Recover analyzer DSP and realtime pipeline corrections

www/meters/ppm_din.js

@@ -8,7 +8,7 @@ import { HEADER_BG, LABEL_COLOR, MID_COLOR, WARN_COLOR } from '../core/theme.js'
 
 export const id = 'ppm-din';
 
-const DEFAULT_DECAY_DB_PER_S = 20 / 1.7; // 20 dB in ca. 1.7 s → ~11.76 dB/s
+const DEFAULT_DECAY_DB_PER_S = 20 / 1.5; // RTW/DIN: 20 dB in 1.5 s
 const DEFAULT_HOLD_MS = 1000;
 
 const DIN_SCALE = [
@@ -79,7 +79,7 @@ export function initShared(CONFIG = {}) {
     },
     // Offset for DIN uses PPM_DIN_OFFSET so that 0 dB on the meter aligns
     // properly with the Permitted Maximum Level (PML).  According to the
-    // DIN Type I specification, 0 dBu (≈−15 dBFS peak) should read −9 dB.
+    // selected alignment profile maps 0 dBu to either -6 dB or legacy -9 dB.
     offset: Number(CONFIG.PPM_DIN_OFFSET) || 0,
     refDbfsFor0: Number.isFinite(CONFIG.PPM_REF_DBFS_PEAK_FOR_0_DBU)
       ? CONFIG.PPM_REF_DBFS_PEAK_FOR_0_DBU