add option to use esp-dsp for IIR filters

Author: stas-sl

.github/workflows/ci.yaml

@@ -11,7 +11,7 @@ jobs:
     name: ${{ matrix.name }}
     runs-on: ubuntu-latest
     env:
-      ESPHOME_VERSION: 2025.7.2
+      ESPHOME_VERSION: 2025.7.4
       PLATFORMIO_LIBDEPS_DIR: ~/.platformio/libdeps
     strategy:
       fail-fast: false

README.md

@@ -83,6 +83,16 @@ sound_level_meter:
   # additional offset if needed
   offset: 0dB                   # default: empty
 
+  # if you have many filters, you might consider using the IIR filter 
+  # implementation from the esp-dsp library. it's written in assembly 
+  # and includes several optimized versions, particularly performant on 
+  # ESP32 or ESP32-S3, and can provide up to 2x faster processing compared 
+  # to my C++ implementation. esp-dsp version uses direct form II, whereas 
+  # the C++ version uses the direct form II transposed. the latter may offer 
+  # slightly better numerical stability, but in most cases, the difference 
+  # is likely negligible.
+  use_esp_dsp: false            # default: false
+
   # under dsp_filters section you can define multiple filters,
   # which can be referenced later by each sensor
 

components/sound_level_meter/__init__.py

@@ -5,6 +5,7 @@
 from esphome import automation, core
 from esphome.automation import maybe_simple_id
 from esphome.components import sensor, microphone
+from esphome.components.esp32 import add_idf_component
 from esphome.const import (
     CONF_ID,
     CONF_SENSORS,
@@ -62,6 +63,7 @@
 CONF_HIGH_FREQ = "high_freq"
 CONF_DSP_FILTERS = "dsp_filters"
 CONF_AUTO_START = "auto_start"
+CONF_USE_ESP_DSP = "use_esp_dsp"
 
 ICON_WAVEFORM = "mdi:waveform"
 
@@ -147,28 +149,42 @@
     }
 )
 
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.GenerateID(): cv.declare_id(SoundLevelMeter),
-        cv.Optional(CONF_MICROPHONE, default={}): microphone.microphone_source_schema(
-            min_bits_per_sample=16,
-            max_bits_per_sample=32,
-        ),
-        cv.Optional(CONF_UPDATE_INTERVAL, default="60s"): cv.positive_time_period_milliseconds,
-        cv.Optional(CONF_AUTO_START, default=True): cv.boolean,
-        cv.Optional(CONF_HIGH_FREQ, default=False): cv.boolean,
-        cv.Optional(CONF_RING_BUFFER_SIZE, default="100ms"): cv.positive_time_period_milliseconds,
-        cv.Optional(CONF_WARMUP_INTERVAL, default="0ms"): cv.positive_time_period_milliseconds,
-        cv.Optional(CONF_TASK_STACK_SIZE, default=4096): cv.positive_not_null_int,
-        cv.Optional(CONF_TASK_PRIORITY, default=2): cv.uint8_t,
-        cv.Optional(CONF_TASK_CORE, default=1): cv.int_range(0, 1),
-        cv.Optional(CONF_MIC_SENSITIVITY): cv.decibel,
-        cv.Optional(CONF_MIC_SENSITIVITY_REF): cv.decibel,
-        cv.Optional(CONF_OFFSET): cv.decibel,
-        cv.Optional(CONF_DSP_FILTERS, default=[]): [CONFIG_DSP_FILTER_SCHEMA],
-        cv.Optional(CONF_SENSORS, default=[]): [CONFIG_SENSOR_SCHEMA],
-    }
-).extend(cv.COMPONENT_SCHEMA)
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(SoundLevelMeter),
+            cv.Optional(
+                CONF_MICROPHONE, default={}
+            ): microphone.microphone_source_schema(
+                min_bits_per_sample=16,
+                max_bits_per_sample=32,
+            ),
+            cv.Optional(
+                CONF_UPDATE_INTERVAL, default="60s"
+            ): cv.positive_time_period_milliseconds,
+            cv.Optional(CONF_AUTO_START, default=True): cv.boolean,
+            cv.Optional(CONF_HIGH_FREQ, default=False): cv.boolean,
+            cv.Optional(
+                CONF_RING_BUFFER_SIZE, default="100ms"
+            ): cv.positive_time_period_milliseconds,
+            cv.Optional(
+                CONF_WARMUP_INTERVAL, default="0ms"
+            ): cv.positive_time_period_milliseconds,
+            cv.Optional(CONF_TASK_STACK_SIZE, default=4096): cv.positive_not_null_int,
+            cv.Optional(CONF_TASK_PRIORITY, default=2): cv.uint8_t,
+            cv.Optional(CONF_TASK_CORE, default=1): cv.int_range(0, 1),
+            cv.Optional(CONF_MIC_SENSITIVITY): cv.decibel,
+            cv.Optional(CONF_MIC_SENSITIVITY_REF): cv.decibel,
+            cv.Optional(CONF_OFFSET): cv.decibel,
+            cv.Optional(CONF_DSP_FILTERS, default=[]): [CONFIG_DSP_FILTER_SCHEMA],
+            cv.Optional(CONF_SENSORS, default=[]): [CONFIG_SENSOR_SCHEMA],
+            cv.Optional(CONF_USE_ESP_DSP, default=False): cv.All(
+                cv.boolean, cv.only_with_esp_idf
+            ),
+        }
+    ).extend(cv.COMPONENT_SCHEMA),
+    cv.only_on_esp32,
+)
 
 SOUND_LEVEL_METER_ACTION_SCHEMA = maybe_simple_id(
     {cv.GenerateID(): cv.use_id(SoundLevelMeter)}
@@ -223,6 +239,9 @@ async def to_code(config):
         cg.add(var.set_mic_sensitivity_ref(config[CONF_MIC_SENSITIVITY_REF]))
     if CONF_OFFSET in config:
         cg.add(var.set_offset(config[CONF_OFFSET]))
+    if config[CONF_USE_ESP_DSP]:
+        add_idf_component(name="espressif/esp-dsp", ref="1.7.0")
+        cg.add_define("USE_ESP_DSP")
 
     for fc in config[CONF_DSP_FILTERS]:
         await add_dsp_filter(fc, var)

components/sound_level_meter/sound_level_meter.cpp

@@ -444,6 +444,17 @@ void SOS_Filter::process(std::vector<float> &data) {
   int n = data.size();
   int m = this->coeffs_.size();
   for (int j = 0; j < m; j++) {
+#ifdef USE_ESP_DSP
+#if defined(USE_ESP32_VARIANT_ESP32)
+    dsps_biquad_f32_ae32(&data[0], &data[0], data.size(), &this->coeffs_[j][0], &this->state_[j][0]);
+#elif defined(USE_ESP32_VARIANT_ESP32S3)
+    dsps_biquad_f32_aes3(&data[0], &data[0], data.size(), &this->coeffs_[j][0], &this->state_[j][0]);
+#elif defined(USE_ESP32_VARIANT_ESP32P4)
+    dsps_biquad_f32_arp4(&data[0], &data[0], data.size(), &this->coeffs_[j][0], &this->state_[j][0]);
+#else
+    dsps_biquad_f32_ansi(&data[0], &data[0], data.size(), &this->coeffs_[j][0], &this->state_[j][0]);
+#endif
+#else
     for (int i = 0; i < n; i++) {
       // y[i] = b0 * x[i] + s0
       float yi = this->coeffs_[j][0] * data[i] + this->state_[j][0];
@@ -454,6 +465,7 @@ void SOS_Filter::process(std::vector<float> &data) {
 
       data[i] = yi;
     }
+#endif
   }
 }
 

components/sound_level_meter/sound_level_meter.h

@@ -12,6 +12,10 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/microphone/microphone_source.h"
 
+#ifdef USE_ESP_DSP
+#include "dsps_biquad.h"
+#endif
+
 namespace esphome::sound_level_meter {
 class SoundLevelMeterSensor;
 class Filter;

configs/10-bands-spectrum-analyzer-example-config.yaml

@@ -6,8 +6,7 @@ external_components:
   - source: github://stas-sl/esphome-sound-level-meter
 
 esp32:
-  board: esp32-s3-devkitc-1
-  variant: esp32s3
+  board: esp32dev
   cpu_frequency: 240MHz
   framework:
     type: esp-idf

configs/advanced-example-config.yaml

@@ -10,7 +10,7 @@ esp32:
   board: esp32dev
   cpu_frequency: 240MHz
   framework:
-    type: arduino
+    type: esp-idf
 
 logger:
   level: DEBUG
@@ -75,6 +75,16 @@ sound_level_meter:
   # additional offset if needed
   offset: 0dB                   # default: empty
 
+  # if you have many filters, you might consider using the IIR filter 
+  # implementation from the esp-dsp library. it's written in assembly 
+  # and includes several optimized versions, particularly performant on 
+  # ESP32 or ESP32-S3, and can provide up to 2x faster processing compared 
+  # to my C++ implementation. esp-dsp version uses direct form II, whereas 
+  # the C++ version uses the direct form II transposed. the latter may offer 
+  # slightly better numerical stability, but in most cases, the difference 
+  # is likely negligible.
+  use_esp_dsp: false            # default: false
+
   # under dsp_filters section you can define multiple filters,
   # which can be referenced later by each sensor
 

configs/minimal-example-config.yaml

@@ -7,8 +7,9 @@ external_components:
 
 esp32:
   board: esp32dev
+  cpu_frequency: 240MHz
   framework:
-    type: arduino
+    type: esp-idf
 
 logger:
   level: DEBUG

configs/sensor-community-example-config.yaml

@@ -7,8 +7,9 @@ external_components:
 
 esp32:
   board: esp32dev
+  cpu_frequency: 240MHz
   framework:
-    type: arduino
+    type: esp-idf
 
 logger:
   level: DEBUG
@@ -102,17 +103,17 @@ interval:
                   X-Sensor: esp32-...  # replace with your sensor ID
                   Content-Type: application/json
                 json: |-
-                    root["software_version"] = "ESPHome " ESPHOME_VERSION;
-                    auto values = root.createNestedArray("sensordatavalues");
+                  root["software_version"] = "ESPHome " ESPHOME_VERSION;
+                  auto values = root["sensordatavalues"].to<JsonArray>();
 
-                    auto LA_eq = values.createNestedObject();
-                    LA_eq["value_type"] = "noise_LAeq";
-                    LA_eq["value"] = id(LAeq_1min).state;
+                  auto LA_eq = values.add<JsonObject>();
+                  LA_eq["value_type"] = "noise_LAeq";
+                  LA_eq["value"] = id(LAeq_1min).state;
 
-                    auto LA_min = values.createNestedObject();
-                    LA_min["value_type"] = "noise_LA_min";
-                    LA_min["value"] = id(LAmin_125ms_1min).state;
+                  auto LA_min = values.add<JsonObject>();
+                  LA_min["value_type"] = "noise_LA_min";
+                  LA_min["value"] = id(LAmin_125ms_1min).state;
 
-                    auto LA_max = values.createNestedObject();
-                    LA_max["value_type"] = "noise_LA_max";
-                    LA_max["value"] = id(LAmax_125ms_1min).state;
+                  auto LA_max = values.add<JsonObject>();
+                  LA_max["value_type"] = "noise_LA_max";
+                  LA_max["value"] = id(LAmax_125ms_1min).state;