diff --git a/NWaves.Benchmarks/FftArrayVsSpan.cs b/NWaves.Benchmarks/Fft/FftArrayVsSpan.cs
similarity index 100%
rename from NWaves.Benchmarks/FftArrayVsSpan.cs
rename to NWaves.Benchmarks/Fft/FftArrayVsSpan.cs
diff --git a/NWaves.Benchmarks/FirFilterV2.cs b/NWaves.Benchmarks/FirFilters/FirFilterV2.cs
similarity index 100%
rename from NWaves.Benchmarks/FirFilterV2.cs
rename to NWaves.Benchmarks/FirFilters/FirFilterV2.cs
diff --git a/NWaves.Benchmarks/FirFiltersVersion2Vs5VsZi.cs b/NWaves.Benchmarks/FirFilters/FirFiltersVersion2Vs5VsZi.cs
similarity index 100%
rename from NWaves.Benchmarks/FirFiltersVersion2Vs5VsZi.cs
rename to NWaves.Benchmarks/FirFilters/FirFiltersVersion2Vs5VsZi.cs
diff --git a/NWaves.Benchmarks/FirFiltersVsBlockConvolvers.cs b/NWaves.Benchmarks/FirFilters/FirFiltersVsBlockConvolvers.cs
similarity index 100%
rename from NWaves.Benchmarks/FirFiltersVsBlockConvolvers.cs
rename to NWaves.Benchmarks/FirFilters/FirFiltersVsBlockConvolvers.cs
diff --git a/NWaves.Benchmarks/IirFilterLinq.cs b/NWaves.Benchmarks/IirFilters/IirFilterLinq.cs
similarity index 100%
rename from NWaves.Benchmarks/IirFilterLinq.cs
rename to NWaves.Benchmarks/IirFilters/IirFilterLinq.cs
diff --git a/NWaves.Benchmarks/IirFilterV2.cs b/NWaves.Benchmarks/IirFilters/IirFilterV2.cs
similarity index 100%
rename from NWaves.Benchmarks/IirFilterV2.cs
rename to NWaves.Benchmarks/IirFilters/IirFilterV2.cs
diff --git a/NWaves.Benchmarks/IirFilterV4.cs b/NWaves.Benchmarks/IirFilters/IirFilterV4.cs
similarity index 100%
rename from NWaves.Benchmarks/IirFilterV4.cs
rename to NWaves.Benchmarks/IirFilters/IirFilterV4.cs
diff --git a/NWaves.Benchmarks/IirFiltersVersion2Vs4Vs5VsZi.cs b/NWaves.Benchmarks/IirFilters/IirFiltersVersion2Vs4Vs5VsZi.cs
similarity index 100%
rename from NWaves.Benchmarks/IirFiltersVersion2Vs4Vs5VsZi.cs
rename to NWaves.Benchmarks/IirFilters/IirFiltersVersion2Vs4Vs5VsZi.cs
diff --git a/NWaves.Benchmarks/MedianFilters.cs b/NWaves.Benchmarks/Misc/MedianFilters.cs
similarity index 100%
rename from NWaves.Benchmarks/MedianFilters.cs
rename to NWaves.Benchmarks/Misc/MedianFilters.cs
diff --git a/NWaves.Benchmarks/MovingAverageFilters.cs b/NWaves.Benchmarks/Misc/MovingAverageFilters.cs
similarity index 100%
rename from NWaves.Benchmarks/MovingAverageFilters.cs
rename to NWaves.Benchmarks/Misc/MovingAverageFilters.cs
diff --git a/NWaves.Benchmarks/OfflineFilterForLoopVsLinq.cs b/NWaves.Benchmarks/Misc/OfflineFilterForLoopVsLinq.cs
similarity index 100%
rename from NWaves.Benchmarks/OfflineFilterForLoopVsLinq.cs
rename to NWaves.Benchmarks/Misc/OfflineFilterForLoopVsLinq.cs
diff --git a/NWaves.Benchmarks/Program.cs b/NWaves.Benchmarks/Program.cs
index 17666fe..5482110 100644
--- a/NWaves.Benchmarks/Program.cs
+++ b/NWaves.Benchmarks/Program.cs
@@ -1,4 +1,6 @@
-namespace NWaves.Benchmarks
+using BenchmarkDotNet.Running;
+
+namespace NWaves.Benchmarks
 {
     class Program
     {
diff --git a/NWaves.Benchmarks/README.md b/NWaves.Benchmarks/README.md
new file mode 100644
index 0000000..353bb3f
--- /dev/null
+++ b/NWaves.Benchmarks/README.md
@@ -0,0 +1,166 @@
+
+Benchmark results on a cheaper hardware:
+
+### IIR filters
+
+Different implementations of IIR filters are compared:
+
+- ```IirFilter``` (ver.0.9.2 of NWaves)
+- ```IirFilter``` (ver.0.9.4 of NWaves)
+- ```IirFilter``` (as of ver.0.9.5 of NWaves)
+- ```ZiFilter```
+
+```ZiFilter``` is noticeably faster than ```IirFilter``` in case when the number of zeros is equal to number of poles (e.g. BiQuad and Butterworth filters).
+
+In case of custom IIR filter (3 zeros and 1 pole) ```ZiFilter``` filtering is slower.
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|                       Method |      Mean |    Error |   StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |
+|----------------------------- |----------:|---------:|---------:|---------:|---------:|---------:|----------:|
+|       FilterVersion092BiQuad |  57.20 ms | 0.133 ms | 0.124 ms | 222.2222 | 222.2222 | 222.2222 |     19 MB |
+|       FilterVersion094BiQuad |  63.14 ms | 0.147 ms | 0.138 ms | 250.0000 | 250.0000 | 250.0000 |     19 MB |
+|       FilterVersion095BiQuad |  55.41 ms | 0.106 ms | 0.094 ms | 200.0000 | 200.0000 | 200.0000 |     19 MB |
+|               FilterZiBiQuad |  41.44 ms | 0.130 ms | 0.122 ms | 307.6923 | 307.6923 | 307.6923 |     19 MB |
+| FilterVersion092Butterworth6 | 103.57 ms | 0.377 ms | 0.353 ms | 200.0000 | 200.0000 | 200.0000 |     19 MB |
+| FilterVersion094Butterworth6 | 108.64 ms | 0.309 ms | 0.274 ms | 200.0000 | 200.0000 | 200.0000 |     19 MB |
+| FilterVersion095Butterworth6 |  96.03 ms | 0.186 ms | 0.165 ms | 333.3333 | 333.3333 | 333.3333 |     19 MB |
+|         FilterZiButterworth6 |  74.91 ms | 0.216 ms | 0.202 ms | 285.7143 | 285.7143 | 285.7143 |     19 MB |
+|       FilterVersion092Custom |  56.77 ms | 0.175 ms | 0.164 ms | 222.2222 | 222.2222 | 222.2222 |     19 MB |
+|       FilterVersion094Custom |  62.86 ms | 0.136 ms | 0.121 ms | 250.0000 | 250.0000 | 250.0000 |     19 MB |
+|       FilterVersion095Custom |  54.71 ms | 0.101 ms | 0.090 ms | 200.0000 | 200.0000 | 200.0000 |     19 MB |
+|               FilterZiCustom |  58.90 ms | 0.146 ms | 0.122 ms | 222.2222 | 222.2222 | 222.2222 |     19 MB |
+
+
+### FIR Filters
+
+Different implementations of FIR filters are compared:
+
+- ```FirFilter``` (ver.0.9.2 - 0.9.4 of NWaves)
+- ```FirFilter``` (as of ver.0.9.5 of NWaves)
+- ```ZiFilter```
+
+This benchmark demonstrates that the newer version of ```FirFilter``` is faster. ```ZiFilter``` is expectedly slower than ```FirFilter```.
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|                   Method |      Mean |     Error |    StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |
+|------------------------- |----------:|----------:|----------:|---------:|---------:|---------:|----------:|
+|  FilterVersion092Kernel5 |  9.782 ms | 0.1544 ms | 0.1444 ms | 234.3750 | 234.3750 | 234.3750 |      4 MB |
+|  FilterVersion095Kernel5 |  9.697 ms | 0.1397 ms | 0.1307 ms | 187.5000 | 187.5000 | 187.5000 |      4 MB |
+|          ZiFilterKernel5 | 11.069 ms | 0.2179 ms | 0.2140 ms | 281.2500 | 281.2500 | 281.2500 |      4 MB |
+| FilterVersion092Kernel35 | 51.575 ms | 0.0910 ms | 0.0807 ms | 300.0000 | 300.0000 | 300.0000 |      4 MB |
+| FilterVersion095Kernel35 | 36.210 ms | 0.0834 ms | 0.0780 ms | 285.7143 | 285.7143 | 285.7143 |      4 MB |
+|         ZiFilterKernel35 | 68.211 ms | 0.0804 ms | 0.0752 ms | 250.0000 | 250.0000 | 250.0000 |      4 MB |
+
+
+### FFT
+
+Different FFTs are compared:
+
+- RealFft (single precision) : ```float[]``` and ```Span<float>```
+- RealFft64 (double precision) : ```double[]``` and ```Span<double>```
+- (Complex)Fft (single precision) : ```float[]``` and ```Span<float>```
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|          Method |     Mean |    Error |   StdDev |   Gen 0 | Gen 1 | Gen 2 | Allocated |
+|---------------- |---------:|---------:|---------:|--------:|------:|------:|----------:|
+|        FftArray | 14.25 ms | 0.023 ms | 0.021 ms | 15.6250 |     - |     - |  24,648 B |
+|         FftSpan | 15.62 ms | 0.024 ms | 0.023 ms |       - |     - |     - |         - |
+|      Fft64Array | 14.53 ms | 0.030 ms | 0.028 ms | 15.6250 |     - |     - |  49,224 B |
+|       Fft64Span | 15.66 ms | 0.055 ms | 0.051 ms |       - |     - |     - |         - |
+| ComplexFftArray | 17.41 ms | 0.081 ms | 0.075 ms |       - |     - |     - |  32,864 B |
+|  ComplexFftSpan | 16.67 ms | 0.033 ms | 0.031 ms |       - |     - |     - |         - |
+
+
+### FIR filters vs. BlockConvolvers
+
+This benchmark demonstrates that OLS and OLA block covolvers are expectedly much faster than FIR filters for longer filter kernels.
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|               Method |      Mean |     Error |    StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |
+|--------------------- |----------:|----------:|----------:|---------:|---------:|---------:|----------:|
+|    FirFilterKernel21 |  2.837 ms | 0.0093 ms | 0.0087 ms | 121.0938 | 121.0938 | 121.0938 |    391 KB |
+|   OverlapAddKernel21 |  3.466 ms | 0.0052 ms | 0.0049 ms | 121.0938 | 121.0938 | 121.0938 |    391 KB |
+|  OverlapSaveKernel21 |  3.452 ms | 0.0065 ms | 0.0061 ms | 121.0938 | 121.0938 | 121.0938 |    391 KB |
+|   FirFilterKernel101 | 10.854 ms | 0.0208 ms | 0.0194 ms | 109.3750 | 109.3750 | 109.3750 |    391 KB |
+|  OverlapAddKernel101 |  4.076 ms | 0.0069 ms | 0.0065 ms | 117.1875 | 117.1875 | 117.1875 |    391 KB |
+| OverlapSaveKernel101 |  4.035 ms | 0.0087 ms | 0.0081 ms | 117.1875 | 117.1875 | 117.1875 |    391 KB |
+|   FirFilterKernel315 | 30.350 ms | 0.0446 ms | 0.0417 ms |  93.7500 |  93.7500 |  93.7500 |    392 KB |
+|  OverlapAddKernel315 |  4.374 ms | 0.0082 ms | 0.0076 ms | 117.1875 | 117.1875 | 117.1875 |    392 KB |
+| OverlapSaveKernel315 |  4.329 ms | 0.0069 ms | 0.0062 ms | 117.1875 | 117.1875 | 117.1875 |    392 KB |
+
+
+### Moving average filters
+
+Recursive implementation of moving average filter (```MovingAverageRecursiveFilter```) is expectedly much faster than FIR subclass (```MovingAverageFilter```).
+
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|                       Method |     Mean |     Error |    StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |
+|----------------------------- |---------:|----------:|----------:|---------:|---------:|---------:|----------:|
+|          MovingAverageFilter | 9.167 ms | 0.1758 ms | 0.1726 ms | 218.7500 | 218.7500 | 218.7500 |      4 MB |
+| MovingAverageFilterRecursive | 3.856 ms | 0.0759 ms | 0.0779 ms | 218.7500 | 218.7500 | 218.7500 |      4 MB |
+
+
+### Median filters
+
+```MedianFilter``` is significantly faster than ```MedianFilter2```.
+
+``` ini
+
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19043.1237 (21H1/May2021Update)
+Intel Pentium CPU G3460 3.50GHz, 1 CPU, 2 logical and 2 physical cores
+.NET SDK=5.0.100
+  [Host]     : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+  DefaultJob : .NET 5.0.0 (5.0.20.51904), X64 RyuJIT
+
+
+```
+|        Method |      Mean |     Error |    StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |
+|-------------- |----------:|----------:|----------:|---------:|---------:|---------:|----------:|
+|  MedianFilter |  9.327 ms | 0.0201 ms | 0.0188 ms | 109.3750 | 109.3750 | 109.3750 |    391 KB |
+| MedianFilter2 | 14.030 ms | 0.0198 ms | 0.0185 ms | 109.3750 | 109.3750 | 109.3750 |    391 KB |