The cover art of Cream's Wheels of Fire, dimmed, beside a dark disc of concentric rings, one for each release of "White Room" measured, from period LPs at the center to the 2026 box set at the edge; each ring glows at its left–right phase difference, near 0 or −90 degrees.

Where Did the 90 Degrees Go? Haeco-CSG in Cream’s Wheels of Fire, from the 1968 LPs to the 2026 De-CSG

Cream’s Wheels of Fire came out in a 2026 Super Deluxe Edition billed as including a version without CSG. So how did CSG survive in the CDs, SACDs, and downloads that came before? I measured nine digital releases and five period LPs. Two questions came out of it, and I could answer only one.

Fairchild Thermo-Stylus Kit advertisement

Things I learned on Phono EQ curves, Pt.12

Pt.11 に引き続き Columbia LP Microgroove レコード登場に関する追加サイドストーリの他、録音記録側(主にカッター針や歪)の技術的背景、録音EQカーブ、再生側の技術的背景、当時の再生EQ補正回路に対する改造など、当時の技術雑誌記事や論文を頼りに読み解いていきます。