diff --git a/spa/plugins/audiomixer/audiomixer.c b/spa/plugins/audiomixer/audiomixer.c
index 5a3d33f82..5ff1d6f24 100644
--- a/spa/plugins/audiomixer/audiomixer.c
+++ b/spa/plugins/audiomixer/audiomixer.c
@@ -295,7 +295,7 @@ impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_
 	}
 	spa_memzero(port, sizeof(struct port));
 
-	if (port_id == this->last_port + 1) {
+	if (port_id + 1 == this->last_port) {
 		int i;
 
 		for (i = this->last_port - 1; i >= 0; i--)
diff --git a/spa/plugins/audiomixer/mixer-dsp.c b/spa/plugins/audiomixer/mixer-dsp.c
index 5a7364327..95f28da4b 100644
--- a/spa/plugins/audiomixer/mixer-dsp.c
+++ b/spa/plugins/audiomixer/mixer-dsp.c
@@ -292,7 +292,7 @@ impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_
 	}
 	spa_memzero(port, sizeof(struct port));
 
-	if (port_id == this->last_port - 1) {
+	if (port_id + 1 == this->last_port) {
 		int i;
 
 		for (i = this->last_port - 1; i >= 0; i--)
diff --git a/spa/plugins/control/mixer.c b/spa/plugins/control/mixer.c
index 518a475ab..c55e907ce 100644
--- a/spa/plugins/control/mixer.c
+++ b/spa/plugins/control/mixer.c
@@ -256,7 +256,7 @@ impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_
 	}
 	spa_memzero(port, sizeof(struct port));
 
-	if (port_id == this->last_port - 1) {
+	if (port_id + 1 == this->last_port) {
 		int i;
 
 		for (i = this->last_port - 1; i >= 0; i--)