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linn/linndrum.cpp: Modeled click filter, improved hihat decay emulation, and did cleanups. (#13610)
* linn/linndrum.cpp: Modeled click filter, improved hihat decay emulation. Primary changes: * Hihat decay knob will alway have an effect, not just at trigger time. * Modeling the "click" filter. * sound/flt_biquad.cpp: Fixed LOWPASS1P and HIGHPASS1P modes for flt_biquad. Other changes: * Renamed input for hihat decay pot. * Updated "mux drums" section comments. * Updated snare_w comments. * Other minor comment changes. * flt_biquad: Added HIGHPASS1P1Z implementation and used in the linndrum. Reverted HIGHPASS1P changes.
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m1macrophage
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commit
4b2084a6c3
@ -527,6 +527,7 @@ void filter_biquad_device::recalc()
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break;
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// For highpass and friends, block the entire signal.
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case biquad_type::HIGHPASS1P:
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case biquad_type::HIGHPASS1P1Z:
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case biquad_type::HIGHPASS:
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case biquad_type::BANDPASS:
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case biquad_type::PEAK:
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@ -563,6 +564,13 @@ void filter_biquad_device::recalc()
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m_a1 = -m_a1;
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m_b1 = m_b2 = m_a2 = 0.0;
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break;
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case biquad_type::HIGHPASS1P1Z:
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normal = 1.0 / (K + 1.0);
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m_b0 = normal;
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m_b1 = -normal;
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m_a1 = (K - 1.0) * normal;
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m_b2 = m_a2 = 0.0;
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break;
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case biquad_type::LOWPASS:
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m_b0 = Ksquared * normal;
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m_b1 = 2.0 * m_b0;
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@ -25,7 +25,8 @@ public:
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PEAK,
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LOWSHELF,
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HIGHSHELF,
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RAWPARAMS
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RAWPARAMS,
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HIGHPASS1P1Z
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};
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struct biquad_params
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@ -67,7 +67,6 @@ copyright-holders:m1macrophage
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<element name="txt_tune_4"><text string="LO"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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<element name="txt_tune_5"><text string="HI"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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<element name="txt_tune_6"><text string="LO"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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<element name="txt_tune_7"><text string="HIHAT"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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<element name="txt_mixer"><text string="MIXER"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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<element name="txt_left_1"><text string="LEFT" align="1"><color red="0.82" green="0.43" blue="0.31"/></text></element>
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@ -534,13 +533,16 @@ copyright-holders:m1macrophage
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<element ref="txt_tuning"><bounds x="1473" y="435" width="118" height="24"/></element>
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<element ref="line"><bounds x="1183" y="445" width="295" height="2"/></element>
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<element ref="line"><bounds x="1590" y="445" width="295" height="2"/></element>
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<repeat count="7">
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<repeat count="6">
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<param name="i" start="1" increment="1"/>
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<param name="x" start="1183" increment="106"/>
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<param name="knob_input" value="pot_tuning_~i~"/>
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<group ref="knob"><bounds x="~x~" y="495" width="54" height="54"/></group>
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<element ref="txt_tune_~i~"><bounds x="~x~" y="560" width="54" height="17"/></element>
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</repeat>
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<param name="knob_input" value="pot_hihat_decay"/>
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<group ref="knob"><bounds x="1819" y="495" width="54" height="54"/></group>
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<element ref="txt_hihat"><bounds x="1819" y="560" width="54" height="17"/></element>
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<element ref="txt_snare"><bounds x="1183" y="582" width="54" height="17"/></element>
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<element ref="txt_toms"><bounds x="1395" y="582" width="54" height="17"/></element>
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<element ref="line"><bounds x="1286" y="590" width="108" height="2"/></element>
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@ -608,10 +610,11 @@ copyright-holders:m1macrophage
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add_simplecounter_knob(view, "knob_pot_tempo", "pot_tempo", 1.5)
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add_simplecounter_knob(view, "knob_pot_volume", "pot_volume", 1.5)
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for i = 1, 7 do
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for i = 1, 6 do
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local knob_input = "pot_tuning_" .. i
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add_simplecounter_knob(view, "knob_" .. knob_input, knob_input, 3.5)
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end
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add_simplecounter_knob(view, "knob_pot_hihat_decay", "pot_hihat_decay", 3.5)
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for i = 1, 16 do
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local pan_input = "pot_pan_" .. i
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@ -28,11 +28,12 @@ There are multiple voice architectures:
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There is a single, time-multiplexed DAC used for all voices, and each voice
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has its own output. All 8 voices can be played simultaneously, but only a
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single loudness variation of each. The bass drum is post-processed by a
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CEM3320 VCF with a hardcoded envelope, but all other voices lack a
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reconstruction filter. The hat is post-processed by a CEM3360 VCA, which can
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operate in 2 variations: slow decay (open hat) and faster, user-controlled
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decay (closed hat). There's a single clock for all voices, which is tuned by
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a trimmer on the circuit board.
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CEM3320 VCF with a hardcoded envelope, the output of which is routed to the
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mixer and an individual output jack. The rest of the voices are sent to the
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mixer unfiltered, but their individual outputs have a ~15.9KHz RC LPF. The hat
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is post-processed by a CEM3360 VCA, which can operate in 2 variations: slow
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decay (open hat) and faster, user-controlled decay (closed hat). There's a
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single clock for all voices, which is tuned by a trimmer on the circuit board.
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* The "snare / sidestick" section consists of a single voice core (and single
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DAC) which can either play the sidestick, or the snare voice (4K samples
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@ -57,14 +58,10 @@ There are multiple voice architectures:
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The driver is based on the LinnDrum's service manual and schematics, and is
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intended as an educational tool.
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Most of the digital functionality is emulated. Audio is partially emulated.
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Reasons for MACHINE_IMPERFECT_SOUND:
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* Missing a few sample checksums.
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* Missing bass drum LPF and filter envelope.
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* Missing snare / sidestick volume envelope.
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* Missing tom / conga LPF and filter envelope.
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* Inaccurate filter for "click".
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* Linear, instead of tanh response for hi-hat VCA.
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PCBoards:
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@ -96,6 +93,7 @@ Example:
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#include "machine/rescap.h"
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#include "machine/timer.h"
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#include "sound/dac76.h"
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#include "sound/flt_biquad.h"
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#include "sound/flt_rc.h"
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#include "sound/flt_vol.h"
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#include "sound/mixer.h"
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@ -200,6 +198,7 @@ public:
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DECLARE_INPUT_CHANGED_MEMBER(mux_drum_tuning_changed);
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DECLARE_INPUT_CHANGED_MEMBER(snare_tuning_changed);
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DECLARE_INPUT_CHANGED_MEMBER(tom_tuning_changed);
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DECLARE_INPUT_CHANGED_MEMBER(hat_decay_changed);
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protected:
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void device_add_mconfig(machine_config &config) override ATTR_COLD;
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@ -222,6 +221,7 @@ private:
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void update_mux_drum_pitch();
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void update_snare_pitch();
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void update_tom_pitch();
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void update_hat_decay();
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// Mux drums.
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required_ioport m_mux_tuning_trimmer;
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@ -233,6 +233,8 @@ private:
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required_device<timer_device> m_hat_trigger_timer; // U37B (LM556).
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required_device<va_rc_eg_device> m_hat_eg;
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required_device<va_vca_device> m_hat_vca; // CEM3360 (U91B).
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bool m_hat_open = false;
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bool m_hat_triggered = false;
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std::array<bool, NUM_MUX_VOICES> m_mux_counting = { false, false, false, false, false, false, false, false };
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std::array<u16, NUM_MUX_VOICES> m_mux_counters = { 0, 0, 0, 0, 0, 0, 0, 0 };
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@ -266,7 +268,8 @@ private:
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required_ioport_array<NUM_MIXER_CHANNELS> m_volume;
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required_ioport_array<NUM_MIXER_CHANNELS> m_pan;
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required_ioport m_master_volume;
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required_device_array<filter_rc_device, NUM_MIXER_CHANNELS> m_voice_hpf;
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required_device_array<filter_rc_device, NUM_MIXER_CHANNELS - 1> m_voice_hpf;
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required_device<filter_biquad_device> m_click_bpf;
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required_device<mixer_device> m_left_mixer; // 4558 op-amp (U1A).
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required_device<mixer_device> m_right_mixer; // 4558 op-amp (U1B).
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required_device<speaker_device> m_left_out; // 4558 op-amp (U2A).
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@ -289,14 +292,15 @@ private:
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RES_R(0), // low conga
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RES_K(5.1), // cowbell
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RES_K(2.4), // clap
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RES_K(0), // click
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RES_R(0), // click
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};
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static constexpr const float MIXER_R_FEEDBACK = RES_K(33);
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static constexpr const float MIXER_R_BEEP = RES_K(510);
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static constexpr const float MIXER_R_BEEP = RES_K(510); // Same value for left and right.
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static constexpr const float OUTPUT_R_INPUT = RES_K(10); // Input resistor of output stage opamp.
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static constexpr const float OUTPUT_R_FEEDBACK = RES_K(10);
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static constexpr const float OUTPUT_C_FEEDBACK = CAP_P(1000);
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static constexpr const float R_ON_CD4053 = RES_R(125); // Typical Ron resistance for 15V supply (-7.5V / 7.5V).
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static constexpr const float VPLUS = 15; // Volts.
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static constexpr const float VCC = 5; // Volts.
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@ -311,7 +315,7 @@ private:
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static constexpr const float HAT_R33 = RES_M(1);
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static constexpr const float HAT_R34 = RES_K(10);
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static constexpr const float HAT_DECAY_POT_R_MAX = RES_K(100);
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static constexpr const float HAT_MAX_CV = VCC * RES_VOLTAGE_DIVIDER(RES_K(8.2), RES_K(10)); // R67, R66.
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static constexpr const float HAT_EG2CV_SCALER = RES_VOLTAGE_DIVIDER(RES_K(8.2), RES_K(10)); // R67, R66.
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// The audio pipeline operates on voltage magnitudes. This scaler normalizes
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// the final output's range to approximately: -1 - 1.
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@ -349,7 +353,7 @@ DEFINE_DEVICE_TYPE(LINNDRUM_AUDIO, linndrum_audio_device, "linndrum_audio_device
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linndrum_audio_device::linndrum_audio_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
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: device_t(mconfig, LINNDRUM_AUDIO, tag, owner, clock)
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, m_mux_tuning_trimmer(*this, ":pot_mux_tuning")
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, m_hat_decay_pot(*this, ":pot_tuning_7")
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, m_hat_decay_pot(*this, ":pot_hihat_decay")
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, m_mux_samples(*this, ":sample_mux_drum_%u", 0)
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, m_mux_timer(*this, "mux_drum_timer")
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, m_mux_dac(*this, "mux_drums_virtual_dac_%u", 1)
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@ -376,6 +380,7 @@ linndrum_audio_device::linndrum_audio_device(const machine_config &mconfig, cons
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, m_pan(*this, ":pot_pan_%u", 1)
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, m_master_volume(*this, ":pot_volume")
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, m_voice_hpf(*this, "voice_hpf_%u", 1)
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, m_click_bpf(*this, "click_bpf")
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, m_left_mixer(*this, "lmixer")
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, m_right_mixer(*this, "rmixer")
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, m_left_out(*this, "lspeaker")
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@ -397,28 +402,18 @@ void linndrum_audio_device::mux_drum_w(int voice, u8 data, bool is_strobe)
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// remain unchanged, or it will get attenuated by a voltage divider.
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// The MUX is always configured in the "no attenuation" mode for the clap
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// and cowbell voices.
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static constexpr const float ATTENUATION = RES_VOLTAGE_DIVIDER(RES_K(10), RES_K(3.3)); // R60, R62.
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static constexpr const float ATTENUATION = RES_VOLTAGE_DIVIDER(RES_K(10), RES_K(3.3) + R_ON_CD4053); // R60, R62.
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const bool attenuate = !BIT(data, 1) && voice != MV_CLAP && voice != MV_COWBELL;
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m_mux_volume[voice]->set_gain(attenuate ? ATTENUATION : 1);
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if (voice == MV_HAT)
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{
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float r = HAT_R33;
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const bool is_open_hat = BIT(data, 2);
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if (!is_open_hat)
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{
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const float r_decay = HAT_DECAY_POT_R_MAX * m_hat_decay_pot->read() / 100.0F;
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r = RES_2_PARALLEL(HAT_R33, HAT_R34 + r_decay);
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}
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m_hat_eg->set_r(r);
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LOGMASKED(LOG_HAT_EG, "Hat decay. Open: %d, r: %g\n", is_open_hat, r);
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m_hat_open = BIT(data, 2);
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m_hat_triggered = is_strobe;
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update_hat_decay();
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if (is_strobe)
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{
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m_hat_eg->set_instant_v(HAT_MAX_CV);
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m_hat_trigger_timer->adjust(PERIOD_OF_555_MONOSTABLE(RES_K(510), CAP_U(0.01))); // R8, C4.
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LOGMASKED(LOG_HAT_EG, "Hat EG triggered.\n");
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}
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LOGMASKED(LOG_HAT_EG, "Hat EG write: %x, %d.\n", data, is_strobe);
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}
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LOGMASKED(LOG_STROBES, "Strobed mux drum %s: %02x (gain: %f)\n",
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@ -450,6 +445,10 @@ void linndrum_audio_device::snare_w(u8 data)
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// the DAC. Bits D2 and D3 from the voice data bus (latched by U42, 74LS74)
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// control the voltage at the end of R72 and R71.
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// While there is a capacitor (C29, 0.01 UF) attached to the DAC's Iref
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// input, it is too small to have a musical effect. Changes in current will
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// stablizie within 0.1 ms, and such changes only happen at voice trigger.
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static constexpr const float R0 = RES_K(3.3); // R70.
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static constexpr const float R1 = RES_K(380); // R69.
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static constexpr const float R2 = RES_K(22); // R72.
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@ -514,9 +513,7 @@ void linndrum_audio_device::tom_w(u8 data)
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void linndrum_audio_device::strobe_click_w(u8 /*data*/)
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{
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static constexpr const float R10 = RES_K(100);
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static constexpr const float C12 = CAP_U(0.01);
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m_click_timer->adjust(PERIOD_OF_555_MONOSTABLE(R10, C12));
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m_click_timer->adjust(PERIOD_OF_555_MONOSTABLE(RES_K(100), CAP_U(0.01))); // R10, C12.
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m_click->level_w(1);
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LOGMASKED(LOG_STROBES, "Strobed click.\n");
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}
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@ -553,6 +550,11 @@ DECLARE_INPUT_CHANGED_MEMBER(linndrum_audio_device::tom_tuning_changed)
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update_tom_pitch();
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}
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DECLARE_INPUT_CHANGED_MEMBER(linndrum_audio_device::hat_decay_changed)
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{
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update_hat_decay();
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}
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void linndrum_audio_device::device_add_mconfig(machine_config &config)
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{
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// *** Mux drums section.
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@ -578,7 +580,7 @@ void linndrum_audio_device::device_add_mconfig(machine_config &config)
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VA_RC_EG(config, m_hat_eg).set_c(HAT_C22);
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VA_VCA(config, m_hat_vca).configure_streaming_cv(true).configure_cem3360_linear_cv();
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m_mux_volume[MV_HAT]->add_route(0, m_hat_vca, 1.0);
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m_hat_eg->add_route(0, m_hat_vca, 1.0);
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m_hat_eg->add_route(0, m_hat_vca, HAT_EG2CV_SCALER);
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// *** Snare / sidestick section.
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@ -619,7 +621,6 @@ void linndrum_audio_device::device_add_mconfig(machine_config &config)
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}
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// *** Mixer.
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const std::array<device_sound_interface *, NUM_MIXER_CHANNELS> voice_outputs =
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{
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m_mux_volume[MV_BASS],
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@ -642,7 +643,9 @@ void linndrum_audio_device::device_add_mconfig(machine_config &config)
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MIXER(config, m_left_mixer); // U1A
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MIXER(config, m_right_mixer); // U1B
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for (int i = 0; i < voice_outputs.size(); ++i)
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assert(voice_outputs.size() - 1 == MIX_CLICK);
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for (int i = 0; i < voice_outputs.size() - 1; ++i) // Skip "click".
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{
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// The filter and gain will be configured in update_volume_and_pan().
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FILTER_RC(config, m_voice_hpf[i]);
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@ -651,6 +654,11 @@ void linndrum_audio_device::device_add_mconfig(machine_config &config)
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m_voice_hpf[i]->add_route(0, m_right_mixer, 1.0);
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}
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FILTER_BIQUAD(config, m_click_bpf); // Configured in update_volume_and_pan().
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voice_outputs[MIX_CLICK]->add_route(0, m_click_bpf, 1.0);
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m_click_bpf->add_route(0, m_left_mixer, 1.0);
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m_click_bpf->add_route(0, m_right_mixer, 1.0);
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auto &beep_hpf = FILTER_RC(config, "beep_hpf");
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const float rc_r = RES_2_PARALLEL(MIXER_R_BEEP, MIXER_R_BEEP);
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beep_hpf.set_rc(filter_rc_device::HIGHPASS, rc_r, 0, 0, CAP_U(0.1)); // C17. Cutoff: ~6.24 Hz.
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@ -677,6 +685,8 @@ void linndrum_audio_device::device_add_mconfig(machine_config &config)
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void linndrum_audio_device::device_start()
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{
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save_item(NAME(m_hat_open));
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save_item(NAME(m_hat_triggered));
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save_item(NAME(m_mux_counting));
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save_item(NAME(m_mux_counters));
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save_item(NAME(m_snare_counting));
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@ -696,6 +706,7 @@ void linndrum_audio_device::device_reset()
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update_mux_drum_pitch();
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update_snare_pitch();
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update_tom_pitch();
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update_hat_decay();
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}
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void linndrum_audio_device::write_dac(dac76_device &dac, u8 sample)
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@ -749,7 +760,8 @@ float linndrum_audio_device::get_snare_tom_pitch_cv(float v_tune)
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TIMER_DEVICE_CALLBACK_MEMBER(linndrum_audio_device::hat_trigger_timer_tick)
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{
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m_hat_eg->set_target_v(0);
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m_hat_triggered = false;
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update_hat_decay();
|
||||
LOGMASKED(LOG_HAT_EG, "Hat EG started decay.\n");
|
||||
}
|
||||
|
||||
@ -851,7 +863,8 @@ void linndrum_audio_device::update_volume_and_pan(int channel)
|
||||
// Since we are interested in voltage gain, rather than actual voltage,
|
||||
// use 1V as the voice's output.
|
||||
static constexpr const float V_VOICE = 1;
|
||||
// DC-blocking capacitor. Same value for all voice outputs.
|
||||
// DC-blocking capacitor. Same value for all voice outputs except for the
|
||||
// "click" and "beep" sounds.
|
||||
static constexpr const float C_VOICE = CAP_U(10);
|
||||
|
||||
const s32 volume = m_volume[channel]->read();
|
||||
@ -864,8 +877,9 @@ void linndrum_audio_device::update_volume_and_pan(int channel)
|
||||
const float r_right_gnd = R1 + RES_2_PARALLEL(r_pan_right, R3);
|
||||
const float r_left_gnd = R2 + RES_2_PARALLEL(r_pan_left, R4);
|
||||
|
||||
// Resistance to ground as seen from the voice's output.
|
||||
const float r_voice_gnd = r0 + RES_3_PARALLEL(r_vol_bottom, r_left_gnd, r_right_gnd);
|
||||
// Resistance to ground as seen from the volume pot's wiper and the voice's output.
|
||||
const float r_wiper_gnd = RES_3_PARALLEL(r_vol_bottom, r_left_gnd, r_right_gnd);
|
||||
const float r_voice_gnd = r0 + r_wiper_gnd;
|
||||
|
||||
float gain_left = 0;
|
||||
float gain_right = 0;
|
||||
@ -891,11 +905,83 @@ void linndrum_audio_device::update_volume_and_pan(int channel)
|
||||
// Using -gain_*, because the summing op-amps are inverting.
|
||||
m_left_mixer->set_input_gain(channel, -gain_left);
|
||||
m_right_mixer->set_input_gain(channel, -gain_right);
|
||||
m_voice_hpf[channel]->filter_rc_set_RC(filter_rc_device::HIGHPASS, r_voice_gnd, 0, 0, C_VOICE);
|
||||
|
||||
LOGMASKED(LOG_MIX, "Gain update for %s - left: %f, right: %f, HPF cutoff: %.2f Hz\n",
|
||||
MIXER_CHANNEL_NAMES[channel], gain_left, gain_right,
|
||||
1.0F / (2 * float(M_PI) * r_voice_gnd * C_VOICE));
|
||||
if (channel == MIX_CLICK)
|
||||
{
|
||||
// Compared to the other voices, the click uses a different value for
|
||||
// the DC blocking capacitor. Furthermore, there is a capacitor to ground
|
||||
// at the volume pot wiper. The resulting filter acts as an HPF (cutoff:
|
||||
// ~1.15 KHz) when the click volume is at max, and becomes a BPF whose
|
||||
// characteristics change as the volume decreases.
|
||||
|
||||
// Capacitor at the output of the 556 timer.
|
||||
static constexpr const float C_CLICK_DCBLOCK = CAP_U(0.01); // C37
|
||||
// Capacitor to ground, at the wiper of the "click" volume fader.
|
||||
static constexpr const float C_CLICK_WIPER = CAP_U(0.047); // No designation.
|
||||
|
||||
// All "click" filter configurations result in singificant attenutation
|
||||
// (< 0.2x), which makes the click very quiet. The filter characteristics
|
||||
// (gain and Fc) have been verified with simulations. So it is possible
|
||||
// there is an error in the schematic. Different capacitor values, or a
|
||||
// supply of 15V (instead of the stated 5V) for the 556 timer generating
|
||||
// the click could explain this.
|
||||
// For now, scale by some number to match the volume of other voices.
|
||||
static constexpr const float CLICK_GAIN_CORRECTION = 5;
|
||||
|
||||
float fc = 0;
|
||||
float q = 1;
|
||||
float gain = 1;
|
||||
if (volume >= 100)
|
||||
{
|
||||
// HPF transfer function: H(s) = (g * s) / (s + w) where
|
||||
// g = C1 / (C1 + C2)
|
||||
// w = 1 / (R * (C1 + C2))
|
||||
fc = 1.0F / (2 * float(M_PI) * r_voice_gnd * (C_CLICK_DCBLOCK + C_CLICK_WIPER));
|
||||
gain = C_CLICK_DCBLOCK / (C_CLICK_DCBLOCK + C_CLICK_WIPER);
|
||||
m_click_bpf->modify(filter_biquad_device::biquad_type::HIGHPASS1P1Z, fc, 1, gain * CLICK_GAIN_CORRECTION);
|
||||
}
|
||||
else if (volume > 0)
|
||||
{
|
||||
// BPF transfer function: H(s) = (A * s) / (s ^ 2 + B * s + C)
|
||||
// Where:
|
||||
// A = 1 / (R1 * C2)
|
||||
// B = (C1 * R1 + C1 * R2 + C2 * R2) / (R1 * R2 * C1 * C2)
|
||||
// C = 1 / (R1 * R2 * C1 * C2).
|
||||
// From the standard transfer function for BPFs, we have:
|
||||
// A = gain * (w / Q)
|
||||
// B = w / Q
|
||||
// C = w ^ 2
|
||||
// The calculations of Fc, Q and gain below are derived from the
|
||||
// equations above, with some algebra.
|
||||
|
||||
const float x = sqrtf(r0 * r_wiper_gnd * C_CLICK_DCBLOCK * C_CLICK_WIPER);
|
||||
const float y = C_CLICK_DCBLOCK * r0 + C_CLICK_DCBLOCK * r_wiper_gnd + C_CLICK_WIPER * r_wiper_gnd;
|
||||
fc = 1.0F / (2 * float(M_PI) * x);
|
||||
q = x / y;
|
||||
gain = r_wiper_gnd * C_CLICK_DCBLOCK / y;
|
||||
|
||||
// The transfer function above includes the effect of the volume
|
||||
// potentiometer. But `gain_left` and `gain_right` already incorporate
|
||||
// that effect. So it needs to be undone from the filter's gain.
|
||||
gain *= 1.0F / RES_VOLTAGE_DIVIDER(r0, r_wiper_gnd);
|
||||
|
||||
m_click_bpf->modify(filter_biquad_device::biquad_type::BANDPASS, fc, q, gain * CLICK_GAIN_CORRECTION);
|
||||
}
|
||||
// Else, if the volume is 0, don't change the BPF's configuration to avoid divisions by 0.
|
||||
|
||||
LOGMASKED(LOG_MIX, "Gain update for %s - left: %f, right: %f, %s cutoff: %.2f Hz, Q: %.3f, Gain: %.3f\n",
|
||||
MIXER_CHANNEL_NAMES[MIX_CLICK], gain_left, gain_right,
|
||||
(volume >= 100) ? "HPF" : "BPF", fc, q, gain);
|
||||
}
|
||||
else
|
||||
{
|
||||
// The rest of the voices just have a DC-blocking filter. Its exact cutoff
|
||||
// will depend on the volume and pan settings, but it won't be audible.
|
||||
m_voice_hpf[channel]->filter_rc_set_RC(filter_rc_device::HIGHPASS, r_voice_gnd, 0, 0, C_VOICE);
|
||||
LOGMASKED(LOG_MIX, "Gain update for %s - left: %f, right: %f, HPF cutoff: %.2f Hz\n",
|
||||
MIXER_CHANNEL_NAMES[channel], gain_left, gain_right,
|
||||
1.0F / (2 * float(M_PI) * r_voice_gnd * C_VOICE));
|
||||
}
|
||||
}
|
||||
|
||||
void linndrum_audio_device::update_master_volume()
|
||||
@ -996,6 +1082,31 @@ void linndrum_audio_device::update_tom_pitch()
|
||||
knob_index, knob_value, cv, freq);
|
||||
}
|
||||
|
||||
void linndrum_audio_device::update_hat_decay()
|
||||
{
|
||||
// When the hat is configed as "open", the EG will discharge through a 1M
|
||||
// resistor. When the hat is "closed", a CD4053 will add a parallel
|
||||
// discharge path through the "hihat decay" pot.
|
||||
float eg_r = HAT_R33;
|
||||
if (!m_hat_open)
|
||||
{
|
||||
const float r_decay_pot = HAT_DECAY_POT_R_MAX * m_hat_decay_pot->read() / 100.0F;
|
||||
eg_r = RES_2_PARALLEL(HAT_R33, HAT_R34 + R_ON_CD4053 + r_decay_pot);
|
||||
}
|
||||
m_hat_eg->set_r(eg_r);
|
||||
|
||||
// When the hat is strobed, it will trigger a 556 (U37A) timer in monostable
|
||||
// mode (see mux_drum_w()). The timer's output pin is connected to the EG
|
||||
// capacitor via a diode, and will maintain that capacitor at VCC until the
|
||||
// timer expires. At that point, the EG capacitor will discharge through eg_r.
|
||||
if (m_hat_triggered)
|
||||
m_hat_eg->set_instant_v(VCC);
|
||||
else
|
||||
m_hat_eg->set_target_v(0);
|
||||
|
||||
LOGMASKED(LOG_HAT_EG, "Hat decay. Open: %d, EG R: %f\n", m_hat_open, eg_r);
|
||||
}
|
||||
|
||||
namespace {
|
||||
|
||||
constexpr const char MAINCPU_TAG[] = "z80";
|
||||
@ -1443,8 +1554,8 @@ INPUT_PORTS_START(linndrum)
|
||||
PORT_ADJUSTER(52, "HI CONGAS TUNING") PORT_CHANGED_MEMBER(AUDIO_TAG, FUNC(linndrum_audio_device::tom_tuning_changed), 0)
|
||||
PORT_START("pot_tuning_6")
|
||||
PORT_ADJUSTER(40, "LO CONGAS TUNING") PORT_CHANGED_MEMBER(AUDIO_TAG, FUNC(linndrum_audio_device::tom_tuning_changed), 0)
|
||||
PORT_START("pot_tuning_7")
|
||||
PORT_ADJUSTER(50, "HIHAT DECAY")
|
||||
PORT_START("pot_hihat_decay")
|
||||
PORT_ADJUSTER(50, "HIHAT DECAY") PORT_CHANGED_MEMBER(AUDIO_TAG, FUNC(linndrum_audio_device::hat_decay_changed), 0)
|
||||
|
||||
PORT_START("pot_pan_1")
|
||||
PORT_ADJUSTER(50, "BASS PAN") PORT_CHANGED_MEMBER(AUDIO_TAG, FUNC(linndrum_audio_device::mix_changed), MIX_BASS)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user