OTL-Suite goes far beyond the typical acoustical analysis in the fields of

**Wind Farm - Atmospheric Refraction****:** OTL-Suite now includes modelling the effects of Atmospheric Refraction in a non-homogeneous atmosphere due to a **temperature gradient** and **wind profile**. Modelling the propagation of sound through such a non-homogeneous atmosphere is one of the most difficult tasks in outdoor acoustics due to the multiple physical phenomena that need to be accounted for such as creeping waves and many others, but it is essential for analysing environments spanning more than 200m - a particular concern to the wind farm industry.

**environmental acoustics****architectural acoustics.**

- Sound Reduction Index (10-10kHz) in narrow bands,
- Rw(C;Ctr) ratings at 100-3150 Hz and 50-5kHz,
- equivalent statistical absorption coefficients 10-10kHz in narrow bands,
- ISO 11654 absorption coefficient,
- a(w), Class and NRC ratings of the structure
- integration angles 78 and 90 degrees
- complex surface impedance of the structures, in narrow bands.

Users can specify unlimited numbers of layers, see results in high resolution in an extended frequency range from 10 Hz to 10kHz, export of values in both high resolution frequency analysis and 1/3 octave analysis, as well as Front-Back, Back-Front performance (in sound absorption and impedance calculations).

For more information or to download the latest version Trial

Are you going to**Euronoise2018**? Meet us at **Booth 25** together with **Infra QSources** and **Eckel Noise Control Technologies**.

]]>Are you going to

In the new update you can now import DXF files with GIS coordinates (which can feature extremely large coordinate values such as from Lambert-93 projection).

Your software should automatically update if you have the "Automatically Check for Updates" enabled. If not, please check for the latest Update through the Updates menu: ]]>

- Generate Average Ground Tool, allows replacing multiple grounds with a single average ground averaged using the least squares method.
- New methodology for shadow zone calculations whereby whenever a single ground is present in the geometry then it is used as the reference ground instead of the XY plane

Using the Generate Average Ground tool, you can replace multiple grounds with a single average ground averaged using the least squares method. This is useful in situations where a terrain model was imported from a .dxf file and then a refraction calculation is needed which assumes a flat ground: ]]>

After a year's of hard work, today we have finally released Olive Tree Lab 4.0! OTL 4.0 includes the following major additions

1) Calculation of source directivity using CLF files.

2) Calculation of binaural impulse responses and stereo sound auralization using HRTF files.

3) Calculation of atmospheric refraction based on meteorological conditions.

Moreover OTL 4.0 introduces the following changes in the licensing policy.

a) Monthly subscriptions are introduced. You can now subscribe to OTL Suite for €195 + VAT/monthly and cancel anytime.

b) OTL Room, OTL Terrain and OTL Office are discontinued.

c) OTL Room Modes is introduced on a subscription basis only for ONLY €9.95 + VAT/monthly.

Feel free to give it a try by downloading Olive Tree Lab 4.0 here

]]>1) Calculation of source directivity using CLF files.

2) Calculation of binaural impulse responses and stereo sound auralization using HRTF files.

3) Calculation of atmospheric refraction based on meteorological conditions.

Moreover OTL 4.0 introduces the following changes in the licensing policy.

a) Monthly subscriptions are introduced. You can now subscribe to OTL Suite for €195 + VAT/monthly and cancel anytime.

b) OTL Room, OTL Terrain and OTL Office are discontinued.

c) OTL Room Modes is introduced on a subscription basis only for ONLY €9.95 + VAT/monthly.

Feel free to give it a try by downloading Olive Tree Lab 4.0 here

We are pleased to present today three projects undertaken by students of Columbia College Chicago who took advantage of the special offers for students and startups.

The first project was undertaken by Alejandro Acosta and is presented in this poster. It is titled**"Analysis and Mitigation of Noise in a Printing Press Factory"** and it uses Olive Tree Lab for predicting SPL inside a printing press factory.

The second project is a work done by Isabel Garcia titled**"A Traffic Noise Assessment Comparing Two Modeling Tools: Traffic Noise Model 2.5 & Olive Tree Lab 3.3"** and can be found here. It discusses the TNM and OTL when compared to measurements. It also makes a comparison between the two methods.

The third poster is called**"Noise Study of a Large Brewery: The Economics of Simplified Modeling" **and it is authored by Tyler Bubenik. It describes the noise evaluation of a large brewery and best practices of utilizing OTL in such cases. The poster can be downloaded here.

The projects were supervised by Professor Dominique Cheenne and supported by PEMARD.

We would like to congratulate the three students and wish them all the best in their careers!

]]>The first project was undertaken by Alejandro Acosta and is presented in this poster. It is titled

The second project is a work done by Isabel Garcia titled

The third poster is called

The projects were supervised by Professor Dominique Cheenne and supported by PEMARD.

We would like to congratulate the three students and wish them all the best in their careers!

In this post I will elaborate on some best practices on how to make calculations in Olive Tree Lab more efficient and spend less time in waiting. Before i get into these practices, i would like to mention that we do our best from our side to make the calculations as fast as possible without compromising on accuracy and without introducing physically unfounded methods. We use smart detection algorithms that use techniques like visibility tracing, prioritized tracing and hybrid tracing to accelerate image source detection and diffraction path detection. We are actively engaged in research in the area of accelerating path detection algorithms with relevant publications. We use parallel programming wherever this is possible and we have also developed GPU based acoustic calculations, waiting to be introduced as soon as we feel that the technology is mature enough for mainstream use.

Now let's see how we can make our calculations in Olive Tree Lab faster. First of all, in order to speed up the calculation process, we need to understand why it is taking so long. The most important bottleneck in the calculation process is the path detection process.

Other factors that affect the calculation time, not in an exponential way though but in a

Now that we have gone through the major parameters that affect calculation time, let's see how we can optimize it.

An important engineering principle in Olive Tree Lab calculations is that as we increase the calculation complexity, the results do not approach the solution in the same rate that the complexity increases. In computational terms the relation of accuracy increase to calculation complexity increase is a sublinear function. As a result, an OTL user should find the

So how do we achieve the above? Let me outline my approach on this in a typical large project. Let's suppose a project with 500 surfaces, 10 sound sources and sound receivers. I would do the following.

1) Make all the obviously irrelevant surfaces in the model inactive (walls that will obviously not contribute to the sound field).

2)Choose a representative Source-Receiver combination and deactivate the rest.

3)Run a simple calculation with a very basic complexity e.g. first order reflections, first order diffractions and 1/3 octave calculations.

4)Progressively increase the calculation complexity and recalculate.

5)Compare subsequent calculation times and calculation results.

6)As soon as I decide where i want to compromise between accuracy and calculation time, I enable all my sources and receivers and I execute my full calculation.

The above procedure can be changed slightly based on the project requirements but it generally highlights what the way of thinking should be about getting optimal calculation times in Olive Tree Lab.

In the future, I will post more ideas on how to make OTL sound propagation calculations more efficient.

Stay tuned!]]>