Thank you Tim, but I have sent a email to asking the price of VAC(binary), they reply says that the price is $4000.(not source code,that maybe even more expensive) if the price only $30,I will very happy to pay for it. ----- Original Message ----- From: Tim Roberts To: wdmaudiodev@xxxxxxxxxxxxx Sent: Saturday, June 27, 2009 12:42 AM Subject: [wdmaudiodev] Re: How to filter microphone voice? kevinrich47 wrote: Sorry,But the price of developer version of VAC is $4000, I'm live in China,This need full year income of mine, mabye after I make this software,I will have enough money to pay the VAC, But I need vac only before I make the software,so ...... The "developer version" means you are asking for the source code so you can make modifications and ship the resulting product as your own. But you don't NEED the source code. I believe you can do what you need just with the binary, by USING the product to create your solution. The binary is only $30 (or $0 for the trial version). -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.