diff --git a/src/Filters/filt.jl b/src/Filters/filt.jl
index aa214650..e3e0238d 100644
--- a/src/Filters/filt.jl
+++ b/src/Filters/filt.jl
@@ -32,8 +32,8 @@ filt(f::PolynomialRatio{:z}, x) = filt(coefb(f), coefa(f), x)
 ## SecondOrderSections
 
 # filt! algorithm (no checking, returns si)
-function _filt!(out::AbstractArray, si::AbstractArray{S,N}, f::SecondOrderSections{:z},
-                x::AbstractArray, col::Union{Int,CartesianIndex}) where {S,N}
+function _filt!(out::AbstractArray, si::AbstractMatrix{S}, f::SecondOrderSections{:z},
+                x::AbstractArray, col::CartesianIndex) where {S}
     g = f.g
     biquads = f.biquads
     @inbounds for i in axes(x, 1)
@@ -68,7 +68,7 @@ filt(f::SecondOrderSections{:z,T,G}, x::AbstractArray{S}) where {T,G,S<:Number}
 
 # filt! algorithm (no checking, returns si)
 function _filt!(out::AbstractArray, si1::Number, si2::Number, f::Biquad{:z},
-                x::AbstractArray, col::Union{Int,CartesianIndex})
+                x::AbstractArray, col::CartesianIndex)
     @inbounds for i in axes(x, 1)
         xi = x[i, col]
         yi = muladd(f.b0, xi, si1)
@@ -162,23 +162,40 @@ function filt!(out::AbstractArray{<:Any,N}, f::DF2TFilter{<:PolynomialRatio,Arra
         mul!(out, x, b[1])
     else
         a = coefa(f.coef)
+        outer_dims = CartesianIndices(axes(x)[2:end])
+
         if length(a) != 1
-            for col in CartesianIndices(axes(x)[2:end])
+            for col in outer_dims
                 _filt_iir!(out, b, a, x, view(si, :, col), col)
             end
         elseif n <= SMALL_FILT_CUTOFF
-            vtup = ntuple(j -> b[j], Val(length(b)))
-            for col in CartesianIndices(axes(x)[2:end])
-                _filt_fir!(out, vtup, x, view(si, :, col), col, Val(true))
-            end
+            _small_filt_fir_storesi!(out, b, x, si, Val(length(b)))
         else
-            for col in CartesianIndices(axes(x)[2:end])
+            for col in outer_dims
                 _filt_fir!(out, b, x, view(si, :, col), col)
             end
         end
     end
     return out
 end
+function _small_filt_fir_storesi!(
+    out::AbstractArray, h::AbstractVector, x::AbstractArray,
+        si::Array, ::Val{bs}) where {bs}
+
+    bs < 2 && throw(ArgumentError("invalid tuple size"))
+    length(h) != bs && throw(ArgumentError("length(h) does not match bs"))
+    b = ntuple(j -> h[j], Val(bs))
+    col_len = size(si, 1)
+    LI = LinearIndices(si)
+    for col in CartesianIndices(axes(x)[2:end])
+        @static if VERSION > v"1.12-"
+            si_vec = Base.wrap(Array, memoryref(si.ref, LI[1, col]), col_len)
+        else
+            si_vec = view(si, :, col)
+        end
+        _filt_fir!(out, b, x, si_vec, col, Val(true))
+    end
+end
 
 ## SecondOrderSections
 DF2TFilter(coef::SecondOrderSections{:z,T}, coldims::Tuple{Vararg{Integer}}) where {T} = DF2TFilter(coef, T, coldims)
diff --git a/src/dspbase.jl b/src/dspbase.jl
index 7f97a96d..7ac711e2 100644
--- a/src/dspbase.jl
+++ b/src/dspbase.jl
@@ -115,21 +115,23 @@ end
 const SMALL_FILT_VECT_CUTOFF = 19
 
 # Transposed direct form II
-@generated function _filt_fir!(out, b::NTuple{N,T}, x, siarr, col, ::Val{StoreSI}=Val(false)) where {N,T,StoreSI}
+@generated function _filt_fir!(out, b::NTuple{N,T}, x, siarr, col, ::Val{StoreSI}) where {N,T,StoreSI}
     silen = N - 1
     si_end = Symbol(:si_, silen)
 
     quote
         N <= SMALL_FILT_VECT_CUTOFF && checkbounds(siarr, $silen)
         Base.@nextract $silen si siarr
+        VECTORIZE_LARGER = N > SMALL_FILT_VECT_CUTOFF
         for i in axes(x, 1)
             xi = x[i, col]
             val = muladd(xi, b[1], si_1)
+            if VECTORIZE_LARGER
+                @inbounds out[i, col] = val
+            end
             Base.@nexprs $(silen - 1) j -> (si_j = muladd(xi, b[j+1], si_{j + 1}))
             $si_end = xi * b[N]
-            if N > SMALL_FILT_VECT_CUTOFF
-                @inbounds out[i, col] = val
-            else
+            if !VECTORIZE_LARGER
                 out[i, col] = val
             end
         end
@@ -149,7 +151,7 @@ function _small_filt_fir!(
     length(h) != bs && throw(ArgumentError("length(h) does not match bs"))
     b = ntuple(j -> h[j], Val(bs))
     for col in CartesianIndices(axes(x)[2:end])
-        _filt_fir!(out, b, x, si, col)
+        _filt_fir!(out, b, x, si, col, Val(false))
     end
 end
 
diff --git a/src/periodograms.jl b/src/periodograms.jl
index 6bbce435..9c1d1b5c 100644
--- a/src/periodograms.jl
+++ b/src/periodograms.jl
@@ -482,7 +482,7 @@ function periodogram(s::AbstractMatrix{T};
         ptype = 0
     elseif radialsum
         ptype = 1
-    elseif radialavg
+    else    # if radialavg
         ptype = 2
     end
     norm2 = length(s)