David Christensen wrote: > These are the equations and conversion factors needed: > > Bel = log10(power) > > power = 10 ** Bel > > 1 Bel = 10 dB > > So, your calculation should be: > > 2021-08-23 23:42:34 dpchrist@dipsy ~ > $ perl -e '$p=0; $p += 10**($_/10) for @ARGV; print > 10*log($p)/log(10), "\n"' 14.9 15.9 15.9 14.7 29.0 > 29.696732023509
OK, so then the data is 5 fans: 23.3 dB 5 fans and HDD: 30.0 dB ;;; -*- lexical-binding: t -*- ;;; ;;; this file: ;;; https://dataswamp.org/~incal/emacs-init/audio.el (defun db (d &rest ds) (let ((all (cons d ds)) (sum 0) ) (cl-loop for a in all do (cl-incf sum (expt 10 (/ a 10.0))) ) (format "%.1f dB" (* 10 (/ (log sum) (log 10))) ))) ;; (db 18.9 14.9 14.7 15.9 15.9) ; 23.3 dB ;; (db 18.9 14.9 14.7 15.9 15.9 29) ; 30.0 dB > That said, I would just add the continuous fan noise [...] > And consider the 29.0 dB HDD vibration separately. Why? -- underground experts united https://dataswamp.org/~incal
