f 1900 Hz · α 0.99 · reflected energy 1% Absorption values from our Case A simulation (10 mm air gap). Schematic, not to scale.
Numerical impedance-tube testing

Absorption and transmission loss from your CAD file in 72 hours.

Send an STL or STEP file. We simulate your design in a virtual impedance tube and return α(f), surface impedance and transmission loss. You skip printing the sample, shipping it, and waiting for a lab slot.

Ø29 mm & Ø100 mm tubes ISO 10534-2 configuration ASTM E2611 transmission loss
Validation · 10 mm air gap
Our simulation of a micro-perforated panel against the tube measurement published by Sekar et al. (2021).
Why virtual

Architected absorbers are expensive to test physically.

TPMS lattices, resonator arrays and metamaterial cells have to be 3D printed before a lab can test them. Print defects then blur the result you wanted to see. We test the geometry exactly as you designed it.

Physical lab route

  1. Print the sample to tube diameter 3–7 days
  2. Ship internationally 3–10 days
  3. Wait for a lab slot 1–3 weeks
  4. Measurement and report 2–5 days
Typical total2–6 weeks

Virtual Tube Lab

  1. Upload STL / STEP files minutes
  2. Geometry check and PayPal link ≤ 1 business day
  3. Simulation in the virtual tube 1–2 days
  4. Data, plots and report included
Typical total≤ 72 hours
How it works

Four steps from file to frequency response.

Upload your geometry

STL, STEP or IGES of a single sample, or the unit cell plus the sample thickness.

Choose the test

Tube diameter, frequency range, backing condition (rigid or air gap) and whether you need transmission loss.

We simulate

We resolve the full pore geometry, including visco-thermal losses in the narrow channels, inside a model of the standard tube configuration.

You get the results

CSV data, publication-ready plots and a short technical report on the method and its validation.

Deliverables

The same quantities a tube lab reports.

QuantityDescriptionStandard configuration
α(f)Normal-incidence sound absorption coefficientISO 10534-2 / ASTM E1050
Zs(f)Normalised surface impedance, real and imaginary partsISO 10534-2
R(f)Complex reflection coefficientISO 10534-2
TL(f)Normal-incidence transmission loss, from the transfer matrixASTM E2611
ReportMethod, mesh convergence, validation reference and plotsPDF + CSV
Built for

Designs that exist as CAD

  • TPMS lattices: gyroid, Schwarz-P, diamond and graded variants
  • Helmholtz resonator arrays and micro-perforated panels
  • Acoustic metamaterial unit cells and labyrinthine absorbers
  • 3D-printed panels before you commit to printing them
  • Parametric studies with tens of design variants
Not a substitute for

Accredited certification

  • Accredited test reports required for product certification or building-code compliance
  • Random-incidence absorption (ISO 354 reverberation room)
  • Foams and fibrous materials with no geometry file

Most clients use us to narrow a design down, then certify the final version physically.

Validation

Reproducing published impedance-tube measurements.

Two cases from the literature, each simulated from geometry alone and compared with the published measurement. No parameters were fitted to the measured data.

Case AMicro-perforated panel with 5, 10 and 15 mm air gaps

Hover the plot to read values
Solid lines: Virtual Tube Lab simulation. Dashed lines with markers: impedance-tube measurement traced from Sekar, V., Eh Noum, S. Y., Putra, A., Sivanesan, S., Chin, K. C., Wong, Y. S., & Kassim, D. H. (2021). Acoustic properties of micro-perforated panels made from oil palm empty fruit bunch fiber reinforced polylactic acid. Sound & Vibration, 55(4), 343–352. https://doi.org/10.32604/sv.2021.014916 (Fig. 9, CC BY 4.0).
Absorption peak
Air gapfpeak simfpeak expΔfαpeak sim / exp
5 mm2610 Hz2720 Hz−4.1 %1.00 / 0.99
10 mm1800 Hz1900 Hz−5.2 %1.00 / 0.99
15 mm1485 Hz1575 Hz−5.7 %0.99 / 0.98

At every gap the model reproduces the peak absorption, the shape of the curve, and how the peak moves as the gap changes. The measured peaks sit 90–115 Hz (about 5%) higher in frequency, a consistent offset across all three configurations. The simulation was solved in 45 Hz steps.

Case B3D-printed periodic lattice (OPC-5) with a 40 mm air gap

Solid line: Virtual Tube Lab simulation. Dashed line with markers: impedance-tube measurement of the OPC-5 sample (5 mm periodic cell, 60 mm thick) with a 40 mm air gap, traced from Fig. 12(b) of Zieliński, T. G., Opiela, K. C., Pawłowski, P., Dauchez, N., Boutin, T., Kennedy, J., … Groby, J. P. (2020). Reproducibility of sound-absorbing periodic porous materials using additive manufacturing technologies: Round robin study. Additive Manufacturing, 36, 101564. https://doi.org/10.1016/j.addma.2020.101564
Absorption peaks
Peakf simf expΔfα sim / exp
2nd2040 Hz1970 Hz+3.6 %0.87 / 0.84
3rd3720 Hz3675 Hz+1.2 %0.94 / 0.91
4th4620 Hz4665 Hz−1.0 %0.98 / 0.96

The lattice comes from an international round-robin study in which several laboratories printed and tested the same designs. The model resolves every pore and channel of the printed cell and places all three peaks in this band within 4% of the measurement. The simulation was solved in 60 Hz steps.

Pricing

$50 per sample. $40 from your tenth.

Every sample includes α(f), surface impedance, reflection coefficient, CSV data, plots and a short report. Your first nine samples are $50 each, and every sample from the tenth onward is $40.

Samples 1–9
$50 each
  • Start with a single design
  • Delivered within 72 h
Order samples
Sample 10 onward
$40 each
  • Parametric sets and full design families
  • Comparison plot across all samples
Order in volume
Custom project
Let’s talk
  • Optimisation for a target frequency band
  • As-printed tolerance analysis
  • Ongoing support for an R&D programme
Discuss a project
Add-onWhat you getPrice
TLTransmission loss from the four-microphone transfer matrix (ASTM E2611 configuration)+$20 / sample
Full bandBoth tube diameters (Ø100 and Ø29 mm) stitched into one curve from 50 Hz+$15 / sample
PriorityResults within 24 h+50%

Prices in USD, excluding any applicable taxes. Payment by PayPal after we check your files. Example orders: 1 sample $50 · 9 samples $450 · 10 samples $490 · 20 samples $890.

Your engineer

Dr. Gasem

I hold a PhD in Mechanical Engineering, and my work spans fluid mechanics, acoustics and heat transfer. I set up, run and check every simulation myself, including the validation cases above.

PhD, Mechanical Engineering Fluid mechanics Acoustics Heat transfer
FAQ

Questions engineers ask first.

Is this an ISO 10534-2 test?

It is a numerical simulation of the ISO 10534-2 test configuration (and of ASTM E2611 for transmission loss). It reports the same quantities, but it is not an accredited measurement. If you need a certified report for compliance, use our results to choose the final design and then have that design measured by an accredited lab.

How close are the results to a real tube measurement?

In our two validation cases, peak frequencies agreed with the published measurements within 1–6%: a micro-perforated panel at three air gaps, and a 3D-printed periodic lattice from an international round-robin study. Differences between a model and a tube test usually come from the printed sample: surface roughness, trapped powder or resin, and dimensional tolerance. We can quantify those effects with an as-printed tolerance study.

Do you need material parameters such as porosity or flow resistivity?

No. For designs supplied as CAD, we resolve the pore geometry directly. The air properties and the geometry define the result.

Which file formats do you accept?

STL, STEP and IGES. For periodic lattices, you can send just the unit cell along with the sample thickness and diameter.

Is my design kept confidential?

Yes. Uploaded files are stored privately in our own storage behind unguessable links, used only for your project, and deleted automatically after 90 days. If you need an NDA, tick the NDA box on the form and we sign it before you upload anything.

Can you work with clients outside my country?

Yes. The service is fully remote and we work with universities and companies worldwide. Payment by PayPal or card through PayPal, after we confirm your files can be simulated.

Get a quote

Send your design.

Upload your geometry and we check it within one business day. If it can be simulated, we send a PayPal payment link and start as soon as you pay.

  1. Upload your STL or STEP files with a short brief.
  2. We check the geometry and confirm the price.
  3. You pay by PayPal or card, only after that check.
  4. Results arrive within 72 hours.
Drop STL / STEP files here or STL, STEP, IGES, 3MF, OBJ or ZIP · up to 95 MB each · up to 10 files
    Estimated price$50
    No payment now. You pay by PayPal after we confirm your files.