Hi Devendra, > audio quality is not really good in waveCyclic miniport driver >> > What makes you think so? My conjecture is that the IRP handling and queueing is done by portcls in our buffer, whose address we give to PortCls through SystemAddress(). So it may due to overrunning of read pointer in buffer. Due to which buffer gets emptied and waits for new IRPs to get write pointer move ahead, then everything moves smoothly for few seconds. Same thing repeated again. Since that read /write pointer is not in our hand, we can not much about it. That's where WavePCI has advantage over WaveCyclic. -- Thanks and regards Pritesh