k-Wave User Forum » Topic: Simulating speaker box

k-Wave User Forum » Topic: Simulating speaker box - Open baffle http://www.k-wave.org/forum/topic/simulating-speaker-box-open-baffle Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 01:09:15 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php Bradley Treeby on "Simulating speaker box - Open baffle" http://www.k-wave.org/forum/topic/simulating-speaker-box-open-baffle#post-8373 Thu, 16 Dec 2021 11:05:53 +0000 Bradley Treeby 8373@http://www.k-wave.org/forum/ At the very beginning of the simulation with both sources, the amplitudes look roughly the same, so at first glance it looks setup correctly. My guess would be its because of the channeling effect of the baffle. Simbo_Saheed on "Simulating speaker box - Open baffle" http://www.k-wave.org/forum/topic/simulating-speaker-box-open-baffle#post-8331 Tue, 19 Oct 2021 13:17:55 +0000 Simbo_Saheed 8331@http://www.k-wave.org/forum/ Hi Im trying to simulate open baffle speaker box. I based my code on examples with Slit Diffraction (for replacing boundary conditions) and from Transducer Field Patterns Example. I'm simulating the membrane by putting two sources - one in front of baffle, one on the other side with opposite phase - In comments of the code. The code below is for one side of membrane only. The problem is, that the source placed inside of the box, creates much bigger pressure field, than the source outside. I'm not sure, if this is caused by standing wave resonance of the open box, or by some computational mistake I missed. But the difference is massive, the sources have completely same initial conditions, on the link below is the image of recorded RMS pressure in Pascals for both cases. Graph link: <a href="https://ibb.co/G382xJR" rel="nofollow">https://ibb.co/G382xJR</a> THE CODE: clearvars; % ========================================================================= % SIMULATION % ========================================================================= % create the computational grid Nx = 200; % number of grid points in the x (row) direction Ny = Nx; % number of grid points in the y (column) direction dx = 0.025; % grid point spacing in the x direction - vždy 2,5cm [m] dy = 0.025; % grid point spacing in the y direction [m] kgrid = kWaveGrid(Nx, dx, Ny, dy); t_end=0.5; % set end of calculation [s] %define properties of test signal source_freq = 60; % [Hz] source_mag = 1; % [Pa] % define the properties of the propagation medium medium.sound_speed = 344; % [m/s] %kgrid.makeTime(medium.sound_speed); %kgrid.t_array = makeTime(kgrid, medium.sound_speed, 0.3, 0.050); % create the speaker slit_mask = zeros(Nx, Ny); % front baffle of speaker slit_mask(Nx/2,41:58) = 1; % left baffle of speaker slit_mask(Nx/2+1:Nx/2+52,41) = 1; % right baffle of speaker slit_mask(Nx/2+1:Nx/2+52,58) = 1; % define a transducer element source.p_mask = zeros(Nx, Ny); source.p_mask(Nx/2+1, 43:55) = 1; % source.p_mask(Nx/2-1, 43:55) = 1; FOR BOTH SIDES OF SOURCE % assign the slit to the properties of the propagation medium barrier_scale = 15; c0=344; rho0=1.29; medium.sound_speed = c0 * ones(Nx, Ny); medium.density = rho0 * ones(Nx, Ny); medium.sound_speed(slit_mask == 1) = barrier_scale * c0; medium.density(slit_mask == 1) = 310 * rho0; % assign the reference sound speed to the background medium medium.sound_speed_ref = c0; % create the time array %kgrid.makeTime(medium.sound_speed); kgrid.t_array = makeTime(kgrid, medium.sound_speed, 0.3, 0.050); %define a time varying sinusoidal source signal_A=[source_mag * sin(2 * pi * source_freq * kgrid.t_array)]; % ========================================================================= % signal for Both sides of source % signal_A=[source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi);source_mag * sin(2 * pi * source_freq * kgrid.t_array); source_mag2 * sin(2 * pi * source_freq * kgrid.t_array+pi)]; % ========================================================================= source.p=signal_A; % create a display mask to display the transducer display_mask = source.p_mask; % create a sensor mask covering the entire computational domain using the % opposing corners of a rectangle sensor.mask = [1, 1, Nx, Ny].'; % set the record mode capture the final wave-field and the statistics at % each sensor point sensor.record = {'p_final', 'p_max', 'p_rms'}; % assign the input options input_args = {'DisplayMask',slit_mask, 'PMLInside', false, 'PlotPML', false}; % run the simulation sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor, input_args{:}); % ========================================================================= % VISUALISATION % ========================================================================= % add the source mask onto the recorded wave-field sensor_data.p_final(source.p_mask ~= 0) = 1; sensor_data.p_max(source.p_mask ~= 0) = 1; sensor_data.p_rms(source.p_mask ~= 0) = 1; % plot the final wave-field figure; subplot(1, 3, 1); imagesc(kgrid.y_vec * 1e3, kgrid.x_vec * 1e3, sensor_data.p_final, [-1 1]); colormap(getColorMap); ylabel('x-position [mm]'); xlabel('y-position [mm]'); axis image; title('Final Wave Field'); % plot the maximum recorded pressure subplot(1, 3, 2); imagesc(kgrid.y_vec * 1e3, kgrid.x_vec * 1e3, sensor_data.p_max, [-1 1]); colormap(getColorMap); ylabel('x-position [mm]'); xlabel('y-position [mm]'); axis image; title('Maximum Pressure'); % plot the rms recorded pressure subplot(1, 3, 3); imagesc(kgrid.y_vec * 1e3, kgrid.x_vec * 1e3, sensor_data.p_rms, [0 0.5]); colormap(getColorMap); ylabel('x-position [mm]'); xlabel('y-position [mm]'); axis image; title('RMS Pressure'); scaleFig(2, 1);