function P = maraca_defaults()
% MARACA_DEFAULTS Default parameters, mirroring the web app's params.ts.
% The output duration is not a parameter: it is
% stroke_count / stroke_rate_hz + tail_s.

% Shell geometry (complete thin spherical shell)
P.shell_radius_m = 0.034;
P.shell_thickness_m = 0.0022;

% Shell material (dried gourd / hardwood veneer scale)
P.density = 720.0;
P.youngs_modulus = 2.5e9;
P.poisson_ratio = 0.30;
P.stiffness_trim = 1.00;
P.max_mode_l = 16;
P.max_mode_hz = 22000.0;

% Damping
P.loss_factor = 0.015;
P.loss_slope = 6.0e-7;
P.radiation_loss = 1.0;

% Grains (seed beads)
P.grain_radius_m = 0.0015;
P.grain_density = 1300.0;
P.grain_youngs = 6.0e8;
P.grain_size_spread = 0.25;
P.restitution = 0.55;

% Shake gesture / stochastic impact process
P.stroke_rate_hz = 4.5;
P.stroke_count = 8;
P.accent_period = 2;
P.accent_gain = 1.5;
P.grain_count = 320;
P.bounces_per_grain = 1.3;
P.shake_velocity = 2.2;
P.slosh_lag_ms = 14.0;
P.burst_width_ms = 45.0;
P.impact_spread_deg = 35.0;
P.seed = 1;

% Closed air cavity
P.cavity_coupling = 1.0;

% Radiation / listener
P.direct_gain = 1.0;
P.listener_x_m = 0.15;
P.listener_y_m = 0.25;
P.listener_z_m = 0.30;
P.speed_of_sound = 343.0;
P.air_density = 1.204;

% Rendering / output
P.sample_rate = 48000;
P.oversample = 2;
P.tail_s = 0.40;
P.pre_delay_ms = 3.0;
P.normalize = 1;
P.peak_dbfs = -3.0;
P.full_scale_pa = 20.0;
end