FOREST — Restoration Plan

Bogdan Perzyński, 52-42-N-23-52-E · Liliana Bloch Gallery, Dallas · 29 August 2026
Prepared by Jim Slagle, with AI assistance (Claude, Anthropic), from the project record, manufacturer documentation, and bench measurements. Companion tools: the calibration app · bench certification video (30 s)

The short version

The mystery of the two “bad” relays is solved, and the news is good on every front.

First: the continuity test Bogdan directed near midnight on 21 August found the real fault — the cable feeding audio from the Mackie to the relay had an open return conductor. Signal could leave the mixer but the circuit was never complete. Every relay connected through that cable was receiving nothing at all, which is why no amount of adjustment on either unit ever changed anything. The cable was repaired on the spot at 11:45 that night, minutes before closing — too late to test.

Second: on 27 August the RDL ST-ACR2 was put through a full bench certification with laboratory instruments (signal generator, oscilloscope, precision meter). It passed every test. Thirty seconds of video: youtu.be/tHjqgSkfVFQ — the relay triggers on audio, holds, and releases exactly per RDL's specification. The unit was never defective; the broken cable upstream had been silently starving it. It has already been programmed on the bench with the production 15-second release delay, so it arrives at the gallery ready to install.

Therefore: one more gallery visit — quiet, roughly 90 minutes, at whatever hour suits Liliana — should complete the piece: verify the repaired cable end-to-end, install the certified relay, calibrate entirely from the Mackie (no trimmer adjustments on site), and rehearse. Whatever happens, the exhibition's film mode is left running when we walk out.

For the gallery

One visit by Jim, approximately 90 minutes, scheduled at the gallery's convenience outside public hours. The work is confined to the equipment case, the mixer, and one cable — no ladders, no changes to anything mounted overhead. Hard stop at the agreed time. The exhibition plays normally (film mode) from the moment the visit ends, whether or not the interactive feature is declared finished that day. This is intended to be the final technical visit before deinstallation.

What the bench work established

FindingEvidence
The audio feed cable had an open return conductor; the repair made on 21 Aug is the correct fix but has never been verified end-to-end in the system. Continuity tests of 21 Aug (directed by Bogdan); photos of both cable ends.
The RDL ST-ACR2 is fully functional: correct rest state, clean trigger on a measured signal, correct hold-and-release. Release delay programmed and verified at 14.5 s (consecutive measured runs). Bench video; measurement log of 27 Aug.
The relay's trigger threshold is pre-set on the bench against a measured test tone — just-trigger at 0.28 V RMS, 1 kHz, verified not to trigger 6 dB lower (value recorded on tape on the unit). All gallery calibration therefore happens at the Mackie's controls; the relay's trimmers are not touched on site. Bench measurement, 27–28 Aug.
The LED's idle state shows a faint red leakage glow; its true ON (triggered) state is dramatically brighter — visible in the video. On both gallery nights, the faint idle glow was being read as "on," which made the unit look unresponsive. Knowing the two states by sight makes the LED useful again during calibration. Bench video (opening shot vs. trigger moment).
The 24 V supply is healthy (24.43 V measured) and its negative output is internally bonded to earth ground — the control system has a proper ground reference by design. Bench measurement, 27 Aug.

What to bring

ItemPurpose
The certified RDL ST-ACR2 + its 24 V supply (transported gently; settings are part of the cargo)The relay going back in
Multimeter + small screwdrivers + hookup wire/clip leadsVerification and wiring
Phone № 1 with the calibration app; phone № 2 with the NIOSH SLM appRepeatable test noise; SPL logging
Headphones + ¼″ adapter, masking tape, marker, flashlightTracing, labeling, light

Phase 1 — Verify the signal path (≈20 min)

Master power strip OFF for this phase.

  1. Locate the repaired audio cable (Mackie AUX SEND 1 → ¼″-to-3.5 mm adapter cable → screw-terminal coupler → shielded cable to the relay position). Inspect every junction and confirm both conductors (red and black) are landed at both ends. Some connections were adjusted during later troubleshooting; whatever the as-found state, restore it to: red and black both terminated, shield unused at both ends.
  2. Continuity, end to end: tip of the ¼″ plug ↔ red conductor at the far end (beep); sleeve of the ¼″ plug ↔ black conductor at the far end (beep); tip ↔ sleeve (no beep). This single test retires the fault that defeated both prior sessions.
  3. Disconnect the iDili unit entirely (audio, power, and control wires), box it with its packaging, and set it with the spare equipment for pickup on deinstallation day.

Phase 2 — Install the certified relay (≈15 min)

  1. Terminal connections (numbered left to right):
    ScrewConnection
    1 (IN +)Red conductor (signal hot from AUX SEND 1 tip)
    2 (IN −)Black conductor (signal return from the ¼″ sleeve) — electrically identical to landing it on 3, thanks to the jumper
    2–3Blue jumper bridging 2 and 3 (confirm it is on 2–3)
    4 (PWR +)Red from 24 V supply
    5 (PWR ⏚)Black from 24 V supply
    7 (COM) & 9 (NO)The two control wires to the BrightSign DA15 (either wire on either screw)
    6, 8, 10–12Empty
  2. Before powering: continuity across screws 7–9 → open. Tug-test every landed wire.
  3. Power up (master strip ON). Confirm ≈24 V across screws 4–5. BrightSign boots to the film; projectors show the program. Note the wall-clock time the film starts — Phase 5 depends on it.
  4. Mute-path check: briefly jumper screws 7–9 with a clip lead → projectors blank and audio mutes; remove → program returns. (This confirms the player side independently of everything else. It worked identically in bench logic: contact closed = jail.)

Phase 3 — Program audio (channels 11-12), per Bogdan (≈15 min)

  1. Channels 11-12 (BrightSign feed): Aux 1 and Aux 2 fully counter-clockwise; every other knob at U; MUTE and SOLO up. Channel 11-12 GAIN: start fully counter-clockwise.
  2. Master section: MAIN MIX at U; SOURCE buttons up; AUX RETURNS off. Speakers powered, pod volume ≈50%.
  3. Bring channel 11-12 GAIN up until the forest soundtrack is clean, unclipped, and undistorted at gallery volume — Bogdan's procedure verbatim: the BrightSign outputs a strong signal, so approach from below.
  4. Confirm the mute-path check of Phase 2 still mutes and restores audio as well as video.

Phase 4 — Calibrate the microphone path, mixer only (≈20 min)

The relay's threshold was fixed on the bench; sensitivity is now set entirely with mixer levels. No trimmers.

  1. Channel 1 (EV mic): LOW CUT in; EQ centered; PAN centered; channel volume down (the mic must never enter the main mix); AUX 2 off. Rear panel: phantom power OFF (dynamic mic).
  2. Set the speech reference: press channel 1 SOLO, speak at normal visitor volume, adjust channel 1 TRIM until peaks reach −12 dB on the meters (Bogdan's target). Un-press SOLO.
  3. Start with channel 1 AUX 1 at 12 o'clock and AUX 1 MASTER at 12 o'clock (AUX 1 SELECT button up = pre-fader).
  4. Stand in for a visitor with the app: phone at maximum volume, speech-band noise at the CAL (−4 dB) preset. Let it play ~10 s first — at max volume the phone's speaker-protection DSP settles in steps on the first sustained run (measured 28 Aug). Then move the phone toward or away from the mic until the soloed channel-1 meters again peak at ≈−12 dB (the same reference the voice just set), and mark that distance with tape — it is the repeatable stand-in for “visitor speaking.” Un-press SOLO.
  5. From the marked distance, raise channel 1 AUX 1 slowly until the relay clicks and the system enters jail (screen blanks, audio mutes). Give it a small margin beyond the click point, then verify: noise on → jail within a moment; noise off → program returns after ≈15 s (time it with the app's stopwatch).
  6. Margin check, exact by construction: at the QUIET (−10 dB) preset — 6 dB below CAL — the relay must not trigger in 30 s; back at CAL it must trigger promptly. This mirrors the bench verification, so pass = the whole chain is calibrated coherently.
  7. Log with the SPL app: the room level at which jail engages: dBA. Quiet-gallery sounds (footsteps, HVAC) must not trigger; if they do, back AUX 1 down slightly.

Phase 5 — The woodpecker check (≈10 min)

Bogdan's own threshold definition: the loudest passage of the film — the woodpecker section — is the maximum acceptable loudness; anything above it earns 15 seconds of jail. The microphone hears the speakers, so this passage must not trigger the relay, or the piece would jail itself. Per Bogdan (29 Aug): the loudest woodpecker plays at 4:20–7:20 (m:s) into the film, and the final fine-tuning of TRIM, AUX 1, and AUX 1 MASTER should be done during that three-minute window (Phase 4 sets their starting points).

The player cannot be cued to a time index, but it doesn't need to be: the film is a 38:59 loop, so the passage arrives by clock. From the wall-clock time the film started (noted in Phase 2), the window runs start + 4:20 → 7:20, and again at +43:19 → 46:19, then +82:18 → 85:18, and so on. Do this check at whichever pass follows Phase 4 — and if there's a wait, spend it on Phase 6's photographs, then come back. (Most of the soundtrack is quiet birdsong and insects; the woodpecker is the one loud event, which is exactly why Bogdan chose it as the reference.)

  1. With everything at production settings, listen through the full 4:20–7:20 passage at gallery volume, watching the relay. It must stay quiet (LED stays at its faint idle glow) throughout; make Bogdan's final TRIM / AUX 1 / AUX 1 MASTER touches inside this window.
  2. If it triggers: reduce channel 1 AUX 1 slightly and re-verify both this check and the Phase 4 speech trigger. The gap between "woodpecker" and "conversation louder than the woodpecker" is the artistic intent; set the level in that gap.

Bogdan is exporting the three-minute woodpecker passage as an audio file. When it arrives, it can stand in on demand: play it into channels 11-12 in place of the BrightSign feed, matched to the same meter level, to rehearse this check without waiting for the loop — then run the real passage once from the BrightSign as the check of record.

Phase 6 — Dress rehearsal and handoff (≈10 min)

  1. Human test: two or three people chatting at visitor volume near the mic → jail within a moment; silence → program returns ≈15 s later. Twice.
  2. Morning-launch test: master strip OFF, wait 30 s, ON. Everything must self-restore: player boots to the film, audio playing, jail triggerable.
  3. Photograph every knob on the mixer and the speaker pod as the reference of record. Staff touch only the master power switch; if program volume must change, channel 11-12 GAIN only (then re-check Phase 5). Channel 1 and the relay are the artist's settings.
  4. Leave the iDili (boxed) and other spares together for deinstallation-day pickup.

If something unexpected appears

Any step that fails, fails toward safety: with the control wires parked off screws 7–9 (or the relay's supply unplugged), the contact stays open and the exhibition simply plays as the film it has been all month. Reversion takes under five minutes at any point, and the visit ends at the agreed time regardless of progress. There is no failure mode in this plan that leaves the gallery worse than it started.

Final settings record

ItemValue
Relay release delay (bench-programmed)14.5 s
Relay trigger threshold (bench, 1 kHz)Just-trigger at 0.28 V RMS (0.79 Vpp); no-trigger at −6 dB — on tape on the unit
Ch 1 TRIM (speech −12 dB, soloed)
Phone-to-mic marked distance (app at CAL −4 dB ≙ −12 dB meters)
Ch 1 AUX 1 / AUX 1 MASTER
Ch 11-12 GAIN
Jail-engage room level (SPL app) dBA
Woodpecker check

Sources: RDL ST-ACR Series documentation (891-0031H); BrightSign 4K Hardware Manual; Mackie 1202-VLZ documentation; Bogdan Perzyński's procedures for channels 11-12 and the woodpecker reference (21 Aug 2026); bench measurements and video of 27 Aug 2026. Drafted with the assistance of Claude (Anthropic); reviewed and edited by Jim Slagle.