Precision Sound Level Meter

Engineering Psychology

Accession Number: 2014.ep.3

Instrument Name: Precision Sound Level Meter

Description:

Instrument: The instrument has rectangular-shaped, pale-green, painted-metal body. The head of the instrument is cone-shaped, with a round-metal output for attaching a microphone. The interface of the instrument has a large, clear plastic and black painted-metal rotary knob, ranging from 10dB to 130dB. Below the knob is a glass meter dial, containing a measurement scale and a measurement needle. Below the dial is a medium-sized black painted-metal knob. Adjacent to the right side of the knob is a silver, metal input and output for an amplifier. Adjacent to the left side of the knob is another set of silver, metal input and output for a Octave Filter, which is attached below the body of the device. The body of the device is heavy and includes leather strap for carrying. ***The instrument is designed to be battery-powered, but it is unknown whether batteries are currently contained inside the device.

Case: The device is contained inside a leather hard-case, with brushed-metal edging separating the top and bottom parts of the case. The case is sealed using metal latches that are placed on in either side of a plastic handle. The inner lid of the case contains five paper manuals for operating functions for device and accessories: 1. Precision Sound Level Meter 2203, 2. Artificial Ear Type 4152, 3. 2230 Brüel & Kjær Start-Up Guide, 4. Service Instructions Octave Filter Installation 1613, 5. Service Instructions Precision Sound Level Meter 2230. The inside of the case is lined with foam, cushioning the Precision Sound Level Meter and its accessories.

Primary Materials:

Instrument: Painted Metal, Plastic, ?Steel Case: Leather, ?Steel, Plastic

Markings:

Several of the objects contained in the case feature a maker’s mark and serial number:

Instrument Anterior: “PRECISION SOUND LEVEL METER, TYPE 2203″, “OCTAVE FILTER TYPE 1613″

Plaque on instrument base: “BRUEL & KJAER, COPENHAGEN, SERIAL NUMBER: 290753)

Plaque on Posterior of Wooden Consender Microphone: “TYPE 4144, BRUEL & KJAER, COPENHAGEN, SERIAL NUMBER: 281046″

Plaque on Posterior of Wooden Condenser Microphone: “TYPE 4145, BRUEL & KJAER, COPENHAGEN, SERIAL NUMBER: 281597″

Plaque on base of Artificial Ear Type: “ARTIFICIAL EAR, TYPE 4152, BRUEL & KJAER, COPENHAGEN, SERIAL NUMBER: 304684″, “BRUEL & KJAER CANADA LTD, 809 LAJOIE AVE, (MONTREAL 760), QUE, PURCHASE DATE: JUNE 11 1970″

Dimensions (cm):

Instrument (with Octave Filter Set): Height= 6.35 cm. Width= 46.99 cm, Length= 12.7 cm, Case:

Function:

The original manual states that the device’s most common use is “mainly intended for the quick and accurate measurement of noise from traffic, and within factories and buildings as the instrument gives a direct scale reading in decibels” [Christensen, 2010]. The Artificial Ear attachment can be used for measuring sound in a similar way to the human ear, giving an objective, reproducible indication of sound level.

Condition:

The apparatus is good condition. The outer latch on the device’s case is broken. As a result, the case should not be picked by its handle and handled carefully to prevent its contents from falling out. The metal edging on the case displays signs of oxidization. The foam lining protecting objects inside the case has begun to flake significantly. The Precision Sound Level Meter is in excellent condition, with very few signs of cosmetic wear. The wooden box containing the Condenser Microphone Cartridge Type 4144 has a broken latch which has been repaired with masking tape. Artificial Ear is missing a rubber stopper on its base. The Microphone Windscreen is missing from the case, but may be misplaced with other objects in UTSIC’s collection.

Manufacturer: Brüel & Kjær

Date of Manufacture: ca. ?1967 – 1970

Provenance:

Purchased for the University of Toronto between 1970 and 1980 by Professor Patrick J. Foley.

Acquired from Professor Paul Milgram of the University of Toronto Engineering Psychology Department in October 2012.

Additional Information and References:

1. Brüel & Kjær, “Instructions and Applications: Artificial Ear Type 4152”, Copenhagen: Brüel & Kjær.

2. Brüel & Kjær. 1969. Instructions and Applications: Precision Sound Level Meter 2203, Copenhagen: Brüel & Kjær.

3. Christensen, Leif Sloth. 2010. “50th Anniversary of World’s First Sound Level Meter.” Waves 1 (2): March 8 2014.

4. Milgram, Paul., e-mail message to Dalby, Meaghan. March 3 2014.

Donated to UTSIC: Yes

Historical Notes:

The Brüel & Kjær Precision Sound Level Meter 2203 was the world’s first precision hand-held meter. This type was produced for twenty-one years, selling over 17,300 units [Christensen, 2010]. Unlike previous models, the 2203 could be operated by one person as the configuration of attaching a stable, free-standing, microphone to the device allowed sound to be measured without the need of an assistant to hold the microphone.

At the University of Toronto, the device was likely used by Professor Patrick J. Foley to demonstrate measurement techniques in Human Factors classes [Milgram, 2014]