[nmstudioo]

Preserves the v7 limiter byte-for-byte. Adds optional Bass/Treble one-pole shelves with 20 ms gain smoothing.

Design

• Stage order: pre-gain → tone shelves → DC blocker → limiter
• Six @init slider defaults (RootlessJamesDSP UI requires them per HyperAudio v2 docs)
• b_gain != 1.0 bypass: neutral position is bit-identical to v7 output
• Snap-to-target on smoothed gains so slider return-to-zero is exact

Offline verification (via tests/eel/eel2py.py, numpy)

• Neutral (bass=0, treb=0) delta from v7: +0.000000 dB at every frequency
• Treble +6 dB: +0.51/+1.54/+3.14/+3.92/+4.51 dB at 1k/2k/4k/6k/10k (correct high-shelf direction)
• Treble −6 dB: −0.17/−0.59/−1.65/−2.50/−3.41 dB (mirror curve, expected one-pole asymmetry)
• Bass +6 dB: +4.87/+1.02/+0.35 dB at 100/500/1000 Hz (correct low-shelf direction)
• Limiter region: byte-identical to v7 (only desc: and //tags: differ)

Known characteristics (not bugs)

• One-pole shelves: +6 dB nominal gives ~+4.5 dB effective at 10 kHz
• Treble crossover at 4 kHz leaks ~+0.5 dB into 1 kHz presence range at +6 dB
• Bass crossover at 150 Hz leaks ~+1 dB into 500 Hz at +6 dB
• These are characteristics of the one-pole topology; a biquad shelf would be steeper (future work)

Pending

• Device test: UI renders 6 sliders, sliders move without clicks, subjective quality
• No files in src/profiles/ modified