OROS Wiki - User contributions [en]

TL Tool - Sound Transmission Loss Measurement

2026-05-27T09:34:03Z

LaurentM OROS: Replace chart placeholders with real GUI screenshots (3 captures)

[[category:WikiOros]]
[[category:Software]]
[[category:Acoustics]]
{{#seo:
|title=TL Tool - Sound Transmission Loss Measurement Software | OROS
|keywords=sound transmission loss, TL, ASTM E2611, impedance tube, 4 microphone, transfer matrix, absorption coefficient, NVGate
|description=OROS standalone application for measuring Sound Transmission Loss and absorption coefficient using the 4-microphone impedance tube method (ASTM E2611). Plug-and-play .exe, integrated with NVGate.
}}

__TOC__

<div style="background:linear-gradient(120deg,#001F5B 0%,#0055A5 100%);color:white;padding:22px 28px;border-radius:10px;margin-bottom:18px;">
<span style="font-size:1.5em;font-weight:bold;">TL Tool — Sound Transmission Loss</span><br/><br/>
</div>

{| class="wikitable" style="width:100%;border-collapse:collapse;"
! style="background:#0055A5;color:white;width:22%;" | Parameter
! style="background:#0055A5;color:white;" | Value
|-
| '''Delivery''' || [https://partnerzone.digigram.com/s/QjZaMrTZCrDQTJa download here] version from 22/05/2026 - Beta version - download at your own risk !
|-
| '''Measurement methods''' || 4-mic transfer matrix (ASTM E2611) • 2-mic standing wave (ISO 10534-2)
|-
| '''Results''' || TL [dB], absorption α, ISO 11654 class (α_w, NRC, SAA)
|-
| '''Octave resolution''' || 1/3 • 1/6 • 1/12 • 1/24 octave
|-
| '''NVGate integration''' || Live acquisition • automatic result injection
|-
| '''Export''' || CSV (frequency, TL, α)
|}

== Standards ==

<div style="display:flex;gap:12px;flex-wrap:wrap;margin:14px 0;">
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ASTM E2611</div>
Transfer matrix method — 4-microphone impedance tube.<br/>
<small>Recommended for Transmission Loss.</small>
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 10534-2 / ASTM E1050</div>
Two-microphone standing wave method.<br/>
<small>Absorption coefficient only.</small>
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 11654</div>
Weighted sound absorption coefficient α_w and absorption class (A–E).
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 9613-1</div>
Speed of sound and air density from temperature and pressure.
</div>
</div>

== Tube Setup ==

=== Geometry ===

<pre style="background:#1a1a2e;color:#e0e0e0;padding:16px;border-radius:8px;font-size:0.95em;">
[SP] x1 x2 x3 x4 [ Sample ]
||||----o-------o---------------o-------o-----[=========]
Source \____Source side_____/ \___Trans. side___/
</pre>

[[File:TL_Tool_tube_4mic_100mm.png|center|480px|Tube d'impedance 4 microphones — Ø100 mm default configuration]]
* '''SP''' — Sound source (loudspeaker)
* '''x1, x2''' — Upstream microphones (source side)
* '''x3, x4''' — Downstream microphones (transmission side)
* '''Sample''' — Material under test, placed between x2 and x3

=== Default Parameters ===

{| class="wikitable" style="width:65%;"
! style="background:#003F87;color:white;" | Parameter
! style="background:#003F87;color:white;" | Default
! style="background:#003F87;color:white;" | Notes
|-
| x1 || 50 mm || Configurable in Tube Setup tab
|-
| x2 || 150 mm ||
|-
| x3 || 350 mm ||
|-
| x4 || 450 mm ||
|-
| Tube diameter D || 100 mm || Determines f_max
|-
| Temperature || 20 °C || Affects speed of sound
|-
| Pressure || 1013.25 hPa || Affects air density
|}

<div style="border-left:4px solid #17a2b8;background:#e8f7fa;padding:12px 16px;border-radius:0 6px 6px 0;margin:10px 0;">
ℹ️ '''Valid frequency range''' is computed automatically from tube geometry and air properties.
Measurements outside [f_min, f_max] are masked and excluded from results.
</div>

== Software Interface ==

The application is organized in five tabs:

{| style="width:100%;border-collapse:collapse;"
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''📋 Material''' — Material name, notes, measurement mode (2-mic / 4-mic)
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;background:#f8fbff;" |
'''📐 Tube Setup''' — Microphone positions, diameter, temperature, pressure
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''🎤 Acquisition''' — NVGate channel config, FFT settings, run/stop, phase calibration
|-
| style="width:4px;background:#17a2b8;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;background:#f8fbff;" |
'''📈 TL Result''' — Transmission Loss curves (fine band + octave bands)
|-
| style="width:4px;background:#17a2b8;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''🔊 Absorption''' — Absorption coefficient α + ISO 11654 rating
|}

=== Top Toolbar ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;" | Button
! style="background:#003F87;color:white;" | Action
|-
| '''Calculate''' || Run TL / absorption computation from acquired data
|-
| Fine band ☐ || Show / hide fine-frequency-resolution plots
|-
| 1/N octave selector || Select octave resolution: 1/3 • 1/6 • 1/12 • 1/24
|-
| '''Send to NVGate''' || Inject octave result into NVGate display window
|-
| '''Send fine band''' || Inject fine-band result into NVGate
|-
| '''Export CSV''' || Save results to CSV file
|}

== Measurement Modes ==

=== 4-Microphone Mode (Recommended) — ASTM E2611 ===

<div style="display:flex;gap:16px;flex-wrap:wrap;margin:12px 0;">
<div style="flex:1;min-width:220px;background:#f0f7ff;border:1px solid #0055A5;border-radius:8px;padding:16px;">
<div style="color:#0055A5;font-weight:bold;font-size:1.05em;margin-bottom:8px;">✓ Two-Load Method</div>
<b>Recommended — ASTM E2611 §8</b><br/><br/>
Two measurements with different tube terminations.<br/>
The software builds the full <b>transfer matrix [T]</b> of the sample and extracts TL from T⊂12;.<br/><br/>
<small>● Load 1: anechoic termination<br/>● Load 2: rigid cap</small>
</div>
<div style="flex:1;min-width:220px;background:#fff8f0;border:1px solid #cc8800;border-radius:8px;padding:16px;">
<div style="color:#cc8800;font-weight:bold;font-size:1.05em;margin-bottom:8px;">⚠ Single-Load Method</div>
One measurement only, anechoic termination assumed.<br/><br/>
Less accurate — use only when Load 2 cannot be measured.
</div>
</div>

=== 2-Microphone Mode — ISO 10534-2 ===

Uses CH1 and CH2 only (source-side microphones):
* Reflection coefficient R(f) from standing wave decomposition
* Absorption coefficient α(f) = 1 − |R|²

[[File:TL_Tool_tube_2mic.png|center|480px|Tube configuration for 2-microphone mode (ISO 10534-2)]]

== Step-by-Step Measurement Procedure ==

<div style="counter-reset:step-counter;margin:16px 0;">

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">1</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Configure Channels</b><br/>
In the <i>Acquisition</i> tab: set coupling (ICP), label and sensitivity for each microphone.<br/>
Click <b>Configure NVGate</b> → channels are enabled, FRF results are registered.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">2</div>
<div style="flex:1;border:1px solid #d4edda;border-radius:8px;padding:14px;background:#f4fff6;">
<b>Phase Calibration</b> <i>(recommended)</i><br/>
Compensates microphone phase mismatch:<br/>
● Place Mic 1 & Mic 2 at the same port → <b>Calibrate CH1/CH2</b><br/>
● Physically swap microphones → <b>Measure (swapped)</b><br/>
● Repeat for CH1/CH3 and CH1/CH4<br/>
● Save calibration — applied automatically during calculation.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">3</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Load 1 Measurement</b><br/>
Insert the sample with <b>anechoic termination</b>.<br/>
Click <b>Run Load 1</b> → NVGate acquires and stops automatically.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">4</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Load 2 Measurement</b> <i>(two-load mode)</i><br/>
Change termination to <b>rigid cap</b>.<br/>
Click <b>Run Load 2</b> → NVGate acquires and stops automatically.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#17a2b8;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">5</div>
<div style="flex:1;border:1px solid #b8e4ec;border-radius:8px;padding:14px;background:#eefafc;">
<b>Calculate</b><br/>
Click <b>Calculate</b>. The software:<br/>
● Retrieves FRFs and auto-spectrum from NVGate<br/>
● Applies phase calibration<br/>
● Computes TL (fine band) and absorption coefficient<br/>
● Synthesizes octave bands<br/>
● Displays results and injects them into NVGate
</div>
</div>

</div>

== Results ==

=== TL Result Tab ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;width:30%;" | Panel
! style="background:#003F87;color:white;" | Content
|-
| Fine band (left) || TL in dB vs. frequency — valid range highlighted, singularities masked
|-
| Octave bands (right) || TL per 1/N octave band, color-coded
|-
| Status bar || c [m/s], ρ [kg/m³], f_min, f_max, calculation time
|}

[[File:TL_Tool_GUI_transmission_loss.png|center|700px|TL Tool — Transmission Loss tab : bande fine (FFT) et barres 1/12 octave]]
=== Absorption Tab ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;width:30%;" | Panel
! style="background:#003F87;color:white;" | Content
|-
| Fine band (left, optional) || α(f) from 0 to 1 — valid range highlighted
|-
| Octave bands (right) || α per 1/3 octave band
|-
| ISO 11654 table || α_w • Class (A–E) • SAA • NRC • α at 250/500/1k/2k/4k Hz
|}

[[File:TL_Tool_GUI_rating_iso11654.png|center|700px|TL Tool — onglet Rating ISO 11654 : classement A–E du coefficient d'absorption]]
=== CSV Export ===

Click <b>Export CSV</b> (bottom-left). Header includes: material name, date, tube geometry, air properties, valid frequency range.

<div style="display:flex;gap:16px;flex-wrap:wrap;margin:10px 0;">
<div style="flex:1;min-width:200px;">
<div style="background:#2d2d2d;color:#a8ff78;padding:12px;border-radius:6px;font-family:monospace;font-size:0.9em;">
<b style="color:#fff;">4-mic mode:</b><br/>
Frequency_Hz, TL_dB, Alpha<br/>
100.0000, 18.423, 0.123<br/>
125.0000, 20.115, 0.145<br/>
...
</div>
</div>
<div style="flex:1;min-width:200px;">
<div style="background:#2d2d2d;color:#a8ff78;padding:12px;border-radius:6px;font-family:monospace;font-size:0.9em;">
<b style="color:#fff;">2-mic mode:</b><br/>
Frequency_Hz, Alpha<br/>
100.0000, 0.452<br/>
125.0000, 0.481<br/>
...
</div>
</div>
</div>

=== NVGate Display ===

After calculation, results are automatically injected into NVGate:
* Octave bar chart (1/3, 1/6, 1/12 or 1/24 depending on toolbar selection)
* Fine-band curve (optional)
* Each resolution uses a dedicated NVGate window to avoid conflicts

== Delany-Bazley-Miki Model ==

<div style="background:#f0f7ff;border:1px solid #0055A5;border-radius:8px;padding:16px;margin:10px 0;">
The software includes a <b>DBM fitting tool</b> for porous absorbers.<br/>
From the measured α(f) or TL(f), it extracts the <b>flow resistivity σ</b> [Pa·s/m²] by minimizing the RMS error between measurement and model.<br/>
σ can then be used to predict material performance at any frequency or thickness.<br/><br/>
→ See the [[TL_Tool_-_Acoustic_Formulas_Reference|Formulas Reference]] for full DBM equations.
</div>

[[File:TL_Tool_GUI_propagation.png|center|700px|TL Tool — onglet Propagation : nombre d'onde, atténuation, impédance caractéristique]]

== Multi-Tube Merge ==

For a wide frequency range, measurements from a <b>large-diameter tube</b> (low frequencies) and a <b>small-diameter tube</b> (high frequencies) can be merged into a single spectrum.

The blend zone [f_blend_lo, f_blend_hi] uses a cosine cross-fade, ensuring a smooth transition.

[[File:TL_Tool_tube_4mic_29mm.png|center|400px|Small-diameter tube (Ø29 mm) for high-frequency measurements]]
== Configuration ==

Settings are saved automatically in <code>config_tl.json</code> next to <code>TL_Tool.exe</code>:

{| class="wikitable" style="width:75%;"
! style="background:#003F87;color:white;" | Parameter
! style="background:#003F87;color:white;" | Default
! style="background:#003F87;color:white;" | Description
|-
| x1 – x4 || 50/150/350/450 mm || Microphone positions from source
|-
| Tube diameter || 100 mm || Determines f_max
|-
| Temperature || 20 °C || Air temperature
|-
| Pressure || 1013.25 hPa || Atmospheric pressure
|-
| Octave resolution || 1/12 || Default resolution (3/6/12/24)
|-
| TL method || Two-load || Calculation method
|-
| Phase calibration || (none) || Path to .npz calibration file
|}

== See Also ==

* [[TL_Tool_-_Acoustic_Formulas_Reference|📐 Acoustic Formulas Reference]] — all equations used in the software
* [[NVGate]] — OROS analysis software
* [[NVGate_FFT|FFT Analysis in NVGate]]
* [[NVGate_Octave_Analyzer|Octave Analysis]]
* [[FFT_Spectrum_Analyzer_Multipurpose|OROS FFT Analyzer Hardware]]

== References ==

* ASTM E2611 — ''Normal Incidence Determination of Porous Material Acoustical Properties Based on the Transfer Matrix Method''
* ISO 10534-2 — ''Determination of sound absorption coefficient and impedance in impedance tubes''
* ISO 9613-1 — ''Attenuation of sound during propagation outdoors — Calculation of the absorption of sound by the atmosphere''
* ISO 11654 — ''Sound absorbers for use in buildings — Rating of sound absorption''
* Miki Y. (1990) — ''Acoustical properties of porous materials — modifications of Delany-Bazley models''

File:TL Tool GUI propagation.png

2026-05-27T09:34:03Z

LaurentM OROS: TL Tool GUI screenshot

TL Tool GUI screenshot

File:TL Tool GUI rating iso11654.png

2026-05-27T09:34:03Z

LaurentM OROS: TL Tool GUI screenshot

TL Tool GUI screenshot

File:TL Tool GUI transmission loss.png

2026-05-27T09:34:03Z

LaurentM OROS: TL Tool GUI screenshot

TL Tool GUI screenshot

TL Tool - Sound Transmission Loss Measurement

2026-05-27T09:17:52Z

LaurentM OROS: Add 5 screenshot(s): Tube Setup, 2-mic mode, TL Result Tab, Absorption Tab, Multi-Tube Merge

[[category:WikiOros]]
[[category:Software]]
[[category:Acoustics]]
{{#seo:
|title=TL Tool - Sound Transmission Loss Measurement Software | OROS
|keywords=sound transmission loss, TL, ASTM E2611, impedance tube, 4 microphone, transfer matrix, absorption coefficient, NVGate
|description=OROS standalone application for measuring Sound Transmission Loss and absorption coefficient using the 4-microphone impedance tube method (ASTM E2611). Plug-and-play .exe, integrated with NVGate.
}}

__TOC__

<div style="background:linear-gradient(120deg,#001F5B 0%,#0055A5 100%);color:white;padding:22px 28px;border-radius:10px;margin-bottom:18px;">
<span style="font-size:1.5em;font-weight:bold;">TL Tool — Sound Transmission Loss</span><br/><br/>
</div>

{| class="wikitable" style="width:100%;border-collapse:collapse;"
! style="background:#0055A5;color:white;width:22%;" | Parameter
! style="background:#0055A5;color:white;" | Value
|-
| '''Delivery''' || [https://partnerzone.digigram.com/s/QjZaMrTZCrDQTJa download here] version from 22/05/2026 - Beta version - download at your own risk !
|-
| '''Measurement methods''' || 4-mic transfer matrix (ASTM E2611) • 2-mic standing wave (ISO 10534-2)
|-
| '''Results''' || TL [dB], absorption α, ISO 11654 class (α_w, NRC, SAA)
|-
| '''Octave resolution''' || 1/3 • 1/6 • 1/12 • 1/24 octave
|-
| '''NVGate integration''' || Live acquisition • automatic result injection
|-
| '''Export''' || CSV (frequency, TL, α)
|}

== Standards ==

<div style="display:flex;gap:12px;flex-wrap:wrap;margin:14px 0;">
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ASTM E2611</div>
Transfer matrix method — 4-microphone impedance tube.<br/>
<small>Recommended for Transmission Loss.</small>
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 10534-2 / ASTM E1050</div>
Two-microphone standing wave method.<br/>
<small>Absorption coefficient only.</small>
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 11654</div>
Weighted sound absorption coefficient α_w and absorption class (A–E).
</div>
<div style="flex:1;min-width:180px;border:2px solid #0055A5;border-radius:8px;padding:14px;">
<div style="background:#0055A5;color:white;font-weight:bold;padding:4px 10px;border-radius:4px;margin-bottom:8px;">ISO 9613-1</div>
Speed of sound and air density from temperature and pressure.
</div>
</div>

== Tube Setup ==

=== Geometry ===

<pre style="background:#1a1a2e;color:#e0e0e0;padding:16px;border-radius:8px;font-size:0.95em;">
[SP] x1 x2 x3 x4 [ Sample ]
||||----o-------o---------------o-------o-----[=========]
Source \____Source side_____/ \___Trans. side___/
</pre>

[[File:TL_Tool_tube_4mic_100mm.png|center|480px|Tube d'impedance 4 microphones — Ø100 mm default configuration]]
* '''SP''' — Sound source (loudspeaker)
* '''x1, x2''' — Upstream microphones (source side)
* '''x3, x4''' — Downstream microphones (transmission side)
* '''Sample''' — Material under test, placed between x2 and x3

=== Default Parameters ===

{| class="wikitable" style="width:65%;"
! style="background:#003F87;color:white;" | Parameter
! style="background:#003F87;color:white;" | Default
! style="background:#003F87;color:white;" | Notes
|-
| x1 || 50 mm || Configurable in Tube Setup tab
|-
| x2 || 150 mm ||
|-
| x3 || 350 mm ||
|-
| x4 || 450 mm ||
|-
| Tube diameter D || 100 mm || Determines f_max
|-
| Temperature || 20 °C || Affects speed of sound
|-
| Pressure || 1013.25 hPa || Affects air density
|}

<div style="border-left:4px solid #17a2b8;background:#e8f7fa;padding:12px 16px;border-radius:0 6px 6px 0;margin:10px 0;">
ℹ️ '''Valid frequency range''' is computed automatically from tube geometry and air properties.
Measurements outside [f_min, f_max] are masked and excluded from results.
</div>

== Software Interface ==

The application is organized in five tabs:

{| style="width:100%;border-collapse:collapse;"
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''📋 Material''' — Material name, notes, measurement mode (2-mic / 4-mic)
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;background:#f8fbff;" |
'''📐 Tube Setup''' — Microphone positions, diameter, temperature, pressure
|-
| style="width:4px;background:#0055A5;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''🎤 Acquisition''' — NVGate channel config, FFT settings, run/stop, phase calibration
|-
| style="width:4px;background:#17a2b8;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;background:#f8fbff;" |
'''📈 TL Result''' — Transmission Loss curves (fine band + octave bands)
|-
| style="width:4px;background:#17a2b8;" |
| style="padding:10px 16px;border:1px solid #cce0ff;border-left:none;" |
'''🔊 Absorption''' — Absorption coefficient α + ISO 11654 rating
|}

=== Top Toolbar ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;" | Button
! style="background:#003F87;color:white;" | Action
|-
| '''Calculate''' || Run TL / absorption computation from acquired data
|-
| Fine band ☐ || Show / hide fine-frequency-resolution plots
|-
| 1/N octave selector || Select octave resolution: 1/3 • 1/6 • 1/12 • 1/24
|-
| '''Send to NVGate''' || Inject octave result into NVGate display window
|-
| '''Send fine band''' || Inject fine-band result into NVGate
|-
| '''Export CSV''' || Save results to CSV file
|}

== Measurement Modes ==

=== 4-Microphone Mode (Recommended) — ASTM E2611 ===

<div style="display:flex;gap:16px;flex-wrap:wrap;margin:12px 0;">
<div style="flex:1;min-width:220px;background:#f0f7ff;border:1px solid #0055A5;border-radius:8px;padding:16px;">
<div style="color:#0055A5;font-weight:bold;font-size:1.05em;margin-bottom:8px;">✓ Two-Load Method</div>
<b>Recommended — ASTM E2611 §8</b><br/><br/>
Two measurements with different tube terminations.<br/>
The software builds the full <b>transfer matrix [T]</b> of the sample and extracts TL from T⊂12;.<br/><br/>
<small>● Load 1: anechoic termination<br/>● Load 2: rigid cap</small>
</div>
<div style="flex:1;min-width:220px;background:#fff8f0;border:1px solid #cc8800;border-radius:8px;padding:16px;">
<div style="color:#cc8800;font-weight:bold;font-size:1.05em;margin-bottom:8px;">⚠ Single-Load Method</div>
One measurement only, anechoic termination assumed.<br/><br/>
Less accurate — use only when Load 2 cannot be measured.
</div>
</div>

=== 2-Microphone Mode — ISO 10534-2 ===

Uses CH1 and CH2 only (source-side microphones):
* Reflection coefficient R(f) from standing wave decomposition
* Absorption coefficient α(f) = 1 − |R|²

[[File:TL_Tool_tube_2mic.png|center|480px|Tube configuration for 2-microphone mode (ISO 10534-2)]]

== Step-by-Step Measurement Procedure ==

<div style="counter-reset:step-counter;margin:16px 0;">

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">1</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Configure Channels</b><br/>
In the <i>Acquisition</i> tab: set coupling (ICP), label and sensitivity for each microphone.<br/>
Click <b>Configure NVGate</b> → channels are enabled, FRF results are registered.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">2</div>
<div style="flex:1;border:1px solid #d4edda;border-radius:8px;padding:14px;background:#f4fff6;">
<b>Phase Calibration</b> <i>(recommended)</i><br/>
Compensates microphone phase mismatch:<br/>
● Place Mic 1 & Mic 2 at the same port → <b>Calibrate CH1/CH2</b><br/>
● Physically swap microphones → <b>Measure (swapped)</b><br/>
● Repeat for CH1/CH3 and CH1/CH4<br/>
● Save calibration — applied automatically during calculation.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">3</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Load 1 Measurement</b><br/>
Insert the sample with <b>anechoic termination</b>.<br/>
Click <b>Run Load 1</b> → NVGate acquires and stops automatically.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#0055A5;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">4</div>
<div style="flex:1;border:1px solid #cce0ff;border-radius:8px;padding:14px;background:#f8fbff;">
<b>Load 2 Measurement</b> <i>(two-load mode)</i><br/>
Change termination to <b>rigid cap</b>.<br/>
Click <b>Run Load 2</b> → NVGate acquires and stops automatically.
</div>
</div>

<div style="display:flex;align-items:flex-start;margin-bottom:16px;gap:14px;">
<div style="flex-shrink:0;width:36px;height:36px;background:#17a2b8;color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:bold;font-size:1.1em;line-height:36px;text-align:center;">5</div>
<div style="flex:1;border:1px solid #b8e4ec;border-radius:8px;padding:14px;background:#eefafc;">
<b>Calculate</b><br/>
Click <b>Calculate</b>. The software:<br/>
● Retrieves FRFs and auto-spectrum from NVGate<br/>
● Applies phase calibration<br/>
● Computes TL (fine band) and absorption coefficient<br/>
● Synthesizes octave bands<br/>
● Displays results and injects them into NVGate
</div>
</div>

</div>

== Results ==

=== TL Result Tab ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;width:30%;" | Panel
! style="background:#003F87;color:white;" | Content
|-
| Fine band (left) || TL in dB vs. frequency — valid range highlighted, singularities masked
|-
| Octave bands (right) || TL per 1/N octave band, color-coded
|-
| Status bar || c [m/s], ρ [kg/m³], f_min, f_max, calculation time
|}

[[File:TL_Tool_result_fineband.png|center|700px|TL Result tab — fine band (blue) and 1/12 octave bars (orange)]]
=== Absorption Tab ===

{| class="wikitable" style="width:100%;"
! style="background:#003F87;color:white;width:30%;" | Panel
! style="background:#003F87;color:white;" | Content
|-
| Fine band (left, optional) || α(f) from 0 to 1 — valid range highlighted
|-
| Octave bands (right) || α per 1/3 octave band
|-
| ISO 11654 table || α_w • Class (A–E) • SAA • NRC • α at 250/500/1k/2k/4k Hz
|}

[[File:TL_Tool_result_demo.png|center|700px|TL (left) and absorption coefficient (right) — demo measurement on 3 kg/m² mass law sample]]
=== CSV Export ===

Click <b>Export CSV</b> (bottom-left). Header includes: material name, date, tube geometry, air properties, valid frequency range.

<div style="display:flex;gap:16px;flex-wrap:wrap;margin:10px 0;">
<div style="flex:1;min-width:200px;">
<div style="background:#2d2d2d;color:#a8ff78;padding:12px;border-radius:6px;font-family:monospace;font-size:0.9em;">
<b style="color:#fff;">4-mic mode:</b><br/>
Frequency_Hz, TL_dB, Alpha<br/>
100.0000, 18.423, 0.123<br/>
125.0000, 20.115, 0.145<br/>
...
</div>
</div>
<div style="flex:1;min-width:200px;">
<div style="background:#2d2d2d;color:#a8ff78;padding:12px;border-radius:6px;font-family:monospace;font-size:0.9em;">
<b style="color:#fff;">2-mic mode:</b><br/>
Frequency_Hz, Alpha<br/>
100.0000, 0.452<br/>
125.0000, 0.481<br/>
...
</div>
</div>
</div>

=== NVGate Display ===

After calculation, results are automatically injected into NVGate:
* Octave bar chart (1/3, 1/6, 1/12 or 1/24 depending on toolbar selection)
* Fine-band curve (optional)
* Each resolution uses a dedicated NVGate window to avoid conflicts

== Delany-Bazley-Miki Model ==

<div style="background:#f0f7ff;border:1px solid #0055A5;border-radius:8px;padding:16px;margin:10px 0;">
The software includes a <b>DBM fitting tool</b> for porous absorbers.<br/>
From the measured α(f) or TL(f), it extracts the <b>flow resistivity σ</b> [Pa·s/m²] by minimizing the RMS error between measurement and model.<br/>
σ can then be used to predict material performance at any frequency or thickness.<br/><br/>
→ See the [[TL_Tool_-_Acoustic_Formulas_Reference|Formulas Reference]] for full DBM equations.
</div>

== Multi-Tube Merge ==

For a wide frequency range, measurements from a <b>large-diameter tube</b> (low frequencies) and a <b>small-diameter tube</b> (high frequencies) can be merged into a single spectrum.

The blend zone [f_blend_lo, f_blend_hi] uses a cosine cross-fade, ensuring a smooth transition.

[[File:TL_Tool_tube_4mic_29mm.png|center|400px|Small-diameter tube (Ø29 mm) for high-frequency measurements]]
== Configuration ==

Settings are saved automatically in <code>config_tl.json</code> next to <code>TL_Tool.exe</code>:

{| class="wikitable" style="width:75%;"
! style="background:#003F87;color:white;" | Parameter
! style="background:#003F87;color:white;" | Default
! style="background:#003F87;color:white;" | Description
|-
| x1 – x4 || 50/150/350/450 mm || Microphone positions from source
|-
| Tube diameter || 100 mm || Determines f_max
|-
| Temperature || 20 °C || Air temperature
|-
| Pressure || 1013.25 hPa || Atmospheric pressure
|-
| Octave resolution || 1/12 || Default resolution (3/6/12/24)
|-
| TL method || Two-load || Calculation method
|-
| Phase calibration || (none) || Path to .npz calibration file
|}

== See Also ==

* [[TL_Tool_-_Acoustic_Formulas_Reference|📐 Acoustic Formulas Reference]] — all equations used in the software
* [[NVGate]] — OROS analysis software
* [[NVGate_FFT|FFT Analysis in NVGate]]
* [[NVGate_Octave_Analyzer|Octave Analysis]]
* [[FFT_Spectrum_Analyzer_Multipurpose|OROS FFT Analyzer Hardware]]

== References ==

* ASTM E2611 — ''Normal Incidence Determination of Porous Material Acoustical Properties Based on the Transfer Matrix Method''
* ISO 10534-2 — ''Determination of sound absorption coefficient and impedance in impedance tubes''
* ISO 9613-1 — ''Attenuation of sound during propagation outdoors — Calculation of the absorption of sound by the atmosphere''
* ISO 11654 — ''Sound absorbers for use in buildings — Rating of sound absorption''
* Miki Y. (1990) — ''Acoustical properties of porous materials — modifications of Delany-Bazley models''

File:TL Tool result demo.png

2026-05-27T09:17:51Z

LaurentM OROS: TL Tool screenshot - automatic upload