diff --git a/src/Filters/stream_filt.jl b/src/Filters/stream_filt.jl
index 235c02e42..10d424ce6 100644
--- a/src/Filters/stream_filt.jl
+++ b/src/Filters/stream_filt.jl
@@ -229,7 +229,7 @@ function setphase!(kernel::FIRArbitrary, ϕ::Real)
     (ϕ, xThrowaway) = modf(ϕ)
     kernel.inputDeficit += round(Int, xThrowaway)
     kernel.ϕAccumulator = ϕ*(kernel.Nϕ) + 1.0
-    kernel.ϕIdx         = round(kernel.ϕAccumulator)
+    kernel.ϕIdx         = floor(kernel.ϕAccumulator)
     kernel.α            = modf(kernel.ϕAccumulator)[1]
     nothing
 end
diff --git a/test/filt_stream.jl b/test/filt_stream.jl
index 65457f1e0..1c17e1c03 100644
--- a/test/filt_stream.jl
+++ b/test/filt_stream.jl
@@ -365,3 +365,11 @@ end
 # check that these don't throw; the output should actually probably be longer
 @test resample(1:2, 3, [zeros(2); 1; zeros(3)]) == [1, 0, 0, 2] # [1, 0, 0, 2, 0, 0]
 @test resample(1:2, 3//2, [zeros(2); 1; zeros(3)]) == [1, 0] # [1, 0, 0]
+let H = FIRFilter(2.22)
+    setphase!(H, 0.99)
+    @test length(filt(H, 1:2)) == 3
+end
+let H = FIRFilter(122.2)
+    setphase!(H, 0.99)
+    @test length(filt(H, 1:2)) == 124
+end