Kohji Matsubayashi (松林弘治)

Things I learned on Phono EQ curves, Pt. 10

EQカーブの歴史、ディスク録音の歴史を学ぶ本シリーズ。前回 Pt.9 では、1940年代に市販用シェラック盤がどのような設定で聴かれていたか、そしてどのように記録されていたか、を調べました。

On the previous part 9, I studied on the settings and the trends of how the commercial shellac records were reproduced (and recorded) in the 1940s.


This time, I am going to continue learning the history of disc recording – some of the notable discussion after WWII, especially the 1949 revision of the NAB Standards, around the advent of microgroove LP records. More detailed stories on equalization curves will hopefully included on this Pt.10 and the following parts.

MacArthur Cuts Radio Rep In Japanese Area (1945)

source: “MacArthur Cuts Radio Rep In Japanese Area”, The Billboard, Vol.57, No.42, October 20, 1945, p.4

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Kohji Matsubayashi (松林弘治)

Things I learned on Phono EQ curves, Pt. 9

EQカーブの歴史、ディスク録音の歴史を学ぶ本シリーズ。前回 Pt.8 では、1942年に策定された、放送局用トランスクリプション盤向けの録音・再生標準規格、通称「NABカーブ」についての歴史を調べました。

On the previous part 8, I studied on the history and background of “1942 NAB Curve”, the first recording/reproducing standards for electrical transcription discs used in the broadcasting industry.


This time, I am going to continue learning the history of disc recording – during the WWII, as well as post-WWII period, until the advent of microgroove LP records. This include growing discontent with the quality and experience with commercial shellac records, as well as how listeners and engineers tried to deal with “EQ curves” in these years. So this article is the exploration of “how the things were regarded at that time”, not of “what is the correct answer”.


Please note that this article contains the topics whose primary information (such as technical documentation and engineers’ notes) is rarely found, and I am going to read many magazine articles about the topics, to understand the situation of the 1940s indirectly.

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Kohji Matsubayashi (松林弘治)

Things I learned on Phono EQ curves, Pt. 8

前回 Pt.7 では、圧電素子を使ったクリスタルカートリッジの普及とジュークボックスの関係、また Brush Development が提唱していたクリスタルカッターを使った定振幅記録再生(イコライズレス)の試みなど、あれこれについて調べました。

On the previous part 7, I studied on the advent of piezo-electric pickups and the relationship with jukeboxes; an attempt to popularize constant-amplitude recording/reproducing without utilizing equalizers, etc.

今回はその続きで、ついに、史上初めて標準規格として策定された、1942 NAB の経緯について、長文になりますがみていきましょう。

This time, I am going to continue learning the history of 1942 NAB Standards, the first standardization ever in industry. It will become a very long article, but anywhere here we go.

Standard Frequency Characteristics for “Vertical and or “Lateral” Recordings (Nov. 23, 1942)

Western Electric Vertical/Lateral Recording Characteristics (1942 NAB), drawn on Nov. 23, 1942
Western Electric 社の縦振動/横振動用録音カーブ (1942 NAB vertical/lateral) をプロットした貴重なグラフ (Nicholas Bergh さん提供)
photo courtesy of Nicholas Bergh.

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Kohji Matsubayashi (松林弘治)

Things I learned on Phono EQ curves, Pt. 4

前回 は、大恐慌時代の1930年代前半、WE特許使用料回避のため生まれたBlumleinシステムや、当時のRCA VictorやColumbiaの状況など、あれこれについて調べました。

On the previous part, I studied on the history of the improvement of disc recording technology for commercial discs, including the Blumlein system, situations of RCA Victor and Columbia in the 1930s (during the Great Depression), etc.


This time, I am going to continue learning the history, from the disc recording technology for professional talking motion pictures and broadcast stations (not regular records for consumer market), and the very important technology that consiously used treble pre-emphasis for the first time in history, to increase S/N ratio.

Vertical cutting vs Lateral cutting (Read, 1952)

source: “The Recording and Reproduction of Sound”, Oliver Read, 2nd Edition, 1952, p.21, Fig. 3-3B.

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Kohji Matsubayashi (松林弘治)

Things I learned on Phono EQ curves, Pt. 1

Pt.0 (はじめに) の続きです。

This article is a sequel to “Things I learned on Phono EQ curves, Pt.0”.


Before digging deeper about EQ curves, I started to study from the very beginning: why the EQ curve was born, why it was/is needed for phonograph recording (and playback). Also, I tried to re-study the very basic – how the recording sounds are converted to a modulated spiral groove. So I’m afraid it will take very long before I reach the story of the EQ curve itself…

Digital image of the surface of 78 rpm record taken with optical magnification. The illumination is coaxial (the light falls vertically onto horizontal record), therefore only horizontal parts of the record reflect the light back into the optical system. These include the inter-groove surface of the record represented by the wide bands in the picture, and the bottom portion of the groove, represented by the thin lines. The scratches on the inter-groove surface are clearly seen. The size of the imaged surface is 2.35 x 2.19 mm 2 .

Audio Reconstruction of Mechanically Recorded Sound by Digital Processing of Metrological Data – Scientific Figure on ResearchGate.
Available from: https://www.researchgate.net/figure/Digital-image-of-the-surface-of-78-rpm-record-taken-with-optical-magnification-The_fig1_242606860 (accessed 4 Sep, 2022)

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Kohji Matsubayashi (松林弘治)

What the EP (Extended Playing) Originally Stands For

Google Books 上で The Billboard (米「ビルボード」誌)のバックナンバーが1942年のものからほぼ全て閲覧可能になっています。これにより、レーベル、レコード製造、アーティストの動向など、当時のレコード業界のさまざまな側面の歴史を調査するのが格段に楽になりました。これまでは、図書館のような施設で閲覧したり、目星をつけた号を古本屋やオンラインオークションで購入するしかなかったのですから、コンピュータ上でネットワーク越しに検索しながら目当ての記事を閲覧できるというのは、隔世の感があります。

Almost all back issues of The Billboard magazine (since 1942) is searchable and browsable on Google Books website. This enables us to do very convenient research through the web, on history of record labels, record production, artists and many other topics on record industries in the past. Previously we had to go to libaries to look for specific back issues, or we had to look for and buy them at second hand bookstores or at online auctions.

今回は、マイクログルーヴレコード黎明期の「コロンビア対RCAヴィクター」 「33 1/3 対 45」回転数競争あたりからはじめて、諸説入り乱れて解釈が分かれている「EP」というタームについて、過去の資料を探ってみましょう。Wikipedia 日本語版 では 33 1/3回転7インチ盤である、と書かれている EP盤ですが、それは 誤り で、あくまで45回転7インチ盤の一種である、ということがお分かり頂けるかと思います。

This time I am looking up some back issues, to what the term “EP” originally stood for – the term sometimes has been misunderstood (and there has been various opinions on it). So let’s get started with the old 1948 article on the “Speed Battle” – 33 1/3 v.s. 45, Columbia v.s. RCA Victor.

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