Merge pull request #2 from Dimev/modfm

Awesome! Thanks a lot for the work and polish!

src/dsp/mod.rs

@@ -507,6 +507,8 @@ mod node_delay;
 #[allow(non_upper_case_globals)]
 mod node_fbwr_fbrd;
 #[allow(non_upper_case_globals)]
+mod node_formfm;
+#[allow(non_upper_case_globals)]
 mod node_map;
 #[allow(non_upper_case_globals)]
 mod node_mix3;
@@ -593,6 +595,7 @@ use node_cqnt::CQnt;
 use node_delay::Delay;
 use node_fbwr_fbrd::FbRd;
 use node_fbwr_fbrd::FbWr;
+use node_formfm::FormFM;
 use node_map::Map;
 use node_mix3::Mix3;
 use node_mux9::Mux9;
@@ -1496,6 +1499,12 @@ macro_rules! node_list {
                (1  offs  n_id      d_id  r_s    f_def stp_d -1.0, 1.0, 0.0)
                {2 0 mode setting(0) mode fa_noise_mode 0 1}
                [0 sig],
+            formfm => FormFM UIType::Generic UICategory::Osc
+               (0 freq n_pit d_pit r_fq f_freq stp_d -1.0, 0.5647131, 440.0)
+               (1 form n_pit d_pit r_fq f_freq stp_d -1.0, 0.5647131, 440.0)
+               (2 side  n_id d_id r_id f_def stp_d 0.0, 1.0, 0.2)
+               (3 peak  n_id d_id r_id f_def stp_d 0.0, 1.0, 0.4)
+               [0 sig],
             sfilter => SFilter UIType::Generic UICategory::Signal
                (0  inp   n_id      d_id  r_id   f_def stp_d -1.0, 1.0, 0.0)
                (1 freq  n_pit      d_pit r_fq  f_freq  stp_d -1.0, 0.5647131, 1000.0)

src/dsp/node_ad.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{sqrt4_to_pow4, TrigSignal, Trigger};
 use crate::dsp::{
     DspNode, GraphAtomData, GraphFun, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{sqrt4_to_pow4, TrigSignal, Trigger};
 
 #[macro_export]
 macro_rules! fa_ad_mult {

src/dsp/node_allp.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::AllPass;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::AllPass;
 
 /// A simple amplifier
 #[derive(Debug, Clone)]

src/dsp/node_biqfilt.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::*;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::*;
 
 #[macro_export]
 macro_rules! fa_biqfilt_type {

src/dsp/node_bosc.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::PolyBlepOscillator;
 use crate::dsp::{
     DspNode, GraphAtomData, GraphFun, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::PolyBlepOscillator;
 
 #[macro_export]
 macro_rules! fa_bosc_wtype {

src/dsp/node_bowstri.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{DelayBuffer, FixedOnePole, Biquad};
 use crate::dsp::{
     denorm, denorm_offs, inp, out, DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{Biquad, DelayBuffer, FixedOnePole};
 
 // Bowed String instrument oscillator
 // Bowed string model, a la Smith (1986),

src/dsp/node_comb.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp;
 
 #[macro_export]
 macro_rules! fa_comb_mode {

src/dsp/node_cqnt.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{ChangeTrig, CtrlPitchQuantizer};
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{ChangeTrig, CtrlPitchQuantizer};
 
 #[macro_export]
 macro_rules! fa_cqnt {

src/dsp/node_delay.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{crossfade, DelayBuffer, TriggerSampleClock};
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{crossfade, DelayBuffer, TriggerSampleClock};
 
 #[macro_export]
 macro_rules! fa_delay_mode {

src/dsp/node_formfm.rs

@@ -0,0 +1,132 @@
+// Copyright (c) 2022 Dimas Leenman <skythedragon@outlook.com>
+// This file is a part of HexoDSP. Released under GPL-3.0-or-later.
+// See README.md and COPYING for details.
+
+use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
+use crate::nodes::{NodeAudioContext, NodeExecContext};
+
+/// A simple amplifier
+#[derive(Debug, Clone)]
+pub struct FormFM {
+    inv_sample_rate: f32,
+    phase: f32,
+}
+
+impl FormFM {
+    pub fn new(_nid: &NodeId) -> Self {
+        Self { inv_sample_rate: 1.0 / 44100.0, phase: 0.0 }
+    }
+    pub const freq: &'static str = "Formant freq\nBase frequency to oscilate at\n";
+    pub const form: &'static str = "Formant form\nFrequency of the formant\nThis affects how much lower or higher tones the sound has.";
+    pub const side: &'static str =
+        "Formant side\nWhich side the peak of the wave is. Values more towards 0.0 or 1.0 make the base frequency more pronounced";
+    pub const peak: &'static str =
+        "Formant peak\nHow high the peak amplitude is. Lower values make the effect more pronounced";
+    pub const sig: &'static str = "Formant sig\nGenerated formant signal";
+    pub const DESC: &'static str = r#"Formant oscillator
+
+Simple formant oscillator that generates a formant like sound.
+Loosely based on the ModFM synthesis method.
+"#;
+    pub const HELP: &'static str = r#"formfm - Direct formant synthesizer
+
+This is a formant synthesizer that directly generates 
+the audio of a single formant.
+
+This can be seen as passing a saw wave with frequency `freq` 
+into a bandpass filter with the cutoff at `form`
+
+`freq` controls the base frequency of the formant.
+`form` controls the formant frequency. Lower values give more bass to the sound, 
+and higher values give the high frequencies more sound.
+
+`side` controls where the peak of the carrier wave is, 
+and in turn controls the bandwidth of the effect. The more towards 0.0 or 1.0,
+the more the formant is audible.
+
+`peak` controls how high the peak of the carrier wave is.
+This also controls the bandwidth of the effect, where lower means a higher 
+bandwidth, and thus more audible formant.
+"#;
+}
+
+impl DspNode for FormFM {
+    fn outputs() -> usize {
+        1
+    }
+
+    fn set_sample_rate(&mut self, srate: f32) {
+        self.inv_sample_rate = 1.0 / srate;
+    }
+
+    fn reset(&mut self) {
+        self.phase = 0.0;
+    }
+
+    #[inline]
+    fn process<T: NodeAudioContext>(
+        &mut self,
+        ctx: &mut T,
+        _ectx: &mut NodeExecContext,
+        _nctx: &NodeContext,
+        _atoms: &[SAtom],
+        inputs: &[ProcBuf],
+        outputs: &mut [ProcBuf],
+        _ctx_vals: LedPhaseVals,
+    ) {
+        use crate::dsp::{denorm, inp, out};
+
+        let base_freq = inp::FormFM::freq(inputs);
+        let formant_freq = inp::FormFM::form(inputs);
+        let side_val = inp::FormFM::side(inputs);
+        let peak_val = inp::FormFM::peak(inputs);
+        let out = out::FormFM::sig(outputs);
+
+        for frame in 0..ctx.nframes() {
+            // get the inputs
+            let base_freq = denorm::FormFM::freq(base_freq, frame);
+            let formant_freq = denorm::FormFM::form(formant_freq, frame);
+            let side_val = denorm::FormFM::side(side_val, frame).min(1.0 - 1e-6).max(1e-6);
+            let peak_val = denorm::FormFM::peak(peak_val, frame);
+
+            // make a triangle wave, with the peak at carrier center
+            let carrier_base =
+                (self.phase / side_val).min((1.0 - self.phase) / (1.0 - side_val));
+
+            // smoothstep
+            let carrier = 1.0
+                - ((1.0 - peak_val)
+                    * (carrier_base * carrier_base * (3.0 - 2.0 * carrier_base)));
+
+            // multiple of the frequency the modulators are at
+            let multiple = formant_freq / base_freq.max(1e-6);
+
+            // round them to the closest integer of the formant freq
+            let freq_a = multiple.floor();
+            let freq_b = freq_a + 1.0;
+
+            // and how much to lerp between them
+            let blend = multiple.fract();
+
+            // get the true modulator
+            let modulator = (1.0 - blend)
+                * if multiple < 1.0 {
+                    0.0
+                } else {
+                    (std::f32::consts::TAU * self.phase * freq_a).cos()
+                }
+                + blend * (std::f32::consts::TAU * self.phase * freq_b).cos();
+
+            // entire wave
+            let wave = carrier * modulator;
+
+            // increment phase (very imporant)
+            self.phase += base_freq * self.inv_sample_rate;
+
+            // wrap around
+            self.phase = self.phase.fract();
+
+            out.write(frame, wave);
+        }
+    }
+}

src/dsp/node_mux9.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::Trigger;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::Trigger;
 
 #[macro_export]
 macro_rules! fa_mux9_in_cnt {

src/dsp/node_noise.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::Rng;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::Rng;
 
 #[macro_export]
 macro_rules! fa_noise_mode {

src/dsp/node_pverb.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{DattorroReverb, DattorroReverbParams, crossfade};
 use crate::dsp::{denorm, DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{crossfade, DattorroReverb, DattorroReverbParams};
 
 pub struct DatParams {
     frame: usize,

src/dsp/node_quant.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{ChangeTrig, Quantizer};
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{ChangeTrig, Quantizer};
 
 #[macro_export]
 macro_rules! fa_quant {

src/dsp/node_rndwk.rs

@@ -2,9 +2,9 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{Rng, SlewValue, Trigger};
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{Rng, SlewValue, Trigger};
 
 /// A triggered random walker
 #[derive(Debug, Clone)]

src/dsp/node_sampl.rs

@@ -2,10 +2,10 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{cubic_interpolate, Trigger};
 use crate::dsp::{at, denorm, denorm_offs, inp, out}; //, inp, denorm, denorm_v, inp_dir, at};
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{cubic_interpolate, Trigger};
 
 #[macro_export]
 macro_rules! fa_sampl_dir {

src/dsp/node_scope.rs

@@ -8,12 +8,12 @@
 // Copyright by Andrew Belt, 2021
 
 //use super::helpers::{sqrt4_to_pow4, TrigSignal, Trigger};
-use synfx_dsp::CustomTrigger;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::SCOPE_SAMPLES;
 use crate::nodes::{NodeAudioContext, NodeExecContext};
 use crate::ScopeHandle;
 use std::sync::Arc;
+use synfx_dsp::CustomTrigger;
 
 #[macro_export]
 macro_rules! fa_scope_tsrc {

src/dsp/node_sfilter.rs

@@ -2,13 +2,13 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
+use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
+use crate::nodes::{NodeAudioContext, NodeExecContext};
 use synfx_dsp::{
     process_1pole_highpass, process_1pole_lowpass, process_1pole_tpt_highpass,
     process_1pole_tpt_lowpass, process_hal_chamberlin_svf, process_simper_svf,
     process_stilson_moog,
 };
-use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
-use crate::nodes::{NodeAudioContext, NodeExecContext};
 
 #[macro_export]
 macro_rules! fa_sfilter_type {

src/dsp/node_sin.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::fast_sin;
 use crate::dsp::{
     denorm_offs, inp, out, DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::fast_sin;
 
 /// A sine oscillator
 #[derive(Debug, Clone)]

src/dsp/node_test.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::TrigSignal;
 use crate::dsp::{
     DspNode, GraphAtomData, GraphFun, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::TrigSignal;
 
 #[macro_export]
 macro_rules! fa_test_s {

src/dsp/node_tseq.rs

@@ -2,10 +2,10 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{Trigger, TriggerPhaseClock};
 use crate::dsp::tracker::TrackerBackend;
 use crate::dsp::{DspNode, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom};
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{Trigger, TriggerPhaseClock};
 
 use crate::dsp::MAX_BLOCK_SIZE;
 

src/dsp/node_tslfo.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{TriSawLFO, Trigger};
 use crate::dsp::{
     DspNode, GraphAtomData, GraphFun, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{TriSawLFO, Trigger};
 
 #[derive(Debug, Clone)]
 pub struct TsLFO {

src/dsp/node_vosc.rs

@@ -2,11 +2,11 @@
 // This file is a part of HexoDSP. Released under GPL-3.0-or-later.
 // See README.md and COPYING for details.
 
-use synfx_dsp::{Oversampling, apply_distortion, VPSOscillator};
 use crate::dsp::{
     DspNode, GraphAtomData, GraphFun, LedPhaseVals, NodeContext, NodeId, ProcBuf, SAtom,
 };
 use crate::nodes::{NodeAudioContext, NodeExecContext};
+use synfx_dsp::{apply_distortion, Oversampling, VPSOscillator};
 
 #[macro_export]
 macro_rules! fa_vosc_ovrsmpl {

src/lib.rs

@@ -321,8 +321,8 @@ pub mod monitor;
 pub mod nodes;
 pub mod sample_lib;
 pub mod scope_handle;
-pub mod wblockdsp;
 mod util;
+pub mod wblockdsp;
 
 pub use cell_dir::CellDir;
 pub use chain_builder::MatrixCellChain;

src/matrix.rs

@@ -8,9 +8,9 @@ use crate::matrix_repr::*;
 pub use crate::monitor::MON_SIG_CNT;
 pub use crate::nodes::MinMaxMonitorSamples;
 use crate::nodes::{NodeConfigurator, NodeGraphOrdering, NodeProg, MAX_ALLOCATED_NODES};
+use crate::wblockdsp::{BlkJITCompileError, BlockFun, BlockFunSnapshot};
 pub use crate::CellDir;
 use crate::ScopeHandle;
-use crate::wblockdsp::{BlockFun, BlockFunSnapshot, BlkJITCompileError};
 
 use std::collections::{HashMap, HashSet};
 

src/matrix_repr.rs

@@ -3,8 +3,8 @@
 // See README.md and COPYING for details.
 
 use crate::dsp::{NodeId, ParamId, SAtom};
-use serde_json::{json, Value};
 use crate::wblockdsp::BlockFunSnapshot;
+use serde_json::{json, Value};
 
 #[derive(Debug, Clone, Copy)]
 pub struct CellRepr {

src/nodes/node_conf.rs

@@ -6,15 +6,15 @@ use super::{
     FeedbackFilter, GraphMessage, NodeOp, NodeProg, MAX_ALLOCATED_NODES, MAX_AVAIL_CODE_ENGINES,
     MAX_AVAIL_TRACKERS, MAX_INPUTS, MAX_SCOPES, UNUSED_MONITOR_IDX,
 };
-use crate::wblockdsp::*;
 use crate::dsp::tracker::{PatternData, Tracker};
 use crate::dsp::{node_factory, Node, NodeId, NodeInfo, ParamId, SAtom};
 use crate::monitor::{new_monitor_processor, MinMaxMonitorSamples, Monitor, MON_SIG_CNT};
 use crate::nodes::drop_thread::DropThread;
-#[cfg(feature = "synfx-dsp-jit")]
-use synfx_dsp_jit::engine::CodeEngine;
+use crate::wblockdsp::*;
 use crate::SampleLibrary;
 use crate::ScopeHandle;
+#[cfg(feature = "synfx-dsp-jit")]
+use synfx_dsp_jit::engine::CodeEngine;
 
 use ringbuf::{Producer, RingBuffer};
 use std::collections::HashMap;

src/wblockdsp/compiler.rs

@@ -210,7 +210,7 @@ pub struct Block2JITCompiler {
 
 #[cfg(not(feature = "synfx-dsp-jit"))]
 pub enum ASTNode {
-    NoSynfxDSPJit
+    NoSynfxDSPJit,
 }
 
 impl Block2JITCompiler {

src/wblockdsp/definition.rs

@@ -208,7 +208,9 @@ pub fn setup_hxdsp_block_language(
         });
     }
 
-    dsp_lib.borrow().for_each(|node_type| -> Result<(), ()> {
+    dsp_lib
+        .borrow()
+        .for_each(|node_type| -> Result<(), ()> {
             let max_ports = node_type.input_count().max(node_type.output_count());
             let is_stateful = node_type.is_stateful();
 
@@ -240,7 +242,8 @@ pub fn setup_hxdsp_block_language(
             });
 
             Ok(())
-    }).expect("seriously no error here");
+        })
+        .expect("seriously no error here");
 
     lang.define_identifier("in1");
     lang.define_identifier("in2");

src/wblockdsp/mod.rs

@@ -6,10 +6,10 @@
 
 */
 
+mod compiler;
 mod definition;
 mod language;
-mod compiler;
 
+pub use compiler::*;
 pub use definition::*;
 pub use language::*;
-pub use compiler::*;

tests/node_formfm.rs

@@ -0,0 +1,164 @@
+// Copyright (c) 2022 Dimas Leenman <skythedragon@outlook.com>
+// This file is a part of HexoDSP. Released under GPL-3.0-or-later.
+// See README.md and COPYING for details.
+
+mod common;
+use common::*;
+
+#[test]
+fn check_normalized_if_freq_lower_than_formant_freq() {
+    let (node_conf, mut node_exec) = new_node_engine();
+
+    let mut matrix = Matrix::new(node_conf, 3, 3);
+
+    let mut chain = MatrixCellChain::new(CellDir::B);
+    chain.node_out("formfm", "sig").node_inp("out", "ch1").place(&mut matrix, 0, 0).unwrap();
+
+    matrix.sync().unwrap();
+
+    let formant = NodeId::FormFM(0);
+
+    // params
+    let freq_p = formant.inp_param("freq").unwrap();
+    let form_p = formant.inp_param("form").unwrap();
+    let side_p = formant.inp_param("side").unwrap();
+    let peak_p = formant.inp_param("peak").unwrap();
+
+    // set params to reasonable values
+    matrix.set_param(freq_p, SAtom::param(-0.2));
+    matrix.set_param(form_p, SAtom::param(0.0));
+    matrix.set_param(side_p, SAtom::param(0.2));
+    matrix.set_param(peak_p, SAtom::param(0.4));
+
+    // run
+    let res = run_for_ms(&mut node_exec, 100.0);
+
+    // and check it's normalized
+    let max = res.0.iter().fold(0.0 as f32, |acc, x| acc.max(*x));
+    let min = res.0.iter().fold(0.0 as f32, |acc, x| acc.min(*x));
+    assert!(max > 0.8 && max < 1.01 && min < -0.8 && min > -1.01);
+}
+
+#[test]
+fn check_no_dc_bias_at_formant_freq_lower_than_freq() {
+    let (node_conf, mut node_exec) = new_node_engine();
+
+    let mut matrix = Matrix::new(node_conf, 3, 3);
+
+    let mut chain = MatrixCellChain::new(CellDir::B);
+    chain.node_out("formfm", "sig").node_inp("out", "ch1").place(&mut matrix, 0, 0).unwrap();
+
+    matrix.sync().unwrap();
+
+    let formant = NodeId::FormFM(0);
+
+    // params
+    let freq_p = formant.inp_param("freq").unwrap();
+    let form_p = formant.inp_param("form").unwrap();
+    let side_p = formant.inp_param("side").unwrap();
+    let peak_p = formant.inp_param("peak").unwrap();
+
+    // set params to reasonable values
+    matrix.set_param(freq_p, SAtom::param(0.0));
+    matrix.set_param(form_p, SAtom::param(-0.2));
+    matrix.set_param(side_p, SAtom::param(0.2));
+    matrix.set_param(peak_p, SAtom::param(0.4));
+
+    // run
+    let res = run_for_ms(&mut node_exec, 100.0);
+
+    // average should remain at ~0
+    let sum = res.0.iter().sum::<f32>();
+    let avg = sum / res.0.len() as f32;
+
+    assert!(avg > -0.05 && avg < 0.05);
+}
+
+#[test]
+fn check_no_nan() {
+    let (node_conf, mut node_exec) = new_node_engine();
+
+    let mut matrix = Matrix::new(node_conf, 3, 3);
+
+    let mut chain = MatrixCellChain::new(CellDir::B);
+    chain.node_out("formfm", "sig").node_inp("out", "ch1").place(&mut matrix, 0, 0).unwrap();
+
+    matrix.sync().unwrap();
+
+    let formant = NodeId::FormFM(0);
+
+    // params
+    let freq_p = formant.inp_param("freq").unwrap();
+    let form_p = formant.inp_param("form").unwrap();
+    let side_p = formant.inp_param("side").unwrap();
+    let peak_p = formant.inp_param("peak").unwrap();
+
+    // set params to non-reasonable values here
+    // base freq 0
+    matrix.set_param(freq_p, SAtom::param(-1.0));
+    matrix.set_param(form_p, SAtom::param(0.0));
+    matrix.set_param(side_p, SAtom::param(0.2));
+    matrix.set_param(peak_p, SAtom::param(0.4));
+
+    // run
+    let res = run_for_ms(&mut node_exec, 100.0);
+
+    // and check there's no NaN
+    assert!(res.0.iter().all(|x| !x.is_nan()));
+
+    // set params to non-reasonable values here
+    // side to 0
+    matrix.set_param(freq_p, SAtom::param(-0.2));
+    matrix.set_param(form_p, SAtom::param(0.0));
+    matrix.set_param(side_p, SAtom::param(-1.0));
+    matrix.set_param(peak_p, SAtom::param(0.4));
+
+    // run
+    let res = run_for_ms(&mut node_exec, 100.0);
+
+    // and check there's no NaN
+    assert!(res.0.iter().all(|x| !x.is_nan()));
+
+    // set params to non-reasonable values here
+    // side to 1
+    matrix.set_param(freq_p, SAtom::param(-0.2));
+    matrix.set_param(form_p, SAtom::param(0.0));
+    matrix.set_param(peak_p, SAtom::param(1.0));
+    matrix.set_param(side_p, SAtom::param(0.4));
+
+    // run
+    let res = run_for_ms(&mut node_exec, 100.0);
+
+    // and check there's no NaN
+    assert!(res.0.iter().all(|x| !x.is_nan()));
+}
+
+#[test]
+fn check_formant_freq() {
+    let (node_conf, mut node_exec) = new_node_engine();
+
+    let mut matrix = Matrix::new(node_conf, 3, 3);
+
+    let mut chain = MatrixCellChain::new(CellDir::B);
+    chain.node_out("formfm", "sig").node_inp("out", "ch1").place(&mut matrix, 0, 0).unwrap();
+
+    matrix.sync().unwrap();
+
+    let formant = NodeId::FormFM(0);
+
+    // params
+    let freq_p = formant.inp_param("freq").unwrap();
+    let form_p = formant.inp_param("form").unwrap();
+    let side_p = formant.inp_param("side").unwrap();
+    let peak_p = formant.inp_param("peak").unwrap();
+
+    // set params to reasonable values
+    matrix.set_param(freq_p, SAtom::param(-0.2));
+    matrix.set_param(form_p, SAtom::param(0.0));
+    matrix.set_param(side_p, SAtom::param(0.2));
+    matrix.set_param(peak_p, SAtom::param(0.4));
+
+    // run
+    let fft = run_and_get_avg_fft4096_now(&mut node_exec, 100);
+    assert_eq!(fft, vec![(323, 106), (334, 131), (431, 430), (441, 708), (452, 288), (549, 140)]);
+}