diff --git a/synth/bank_test.go b/synth/bank_test.go
index 4056bda..37dd5e2 100644
--- a/synth/bank_test.go
+++ b/synth/bank_test.go
@@ -8,7 +8,7 @@ import (
 )
 
 func TestNewBankHas14Layers(t *testing.T) {
-	b := NewBank(1.0)
+	b := NewBank(1.0, ClassFreqConfigs)
 	if len(b.layers) != 14 {
 		t.Errorf("NewBank() has %d layers, want 14", len(b.layers))
 	}
@@ -21,7 +21,7 @@ func TestNewBankHas14Layers(t *testing.T) {
 }
 
 func TestRenderWindowOutputLength(t *testing.T) {
-	b := NewBank(1.0)
+	b := NewBank(1.0, ClassFreqConfigs)
 	snap := classify.WindowSnapshot{
 		Counts:       make(map[classify.TrafficClass]int64),
 		TotalPackets: 0,
@@ -34,7 +34,7 @@ func TestRenderWindowOutputLength(t *testing.T) {
 }
 
 func TestRenderWindowSilentWhenNoTraffic(t *testing.T) {
-	b := NewBank(1.0)
+	b := NewBank(1.0, ClassFreqConfigs)
 	// Empty counts — no class ever seen — all layers should stay at zero amplitude
 	snap := classify.WindowSnapshot{
 		Counts:       make(map[classify.TrafficClass]int64),
@@ -51,7 +51,7 @@ func TestRenderWindowSilentWhenNoTraffic(t *testing.T) {
 }
 
 func TestRenderWindowNonZeroWithTraffic(t *testing.T) {
-	b := NewBank(1.0)
+	b := NewBank(1.0, ClassFreqConfigs)
 	counts := make(map[classify.TrafficClass]int64)
 	counts[classify.ClassICMP] = 100
 	snap := classify.WindowSnapshot{
@@ -74,15 +74,15 @@ func TestRenderWindowNonZeroWithTraffic(t *testing.T) {
 }
 
 func TestMixerNoClip(t *testing.T) {
-	b := NewBank(0.01) // fast EMA to quickly ramp up to near-max amplitude
+	b := NewBank(0.01, ClassFreqConfigs) // fast EMA to quickly ramp up to near-max amplitude
 	counts := make(map[classify.TrafficClass]int64)
 	// All 14 classes at max count — worst-case mixing scenario
-	for _, class := range classify.AllClasses() {
+	for class := range ClassFreqConfigs {
 		counts[class] = 1000
 	}
 	snap := classify.WindowSnapshot{
 		Counts:       counts,
-		TotalPackets: 14000,
+		TotalPackets: int64(len(ClassFreqConfigs)) * 1000,
 		WindowIndex:  0,
 	}
 	// Render multiple windows to let EMA converge
@@ -102,7 +102,7 @@ func TestMixerNoClip(t *testing.T) {
 }
 
 func TestStereoPan(t *testing.T) {
-	b := NewBank(0.01) // fast EMA
+	b := NewBank(0.01, ClassFreqConfigs) // fast EMA
 	counts := make(map[classify.TrafficClass]int64)
 	// ClassDHCP has pan=-0.75 (wide-left in config.go)
 	counts[classify.ClassDHCP] = 1000
@@ -130,7 +130,7 @@ func TestStereoPan(t *testing.T) {
 }
 
 func TestMultipleWindowsEMAConvergence(t *testing.T) {
-	b := NewBank(1.0)
+	b := NewBank(1.0, ClassFreqConfigs)
 	counts := make(map[classify.TrafficClass]int64)
 	counts[classify.ClassICMP] = 100
 	snap := classify.WindowSnapshot{
@@ -150,6 +150,44 @@ func TestMultipleWindowsEMAConvergence(t *testing.T) {
 	}
 }
 
+func TestNewBankDynamicGain(t *testing.T) {
+	// Create a config map with only 3 classes
+	cfgs := map[classify.TrafficClass]FreqConfig{
+		classify.ClassICMP:  ClassFreqConfigs[classify.ClassICMP],
+		classify.ClassDNS:   ClassFreqConfigs[classify.ClassDNS],
+		classify.ClassHTTPS: ClassFreqConfigs[classify.ClassHTTPS],
+	}
+	b := NewBank(0.01, cfgs)
+	if len(b.layers) != 3 {
+		t.Errorf("NewBank with 3 configs has %d layers, want 3", len(b.layers))
+	}
+	// Verify gainPerLayer is 1/3
+	expected := 1.0 / 3.0
+	if b.gainPerLayer != expected {
+		t.Errorf("gainPerLayer = %v, want %v", b.gainPerLayer, expected)
+	}
+}
+
+func TestNewBankCustomConfigNoClip(t *testing.T) {
+	cfgs := map[classify.TrafficClass]FreqConfig{
+		classify.ClassICMP: ClassFreqConfigs[classify.ClassICMP],
+		classify.ClassDNS:  ClassFreqConfigs[classify.ClassDNS],
+	}
+	b := NewBank(0.01, cfgs)
+	counts := map[classify.TrafficClass]int64{
+		classify.ClassICMP: 1000,
+		classify.ClassDNS:  1000,
+	}
+	snap := classify.WindowSnapshot{Counts: counts, TotalPackets: 2000, WindowIndex: 0}
+	for i := 0; i < 10; i++ {
+		for _, frame := range b.RenderWindow(snap) {
+			if frame[0] > 1.0 || frame[0] < -1.0 || frame[1] > 1.0 || frame[1] < -1.0 {
+				t.Fatalf("clipped with 2-class config: L=%v R=%v", frame[0], frame[1])
+			}
+		}
+	}
+}
+
 // windowRMS computes the root mean square amplitude across all stereo frames.
 func windowRMS(frames [][2]float64) float64 {
 	var sum float64
diff --git a/synth/config_test.go b/synth/config_test.go
index f1e822c..e969a7e 100644
--- a/synth/config_test.go
+++ b/synth/config_test.go
@@ -59,7 +59,8 @@ func TestClassFreqConfigsComplete(t *testing.T) {
 }
 
 func TestNumLayersMatchesAllClasses(t *testing.T) {
-	if synth.NumLayers != len(classify.AllClasses()) {
-		t.Errorf("NumLayers=%d but AllClasses() has %d entries", synth.NumLayers, len(classify.AllClasses()))
+	if len(synth.ClassFreqConfigs) != len(classify.AllClasses()) {
+		t.Errorf("ClassFreqConfigs has %d entries but AllClasses() has %d entries",
+			len(synth.ClassFreqConfigs), len(classify.AllClasses()))
 	}
 }