MODET₆₀ BAR (2s scale)T₆₀ PRET₆₀ POST [±range]T₆₀ AVAAΔIMPROVSOURCE
● ≤0.35s Mastering
● ≤0.55s General controlled
● ≤0.75s Lively
TDA
Tuned diaphragmatic absorber within −3dB bandwidth
BRDBAND
Broadband porous panels (>15% T₆₀ reduction) COMBINED
Both systems contributing
SHELL
Room shell only — no targeted treatment
T₆₀ = per-mode modal decay · T₆₀ Pre/Post use measured baseline when REW untreated file is loaded · otherwise loss-budget model
[+Xs / ≤Ys] = predicted measurement range — physics-informed estimate, not a statistically derived confidence interval · actual T₆₀ likely within this range
Broadband Eyring RT₆₀ shown separately on the RT₆₀ canvas above.
~ = δ_tda > 2×δ_boundary — model accuracy decreasing · estimated variance ±15–30%
⊗ = δ_tda > 4×δ_boundary — saturation cap applied · estimated variance ±30–70% · REW validation essential ⊠ = Passive treatment limit — hard floor reached · further TDAs ineffective · hover for detail
⚠ = within 'Controlled' but may exceed mastering / mixing targets (0.20–0.45 s)
BASS CHARACTER REFERENCE
> 0.75 s
Boomy
Bass is slow and indistinct — modes overwhelm the mix
0.55 – 0.75 s
Lively
Warm character but definition is suffering — treatment will make a clear difference
0.25 – 0.55 s
Controlled
Defined and workable — but a wide range. Mastering: target 0.20–0.35s. Mixing: 0.25–0.45s. General listening: 0.30–0.55s.
< 0.25 s
Over-damped
Unnaturally tight and dry — too much absorption for musical use
Application targets at 35–80 Hz
Mastering / critical 0.20 – 0.35 s Mixing / tracking 0.25 – 0.45 s Listening / project 0.30 – 0.55 s
A reading within ‘Controlled’ does not mean treatment is unnecessary. At 70 Hz, drywall resonance and broadband panels already contribute — the residual RT60 may still exceed mastering or critical mixing targets.
🎧 Listening Position — drag marker on heatmap
—Untreated SPL
—Treated SPL
—Improvement
—X position
—Y position
—Zone
Click or drag anywhere on the floor plan heatmap to place listening position
Per-Mode T₆₀ at This Position
Freq = mode Hz · T₆₀ = post-treatment decay · AT POS = % of peak pressure at your location (100% = sitting in antinode, 0% = sitting in null) · HEARD = practical audibility at this seat
% of room SA covered · α = (1−cov)×shell + cov×OC703 (ISO 354)
PSI AVAA C20 — Active Pressure Zeroing
Effective 15–150 Hz · 1.4 m² equivalent absorption per unit · broadband flat response
Simulated as active boundary absorber at modal pressure maxima
2
Placement (click to assign — corners recommended)
A_eff total
2.8 m²
Freq range
15–150 Hz
Model Assumptions
· Ideal pressure zeroing assumed (PSI spec figure)
· Real performance degrades below 25 Hz (speaker excursion limit)
· Effectiveness rolls off above 120 Hz (spatial aliasing)
· Unit interaction not modelled
· Actual in-room results may vary ±30% from prediction
· RT₆₀ canvas shows AVAA curve alongside TDA for comparison
PSI AVAA C20 ≈ $2,200/unit · requires AC power · active electronics
Nodal 30 — 0 of 4 placed
FRONTREARLR
Corner 0 | Wall 00 unplaced
Corner Stacking — all channels
max stack——— total
4
Tuning
34 Hz
1.0
α peak
0.330
−3dB BW
±18.2Hz
OC 705
—
from membrane
—
⚠ DEEPER ENCLOSURE REQUIRED
35 HzTarget f₀
Q = 1.0Q factor
Click corner to add unit (cycles 0→1→2→3→4→remove) | ×N = stacked
Advanced — Custom Unit 2 — 0 of 0 placed
FRONTREARLR
Corner 0 | Wall 0—
0
Tuning
35 Hz
1.0
α peak
0.461
−3dB BW
±18.0Hz
OC 705
—
from membrane
—
⚠ DEEPER ENCLOSURE REQUIRED
35 HzTarget f₀
Q = 1.0Q factor
Click corner to add unit (cycles 0→1→2→3→4→remove) | ×N = stacked
Custom Unit — 0 of 0 placed
Advanced custom channel for exploring alternative tuning configurations or modelling a second unit type. Defaults to Nodal 30 parameters (35 Hz, Q=1.0). Set f₀ and Q to match any target mode frequency.
FRONTREARLR
Corner 0 | Wall 0—
0
Tuning
35 Hz
1.0
α peak
0.457
−3dB BW
±18.4Hz
OC 705
—
from membrane
—
⚠ DEEPER ENCLOSURE REQUIRED
⚠ RESISTIVE-DOMINANT ABSORPTION — Q < 1.0
35 HzTarget f₀
Q = 1.0Q factor
Click corner to add unit (cycles 0→1→2→3→4→remove) | ×N = stacked
Corner Gain Calibration — Gcorner
4.0
Physical range 20–70 Hz: 2.0 — single-boundary pressure gain only 4.0 — default · single-wall pressure doubling² 4.0 — recommended for 1st-order axial modes 6.0 — tangential mode coincidence contribution 8.0 — theoretical max (tri-axial · not physical
for 20–70 Hz in typical rooms)
REW Calibration Workflow
1. Export REW waterfall (.txt) before treatment → drop in REW Import panel
2. Model auto-computes T60M at all room mode frequencies
T₆₀ Pre column now matches measured values at each mode
3. Install TDAs. Export treated waterfall → drop in REW Import panel
Gcorner is auto-calibrated from treated T60M values
4. Export JSON captures both measurements + model predictions
Method A — Waterfall Export (recommended, full range) REW Waterfall settings: Mode=Fourier · Window=300ms · Rise Time=30ms
Total Slices=1000 · Smoothing=1/48 oct · Normalize unchecked · CSD unchecked Export: Waterfall graph → File → Export → Export data as text (.txt)
Both files must use identical settings and mic/speaker positions. T60M is computed
automatically at all room mode frequencies (axial modes ≤80 Hz prioritised).
Rise Time (ms)Match REW Rise Time exactly
■ Untreated — waterfall export (.txt)
↑ Drop waterfall export or click to browse
■ Treated — waterfall export (.txt) (optional)
↑ Drop waterfall export or click to browse
Method B — Manual T60M Entry
Use if waterfall export is unavailable. In REW's RT60 Decay tab:
press Generate → Calculate RT60 model. Position cursor at each mode frequency —
the upper panel shows T60M. Enter values below. Works for all frequencies.
T60M at mode frequencies
Export Results
Export your room configuration, calibrated model predictions, and REW
waterfall T60M data (or RT-Parameters T60) as a structured JSON file for submission to the
GroundControl performance database, or as a formatted PDF report for
your own records.
Submit to database
Send your JSON export to
data@groundcontrol.audio
or upload at groundcontrol.audio/submit.
Customer submissions support ongoing model calibration and are
held confidentially. Room geometry data only — no personal information
is included in the export.
Enclosure Cavity Depth — Dcavity
220 mm
80 mm — shallow / space-limited140 mm — 7" outside depth210 mm — default · 9" outside depth240 mm — 10" outside · deep sub-28 Hz
Tuning effects:
Deeper cavity → lower f₀ for a given panel mass · less MLV required
Shallower cavity → higher f₀ crossover to Richlite-only · more false-back risk
OC 705 position, slab selection, and false-back warnings update live.
Affects: panel mass · cavity depth note · MLV requirement · OC 705 position · false-back threshold
Membrane Dimensions
609 mm
762 mm
Active face area:0.4641 m²
Dimensions (in):24.0" × 30.0"
Effect on model:
Larger membrane → greater absorption area → higher dB reduction per unit
Scales linearly with area in reductionDB and modal T₆₀ calculations Note: membrane face area only — frame geometry unchanged
Legend
SPL Distribution
Pressure Maximum
Pressure Null
Decay graph
T60 Untreated (model)
T60 Treated (model)
REW T60 Untreated
REW T60 Treated
Model limitations — please read
The per-mode decay predictions use a modal loss-budget model (r60) that computes T60 at each axial room mode frequency from the total room surface absorption, using the Sabine-weighted boundary damping term rather than per-surface modal coupling. Construction profiles are calibrated to produce physically correct untreated T60 values — residential drywall gives 1.2–1.5s at 30–35 Hz, concrete 4–5s — consistent with real REW measurements in those room types.
TDA predictions are computed as additional modal damping on top of the measured or modelled baseline. When a REW untreated waterfall is loaded, the baseline is back-calculated from the measurement at each mode, making T60 Post a calibrated prediction rather than a model approximation. Loading an after-treatment waterfall enables G_corner calibration — validating the corner gain assumption against your actual room.
Known limitations: The model treats each mode independently and does not capture mode coupling, oblique/tangential mode interactions, or position-dependent pressure distribution within a mode. TDA absorption is modelled as uniform area loading — spatial placement affects the corner boost factor but not the modal pressure distribution. Predictions are most reliable for axial modes below 100 Hz. For accurate validation, use REW (Room EQ Wizard) with a calibrated measurement microphone before and after treatment using the waterfall export settings shown in the REW Import panel.