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hi bennetng, that was very informative
im wondering if you have seen the Sound Devices patent for their triple ADC that claims 168 dB of dynamic range?
https://patentimages.storage.googleapis.com/a7/6b/f5/77e31e68cca8b7/US9654134.pdf
Their implementation in the Mixpre-II series states 142dB of dynamic range in the ADC section. That series uses 32-bit float files. In your opinion would such a setup theoretically perform better writing to 32-bit fixed? The EIN of the unit is -128dBU which both float and fixed can contain.
I think you will find bennetng's posting is usually very informative.
As for EIN, there are physical limits to how good that can be. It is usually applied to microphone pre-amps with a source impedance of 150 ohms. A maximum value is 130.9 dbU over 20hz-20,000 hz. This is how much thermal noise a 150 ohm resistor would create.
The advantage to floating point is you won't clip the signal. Mixpre's are meant for portable on location recording often of sound for video. So doing it via floating point means you don't get clipped levels for live events. Writing to fixed 32 bit is plenty of range, but doesn't give you the options to avoid clipping or the noise floor that floating operations do. You'd still need to have your max level set not to exceed it and while the noise floor of 32 bit fixed is plenty low enough your analog circuitry handled that way won't make use of the 32 bit range anyway. The advantage of float is being able to scale up and down without clipping so it fits optimally in the dynamic range of the rest of the analog circuitry.
I'm probably explaining it poorly.
Sound Devices explains it.
https://www.sounddevices.com/32-bit-float-files-explained/