diff --git a/build/portal/graphs/make-collectd-graphs.sh b/build/portal/graphs/make-collectd-graphs.sh
index 9b4718f..b777780 100755
--- a/build/portal/graphs/make-collectd-graphs.sh
+++ b/build/portal/graphs/make-collectd-graphs.sh
@@ -501,7 +501,7 @@ signal_graph() {
   --title "$3 Signal Level" \
   --vertical-label "dBFS" \
   --upper-limit 1    \
-  --lower-limit -40 \
+  --lower-limit -45 \
   --rigid \
   --units-exponent 0 \
   "TEXTALIGN:center" \