diff --git a/tests/io-test b/tests/io-test
index 11530a3..360949f 100755
--- a/tests/io-test
+++ b/tests/io-test
@@ -17,9 +17,11 @@ ex=./3-options-input-fn
 
 types=(f32 f64 s32 s16)
 
+zs=(160 160 160 120 180 180 120 120)
+
 do_one() {
   $ex $ir $or $c $1 $2 $3 < $c.${types[$1]} |
-  sox -t ${types[$2]} -r $or -c $c - -n spectrogram -X50 -hwk -z180 -o io$c$n.png
+  sox -t ${types[$2]} -r $or -c $c - -n spectrogram -X50 -hwk -z${zs[$n]} -o io$c$n.png
   n=`expr $n + 1`
 }
 
diff --git a/tests/q-test b/tests/q-test
index 89cf64f..454a41a 100755
--- a/tests/q-test
+++ b/tests/q-test
@@ -11,16 +11,19 @@ set -e
 
 tool=./3-options-input-fn
 
-spec="spectrogram -z180 -Z-20 -wd -ho"
-ext=f32; e=0
 ext=f64; e=1
-c=2
-q1=4; q2=4
+c=1
 q1=0; q2=7
 
 rates=48000
 rates="48000 77773 96000"
 
+z=(50 87 87 87 111 135 159 180 95)
+
+zz() {
+	echo "spectrogram -z${z[$1]} -Z-30 -wd -ho"
+}
+
 for rate0 in $rates; do
 
 rate1=$rate0
@@ -53,10 +56,11 @@ sox -r $rate1 -n -c $c 0.$ext synth 8 sin 0:$rate1n gain -1
 
 for q in `seq $q1 $q2`; do
 	f=q$rate1-$rate2-a-$q
-	$tool $rate1 $rate2 $c $e $e $q  0 < 0.$ext | sox -c$c -r$rate2 -t $ext - -n $spec $f.png
+	$tool $rate1 $rate2 $c $e $e $q  0 < 0.$ext | sox -c$c -r$rate2 -t $ext - -n $(zz $q) $f.png
 done
+q=8
 f=q$rate1-$rate2-a-v
-$tool $rate1 $rate2 $c $e $e 4 20 < 0.$ext | sox -c$c -r$rate2 -t $ext - -n $spec $f.png
+$tool $rate1 $rate2 $c $e $e 4 20 < 0.$ext | sox -c$c -r$rate2 -t $ext - -n $(zz $q) $f.png
 
 
 
@@ -67,10 +71,11 @@ sox -r $rate1 -n 0.$ext synth 1s sq pad .03 .03  gain -1
 
 for q in `seq $q1 $q2`; do
 	f=q$rate1-$rate2-b-$q
-	$tool $rate1 $rate2 1 $e $e $q  0 < 0.$ext | sox -c1 -r$rate2 -t $ext - $f.wav $spec $f.png -X 2000
+	$tool $rate1 $rate2 1 $e $e $q  0 < 0.$ext | sox -c1 -r$rate2 -t $ext - $f.wav $(zz $q) $f.png -X 2000
 done
+q=8
 f=q$rate1-$rate2-b-v
-$tool $rate1 $rate2 1 $e $e 4 20 < 0.$ext | sox -c1 -r$rate2 -t $ext - $f.wav $spec $f.png -X 2000
+$tool $rate1 $rate2 1 $e $e 4 20 < 0.$ext | sox -c1 -r$rate2 -t $ext - $f.wav $(zz $q) $f.png -X 2000
 
 # Combine impuse responses into multi-channel file (for inspection in Audacity):
 sox -M q$rate1-$rate2-b-?.wav q$rate1-$rate2.wav