How much gain do I need?

There is a constant question of microphone gain. And here is the microphone Gainstrolabe, an ancient device (this is humor) to answer this question depending on how loud you speak.

This Gainstrolabe (chart) shows the amount of vocal preamplifier gain required to target 100% on a common, 1.228V VU analog meter (at 1000Hz,) typical on analog recording gear. This with common conversational speech levels of 60dB(A) measured at one meter distance, and interpolated to more useful recording distances.

1.228V 100% dBVU is an agreed upon standard, and although there are multiple conflicting standards for digital and digital equivalency, this 0dBVU at 1000Hz signal should result in -18dB on a dBFS digital console meter or in recording software. A common digital voice recording target.

Most microphone preamps provide at least 50dB gain, with some providing 60 and a few, 70dB. So 70dB is a realistic maximum. A few ribbon microphone preamps offer 80dB of gain, but are not computer interfaces.

Your microphone specification hopefully has something that looks like this:

18mV/Pa

Find the most similar number along the left side of this chart. To the immediate right is the amount of gain required at a few common distances.

You may have to turn mobile devices horizontally for the chart to display properly

mV/Pa1″3″6″Examples
76.8
68.4
60.9
54.3
48.3
43.1
38.4
34.2
30.5
27.1
24.2
21.5
19.2
17.1
15.2
13.6
12.1
10.8
9.59
8.55
7.61
6.78
6.04
5.38
4.8
4.27
3.81
3.39
3.02
2.69
2.4
2.14
1.9
1.7
1.51
1.35
1.2
1.07		26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63		35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72		41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78		sE DCM6 with boost

sE DCM8 with boost




RODE NT1 4th, Blue Spark SL
sE X1s, RODE NTG3 shotgun
U87Ai, Lewitt LCT 440 PURE
sE 2200, NT1 5th, 416, TLM103
Blue SONA, AT2035
AKG P220, sE7, ETHOS
AT 4047/SV
KSM32, MXL 990, V67G







AKG C1000 pencil, RODE M2
SM81 pencil



SM94 pencil
SM86, e614, M88
KSM8, AKG D5, e835
SM87, sE DCM3 , sE DCM6
MD431 II
sE V7, SM58, sE DCM8, e945
SM57, MV7, Procaster, MD441U
RE20
SM48
Beyerdynamic M201
SM7B

Of course, you can record with less gain than needed and try to boost later or use a lifter/booster. You would simply subtract the cloud lifter/booster gain to see the remaining requirement from the preamp. there are advantages and disadvantages of this but the booster discussion is a different subject entirely.

Example USB interface with 70dB gain:
MOTU UltraLite MK5

Example USB interfaces with 60dB gain:
RME BabyFace
Presonus STUDIO 26c
SSL2

Example USB interfaces with 50dB gain:
Behringer UM2
Behringer UMC204HD/404HD
MOTU M2
Steinberg UR22C