Question about recording technology - capturing low level harmonics

[Deke609]

Question for those in the know about how music is recorded.

Suppose we have a hypothetical tone that has a 1 kHz fundamental and a -30dB 2nd harmonic. If my math is right [dB = 10*log (1 + x)], then the -30dB 2nd harmonic is 1/1000th as strong as the fundamental. Is recording tech sensitive enough to capture that without noise/distortion?

I ask in relation to the never-ending debate and puzzling about THD and tube amps. I'm wondering whether some of the low level harmonics get lost in the recording process but then an approximation of the same low level harmonics can be "put back" by the amp.

cheers and thanks, Derek

[Paul Birkeland]

This is pretty well covered here:
http://www.sengpielaudio.com/calculator-thd.htm

[Deke609]

Thanks PB. Did I use the wrong equation? Is it 20*log, not 10*log? 

Either way - the -30dB 2nd harmonic is going to be pretty small relative to the fundamental. So I'm still wondering whether some of the low level harmonics get lost in the recording process.

cheers and thanks, derek

[Paul Joppa]

It will get recorded.

[Deke609]

Huh. Many thanks PJ.

[grufti]

I had no clue that Mr. Sengpiel's audio and recording site was at least partially available in English. I'm German, so I never even looked for any translations.

Eberhard Sengpiel made many orchestral recordings alongside recordings of just about everything else. He also taught at Universität der Künste Berlin [Berlin University of the Arts]. He died in 2014. His site is being maintained by his son, because it is such a precious resource.

Good microphones are insanely sensitive and the remainder of a good recording chain will capture what they pick up. You will often hear things in your newly recorded tracks that you were not aware of while you were listening live. Ears are no microphones and microphones are no ears.