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Extech · Extech 407732-KIT Sound Level Meter Kit, 35-130dB, with Calibrator
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Verdict
The 407732-KIT is the right way to buy a general-purpose sound level meter if the readings will be reported to anyone. The meter is a Type 2 instrument with a 35 to 130 dB range, A and C weighting and fast and slow response, which covers workplace, classroom, plant-room and neighbourhood noise checks. The kit adds a calibrator, and that is the point: a sound meter should be checked against a known level before and after each session, and without a calibrator there is no way to do it. A caution about the Amazon listing: its feature bullets describe a humidity and temperature datalogger, not this meter, so we have relied on the listing title and on Extech’s documentation. For a display-only meter without the calibrator, the Extech SL510 is the lower-cost option.
Who It Is For
- Health and safety officers doing workplace noise screening that will be written up.
- Facilities teams checking plant rooms, ventilation and open-plan offices.
- Consultants and estates staff who need a verified reading rather than an indication.
Our guide to choosing a sound level meter explains when a Type 2 meter is enough and when a Type 1 instrument is required.
Documented Specifications
| Item | Documentation |
|---|---|
| Class | Type 2 general-purpose |
| Range | 35 to 130 dB |
| Weighting | A and C (Extech documentation) |
| Response | Fast and slow (Extech documentation) |
| Kit contents | Meter and sound calibrator |
| Listing note | Amazon bullets describe a different product; title and Extech datasheet used |
About the Listing
The Amazon listing title correctly identifies the 407732-KIT and its range and calibrator, but the five feature bullets talk about datalogging 16,000 readings, a triple LCD showing humidity and temperature, and programmable alarms. Those describe an Extech datalogger, not a sound meter. Listing errors of this kind are common with older instrument stock, and they are a reason to confirm the model on the box on arrival and to download the manufacturer datasheet before relying on any figure. Nothing in this review is taken from those bullets.
Why the Calibrator Matters
A sound level meter’s microphone drifts with temperature, humidity and age, and a reading that cannot be tied to a check is an indication rather than a measurement. A calibrator fits over the microphone and generates a reference tone at a stated level. The procedure is to fit it, confirm the meter reads the reference within its tolerance, take the survey readings, and repeat the check at the end. If the two checks agree, the readings between them stand. This is the routine expected in any workplace noise assessment, and it is the reason to buy the kit rather than a bare meter. For a fuller explanation of traceability, see how to read a calibration certificate.
Weighting and Response
A-weighting reduces the low and very high frequencies to approximate how the ear perceives loudness and is the weighting used for almost every occupational and environmental limit. C-weighting is nearly flat and is used for peak levels and for low-frequency plant noise. Fast response tracks fluctuating sound; slow response averages over a longer interval and gives a steadier number for a continuous source. The guidance you are measuring against tells you which combination to use, and the 407732 provides all four.
The 35 to 130 dB Range
The lower limit of 35 dB is quiet enough for a bedroom or a library at night; the upper limit of 130 dB covers pneumatic tools, sirens and concert levels. Between them sit the levels that matter for most surveys: conversation in the 60s, busy traffic in the 70s, a workshop in the 80s and 90s. Most owners use the meter to answer the question of whether a space is above or below a specific threshold, and for that a Type 2 meter with a calibrator is sufficient.
Strengths
- Calibrator included, which most competing meters omit.
- Type 2 class with the standard weightings and responses.
- Range covers quiet rooms through to loud industrial sources.
Limitations
- Amazon listing bullets are for a different product.
- No PC logging on the 407732 itself.
- Type 2, not Type 1; not for legal or laboratory measurements.
How It Compares
The Extech SL510 is a compact Class 2 meter with a backlit display and the same 35 to 130 dB range, without a calibrator. The Extech 407750 adds an RS-232 interface for PC logging. The Extech EN300 includes a sound function among five environmental measurements for quick screening. Choose the 407732-KIT when readings must be verified.
How We Research
This review is based on Extech’s published documentation for the 407732, the Amazon listing title (the bullets describe a different product), and owner reports for Extech sound meters. We did not run laboratory tests.
Recommended Tools
Products shown because their documented specifications fit this guide. Price and availability are on Amazon and can change.
Frequently Asked Questions
What is in the kit?
The listing title states a sound level meter with a 35 to 130 dB range and a calibrator. The calibrator produces a known level at the microphone so the meter can be verified on site.
Why do the Amazon bullets mention humidity and a USB datalogger?
The feature bullets on the listing describe a different Extech product, a humidity and temperature datalogger. They do not apply to the 407732. We used the listing title and Extech documentation instead.
What does Type 2 mean?
A general-purpose accuracy class for sound level meters, accepted for most occupational and environmental noise screening. Type 1 is the precision class used for laboratory and legal measurements.
Does it log to a PC?
Extech documents the 407732 as a display meter. For PC logging over a serial interface, the Extech 407750 is the related model.
Affiliate disclosure: Akermin earns a commission from qualifying Amazon purchases made through links on this page. Our editorial picks are based on documented specifications and owner feedback, not commissions.
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