diff --git a/plugins/spu2-x/src/Reverb.cpp b/plugins/spu2-x/src/Reverb.cpp
index b2a4d28e23..500bd7a395 100644
--- a/plugins/spu2-x/src/Reverb.cpp
+++ b/plugins/spu2-x/src/Reverb.cpp
@@ -143,8 +143,6 @@ StereoOut32 V_Core::DoReverb( const StereoOut32& Input )
 		const s32 IIR_INPUT_B0 = ((_spu2mem[src_b0] * Revb.IIR_COEF) + (INPUT_SAMPLE.Left * Revb.IN_COEF_L))>>16;
 		const s32 IIR_INPUT_B1 = ((_spu2mem[src_b1] * Revb.IIR_COEF) + (INPUT_SAMPLE.Right * Revb.IN_COEF_R))>>16;
 
-		// Faster single-mul approach to interpolation:
-		// (doesn't work yet -- breaks Digital Devil Saga badly)
 		const s32 IIR_A0 = IIR_INPUT_A0 + (((_spu2mem[dest_a0]-IIR_INPUT_A0) * Revb.IIR_ALPHA)>>16);
 		const s32 IIR_A1 = IIR_INPUT_A1 + (((_spu2mem[dest_a1]-IIR_INPUT_A1) * Revb.IIR_ALPHA)>>16);
 		const s32 IIR_B0 = IIR_INPUT_B0 + (((_spu2mem[dest_b0]-IIR_INPUT_B0) * Revb.IIR_ALPHA)>>16);
@@ -155,28 +153,30 @@ StereoOut32 V_Core::DoReverb( const StereoOut32& Input )
 		_spu2mem[dest2_b0] = clamp_mix( IIR_B0 );
 		_spu2mem[dest2_b1] = clamp_mix( IIR_B1 );
 
-		const s32 ACC0 =
+		const s32 ACC0 = (
 			((_spu2mem[acc_src_a0] * Revb.ACC_COEF_A)) +
 			((_spu2mem[acc_src_b0] * Revb.ACC_COEF_B)) +
 			((_spu2mem[acc_src_c0] * Revb.ACC_COEF_C)) +
-			((_spu2mem[acc_src_d0] * Revb.ACC_COEF_D));
+			((_spu2mem[acc_src_d0] * Revb.ACC_COEF_D))
+		) >> 16;
 
-		const s32 ACC1 =
+		const s32 ACC1 = (
 			((_spu2mem[acc_src_a1] * Revb.ACC_COEF_A)) +
 			((_spu2mem[acc_src_b1] * Revb.ACC_COEF_B)) +
 			((_spu2mem[acc_src_c1] * Revb.ACC_COEF_C)) +
-			((_spu2mem[acc_src_d1] * Revb.ACC_COEF_D));
+			((_spu2mem[acc_src_d1] * Revb.ACC_COEF_D)))
+		 >> 16;
 
-		const s32 FB_A0 = (_spu2mem[fb_src_a0] * Revb.FB_ALPHA);
-		const s32 FB_A1 = (_spu2mem[fb_src_a1] * Revb.FB_ALPHA);
+		const s32 acc_fb_mix_a = ACC0 + ((_spu2mem[fb_src_a0] - ACC0) * Revb.FB_ALPHA);
+		const s32 acc_fb_mix_b = ACC1 + ((_spu2mem[fb_src_a1] - ACC1) * Revb.FB_ALPHA);
 
-		const s32 fb_xor_a0 = _spu2mem[fb_src_a0] * ( Revb.FB_ALPHA ^ 0x8000 );
-		const s32 fb_xor_a1 = _spu2mem[fb_src_a1] * ( Revb.FB_ALPHA ^ 0x8000 );
+		const s32 FB_A0 = (_spu2mem[fb_src_a0] * Revb.FB_ALPHA) >> 16;
+		const s32 FB_A1 = (_spu2mem[fb_src_a1] * Revb.FB_ALPHA) >> 16;
 
-		_spu2mem[mix_dest_a0] = clamp_mix( (ACC0 - FB_A0) >> 16 );
-		_spu2mem[mix_dest_a1] = clamp_mix( (ACC1 - FB_A1) >> 16 );
-		_spu2mem[mix_dest_b0] = clamp_mix( (MulShr32(Revb.FB_ALPHA<<16, ACC0) - fb_xor_a0 - (_spu2mem[fb_src_b0] * Revb.FB_X)) >> 16 );
-		_spu2mem[mix_dest_b1] = clamp_mix( (MulShr32(Revb.FB_ALPHA<<16, ACC1) - fb_xor_a1 - (_spu2mem[fb_src_b1] * Revb.FB_X)) >> 16 );
+		_spu2mem[mix_dest_a0] = clamp_mix( ACC0 - FB_A0 );
+		_spu2mem[mix_dest_a1] = clamp_mix( ACC1 - FB_A1 );
+		_spu2mem[mix_dest_b0] = clamp_mix( (acc_fb_mix_a - (_spu2mem[fb_src_b0] * Revb.FB_X)) >> 16 );
+		_spu2mem[mix_dest_b1] = clamp_mix( (acc_fb_mix_b - (_spu2mem[fb_src_b1] * Revb.FB_X)) >> 16 );
 
 		upbuf[ubpos] = clamp_mix( StereoOut32(
 			_spu2mem[mix_dest_a0] + _spu2mem[mix_dest_b0],	// left