent of whether you have
a 32 or a 64-bit processor)....
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It's really unfortunate that we have the 32 bit and the 64 bit option both in the audio bit depth and in memory/CPU layout... I really don't want to know how many people mix these up without knowing. Why couldn't they make 30 and 60 bit CPUs instead, for instance ;-)? The world would be so much simpler... :-)
https://www.kvraudio.com/forum/viewtopic.php?t=357481