Recording

All About Decibels, Part I: What’s your dB IQ?

dBu = dBv

dBu = 20 * log (Voltage / .775 V)
P = V^2 / R
.001 W = V^2 / 600 W
V^2 = .001 W * 600 W
V = sqrt (.001 W * 600 W)
V = .775 Volts

dBm = dBVU

dBm = 10 * log (Power / 1mW)

dBV = 20 * log (Voltage / 1V)

Professional vs. Consumer Levels

+4 dBu = 20 * log (voltage / .775 V)
voltage = 1.228 Volts

-10 dBV = 20 * log (voltage / 1V)
voltage = 0.3162 Volts

20 * log (1.228V / 0.3162V) = 11.79 dB

dBspl

dBspl = 20 * log (Pa / .00002 Pa)

dB	Compares	Reference Level	Formula
dBspl	Sound Pressure	0.00002 Pa	20 * log (spl / .00002 Pa)
dBm	Electrical Power	1mW	10 * log (Power / 1mW)
dBu	Voltage	0.775V	20 * log (Voltage / .775V)
dBV	Voltage	1V	20 * log (Voltage / 1V)
dBFS	Sample Level	65536	20 * log (Sample Level / 65536)

5 String Bass
	B	E	A	D	G
Freq	31	41	55	73	98	196	392	784	1568	3136
1/2 x ms	16	12	9	7	5
ms	32	24	18	14	10
2 x ms	64	48	36	28	20

7 String Guitar
	B	E	A	D	G	B	E
Freq	62	82	110	147	196	247	330	659	1319	2637	5274	10548
1/2 x ms	8	6	4.5	3.5	2.5	2	1.5
ms	16	12	9	7	5	4	3
2 x ms	32	24	18	14	10	8	6

Freq	20	25.2	31.7	40	50.4	63.5
ISO	20	25	31.5	40	50	63
1/2xMS	25	20	15.9	12.5	10	7.9
ms	50	40	31.7	25	200	15.9
2xMS	100	80	63.5	50	40	31.7

Freq	80	100.8	127	160	201.6	254
ISO	80	100	125	160	200	250
1/2xMS	6.3	5	4	3.1	2.5	2
ms	12.5	10	8	6.3	5	4
2xMS	25	20	16	12.5	10	8

Freq	320	403.2	508	640	806.3	1015.9
ISO	315	400	500	630	800	1000
1/2xMS	1.6	1.3	1	0.8	0.6	0.5
ms	3.2	2.5	2	1.6	1.3	1
2xMS	6.3	5	4	3.2	2.5	2

Freq	1280	1612.7	2031.9	2560	3225.4	4063.7
ISO	1250	1600.0	2000	2500	3150	4000
1/2xMS	0.4	0.3	0.3	0.2	0.2	0.1
ms	0.8	0.6	0.5	0.4	0.3	0.3
2xMS	1.6	1.3	1	0.8	0.6	0.5

Freq	5120	6450.8	8127.5	10240	12901.6	16255	20480
ISO	5000	6300	8000	10000	12500	16000	20000
1/2xMS	0.1	0.1	0.1	0.1	0	0	0
ms	0.2	0.2	0.1	0.1	0.1	0.1	0.1
2xMS	0.4	0.3	0.3	0.2	0.2	0.1	0.1

Q	O	N	1	c	1	1	a	1
0.4	3.00	36			2			2
0.7	2.00	24	2	d	3	2	b	3
1.4	1.00	12			4	3	c	4
3	0.50	6	3	e	5			5
6	0.25	3	4	f	6	4	d	6
9	0.17	2			7			7
12	0.13	1.5	5	g	8	5	e	8
18	0.08	1			9	6	f	9
			6	a	10			10
					11	7	g	11
			7	b	12			12
			8	c	13	8	a	13

Q	Oct	Notes	Q	Oct	Notes	Q	Oct	Notes	Q	Oct	Notes
-	-	-	5.00	0.29	3.46	10.00	0.14	1.73	15.00	0.10	1.15
0.10	6.67	80.07	5.10	0.28	3.39	10.10	0.14	1.71	15.10	0.10	1.15
0.20	4.75	57.03	5.20	0.28	3.32	10.20	0.14	1.70	15.20	0.09	1.14
0.30	3.70	44.45	5.30	0.27	3.26	10.30	0.14	1.68	15.30	0.09	1.13
0.40	3.02	36.27	5.40	0.27	3.20	10.40	0.14	1.66	15.40	0.09	1.12
0.50	2.54	30.52	5.50	0.26	3.14	10.50	0.14	1.65	15.50	0.09	1.12
0.60	2.19	26.26	5.60	0.26	3.09	10.60	0.14	1.63	15.60	0.09	1.11
0.70	1.92	23.00	5.70	0.25	3.03	10.70	0.13	1.62	15.70	0.09	1.10
0.80	1.70	20.43	5.80	0.25	2.98	10.80	0.13	1.60	15.80	0.09	1.10
0.90	1.53	18.36	5.90	0.24	2.93	10.90	0.13	1.59	15.90	0.09	1.09
1.00	1.39	16.66	6.00	0.24	2.88	11.00	0.13	1.57	16.00	0.09	1.08
1.10	1.27	15.24	6.10	0.24	2.83	11.10	0.13	1.56	16.10	0.09	1.08
1.20	1.17	14.04	6.20	0.23	2.79	11.20	0.13	1.55	16.20	0.09	1.07
1.30	1.08	13.01	6.30	0.23	2.75	11.30	0.13	1.53	16.30	0.09	1.06
1.40	1.01	12.12	6.40	0.23	2.70	11.40	0.13	1.52	16.40	0.09	1.06
1.50	0.94	11.34	6.50	0.22	2.66	11.50	0.13	1.50	16.50	0.09	1.05
1.60	0.89	10.65	6.60	0.22	2.62	11.60	0.12	1.49	16.60	0.09	1.04
1.70	0.84	10.04	6.70	0.22	2.58	11.70	0.12	1.48	16.70	0.09	1.04
1.80	0.79	9.50	6.80	0.21	2.54	11.80	0.12	1.47	16.80	0.09	1.03
1.90	0.75	9.01	6.90	0.21	2.51	11.90	0.12	1.45	16.90	0.09	1.02
2.00	0.71	8.57	7.00	0.21	2.47	12.00	0.12	1.44	17.00	0.08	1.02
2.10	0.68	8.17	7.10	0.20	2.44	12.10	0.12	1.43	17.10	0.08	1.01
2.20	0.65	7.80	7.20	0.20	2.40	12.20	0.12	1.42	17.20	0.08	1.01
2.30	0.62	7.47	7.30	0.20	2.37	12.30	0.12	1.41	17.30	0.08	1.00
2.40	0.60	7.16	7.40	0.19	2.34	12.40	0.12	1.40	17.40	0.08	0.99
2.50	0.57	6.88	7.50	0.19	2.31	12.50	0.12	1.38	17.50	0.08	0.99
2.60	0.55	6.62	7.60	0.19	2.28	12.60	0.11	1.37	17.60	0.08	0.98
2.70	0.53	6.38	7.70	0.19	2.25	12.70	0.11	1.36	17.70	0.08	0.98
2.80	0.51	6.15	7.80	0.18	2.22	12.80	0.11	1.35	17.80	0.08	0.97
2.90	0.50	5.94	7.90	0.18	2.19	12.90	0.11	1.34	17.90	0.08	0.97
3.00	0.48	5.74	8.00	0.18	2.16	13.00	0.11	1.33	18.00	0.08	0.96
3.10	0.46	5.56	8.10	0.18	2.14	13.10	0.11	1.32	18.10	0.08	0.96
3.20	0.45	5.39	8.20	0.18	2.11	13.20	0.11	1.31	18.20	0.08	0.95
3.30	0.44	5.23	8.30	0.17	2.08	13.30	0.11	1.30	18.30	0.08	0.95
3.40	0.42	5.07	8.40	0.17	2.06	13.40	0.11	1.29	18.40	0.08	0.94
3.50	0.41	4.93	8.50	0.17	2.04	13.50	0.11	1.28	18.50	0.08	0.94
3.60	0.40	4.79	8.60	0.17	2.01	13.60	0.11	1.27	18.60	0.08	0.93
3.70	0.39	4.66	8.70	0.17	1.99	13.70	0.11	1.26	18.70	0.08	0.93
3.80	0.38	4.54	8.80	0.16	1.97	13.80	0.10	1.25	18.80	0.08	0.92
3.90	0.37	4.43	8.90	0.16	1.94	13.90	0.10	1.25	18.90	0.08	0.92
4.00	0.36	4.32	9.00	0.16	1.92	14.00	0.10	1.24	19.00	0.08	0.91
4.10	0.35	4.21	9.10	0.16	1.90	14.10	0.10	1.23	19.10	0.08	0.91
4.20	0.34	4.11	9.20	0.16	1.88	14.20	0.10	1.22	19.20	0.08	0.90
4.30	0.33	4.02	9.30	0.16	1.86	14.30	0.10	1.21	19.30	0.07	0.90
4.40	0.33	3.93	9.40	0.15	1.84	14.40	0.10	1.20	19.40	0.07	0.89
4.50	0.32	3.84	9.50	0.15	1.82	14.50	0.10	1.19	19.50	0.07	0.89
4.60	0.31	3.76	9.60	0.15	1.80	14.60	0.10	1.19	19.60	0.07	0.88
4.70	0.31	3.68	9.70	0.15	1.78	14.70	0.10	1.18	19.70	0.07	0.88
4.80	0.30	3.60	9.80	0.15	1.77	14.80	0.10	1.17	19.80	0.07	0.87
4.90	0.29	3.53	9.90	0.15	1.75	14.90	0.10	1.16	19.90	0.07	0.87

Wet=100/(1+1/(%/100))

Dry	Wet	%	Dry	Wet	%	Dry	Wet	%	Dry	Wet	%	Dry	Wet	%
99	1	1%	89	11	12%	79	21	27%	69	31	45%	59	41	69%
98	2	2%	88	12	14%	78	22	28%	68	32	47%	58	42	72%
97	3	3%	87	13	15%	77	23	30%	67	33	49%	57	43	75%
96	4	4%	86	14	16%	76	24	32%	66	34	52%	56	44	79%
95	5	5%	85	15	18%	75	25	33%	65	35	54%	55	45	82%
94	6	6%	84	16	19%	74	26	35%	64	36	56%	54	46	85%
93	7	8%	83	17	20%	73	27	37%	63	37	59%	53	47	89%
92	8	9%	82	18	22%	72	28	39%	62	38	61%	52	48	92%
91	9	10%	81	19	23%	71	29	41%	61	39	64%	51	49	96%
90	10	11%	80	20	25%	70	30	43%	60	40	67%	50	50	100%