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 (loss-budget model) · validate against REW waterfall T20/T30 per mode
[+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
Per-mode status against target T₆₀. Best unit = highest absorption at that mode frequency. Projections show estimated T₆₀ if additional units are added at corners.
Saved Configurations
Stored locally in this browser. Use the 🔗 Share button to share across devices.
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 40 — 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
34 HzTarget f₀
Q = 1.0Q factor
Click corner to add unit (cycles 0→1→2→3→4→remove) | ×N = stacked
Nodal 50 — 0 of 0 placed
FRONTREARLR
Corner 0 | Wall 0—
0
Tuning
51 Hz
0.9
α peak
0.461
−3dB BW
±18.0Hz
OC 705
—
from membrane
—
⚠ DEEPER ENCLOSURE REQUIRED
51 HzTarget f₀
Q = 0.9Q factor
Click corner to add unit (cycles 0→1→2→3→4→remove) | ×N = stacked
Custom Unit — 0 of 0 placed
Third channel for targeting a specific mode that neither Nodal 40 nor Nodal 50 addresses precisely. Set f₀ and Q to match a measured mode frequency. Predictions carry the standard model uncertainty.
FRONTREARLR
Corner 0 | Wall 0—
0
Tuning
61 Hz
1.5
α peak
0.457
−3dB BW
±18.4Hz
OC 705
—
from membrane
—
⚠ DEEPER ENCLOSURE REQUIRED
⚠ RESISTIVE-DOMINANT ABSORPTION — Q < 1.0
61 HzTarget f₀
Q = 1.5Q 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. Measure untreated room T20/T30 per mode in REW waterfall
2. Match T₆₀ Pre column to REW untreated values by adjusting
Room Construction profile
3. Install TDAs. Re-measure. Match T₆₀ Post to REW treated
values by adjusting Gcorner here
4. Calibrated Gcorner is your room-specific corner gain
RT60 tab export (≥ 50 Hz only)
1. In REW: select measurement → RT60 tab (labelled RT Parameters in newer versions)
2. File → Export → Export RT Parameters as text → save .txt
3. Drop file above · covers modes at 50 Hz and above only For modes below 50 Hz use the Manual Entry table below
Manual T60M Entry — RT60 Decay tab
In REW's RT60 Decay tab: press Generate, then Calculate RT60 model.
Position the cursor at each mode frequency — the upper panel shows T60M for that frequency.
Enter the T60M value (in seconds) for each mode below. Leave blank to skip a mode.
Works below 50 Hz where the file export cannot reach.
Export Results
Export your room configuration, calibrated model predictions, and REW
measured T30 data 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
Model limitations — please read
The RT60 predictions shown for the three tunable TDA units use the Eyring acoustic model, which assumes a statistically diffuse sound field. In small rooms (typically below the Schroeder frequency shown above), the bass range is governed by discrete room modes rather than a diffuse field — the Eyring model is technically outside its strict domain of validity in this regime.
In practice this means: the predicted RT60 reductions are indicative, not precise. The actual reduction in your room may be higher or lower than predicted depending on your specific room dimensions, construction, and measurement position. The model is most reliable as a comparative tool — the difference between untreated and treated predictions is more meaningful than the absolute values.
The modal frequency calculations are exact — the simulation correctly identifies which frequencies are most likely to be problematic in your room. For accurate RT60 measurements, use REW (Room EQ Wizard) with a calibrated microphone before and after treatment. Prototype performance will be published once measured.