The first-ever recording standard — the 1942 NAB and its revisions (1949, 1953 NARTB, 1964)

The first-ever recording standard — the 1942 NAB

Question answered on this page: How was the 1942 NAB standard — the world's first recording and reproducing standard — established? How did its subsequent revisions lead to the RIAA curve?

In short

In May 1942, the NAB (National Association of Broadcasters) established the first-ever recording and reproducing standard. Officially titled "NAB Recording and Reproducing Standards," it targeted broadcast transcription discs (16-inch, 33⅓ rpm) and covered sixteen items ranging from physical disc dimensions to recording frequency characteristics.

The standard went through the following revisions:

→ When was the RIAA curve established? — the 1953–1954 standardization push

Why was standardization needed?

In the late 1930s, broadcast transcription discs were manufactured by multiple companies, each using its own recording characteristics. Broadcasters had to apply different equalization for each disc — an inefficient and confusing situation.

The turning point came in 1939, when RCA/NBC announced the Orthacoustic curve. It combined high-frequency pre-emphasis with a bass shelf to improve the signal-to-noise ratio and dramatically raise the quality of transcription discs. However, the prospect of an RCA proprietary curve becoming the de facto standard was not welcome to competing companies.

Against this backdrop, NAB stepped in to establish a standard that would represent the entire industry.

Committee structure and the standardization process

In May 1941, NAB launched the Recording and Reproducing Standards Committee. The committee chair was NAB's Director of Engineering, Lynne C. Smeby. By August 1941, membership had reached 58, representing "practically all the leaders in the field."

The Executive Committee members were:

• R.M. Morris (NBC) — Executive Committee Chairman
• H.A. Chinn (CBS)
• C. Lauda, Jr. (World Broadcasting System)
• E.T. Mottram (Bell Telephone Laboratories)
• I.P. Rodman (Columbia Recording)
• L.C. Smeby (NAB) — Committee Chairman, Director of Engineering

The committee included experts from RCA, Columbia, Bell Labs, Presto Recording, Audio Devices, and even Harvard professor Frederick V. Hunt — a broad cross-section of everyone involved in recording and reproduction.

"Some controversy occured toward the formulation of sixteen items, but overall the process went very peacefully and democratically."

— Smeby, "Recording and Reproducing Standards," Proc. IRE, August 1942

In May 1942, the standards were approved by the NAB Board of Directors.

→ The full story from committee launch to approval is covered in blog post Pt.8

What the 1942 NAB standard covered

The standard comprised sixteen items covering both physical specifications and recording characteristics.

Physical specifications (items 1–12, 15–16): Outer disc diameter, center hole diameter, groove spacing, turntable speeds (33⅓ and 78.26 rpm), wow factor, record warp, minimum label information, and more.

Recording frequency characteristics (items 13–14): The most important items.

• Item 13: Frequency Characteristic for Vertical Recording — derived from the Bell Labs/Western Electric curve
• Item 14: Frequency Characteristic for Lateral Recording — derived from the RCA/NBC Orthacoustic curve

The high-frequency pre-emphasis time constant for lateral-cut discs was specified as 100 μs (+16 dB at 10 kHz). This value would become a point of contention for years to come.

Notably, the standard specified frequency response curves (graphs) rather than circuit parameters or time constants. This was intentional: studios used diverse circuit designs, and the standard was kept flexible enough not to mandate any particular circuit topology.

The 100 μs pre-emphasis debate

The 1942 NAB curve's high-frequency pre-emphasis drew criticism almost from the start. Serious discussion began after the war, in 1947.

At the 1947 NAB Recording Standards Meeting, several experts raised concerns about 100 μs.

Theodore W. Lindenberg (Fairchild Camera and Instrument) opened the debate:

"I have had the feeling for some time that the high frequency uplift is a little bit overdone. In our present day assembly the greatest thing to my mind is the heavy level of transcriptions. I think that we should consider a decrease in the high frequency pre-emphasis."

— NAB Reports, September 29, 1947, Vol.15, No.39

R.A. Miller (Bell Telephone Laboratories) concurred:

"today Bell Laboratories, as an apparatus designed of equalizers, was being requested continuously to put as many as 24 to 27 restoring networks in their equalizers, and that, therefore, there must be considerable agreement with the present curve and that they generally feel that the rise at the high end is too much for good wide band reproduction."

— ibid.

A.E. Barrett (BBC) noted that the NAB pre-emphasis was too extreme even for BBC equipment:

"the NAB pre-emphasis characteristic was more extreme than the BBC could use with its present equipment, for the tendency to overload on lighter frequencies was too great."

— NAB Recording Standards Meeting, Audio Engineering, October 1947

In response, Executive Committee Chairman R.M. Morris (NBC) struck a cautious note:

"while many believed that the high frequency pre-emphasis had been too high, the adherence to the NAB standards for electrical transcriptions had been good"

— ibid.

The meeting concluded that any revision should be carried out carefully, with due consideration for the impact on existing recording libraries. As a result, 100 μs remained unchanged in 1947.

→ Detailed minutes of the 1947 meeting are covered in blog post Pt.10

The 1949 revision — tape took priority

In April 1949, the NAB standard was revised. However, the disc recording curves were carried over unchanged from 1942.

There were two reasons.

First, formulating a magnetic tape standard was the top priority. After the war, magnetic tape recording was spreading rapidly among broadcasters, and the committee's attention was focused on tape standards.

Second, the Columbia LP complicated matters. Columbia introduced the LP in June 1948, and its recording characteristics were very similar to the 1942 NAB curve. A major change to the disc curve could have created compatibility problems with the newly launched format.

Thus, the 100 μs issue raised in 1947 was once again deferred.

1953 NARTB — finally 75 μs

In June 1953, NAB — by then officially renamed NARTB (National Association of Radio and Television Broadcasters) — undertook a comprehensive revision of the recording and reproducing standards.

The most significant change was that the high-frequency pre-emphasis time constant was lowered from 100 μs to 75 μs. The rise at 10 kHz dropped from +16 dB to +13.7 dB. The frequency response range was also extended from 10 kHz to 15 kHz.

The 75 μs value was identical to the high-frequency time constant of RCA Victor's New Orthophonic curve, which had been in use since around 1952. In December 1953, the AES (Audio Engineering Society) tentatively approved a standard playback curve with the same time constants, and in January 1954, the RIAA approved recording and reproducing characteristics with the same time constants. Three standardization bodies converged within just six months — because their memberships overlapped and they were coordinating their efforts.

H.E. Roys (RCA Victor) was particularly central to this coordination, serving on standardization committees for NAB/NARTB, AES, RIAA, EIA, and ASA (the predecessor of ANSI).

→ The detailed timeline of 1953–1954 standardization is covered in When was the RIAA curve established?

→ Why the RIAA curve stuck as the industry standard is covered in Why did RIAA become the standard?

1964 NAB — vertical removed

In February 1964, NAB revised the recording and reproducing standards once more. Two significant changes were made.

First, vertical-cut discs were removed from the standard. Since 1942, the standard had included recording characteristics for both lateral and vertical. By 1964, vertical-cut transcription discs had long since disappeared.

Second, the lateral characteristic was redefined as a "reproducing" rather than a "recording" characteristic. The 1942 standard had specified the curve from the recording side; the 1964 revision reframed it from the reproducing side. This reflected a shift in the standard's function.

The 1964 NAB disc standard was nearly identical to the 1954 RIAA standard.

→ How vertical-cut discs figured in standardization history is covered in Why did lateral-cut become the standard?

Historical significance of the NAB standard

The NAB standard holds a uniquely important place in the history of sound recording.

The world's first recording and reproducing standard. Before NAB, no comprehensive standard covering recording frequency characteristics existed. Each company recorded with its own curve, and playback equipment had to be adjusted disc by disc.

A precedent for democratic process. The deliberations of a 58-member committee set the template for subsequent standardization by NARTB, AES, and RIAA. Building consensus across the entire industry took time, but the result was a durable standard that everyone could accept.

The lesson of the 100 μs debate. Six years elapsed between the recognition of the problem in 1947 and its resolution in 1953 — a record of the industry struggling between caution toward existing libraries and the pursuit of technical correctness.

Related pages

• → When was the RIAA curve established? — the 1953–1954 standardization push
• → What is the RIAA curve? — definition and time constants
• → Why did RIAA become the standard? — technology, politics, and economics
• → Why did lateral-cut become the standard? — the history of vertical-cut discs
• → What curves existed before RIAA? — major pre-RIAA curves

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