As far as I understand, when we talk about the dynamic range of an ADC we are referring to the ratio of the biggest signal it can handle to the smallest signal it can resolve.

On the other hand the dynamic range is defined as the difference (in dB) between the maximum input level and the noise floor of the ADC. If we neglect the noise floor, we can obtain the formula of such system as 20*log10(2^n) where n is number of bits.

In many forums I found that they are making comparison between old analog players such as vinyls and digital players such as CDs. They are making the comparison by documenting their dynamic ranges in dBs

But how is dynamic range for an analog audio device such as a phonograph or cassette player is obtained?

  • \$\begingroup\$ Some test records have zero-signal sections; playing back those sections, your output will be noise/hum/etc. You can measure the RMS (HP 3403 would measure RMS from 10Hz to 4MHz) output voltage of the signal chain. \$\endgroup\$ – analogsystemsrf Oct 21 '18 at 4:37
  • \$\begingroup\$ Regarding quantization errors, which the CDs produce, you need to be aware of the tonal errors produced by a constant slewrate musical signal. Bernie Widrow wrote a book "Quantization", where about page 60 he discusses at least 3 types of quantization noise. If you modify your question to allow an anwer of "What are various flaws with the digital record-playback?", then I will provide that in a genuine answer. \$\endgroup\$ – analogsystemsrf Oct 21 '18 at 4:43
  • \$\begingroup\$ Forget about quantization for CD digital ect. there are many sources on that, Im wondering mostly how to describe the analog phonograph type vinyl dynamic range. To compare. \$\endgroup\$ – user16307 Oct 21 '18 at 13:58
  • \$\begingroup\$ This is the only source I found so far: analogplanet.com/images/vinyl-dynamic-range.pdf \$\endgroup\$ – user16307 Oct 21 '18 at 14:02

For both types of systems, the dynamic range is defined as the ratio between the maximum usable signal power and the noise power.

The fact that digital systems have quantization as one of the sources of noise (but often not the dominant source of noise) has little to do with this definition.

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In a correctly designed ADC the dither linearises the system, so you end up with a full scale level and a noise floor.

The quantisation distortion is converted to linear noise by the dither, so that at the output of the reconstruction filter you get a linear signal plus noise, just the same as you would in a purely analogue chain.

For a record you have a noise floor (mixture of surface noise, thermal noise, hum...), and you have a limit imposed (mainly) by the ability of the stylus to track the grove, there is a frequency dependent element to this of course due to both the equalisation curve and the mechanics.

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