sound dB meters

Introduction

sound level meters are generally quite cheap for basic models
these usually measure sound level via a capacitative / condenser microphone with a wind filter
basic units usually use only A frequency weighting (often denoted dbA or just dB) which is optimized for general environmental use
- advanced units may also have:
  - C frequency weighting - mainly for assessing engines
  - Z frequency weighting which is essentially a flat response at all frequencies and is often used to measure infrasound - this is denoted as dBZ
most have a switchable option for fast 0.125sec vs slow 1sec
most detect a frequency range of 31.5Hz to 8kHz and measure 30-130dB and provide the option of showing max/min levels
some allow analysis over time on a PC via USB connection and specialized software
most are powered by AAA batteries and have auto-power off

sound level	human hearing
0-20dB	silence - you can bearly hear it
20-40dB	whisper level
40-60dB	ordinary room conversation
60-70dB	noisy
70-90dB	very noisy
90-100dB	very loud
100-120dB	can be unbearable, prolonged exposure causes hair cell damage
>120dB	high risk of hair cell damage even in fairly short exposures

Danoplus SLM-390
- offers A/C/Z weightings
- USB connection for PC analysis
- tripod mount
- measuring levels: 30~70dB, 60~90dB, 80~110dB, 100~130dB
- sampling rate: 2 times/s
- fast 0.125sec / slow 1sec
- 31.5Hz~8kHz
- https://www.aliexpress.com/item/1005007210555769.html ~$AU60
Habotest HT622B
- offers A/C weightings
- USB connection for PC analysis
- measuring levels: 30~80dB, 40~90dB, 50-100dB, 60~110dB, 70-120dB, 80~130dB
- fast 0.125sec / slow 1sec
- 30Hz~8kHz
- https://www.aliexpress.com/item/1005009965720154.html ~$AU35
various more compact A weighting only models
- usually available for under $AU20