As some of you guys might know, the famous Rob Watts has mentioned on more than one occasion that he can hear and measure distortion down to -300 dB. Cited by @amirm here for instance. He also says something similar in this video:
Staring at roughly the 17min mark.
Now I was thinking about a thought experiment that you guys can probably help me with, especially the physics nuts. I'd like to explore what this actually would mean on a physical level? So how little is the voltage change? How many electrons would that actually need? And if we're talking, what about air pressure difference? But you guys can come up with other stuff. Probably the infamous shoutometer will come up, which I find rather uninteresting because it just not model the practical world very well.
So I had a crack at voltage. So let's see how small of a voltage difference -300 dBV is. Well, I had to resort to Wolfram Alpha because my go-to calculator gave me just zero So Wolfram was more helpful and gives 1*10^-15, which is 1 fV RMS (so femtovolt). To count electrons, we need to add some assumptions: we need current. So let's assume it's a DAC, and it's syncing into 20K input impedance of a pre. Now we can calculate the number of electrons needed for this 1 fV voltage. So 1A has 6.24 quintillion electrons (10^18). So, how many electrons does out -300dbV signal have into 20k? Well, it's not even 1 electron per second: it's 0.312 Already feeling silly Rob?
Hope you guys can fact check me on this. Would be fun to do the same for the air pressure difference.. Once again my go-to calc gives 0
Staring at roughly the 17min mark.
Now I was thinking about a thought experiment that you guys can probably help me with, especially the physics nuts. I'd like to explore what this actually would mean on a physical level? So how little is the voltage change? How many electrons would that actually need? And if we're talking, what about air pressure difference? But you guys can come up with other stuff. Probably the infamous shoutometer will come up, which I find rather uninteresting because it just not model the practical world very well.
So I had a crack at voltage. So let's see how small of a voltage difference -300 dBV is. Well, I had to resort to Wolfram Alpha because my go-to calculator gave me just zero So Wolfram was more helpful and gives 1*10^-15, which is 1 fV RMS (so femtovolt). To count electrons, we need to add some assumptions: we need current. So let's assume it's a DAC, and it's syncing into 20K input impedance of a pre. Now we can calculate the number of electrons needed for this 1 fV voltage. So 1A has 6.24 quintillion electrons (10^18). So, how many electrons does out -300dbV signal have into 20k? Well, it's not even 1 electron per second: it's 0.312 Already feeling silly Rob?
Hope you guys can fact check me on this. Would be fun to do the same for the air pressure difference.. Once again my go-to calc gives 0
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