bwp_mini_vca

Digital model of the Moog® Minimoog® Model D VCA circuit.

This model extends the original circuit allowing you to control the power supply voltage, gives you the possibility to control contour and loudness via either parameters or audio-rate input signals, and adds an input bias parameter.

Examples

We can privately hand you one or more example plugins if you are interested.

Contact us

API

Module type: DSP

bwp_mini_vca_coeffs

typedef struct bwp_mini_vca_coeffs bwp_mini_vca_coeffs;

Coefficients and related.

bwp_mini_vca_state

typedef struct bwp_mini_vca_state bwp_mini_vca_state;

Internal state and related.

bwp_mini_vca_init()

static inline void bwp_mini_vca_init(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs);

Initializes input parameter values in coeffs.

bwp_mini_vca_set_sample_rate()

static inline void bwp_mini_vca_set_sample_rate(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	float                             sample_rate);

Sets the sample_rate (Hz) value in coeffs.

bwp_mini_vca_reset_coeffs()

static inline void bwp_mini_vca_reset_coeffs(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs);

Resets coefficients in coeffs to assume their target values.

bwp_mini_vca_reset_state()

static inline float bwp_mini_vca_reset_state(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT        state,
	float                                   x_0,
	float                                   x_contour_0,
	float                                   x_loudness_0);

Resets the given state to its initial values using the given coeffs and the initial input value x_0, contour input value x_contour_0, and loudness input value x_loudness_0.

Returns the corresponding initial output value.

If contour input is not enabled, x_contour_0 is ignored. Likewise, if loudness input is not enabled, x_loudness_0 is ignored.

bwp_mini_vca_reset_state_multi()

static inline void bwp_mini_vca_reset_state_multi(
	const bwp_mini_vca_coeffs * BW_RESTRICT              coeffs,
	bwp_mini_vca_state * BW_RESTRICT const * BW_RESTRICT state,
	const float *                                        x_0,
	const float *                                        x_contour_0,
	const float *                                        x_loudness_0,
	float *                                              y_0,
	size_t                                               n_channels);

Resets each of the n_channels states to its initial values using the given coeffs and the corresponding initial input value in the x_0 array, contour input value in the x_contour_0 array, and loudness input value in the x_loudness_0 array.

The corresponding initial output values are written into the y_0 array, if not BW_NULL.

If contour input is not enabled, x_contour_0 is ignored and can be BW_NULL. Likewise, if loudness input is not enabled, x_loudness_0 is ignored and can be BW_NULL.

bwp_mini_vca_update_coeffs_ctrl()

static inline void bwp_mini_vca_update_coeffs_ctrl(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs);

Triggers control-rate update of coefficients in coeffs.

bwp_mini_vca_update_coeffs_audio()

static inline void bwp_mini_vca_update_coeffs_audio(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs);

Triggers audio-rate update of coefficients in coeffs.

bwp_mini_vca_process1()

static inline float bwp_mini_vca_process1(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT        state,
	float                                   x);

static inline float bwp_mini_vca_process1_contour_in(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT        state,
	float                                   x,
	float                                   x_contour);

static inline float bwp_mini_vca_process1_loudness_in(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT        state,
	float                                   x,
	float                                   x_loudness);

static inline float bwp_mini_vca_process1_contour_in_loudness_in(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT        state,
	float                                   x,
	float                                   x_contour,
	float                                   x_loudness);

These functions process one input sample x using coeffs, while using and updating state. They return the corresponding output sample.

In particular:

  • bwp_mini_vca_process1() assumes that contour input and loudness input are not enabled;
  • bwp_mini_vca_process1_contour_in() assumes that contour input is enabled and x_contour is the corresponding input sample, while loudness input is not enabled;
  • bwp_mini_vca_process1_loudness_in() assumes that contour input is not enabled, while loudness input is enabled and x_loudness is the corresponding input sample;
  • bwp_mini_vca_process1_contour_in_loudness_in() assumes that both contour and loudness inputs are enabled, with x_contour and x_loudness being the corresponding input samples, respectively.

Such assumptions are unchecked even for debugging purposes.

bwp_mini_vca_process()

static inline void bwp_mini_vca_process(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	bwp_mini_vca_state * BW_RESTRICT  state,
	const float *                     x,
	const float *                     x_contour,
	const float *                     x_loudness,
	float *                           y,
	size_t                            n_samples);

Processes the first n_samples of the input buffer x and the corresponding contour input buffer x_contour and loudness input buffer x_loudness, and fills the first n_samples of the output buffer y, while using and updating both coeffs and state (control and audio rate).

If contour input is not enabled, x_contour is ignored and can be BW_NULL. Likewise, if loudness input is not enabled, x_loudness is ignored and can be BW_NULL.

bwp_mini_vca_process_multi()

static inline void bwp_mini_vca_process_multi(
	bwp_mini_vca_coeffs * BW_RESTRICT                    coeffs,
	bwp_mini_vca_state * BW_RESTRICT const * BW_RESTRICT state,
	const float * const *                                x,
	const float * const *                                x_contour,
	const float * const *                                x_loudness,
	float * const *                                      y,
	size_t                                               n_channels,
	size_t                                               n_samples);

Processes the first n_samples of the n_channels input buffers x, the contour input buffers x_contour and the loudness input buffers x_loudness, and fills the first n_samples of the n_channels output buffers y, while using and updating both the common coeffs and each of the n_channels states (control and audio rate).

If contour input is not enabled, x_contour is ignored and can be BW_NULL. Likewise, if loudness input is not enabled, x_loudness is ignored and can be BW_NULL.

bwp_mini_vca_set_contour_in()

static inline void bwp_mini_vca_set_contour_in(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	char                              value);

Sets whether contour input is enabled (value non-0) or not (0) in coeffs.

Default value: non-0 (enabled).

bwp_mini_vca_set_Vcc()

static inline void bwp_mini_vca_set_contour(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	float                             value);

Sets the input contour voltage value (V) in coeffs when contour input is not enabled.

Valid range: [0.f, 15.f].

Default value: 10.f.

bwp_mini_vca_set_loudness_in()

static inline void bwp_mini_vca_set_loudness_in(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	char                              value);

Sets whether loudness input is enabled (value non-0) or not (0) in coeffs.

Default value: 0 (not enabled).

bwp_mini_vca_set_loudness()

static inline void bwp_mini_vca_set_loudness(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	float                             value);

Sets the input loudness voltage value (V) in coeffs when loudness input is not enabled.

Valid range: [0.f, 15.f].

Default value: 10.f.

bwp_mini_vca_set_Vcc()

static inline void bwp_mini_vca_set_Vcc(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	float                             value);

Sets the power supply voltage value (V) in coeffs.

Valid range: [5.f, 15.f].

Default value: 10.f.

bwp_mini_vca_set_bias()

static inline void bwp_mini_vca_set_bias(
	bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	float                             value);

Sets the input bias voltage value (V) in coeffs.

Valid range: [-0.1f, 0.1f].

Default value: 0.f.

bwp_mini_vca_coeffs_is_valid()

static inline char bwp_mini_vca_coeffs_is_valid(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs);

Tries to determine whether coeffs is valid and returns non-0 if it seems to be the case and 0 if it is certainly not. False positives are possible, false negatives are not.

coeffs must at least point to a readable memory block of size greater than or equal to that of bwp_mini_vca_coeffs.

bwp_mini_vca_state_is_valid()

static inline char bwp_mini_vca_state_is_valid(
	const bwp_mini_vca_coeffs * BW_RESTRICT coeffs,
	const bwp_mini_vca_state * BW_RESTRICT  state);

Tries to determine whether state is valid and returns non-0 if it seems to be the case and 0 if it is certainly not. False positives are possible, false negatives are not.

If coeffs is not BW_NULL extra cross-checks might be performed (state is supposed to be associated to coeffs).

state must at least point to a readable memory block of size greater than or equal to that of bwp_mini_vca_state.

C++ wrapper

BrickworksPro::MiniVCA
template<size_t N_CHANNELS = 1>
class MiniVCA {
public:
	MiniVCA();

	void setSampleRate(
		float sampleRate);

	void reset(
		float               x0 = 0.f,
		float               xContour0 = 0.f,
		float               xLoudness0 = 0.f,
		float * BW_RESTRICT y0 = BW_NULL);

# ifndef BW_CXX_NO_ARRAY
	void reset(
		float                                       x0,
		float                                       xContour0,
		float                                       xLoudness0,
		std::array<float, N_CHANNELS> * BW_RESTRICT y0);
# endif

	void reset(
		const float * x0,
		const float * xContour0,
		const float * xLoudness0,
		float *       y0 = BW_NULL);

# ifndef BW_CXX_NO_ARRAY
	void reset(
		std::array<float, N_CHANNELS>               x0,
		std::array<float, N_CHANNELS>               xContour0,
		std::array<float, N_CHANNELS>               xLoudness0,
		std::array<float, N_CHANNELS> * BW_RESTRICT y0 = BW_NULL);
# endif

	void process(
		const float * const * x,
		const float * const * xContour,
		const float * const * xLoudness,
		float * const *       y,
		size_t                nSamples);

# ifndef BW_CXX_NO_ARRAY
	void process(
		std::array<const float *, N_CHANNELS> x,
		std::array<const float *, N_CHANNELS> xContour,
		std::array<const float *, N_CHANNELS> xLoudness,
		std::array<float *, N_CHANNELS>       y,
		size_t                                nSamples);
# endif

	void setContourIn(
		bool value);

	void setContour(
		float value);

	void setLoudnessIn(
		bool value);

	void setLoudness(
		float value);

	void setVcc(
		float value);

	void setBias(
		float value);
...
}

Changelog

  • Version 1.0.0:
    • First release.