diff --git a/docs/docs/bq_gallery.md b/docs/docs/bq_gallery.md
index 2d31fe69..9677a8cb 100644
--- a/docs/docs/bq_gallery.md
+++ b/docs/docs/bq_gallery.md
@@ -7,8 +7,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_highshelf(0.3, +9.0) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_highshelf(0.3, +9.0) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_highshelf", output, options + ", title='Biquad high shelf filter (0.3, +9)'");
 ```
 Result
@@ -22,8 +22,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_lowpass", output, options + ", title='Biquad Low pass filter (0.2, 0.9)'");
 ```
 Result
@@ -38,8 +38,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_lowshelf(0.3, -1.0) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_lowshelf(0.3, -1.0) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_lowshelf", output, options + ", title='Biquad low shelf filter (0.3, -1)'");
 ```
 Result
@@ -53,9 +53,9 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_notch(0.1, 0.5), biquad_notch(0.2, 0.5), biquad_notch(0.3, 0.5),
+biquad_section<fbase> bq[] = { biquad_notch(0.1, 0.5), biquad_notch(0.2, 0.5), biquad_notch(0.3, 0.5),
                                 biquad_notch(0.4, 0.5) };
-output                    = biquad(bq, unitimpulse());
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_notch", output, options + ", title='Four Biquad Notch filters'");
 ```
 Result
@@ -68,8 +68,8 @@ Code
 ```c++ linenums="1"
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
-biquad_params<fbase> bq[] = { biquad_peak(0.3, 0.5, +9.0) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_peak(0.3, 0.5, +9.0) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_peak", output, options + ", title='Biquad Peak filter (0.2, 0.5, +9)'");
 ```
 Result
@@ -83,8 +83,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_peak(0.3, 3.0, -2.0) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_peak(0.3, 3.0, -2.0) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_peak2", output, options + ", title='Biquad Peak filter (0.3, 3, -2)'");
 ```
 Result
@@ -98,8 +98,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_bandpass", output, options + ", title='Biquad band pass (0.25, 0.2)'");
 ```
 Result
@@ -113,8 +113,8 @@ Code
 const std::string options = "phaseresp=True";
 univector<fbase, 128> output;
 
-biquad_params<fbase> bq[] = { biquad_highpass(0.3, 0.1) };
-output                    = biquad(bq, unitimpulse());
+biquad_section<fbase> bq[] = { biquad_highpass(0.3, 0.1) };
+output                     = iir(unitimpulse(), iir_params{ bq });
 plot_save("biquad_highpass", output, options + ", title='Biquad High pass filter (0.3, 0.1)'");
 ```
 Result
diff --git a/docs/docs/iir_gallery.md b/docs/docs/iir_gallery.md
index 6d0ba4e3..bbd50d56 100644
--- a/docs/docs/iir_gallery.md
+++ b/docs/docs/iir_gallery.md
@@ -19,12 +19,11 @@
 Code
 ```c++ linenums="1"
 const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 10), padwidth=8192";
-constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(bessel<fbase>(24), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(bessel<fbase>(24), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("bessel_lowpass24", output, options + ", title='24th-order Bessel filter, lowpass 1khz'");
 
 ```
@@ -41,9 +40,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(bessel<fbase>(12), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(bessel<fbase>(12), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("bessel_lowpass12", output, options + ", title='12th-order Bessel filter, lowpass 1khz'");
 
 ```
@@ -59,9 +58,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(bessel<fbase>(6), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(bessel<fbase>(6), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("bessel_lowpass6", output, options + ", title='6th-order Bessel filter, lowpass 1khz'");
 ```
 Result
@@ -76,9 +75,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(butterworth<fbase>(24), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(butterworth<fbase>(24), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_lowpass24", output,
               options + ", title='24th-order Butterworth filter, lowpass 1khz'");
 ```
@@ -95,9 +94,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(butterworth<fbase>(12), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(butterworth<fbase>(12), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_lowpass12", output,
               options + ", title='12th-order Butterworth filter, lowpass 1khz'");
 ```
@@ -113,9 +112,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_highpass(butterworth<fbase>(12), 1000, 48000);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_highpass(butterworth<fbase>(12), 1000, 48000);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_highpass12", output,
               options + ", title='12th-order Butterworth filter, highpass 1khz'");
 ```
@@ -131,9 +130,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_bandpass(butterworth<fbase>(12), 0.1, 0.2);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_bandpass(butterworth<fbase>(12), 0.1, 0.2);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_bandpass12", output,
               options + ", title='12th-order Butterworth filter, bandpass'");
 ```
@@ -149,9 +148,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_bandstop(butterworth<fbase>(12), 0.1, 0.2);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_bandstop(butterworth<fbase>(12), 0.1, 0.2);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_bandstop12", output,
               options + ", title='12th-order Butterworth filter, bandstop'");
 ```
@@ -167,9 +166,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_bandpass(butterworth<fbase>(4), 0.005, 0.9);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_bandpass(butterworth<fbase>(4), 0.005, 0.9);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("butterworth_bandpass4", output, options + ", title='4th-order Butterworth filter, bandpass'");
 ```
 Result
@@ -184,9 +183,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(chebyshev1<fbase>(8, 2), 0.09);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(chebyshev1<fbase>(8, 2), 0.09);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("chebyshev1_lowpass8", output,
               options + ", title='8th-order Chebyshev type I filter, lowpass'");
 ```
@@ -202,9 +201,9 @@ const std::string options = "phaseresp=True, log_freq=True, freq_dB_lim=(-160, 1
 constexpr size_t maxorder = 32;
 univector<fbase, 1024> output;
 
-zpk<fbase> filt                       = iir_lowpass(chebyshev2<fbase>(8, 80), 0.09);
-std::vector<biquad_params<fbase>> bqs = to_sos(filt);
-output                                = biquad<maxorder>(bqs, unitimpulse());
+zpk<fbase> filt       = iir_lowpass(chebyshev2<fbase>(8, 80), 0.09);
+iir_params<fbase> bqs = to_sos(filt);
+output                = iir(unitimpulse(), iir_params{ bqs });
 plot_save("chebyshev2_lowpass8", output,
               options + ", title='8th-order Chebyshev type II filter, lowpass'");
 ```
diff --git a/examples/biquads.cpp b/examples/biquads.cpp
index 9b001a91..9ce11e07 100644
--- a/examples/biquads.cpp
+++ b/examples/biquads.cpp
@@ -20,74 +20,74 @@ int main()
 
     univector<fbase, 128> output;
     {
-        biquad_params<fbase> bq[] = { biquad_notch(0.1, 0.5), biquad_notch(0.2, 0.5), biquad_notch(0.3, 0.5),
-                                      biquad_notch(0.4, 0.5) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_notch(0.1, 0.5), biquad_notch(0.2, 0.5), biquad_notch(0.3, 0.5),
+                                       biquad_notch(0.4, 0.5) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_notch", output, options + ", title='Four Biquad Notch filters'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_lowpass", output, options + ", title='Biquad Low pass filter (0.2, 0.9)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_highpass(0.3, 0.1) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_highpass(0.3, 0.1) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_highpass", output, options + ", title='Biquad High pass filter (0.3, 0.1)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_peak(0.3, 0.5, +9.0) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_peak(0.3, 0.5, +9.0) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_peak", output, options + ", title='Biquad Peak filter (0.2, 0.5, +9)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_peak(0.3, 3.0, -2.0) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_peak(0.3, 3.0, -2.0) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_peak2", output, options + ", title='Biquad Peak filter (0.3, 3, -2)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_lowshelf(0.3, -1.0) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_lowshelf(0.3, -1.0) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_lowshelf", output, options + ", title='Biquad low shelf filter (0.3, -1)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_highshelf(0.3, +9.0) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_highshelf(0.3, +9.0) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_highshelf", output, options + ", title='Biquad high shelf filter (0.3, +9)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
-        output                    = biquad(bq, unitimpulse());
+        biquad_section<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
+        output                     = iir(unitimpulse(), iir_params{ bq });
     }
     plot_save("biquad_bandpass", output, options + ", title='Biquad band pass (0.25, 0.2)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
+        biquad_section<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
         std::vector<fbase> data(output.size(), 0.f);
         data[0] = 1.f;
-        output  = biquad(bq, make_univector(data));
+        output  = iir(make_univector(data), iir_params{ bq });
     }
     plot_save("biquad_bandpass_stdvector", output, options + ", title='Biquad band pass (0.25, 0.2)'");
 
     {
-        biquad_params<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
-        fbase data[output.size()] = { 0 }; // .size() is constexpr
-        data[0]                   = 1.f;
-        output                    = biquad(bq, make_univector(data));
+        biquad_section<fbase> bq[] = { biquad_bandpass(0.25, 0.2) };
+        fbase data[output.size()]  = { 0 }; // .size() is constexpr
+        data[0]                    = 1.f;
+        output                     = iir(make_univector(data), iir_params{ bq });
     }
     plot_save("biquad_bandpass_carray", output, options + ", title='Biquad band pass (0.25, 0.2)'");
 
     {
         // filter initialization
-        biquad_params<fbase> bq[]       = { biquad_lowpass(0.2, 0.9) };
-        expression_filter<fbase> filter = to_filter(biquad(bq, placeholder<fbase>()));
+        biquad_section<fbase> bq[]      = { biquad_lowpass(0.2, 0.9) };
+        expression_filter<fbase> filter = to_filter(iir(placeholder<fbase>(), iir_params{ bq }));
 
         // prepare data
         output = unitimpulse();
@@ -100,8 +100,8 @@ int main()
 
     {
         // filter initialization
-        biquad_params<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
-        biquad_filter<fbase> filter(bq);
+        biquad_section<fbase> bq[] = { biquad_lowpass(0.2, 0.9) };
+        iir_filter<fbase> filter(bq);
 
         // prepare data
         output = unitimpulse();
@@ -110,7 +110,7 @@ int main()
         filter.apply(output);
     }
     plot_save("biquad_filter_lowpass", output,
-              options + ", title='Biquad Low pass filter (0.2, 0.9) (using biquad_filter)'");
+              options + ", title='Biquad Low pass filter (0.2, 0.9) (using iir_filter)'");
 
     println("SVG plots have been saved to svg directory");
 
diff --git a/examples/ccv.cpp b/examples/ccv.cpp
index 246d22b1..7f2236d4 100644
--- a/examples/ccv.cpp
+++ b/examples/ccv.cpp
@@ -47,7 +47,7 @@ int main()
     auto toc                    = std::chrono::high_resolution_clock::now();
     auto const ccv_time_complex = std::chrono::duration_cast<std::chrono::duration<float>>(toc - tic);
     tic                         = toc;
-    filtered_cnoise_fir         = kfr::fir(cnoise, taps127);
+    filtered_cnoise_fir         = kfr::fir(cnoise, fir_params{ taps127 });
     toc                         = std::chrono::high_resolution_clock::now();
     auto const fir_time_complex = std::chrono::duration_cast<std::chrono::duration<float>>(toc - tic);
     auto const cdiff            = rms(cabs(filtered_cnoise_fir - filtered_cnoise_ccv));
@@ -58,7 +58,7 @@ int main()
     toc                      = std::chrono::high_resolution_clock::now();
     auto const ccv_time_real = std::chrono::duration_cast<std::chrono::duration<float>>(toc - tic);
     tic                      = toc;
-    filtered_noise_fir       = kfr::fir(noise, taps127);
+    filtered_noise_fir       = kfr::fir(noise, fir_params{ taps127 });
     toc                      = std::chrono::high_resolution_clock::now();
     auto const fir_time_real = std::chrono::duration_cast<std::chrono::duration<float>>(toc - tic);
     auto const diff          = rms(filtered_noise_fir - filtered_noise_ccv);
diff --git a/examples/fir.cpp b/examples/fir.cpp
index 2fd687f1..ccdf3cba 100644
--- a/examples/fir.cpp
+++ b/examples/fir.cpp
@@ -105,7 +105,7 @@ int main()
     univector<float> noise = truncate(gen_random_range(random_init(1, 2, 3, 4), -1.f, +1.f), 10000);
 
     // Apply band stop filter
-    univector<float> filtered_noise = fir(noise, taps127);
+    univector<float> filtered_noise = fir(noise, fir_params{ taps127 });
 
 #if PYTHON_IS_INSTALLED
     // Plot results
diff --git a/include/kfr/dsp/biquad_design.hpp b/include/kfr/dsp/biquad_design.hpp
index f2035c2e..27f93626 100644
--- a/include/kfr/dsp/biquad_design.hpp
+++ b/include/kfr/dsp/biquad_design.hpp
@@ -40,7 +40,7 @@ inline namespace CMT_ARCH_NAME
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_allpass(identity<T> frequency, identity<T> Q)
+KFR_FUNCTION biquad_section<T> biquad_allpass(identity<T> frequency, identity<T> Q)
 {
     const T alpha = std::sin(frequency) / 2.0 * Q;
     const T cs    = std::cos(frequency);
@@ -61,7 +61,7 @@ KFR_FUNCTION biquad_params<T> biquad_allpass(identity<T> frequency, identity<T>
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_lowpass(identity<T> frequency, identity<T> Q)
+KFR_FUNCTION biquad_section<T> biquad_lowpass(identity<T> frequency, identity<T> Q)
 {
     const T K    = std::tan(c_pi<T, 1> * frequency);
     const T K2   = K * K;
@@ -81,7 +81,7 @@ KFR_FUNCTION biquad_params<T> biquad_lowpass(identity<T> frequency, identity<T>
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_highpass(identity<T> frequency, identity<T> Q)
+KFR_FUNCTION biquad_section<T> biquad_highpass(identity<T> frequency, identity<T> Q)
 {
     const T K    = std::tan(c_pi<T, 1> * frequency);
     const T K2   = K * K;
@@ -101,7 +101,7 @@ KFR_FUNCTION biquad_params<T> biquad_highpass(identity<T> frequency, identity<T>
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_bandpass(identity<T> frequency, identity<T> Q)
+KFR_FUNCTION biquad_section<T> biquad_bandpass(identity<T> frequency, identity<T> Q)
 {
     const T K    = std::tan(c_pi<T, 1> * frequency);
     const T K2   = K * K;
@@ -121,7 +121,7 @@ KFR_FUNCTION biquad_params<T> biquad_bandpass(identity<T> frequency, identity<T>
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_notch(identity<T> frequency, identity<T> Q)
+KFR_FUNCTION biquad_section<T> biquad_notch(identity<T> frequency, identity<T> Q)
 {
     const T K    = std::tan(c_pi<T, 1> * frequency);
     const T K2   = K * K;
@@ -142,9 +142,9 @@ KFR_FUNCTION biquad_params<T> biquad_notch(identity<T> frequency, identity<T> Q)
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_peak(identity<T> frequency, identity<T> Q, identity<T> gain)
+KFR_FUNCTION biquad_section<T> biquad_peak(identity<T> frequency, identity<T> Q, identity<T> gain)
 {
-    biquad_params<T> result;
+    biquad_section<T> result;
     const T K  = std::tan(c_pi<T, 1> * frequency);
     const T K2 = K * K;
     const T V  = std::exp(std::abs(gain) * (1.0 / 20.0) * c_log_10<T>);
@@ -179,9 +179,9 @@ KFR_FUNCTION biquad_params<T> biquad_peak(identity<T> frequency, identity<T> Q,
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_lowshelf(identity<T> frequency, identity<T> gain)
+KFR_FUNCTION biquad_section<T> biquad_lowshelf(identity<T> frequency, identity<T> gain)
 {
-    biquad_params<T> result;
+    biquad_section<T> result;
     const T K  = std::tan(c_pi<T, 1> * frequency);
     const T K2 = K * K;
     const T V  = std::exp(std::fabs(gain) * (1.0 / 20.0) * c_log_10<T>);
@@ -216,9 +216,9 @@ KFR_FUNCTION biquad_params<T> biquad_lowshelf(identity<T> frequency, identity<T>
  * @return Biquad filter coefficients
  */
 template <typename T = fbase>
-KFR_FUNCTION biquad_params<T> biquad_highshelf(identity<T> frequency, identity<T> gain)
+KFR_FUNCTION biquad_section<T> biquad_highshelf(identity<T> frequency, identity<T> gain)
 {
-    biquad_params<T> result;
+    biquad_section<T> result;
     const T K  = std::tan(c_pi<T, 1> * frequency);
     const T K2 = K * K;
     const T V  = std::exp(std::fabs(gain) * (1.0 / 20.0) * c_log_10<T>);
diff --git a/include/kfr/dsp/dcremove.hpp b/include/kfr/dsp/dcremove.hpp
index d017e3a8..259ae417 100644
--- a/include/kfr/dsp/dcremove.hpp
+++ b/include/kfr/dsp/dcremove.hpp
@@ -34,7 +34,7 @@ namespace kfr
 template <typename E1, typename T = flt_type<expression_value_type<E1>>>
 KFR_INTRINSIC expression_iir<1, T, E1> dcremove(E1&& e1, double cutoff = 0.00025)
 {
-    const biquad_params<T> bqs[1] = { biquad_highpass(cutoff, 0.5) };
+    const biquad_section<T> bqs[1] = { biquad_highpass(cutoff, 0.5) };
     return expression_iir<1, T, E1>(bqs, std::forward<E1>(e1));
 }
 
diff --git a/include/kfr/dsp/ebu.hpp b/include/kfr/dsp/ebu.hpp
index dbb4991f..b3cfbcdb 100644
--- a/include/kfr/dsp/ebu.hpp
+++ b/include/kfr/dsp/ebu.hpp
@@ -186,11 +186,11 @@ struct lra_vec : public univector<T>
 template <typename T>
 KFR_INTRINSIC expression_handle<T, 1> make_kfilter(int samplerate)
 {
-    const biquad_params<T> bq[] = {
+    const biquad_section<T> bq[] = {
         biquad_highshelf(T(1681.81 / samplerate), T(+4.0)),
         biquad_highpass(T(38.1106678246655 / samplerate), T(0.5)).normalized_all()
     };
-    return to_handle(biquad(bq, placeholder<T>()));
+    return to_handle(iir(placeholder<T>(), iir_params{ bq }));
 }
 
 template <typename T>
diff --git a/include/kfr/dsp/iir_design.hpp b/include/kfr/dsp/iir_design.hpp
index 86e8a399..bc911b42 100644
--- a/include/kfr/dsp/iir_design.hpp
+++ b/include/kfr/dsp/iir_design.hpp
@@ -886,7 +886,7 @@ KFR_FUNCTION vec<T, 3> zpk2tf_poly(const complex<T>& x, const complex<T>& y)
 }
 
 template <typename T>
-KFR_FUNCTION biquad_params<T> zpk2tf(const zero_pole_pairs<T>& pairs, identity<T> k)
+KFR_FUNCTION biquad_section<T> zpk2tf(const zero_pole_pairs<T>& pairs, identity<T> k)
 {
     vec<T, 3> zz = k * zpk2tf_poly(pairs.z1, pairs.z2);
     vec<T, 3> pp = zpk2tf_poly(pairs.p1, pairs.p2);
@@ -1082,7 +1082,7 @@ template <typename T>
 KFR_FUNCTION iir_params<T> to_sos(const zpk<T>& filter)
 {
     if (filter.p.empty() && filter.z.empty())
-        return { biquad_params<T>(filter.k, T(0.), T(0.), T(1.), T(0.), 0) };
+        return { biquad_section<T>(filter.k, T(0.), T(0.), T(1.), T(0.), 0) };
 
     zpk<T> filt   = filter;
     size_t length = std::max(filter.p.size(), filter.z.size());
diff --git a/src/capi/capi.cpp b/src/capi/capi.cpp
index b610227d..4c0491c8 100644
--- a/src/capi/capi.cpp
+++ b/src/capi/capi.cpp
@@ -430,8 +430,8 @@ extern "C"
         return try_fn(
             [&]()
             {
-                return reinterpret_cast<KFR_FILTER_F32*>(
-                    new biquad_filter<float>(reinterpret_cast<const biquad_params<float>*>(sos), sos_count));
+                return reinterpret_cast<KFR_FILTER_F32*>(new iir_filter<float>(
+                    iir_params{ reinterpret_cast<const biquad_section<float>*>(sos), sos_count }));
             },
             nullptr);
     }
@@ -440,8 +440,8 @@ extern "C"
         return try_fn(
             [&]()
             {
-                return reinterpret_cast<KFR_FILTER_F64*>(new biquad_filter<double>(
-                    reinterpret_cast<const biquad_params<double>*>(sos), sos_count));
+                return reinterpret_cast<KFR_FILTER_F64*>(new iir_filter<double>(
+                    iir_params{ reinterpret_cast<const biquad_section<double>*>(sos), sos_count }));
             },
             nullptr);
     }
diff --git a/tests/unit/dsp/biquad.cpp b/tests/unit/dsp/biquad.cpp
index 389c94fe..65d91af9 100644
--- a/tests/unit/dsp/biquad.cpp
+++ b/tests/unit/dsp/biquad.cpp
@@ -38,7 +38,7 @@ TEST(biquad_lowpass1)
                   {
                       using T = typename decltype(type)::type;
 
-                      const biquad_params<T> bq = biquad_lowpass<T>(0.1, 0.7);
+                      const biquad_section<T> bq = biquad_lowpass<T>(0.1, 0.7);
 
                       constexpr size_t size = 32;
 
@@ -66,11 +66,9 @@ TEST(biquad_lowpass1)
                           +0xb.5f265b1be1728p-23, +0xd.d2cb83f8483f8p-24,
                       };
 
-                      const univector<T, size> ir  = biquad(bq, unitimpulse<T>());
-                      const univector<T, size> ir2 = iir(unitimpulse<T>(), iir_params{ bq });
+                      const univector<T, size> ir = iir(unitimpulse<T>(), iir_params{ bq });
 
                       CHECK(absmaxof(choose_array<T>(test_vector_f32, test_vector_f64) - ir) == 0);
-                      CHECK(absmaxof(choose_array<T>(test_vector_f32, test_vector_f64) - ir2) == 0);
                   });
 }
 
@@ -81,7 +79,7 @@ TEST(biquad_lowpass2)
                   {
                       using T = typename decltype(type)::type;
 
-                      const biquad_params<T> bq = biquad_lowpass<T>(0.45, 0.2);
+                      const biquad_section<T> bq = biquad_lowpass<T>(0.45, 0.2);
 
                       constexpr size_t size = 32;
 
@@ -109,16 +107,16 @@ TEST(biquad_lowpass2)
                           +0xd.94f05f80af008p-15, -0xc.b66c0799b21a8p-15,
                       };
 
-                      const univector<T, size> ir = biquad(bq, unitimpulse<T>());
+                      const univector<T, size> ir = iir(unitimpulse<T>(), iir_params{ bq });
 
                       CHECK(absmaxof(choose_array<T>(test_vector_f32, test_vector_f64) - ir) == 0);
                   });
 }
 
-TEST(biquad_filter)
+TEST(iir_filter)
 {
-    biquad_params<float> params[16];
-    auto f = biquad_filter<float>(params);
+    biquad_section<float> params[16];
+    auto f = iir_filter<float>(iir_params{ params });
     float buf[256];
     f.apply(buf);
 }
diff --git a/tests/unit/dsp/delay.cpp b/tests/unit/dsp/delay.cpp
index 9d687566..a592e114 100644
--- a/tests/unit/dsp/delay.cpp
+++ b/tests/unit/dsp/delay.cpp
@@ -22,10 +22,10 @@ TEST(delay)
     CHECK_EXPRESSION(delay<3>(v1), 33, [](size_t i) { return i < 3 ? 0.f : (i - 3) + 100.f; });
 
     delay_state<float, 3> state1;
-    CHECK_EXPRESSION(delay(state1, v1), 33, [](size_t i) { return i < 3 ? 0.f : (i - 3) + 100.f; });
+    CHECK_EXPRESSION(delay(v1, std::ref(state1)), 33, [](size_t i) { return i < 3 ? 0.f : (i - 3) + 100.f; });
 
     delay_state<float, 3, tag_dynamic_vector> state2;
-    CHECK_EXPRESSION(delay(state2, v1), 33, [](size_t i) { return i < 3 ? 0.f : (i - 3) + 100.f; });
+    CHECK_EXPRESSION(delay(v1, std::ref(state2)), 33, [](size_t i) { return i < 3 ? 0.f : (i - 3) + 100.f; });
 }
 
 TEST(fracdelay)
diff --git a/tests/unit/dsp/fir.cpp b/tests/unit/dsp/fir.cpp
index 01237259..351a3966 100644
--- a/tests/unit/dsp/fir.cpp
+++ b/tests/unit/dsp/fir.cpp
@@ -100,7 +100,7 @@ TEST(fir)
                           counter() + sequence(1, 2, -10, 100) + sequence(0, -7, 0.5);
                       const univector<T, 6> taps{ 1, 2, -2, 0.5, 0.0625, 4 };
 
-                      CHECK_EXPRESSION(fir(data, taps), 100,
+                      CHECK_EXPRESSION(fir(data, fir_params{ taps }), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -111,7 +111,7 @@ TEST(fir)
 
                       fir_state<T> state(taps.ref());
 
-                      CHECK_EXPRESSION(fir(state, data), 100,
+                      CHECK_EXPRESSION(fir(data, std::ref(state)), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -131,7 +131,7 @@ TEST(fir)
 
                       short_fir_state<9, T> state2(taps);
 
-                      CHECK_EXPRESSION(short_fir<taps.size()>(state2, data), 100,
+                      CHECK_EXPRESSION(short_fir(data, std::ref(state2)), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -140,7 +140,7 @@ TEST(fir)
                                            return result;
                                        });
 
-                      CHECK_EXPRESSION(moving_sum<taps.size()>(data), 100,
+                      CHECK_EXPRESSION(moving_sum(data, taps.size()), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -151,7 +151,7 @@ TEST(fir)
 
                       moving_sum_state<T, 131> msstate1;
 
-                      CHECK_EXPRESSION(moving_sum(msstate1, data), 100,
+                      CHECK_EXPRESSION(moving_sum(data, std::ref(msstate1)), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -162,7 +162,7 @@ TEST(fir)
 
                       moving_sum_state<T> msstate2(133);
 
-                      CHECK_EXPRESSION(moving_sum(msstate2, data), 100,
+                      CHECK_EXPRESSION(moving_sum(data, std::ref(msstate2)), 100,
                                        [&](size_t index) -> T
                                        {
                                            T result = 0;
@@ -181,7 +181,7 @@ TEST(fir_different)
     //    const univector<double, 6> taps{ 1, 2, -2, 0.5, 0.0625, 4 };
     const univector<double, 4> taps{ 1, 2, 3, 4 };
 
-    CHECK_EXPRESSION(fir(data, taps), 100,
+    CHECK_EXPRESSION(fir(data, fir_params{ taps }), 100,
                      [&](size_t index) -> float
                      {
                          double result = 0.0;
@@ -207,7 +207,7 @@ TEST(fir_complex)
         counter() * complex<float>{ 0.f, 1.f } + sequence(1, 2, -10, 100) + sequence(0, -7, 0.5f);
     const univector<float, 6> taps{ 1, 2, -2, 0.5, 0.0625, 4 };
 
-    CHECK_EXPRESSION(fir(data, taps), 100,
+    CHECK_EXPRESSION(fir(data, fir_params{ taps }), 100,
                      [&](size_t index) -> complex<float>
                      {
                          std::complex<float> result = 0.0;