16 bit Audio

The vast majority of Podcast producers are not using multi- thousand dollar Neumann mics and/or highly efficient preamps in acoustically treated environments …

When recording (spoken word) audio via mic input, the noise floor is perceived as the level of ambient noise and residual preamp noise – NOT the system noise. Any such mic input will exhibit a higher perceived noise floor with a reduced SNR compared to a much more efficient DI or electronic instrument.

Consider the quantified theoretical dynamic range of 16 bit audio (96 dB). When recording with a mic in a typical environment – your system is incapable of effectively utilizing the full dynamic range of 16 bit audio due to the noted (elevated) perceived noise.

When producing Podcast audio, wide dynamics capabilities are irrelevant. In fact persistent wide dynamics in spoken word audio intended for Internet/Mobile/Podcast distribution will compromise intelligibility.

With all this in mind, what is the advantage of recording 24 bit (spoken word) Podcast audio with a theoretical dynamic range of 144 dB vs.16 bit audio? In my view there is no advantage, especially when proper down conversion techniques such as Dithering are for the most part ignored. An omission as such will compromise the sonic attributes of down converted audio derived from higher resolution source masters.

Are you striving for an efficient Podcast production workflow with excellent fidelity and adequate frequency response? 44.1 kHz (or 48 kHz) • 16 bit audio will be sufficient. Of course there will be optimization variables and requirements such as quality of gear, optimal recording levels, and ample headroom.

Notes:

– If you are producing highly dynamic episodic dramas, fine arts content, or complex narratives with music and sound effects elements – and you prefer to work with 24 bit media … by all means do so.

– When down converting from 24 bit to 16 bit in preparation for distribution, recognize the significance of Dithering.

– Be aware of MP3 codec filtering attributes, inherent frequency response limitations, artifacts, and the consequences of low bit rate encoding.

– Applying a low-pass filter to lossless audio prior to lossy encoding is recommended. Such a roll-off will effectively supply the lossy encoder with managed high frequency activity that is below the codec’s filtering threshold.

-paul.

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