diff --git a/firmware/baseband/dsp_iir.cpp b/firmware/baseband/dsp_iir.cpp
index e8367a76..8fde51ef 100644
--- a/firmware/baseband/dsp_iir.cpp
+++ b/firmware/baseband/dsp_iir.cpp
@@ -23,7 +23,7 @@
 
 #include <hal.h>
 
-void IIRBiquadFilter::execute(buffer_s16_t buffer_in, buffer_s16_t buffer_out) {
+void IIRBiquadFilter::execute(const buffer_s16_t& buffer_in, const buffer_s16_t& buffer_out) {
 	// TODO: Assert that buffer_out.count == buffer_in.count.
 	for(size_t i=0; i<buffer_out.count; i++) {
 		const int32_t output_sample = execute_sample(buffer_in.p[i]);
@@ -32,7 +32,7 @@ void IIRBiquadFilter::execute(buffer_s16_t buffer_in, buffer_s16_t buffer_out) {
 	}
 }
 
-void IIRBiquadFilter::execute_in_place(buffer_s16_t buffer) {
+void IIRBiquadFilter::execute_in_place(const buffer_s16_t& buffer) {
 	execute(buffer, buffer);
 }
 
diff --git a/firmware/baseband/dsp_iir.hpp b/firmware/baseband/dsp_iir.hpp
index 992145cd..2a04a66d 100644
--- a/firmware/baseband/dsp_iir.hpp
+++ b/firmware/baseband/dsp_iir.hpp
@@ -42,8 +42,8 @@ public:
 	{
 	}
 
-	void execute(buffer_s16_t buffer_in, buffer_s16_t buffer_out);
-	void execute_in_place(buffer_s16_t buffer);
+	void execute(const buffer_s16_t& buffer_in, const buffer_s16_t& buffer_out);
+	void execute_in_place(const buffer_s16_t& buffer);
 
 private:
 	const iir_biquad_config_t config;
diff --git a/firmware/baseband/dsp_squelch.cpp b/firmware/baseband/dsp_squelch.cpp
index 6420a087..2ef331af 100644
--- a/firmware/baseband/dsp_squelch.cpp
+++ b/firmware/baseband/dsp_squelch.cpp
@@ -24,7 +24,7 @@
 #include <cstdint>
 #include <array>
 
-bool FMSquelch::execute(buffer_s16_t audio) {
+bool FMSquelch::execute(const buffer_s16_t& audio) {
 	// TODO: No hard-coded array size.
 	std::array<int16_t, N> squelch_energy_buffer;
 	const buffer_s16_t squelch_energy {
diff --git a/firmware/baseband/dsp_squelch.hpp b/firmware/baseband/dsp_squelch.hpp
index cd8e841d..1a1607d7 100644
--- a/firmware/baseband/dsp_squelch.hpp
+++ b/firmware/baseband/dsp_squelch.hpp
@@ -31,7 +31,7 @@
 
 class FMSquelch {
 public:
-	bool execute(buffer_s16_t audio);
+	bool execute(const buffer_s16_t& audio);
 
 	void set_threshold(const uint32_t new_value);