diff --git a/decor/eta.go b/decor/eta.go
index 38a348a..64ec74a 100644
--- a/decor/eta.go
+++ b/decor/eta.go
@@ -44,7 +44,7 @@
 	} else {
 		average = ewma.NewMovingAverage(age)
 	}
-	return MovingAverageETA(style, NewThreadSafeMovingAverage(average), normalizer, wcc...)
+	return MovingAverageETA(style, average, normalizer, wcc...)
 }
 
 // MovingAverageETA decorator relies on MovingAverage implementation to calculate its average.
@@ -86,7 +86,6 @@
 	return d.Format(d.producer(remaining))
 }
 
-// EwmaUpdate is called concurrently with (d *movingAverageETA).Decor
 func (d *movingAverageETA) EwmaUpdate(n int64, dur time.Duration) {
 	if n <= 0 {
 		d.zDur += dur
diff --git a/decor/moving_average.go b/decor/moving_average.go
index a1be8ad..165ef1e 100644
--- a/decor/moving_average.go
+++ b/decor/moving_average.go
@@ -70,5 +70,5 @@
 
 // NewMedian is fixed last 3 samples median MovingAverage.
 func NewMedian() ewma.MovingAverage {
-	return NewThreadSafeMovingAverage(new(medianWindow))
+	return new(medianWindow)
 }
diff --git a/decor/speed.go b/decor/speed.go
index 808d6b6..b643e10 100644
--- a/decor/speed.go
+++ b/decor/speed.go
@@ -46,7 +46,7 @@
 	} else {
 		average = ewma.NewMovingAverage(age)
 	}
-	return MovingAverageSpeed(unit, format, NewThreadSafeMovingAverage(average), wcc...)
+	return MovingAverageSpeed(unit, format, average, wcc...)
 }
 
 // MovingAverageSpeed decorator relies on MovingAverage implementation
@@ -93,7 +93,6 @@
 	return d.Format(str)
 }
 
-// EwmaUpdate is called concurrently with (d *movingAverageSpeed).Decor
 func (d *movingAverageSpeed) EwmaUpdate(n int64, dur time.Duration) {
 	if n <= 0 {
 		d.zDur += dur