Speaker cabinet and room simulations using computational models

If you place a loudspeaker at an arbitrary position in a small room, is it possible to calculate how it sounds at a chosen location?

Trying to answer this question, an automated computational concept has been developed. By using two, parametrized, acoustic models a spectra of cabinet and room responses can be calculated. The obtained transfer functions are then the foundation for a computationally based speaker cabinet and booth plugin, the CabSolver. 

If the calculated responses are good enough, sonically, we then have the possibility to by-pass both the time-consuming process of recording speaker responses, and the inherent sequence of transfer functions. 

The cascade of IRs inherent to a recording sequence.

So, will the calculated response of virtual speakers be different, good or bad, in comparison to the measured ones used by most cabinet plugins? Which is simply the interesting question!

A guitar and bass track using the CabSolver (don't pay any attention to the amateurish musician!).  The settings emulate two cabinets at different locations in a small room (no postprocessing takes place here, just 'raw' track data).


Hera are some additional tracks using the plugin, CabOne, which is based on the present development version.


Some about the acoustic models

Due to the rather complicated physical nature of a speaker and cabinet arrangement (we are dealing with a double transducer), a pragmatic modelling approach is used to include these energy transitions (electric -> kinetic -> acoustic).

A double transducer; two energy transitions are present, electric -> kinetic -> acoustic.

The speaker and cabinet model is based on few related parameters (some make more sense than others). I use the model for solving the acoustic near field problem, i.e., calculating the pressure response valid for an arbitrary location close to the speaker.

The acoustic near field problem.

A similar modelling approach is also used for the room model, a model based on a few room and cab related parameters. Here, focus is set on the corresponding far field solution of the acoustic problem i.e., I try to relate a chosen position of the cabinet to a stationary 'receiver' in a small room.  So, the acoustic solution gives the transfer function for the room set-up.

By a simple merging procedure, the extracted far- and near field results can be combined to get what I am chasing, a response representing a kind of 'cab-in-a-booth ' sound.

The acoustic far field problem.
Here is a PowerPoint presentation including some additional information concerning this acoustic project, like FFT-plots, parameters etc. 


The acoustic solutions are implemented in a plugin and accessed via a basic GUI. Different sounds, ranging from near field responses to integrated solutions can be dialled-in by using the dropdown menus. The present version gives the option to combine two different speaker cabinet and booth settings. 

The download page

If you are interested in testing CabOne, a downloadable (beta) version is here.

Finally, we end this session by some sections including various stuff related to this acoustic modelling project, old as new!

Have a nice day,