Re: What is the dynamic range and S/N ratio of CD format?
Posted: 09 Nov 2019 15:47
the home of the turntable
Missspoke there. It has nothing to do with finished product CD. Has to do with recording, mixing and editing. For instance increasing the volume of a very weak signal.
Yes, that's loss of resolution, confirmed by a composer/engineer friend of mine as a real thing back in the day, with emphasis on "the day" since 16-bit production started to disappear in the nineties. I don't think it's dependent on frequency BTW.
I believe it occurs at all frequencies below the Nyquist frequency and is exacerbated as the signal frequency goes lower due to the increasing amount of quantization errors per cycle as frequency decreases.Hanuman wrote: ↑10 Nov 2019 03:31Yes, that's loss of resolution, confirmed by a composer/engineer friend of mine as a real thing back in the day, with emphasis on "the day" since 16-bit production started to disappear in the nineties. I don't think it's dependent on frequency BTW.
Each quantization bit gives 6db of dynamic range. But there are only 15 quantization bits. Not 16. The 16th bit (MSB) provides only that the quantization is positive or negative. Not magnitude.
Okay I'll pick little since you granted permission. ;)
The digital data contained on a redbook audio CD has exact non theoretical values and thus an exact actual, not theoretical, dynamic range.
Completely disregards the fact that redbook audio CD data is signed and therefore there are only 15 bits representing magnitude. Thus the redbook audio CD data has a dynamic range of 20Log(max/min) = 20Log(2^15/1) = 90.33 db.jdjohn wrote: ↑13 Nov 2019 23:13"Digital audio at 16-bit resolution has a theoretical dynamic range of 96 dB, but the actual dynamic range is usually lower because of overhead from filters that are built into most audio systems." ... "Audio CDs achieve about a 90-dB signal-to-noise ratio." https://books.google.com/books?id=w0vsd ... &q&f=false
The opening paragraph of this thread is clear that it is about "redbook audio CD (16-bit 44.1 KHz)". But nevertheless DSD/SACD is still bits. Just more of them in a different format. Regardless of which format, generally the more bits, the more accurate the representation.
Then its 90dB indeed.
GuidoK wrote: ↑14 Nov 2019 21:25Then its 90dB indeed.
But your definition is maybe not a commonly used one.
"the ratio between the largest and smallest values that a certain quantity can assume."
The smallest value is of course zero magnitude.
However, if you relate it to the human ear and start at 0dB, that is related to the minimum threshold a human can hear (commonly set at 20µPa)
So there 0dB always relates to a registred signal.
So whether its 90dB or 96dB is more a matter of what definition you give to it.