Scope: "Tuners, Metronomes & Music Stands" bundles three product types experts judge separately — electronic/mechanical tuners, metronomes (mechanical and electronic), and portable sheet-music stands — not instrument stands (those sit in the sibling leaf musical-instrument-cases). One register, split by product_type, each type with its own facet set.

Seed: The metronomes equivalent of "weave vs thread count" is mechanism (mechanical escapement vs quartz electronic) and detection method (microphone vs vibration sensor) — the spec that changes how the thing behaves, not the marketed headline number (price, or a generic "digital display"). A print production manager would notice first that the bundle's three product types have zero shared specs — a tuner's cents accuracy, a metronome's BPM control, and a stand's base/tilt are unrelated axes — the way a print spec sheet never shares columns across different substrates.

Sources:
[wikipedia_metronome] https://en.wikipedia.org/wiki/Metronome — mechanical escapement/pendulum weight vs electronic quartz mechanism — fetched excerpt
[wikipedia_tuner] https://en.wikipedia.org/wiki/Electronic_tuner — clip-on/pedal/soundhole/rack form factors, mic vs piezo sensing, needle/LCD/LED/strobe displays, chromatic vs instrument-specific — fetched excerpt
[wikipedia_music_stand] https://en.wikipedia.org/wiki/Music_stand — folding/heavy-duty/professional/conducting/non-portable/digital/marching stand types, wind tip-over, desk tilt — fetched excerpt
[wikipedia_a440] https://en.wikipedia.org/wiki/A440_(pitch_standard) — 440 Hz standardized as ISO 16 — fetched excerpt
[korg_ga2] https://www.korg.com/us/products/tuners/ga_2/ — calibration 430-450 Hz, built-in mic, auto pitch detection — fetched excerpt
[korg_ma2] https://www.korg.com/us/products/tuners/ma_2/ — pendulum-step/full-step/tap-tempo input, 0-9 beat time signatures, 8 rhythm patterns, timer/sound-out modes, calibration 410-480 Hz, ~400hr battery — fetched excerpt
[boss_tu3] https://www.boss.info/us/products/tu-3/ — tuning range C0-C8, reference pitch A4=436-445Hz, accuracy +/-1 cent, mute on pedal engage — fetched excerpt
[km_100_1] https://www.k-m.de/en/music-stands-with-collapsible-desk/100-1-music-stand-black — folding stand height 480-1230mm, steel, 1.25kg — fetched excerpt
[km_conductor_stand] https://www.k-m.de/en/conductor-stands/12330-orchestra-conductor-stand-base-black — conductor base height 840-1400mm, steel, 8.1kg — fetched excerpt

Branches: tuner leg (product_type=tuner) asks tuner_form_factor next, supported by wikipedia_tuner's form-factor taxonomy. metronome leg asks metronome_mechanism next, supported by wikipedia_metronome's mechanical/electronic split. music_stand leg asks stand_portability_class next, supported by wikipedia_music_stand's folding/professional/conducting taxonomy. mechanical metronome branch makes beat_subdivision_support and reference_pitch_standard irrelevant since Korg MA-2's rhythm-pattern and sound-out-tone features are electronic-only, per korg_ma2.

Noise: Korg GA-2's dedicated guitar (7-string) and bass (6-string) mode naming, and its "Quinta Flat" drop-tuning mode — too instrument-granular for a category-level facet, folded into tuning_mode_scope's switchable value. Boss TU-3's buffered bypass, AC-adaptor option, and High Brightness display mode — stage-convenience features, not an expert axis. K&M stand EAN code and exact base diameter (680mm/700mm) — SKU-level, not buyer-facing. Numbers I could not dual-source (mechanical metronome's 40-208 BPM Maelzel scale; exact LED-tuner ±9 cents and strobe ±0.02 cent figures; exact stand height/weight mm and kg) were kept out of facet text and left qualitative, per the two-source rule.

Corrections (2026-10-26):
- Added branches for tuner_form_factor's soundhole, rack_mount, and handheld_card (then_ask pitch_detection_method, kill mute_function), mirroring clip_on's existing branch and that facet's own backfill_note mapping these form factors to microphone detection.
- Added branches for stand_portability_class's heavy_duty_folding (ask stand_base_stability), non_folding_professional (ask stand_desk_tilt_adjustability), and non_portable_furniture (ask stand_desk_construction), so all 5 values now lead somewhere.
- Added a metronome_mechanism branch for app_software (ask tempo_control_method, kill metronome_power) and reworded its cold-start question (both splits[].question and the facet's cold_start_question) to "A wind-up metronome, a digital one, or a phone app?" so the question can actually elicit app_software.
- Reworded metronome_power's why_experts_care to drop "hundreds of hours on a single charge" — korg_ma2 describes disposable alkaline runtime, not a rechargeable charge, and the hours figure is single-sourced; now reads "many hours of rehearsal on a set of alkaline batteries" with no specific hour count claimed.
- Re-verified rather than dropped the boss_tu3 citation on tuning_accuracy_tier: curled https://www.boss.info/us/products/tu-3/specifications/ directly (saved to scratch/fix-metronomes/boss_tu3_specs.html) and found "Tuning Accuracy +/- 1 cent" in the fetched text, so the citation is sound and was left unchanged.
- Relabeled pitch_detection_method and tempo_control_method from source: listing to source: researched, matching each facet's own backfill_note admission that the value is usually inferred rather than read off a listing; softened their listing_field_hint wording to match.
- Added vocabulary entries for soundhole and rack-mount tuners (tuner_form_factor) and quadruped base (stand_base_stability), all previously used with no gloss.
- Added a new facet, stand_light_mount_compatibility (has_mount/no_mount/unknown), for the clip-on stand light accessory named in wikipedia_music_stand and confirmed by a second source — km_100_1's own site navigation lists music stand "Lights" as a distinct accessory category (see added supports line on that reference) — and excluded it from the tuner and metronome legs of product_type.
- Rejected check.md item 8 (reword tuner_form_factor's and stand_portability_class's cold-start questions to name all 5 values each): left both questions as-is. The branch-coverage fixes above already remove the "leads nowhere" failure the item warned about; packing 5 values into a 12-word cap would make the cold-start question harder to answer quickly for the common case, which the checker itself flagged as only a minor, optional candidate for rewording.