Dynamic range question, Dynamic range of hearing vs. equipment Options

[thesurfingalien]

Hi All,

I am having problems understanding the concept of dynamic range, and more specific how the dynamic range of human hearing relates to the dynamic range as specified for audio equipment.

What I have read on the Net is that the dynamic range of human hearing is, on average, 135 dB (the pain limit / threshold?).

I also understand that the dynamic range of a CD (16 bit) is limited to 96 dB, and for HD (24 bit) recordings 144 dB. This dynamic range is calculated by the bit-depth.

For playback of music (I use 44.1/16 flac only) I use a E-MU 1820 that has a dynamic range of about 115 dB (or so). I am not sure what my amp can do...

However, when I play music I hardly pass 80 dB (or so) listening volume, so the 96 dB CD data (if the recording makes full use of the range that is) gets "compressed", while the relative dynamic range remains.

After the long intro my question in essence is:

Does the human hearing have a similar "resolution" that is comparable to the resolution defined by the bit-depth in (digital) audio? Or am I just comparing apples and pears?

Regards,
Peter

[thesurfingalien]

@All,

Although all info was useful and interesting, I am still struggling with the concept of relating bit-depth to a dB scale...

Perhaps if I (again) rephrase my question...

Given that (for CD) the 16 bit depth is limiting dynamic range to 96 dB, on which basis was decided that the 96 dB was (good) enough? Why not, for example, 128 dB? To me it looks like that will only require a change in the step-size on the dB scale...

Thanks again!
Peter

[drewfx]

@All,

Although all info was useful and interesting, I am still struggling with the concept of relating bit-depth to a dB scale...

Perhaps if I (again) rephrase my question...

Given that (for CD) the 16 bit depth is limiting dynamic range to 96 dB, on which basis was decided that the 96 dB was (good) enough? Why not, for example, 128 dB? To me it looks like that will only require a change in the step-size on the dB scale...

Thanks again!
Peter

96 dB of dynamic range represents the ratio of the loudest sound to the quietest sound - it's the ratio of the largest number available using 16 bits to "1". Thus to get more dynamic range, you need a bigger ratio, which means you have to add more bits.

The "step size" is fixed by the fact that it's binary.