Full past revision history of this site — all changes older than the "Recent updates" shown on the top page

Past revision history

What you'll find on this page: A full chronological list of all changes made to the lower-level pages (In a Nutshell, FAQ, Research Notes) of this site that are no longer shown in the "Recent updates" section on the top page.

For the latest updates, see the "Recent updates" section on the top page.

• April 11, 2026
  • ✏️ How record playback technology evolved — the interplay of stylus pressure, disc materials, and recording characteristics — Added Pierce & Hunt's findings on vertical compliance; minor wording fixes
  • ✏️ What sources did I use for this research? — An overview of the primary sources, books, papers, and interviews encountered over two years of investigation — Added Copeland (2008) to technical references and Moyer (1957) to trade magazines
  • ✏️ What sources did I use for this research? — An overview of the primary sources, books, papers, and interviews encountered over two years of investigation — Added Japanese-language resources section
  • ✏️ Why the RIAA curve became the industry standard — technology, politics, and economics — Added Moyer (1957) "eight characteristics" and "compromise" citations to Factor 2
  • ✏️ Why did the U.S. and Europe use different EQ curves — the divergence in turnover frequencies and its background — Added CCIR background and Copeland (2008) bibliographic details
• April 10, 2026
  • ✏️ Are U.S. stereo LPs recorded with RIAA curves — verification based on technical documents and engineer testimonies — Added primary sources (Westrex 1958 quotation in Evidence 1, new Evidence 5 on the standardization process and Evidence 6 on playback equipment), with tone adjustments
  • ✏️ When was the RIAA curve established — years of pre-history leading up to January 29, 1954 — Clarified the significance of the June 1954 RIAA standard document; added post-approval transition details from "The Curve That Conforms" (1954)
  • 🔔 Newly published: How generative AI is used in producing this site — what AI handles, and what it does not
  • 🔔 Newly published: Why lateral-cut rather than vertical-cut became the standard — the commercial outcome and the 1938 physical justification
  • 🔔 Newly published: The first-ever recording standard — the 1942 NAB and its revisions (1949, 1953 NARTB, 1964)
• April 9, 2026
  • ✏️ Overview and reading guide for "Things I learned on Phono EQ Curves," a 25-part blog series (plus a prologue) researched from primary sources over more than two years. Includes a per-part summary, links to related FAQs, and pointers to source material. — Added link to research sources FAQ in the reading guide
  • ✏️ Are U.S. stereo LPs recorded with RIAA curves — verification based on technical documents and engineer testimonies — Added section on the "label = curve" assumption
  • ✏️ Why so much disagreement about EQ curves, especially in Japan — organizing the structure of the debate — Expanded "The course of overseas debate" section with a concrete example
  • ✏️ (In a Nutshell Part 1) Why wasn't there a unified standard from the start? — From the birth of electrical recording (1925) to the NAB standard (1942) — Added "rolloff" terminology for the playback inverse characteristic; added context on recording technology as trade secrets
  • 🔔 Newly published: What sources did I use for this research? — An overview of the primary sources, books, papers, and interviews encountered over two years of investigation
  • ✏️ Why the RIAA curve became the industry standard — technology, politics, and economics — Added Boegli (1953) citation to Factor 2
  • ✏️ (In a Nutshell Part 2) How did unification finally happen? — From the postwar era to the birth of the RIAA curve (1942–1954) — Corrected the date of the Hollywood Sapphire Group's first meeting
  • ✏️ How did listeners actually play records before RIAA unification — casual listeners, audiophiles, and professionals — Added Boegli (1953) and Kendall (1954) citations to consumer amplifiers section
• April 8, 2026
  • 🔔 Newly published: A 100-year history of phono EQ curves in three parts: from electrical recording to NAB (1925-1942), postwar to RIAA (1942-1954), and stereo LPs to today (1954-present).
  • 🔔 Newly published: Overview and reading guide for "Things I learned on Phono EQ Curves," a 25-part blog series (plus a prologue) researched from primary sources over more than two years. Includes a per-part summary, links to related FAQs, and pointers to source material.
  • 🔔 Newly published: What was the Columbia LP curve (500C-16) — its technical characteristics, adoption history, and transition to RIAA
  • 🔔 Newly published: Do you need a variable-EQ phono equalizer — decision criteria based on your collection
  • 🔔 Newly published: Can you hear a difference when you change the EQ curve? Yes — but "the sound changed" and "the right curve was found" are two different things
  • 🔔 Newly published: Is it the EQ curve or mastering that determines the sound of a record — from the perspective of the entire signal chain
  • 🔔 Newly published: Should you trust listening tests or historical documents when identifying EQ curves — the difference in what each method can answer
  • 🔔 Newly published: What EQ curves were used on 1948–1958 mono LPs — why there is no single right answer
  • 🔔 Newly published: How should pre-RIAA records be played on modern equipment — sorting out practical options
  • 🔔 Newly published: Are there reliable references for EQ curves — research-based resources and criteria for evaluating source reliability
  • 🔔 Newly published: Rudy Van Gelder's cutting equipment and EQ curves — what the equipment records and his own testimony tell us
  • 🔔 Newly published: What was the Sapphire Group — the gatherings that broke down industry secrecy and paved the way for standardization
  • 🔔 Newly published: What factors besides the EQ curve affect the sound of a record — an overview of the signal chain from recording to cutting
  • 🔔 Newly published: Are U.S. stereo LPs recorded with RIAA curves — verification based on technical documents and engineer testimonies
  • 🔔 Newly published: Stokowski and Bell Labs experimental recordings — how a conductor and engineers pioneered high-fidelity recording
  • 🔔 Newly published: Why so much disagreement about EQ curves, especially in Japan — organizing the structure of the debate
  • 🔔 Newly published: What is the hot stylus — the technology that transformed recording quality and helped standardize EQ curves
  • 🔔 Newly published: Records have physical limits: low frequencies make the groove swing too wide, highs get buried in noise. Recording cuts the lows and boosts the highs; playback reverses it. That's phono equalization — the modern standard is the RIAA curve.
  • 🔔 Newly published: When did major U.S. labels move to the RIAA curve — a list based on verifiable documents
  • 🔔 Newly published: When was the RIAA curve established — years of pre-history leading up to January 29, 1954
  • 🔔 Newly published: Who invented the LP — the contributions of three key figures and how to read their conflicting accounts
  • 🔔 Newly published: (In a Nutshell Part 1) Why wasn't there a unified standard from the start? — From the birth of electrical recording (1925) to the NAB standard (1942)
  • 🔔 Newly published: (In a Nutshell Part 3) What does this history mean for playing records today? — Post-RIAA transition, stereo LPs, and the open questions that remain
  • 🔔 Newly published: How record playback technology evolved — the interplay of stylus pressure, disc materials, and recording characteristics
  • 🔔 Newly published: Why the RIAA curve became the industry standard — technology, politics, and economics
  • 🔔 Newly published: Why did the U.S. and Europe use different EQ curves — the divergence in turnover frequencies and its background
  • 🔔 Newly published: (In a Nutshell Part 2) How did unification finally happen? — From the postwar era to the birth of the RIAA curve (1942–1954)
  • 🔔 Newly published: What is the RIAA curve — definition, three time constants, history, and current status
  • 🔔 Newly published: How did listeners actually play records before RIAA unification — casual listeners, audiophiles, and professionals
  • 🔔 Newly published: Key terms in phono EQ curves — turnover, time constants, curve notation, and more
  • 🔔 Newly published: What EQ curve should you use for 78 rpm records — an honest look at an open question
  • 🔔 Newly published: What EQ curves were used before RIAA, and why were there so many
  • 🔔 Newly published: What was the Battle of the Speeds — Columbia LP vs RCA Victor 45, how it was resolved, and its connection to EQ curves