diff --git a/cmProc.c b/cmProc.c
index 1aee6fc..1d167a1 100644
--- a/cmProc.c
+++ b/cmProc.c
@@ -443,7 +443,13 @@ cmRC_t      cmWndFuncInit(  cmWndFunc* p, unsigned wndId, unsigned wndSmpCnt, do
     case kUnityWndId:      cmVOS_Fill(       p->wndV, p->outN, 1.0 ); break;
     case kKaiserWndId:    
       {
-        double beta = cmVOS_KaiserBetaFromSidelobeReject(fabs(kslRejectDb));
+        double beta;
+        
+        if( cmIsFlag(wndId,kSlRejIsBetaWndFl) )
+          beta = kslRejectDb;
+        else
+          beta = cmVOS_KaiserBetaFromSidelobeReject(fabs(kslRejectDb));
+        
         cmVOS_Kaiser( p->wndV,p->outN, beta); 
       }
       break;
diff --git a/cmProc.h b/cmProc.h
index 5034fb6..bead204 100644
--- a/cmProc.h
+++ b/cmProc.h
@@ -158,7 +158,8 @@ extern "C" {
     kWndIdMask       = 0x0ff,      
 
     kNormByLengthWndFl = 0x100,  // mult by 1/wndSmpCnt 
-    kNormBySumWndFl    = 0x200   // mult by wndSmpCnt/sum(wndV)
+    kNormBySumWndFl    = 0x200,  // mult by wndSmpCnt/sum(wndV)
+    kSlRejIsBetaWndFl  = 0x400   // kaiserSideLobeRejectDb param. is actually kaiser beta arg. 
   };
 
   typedef struct