Creating an audio delay

I am looking to develop some software which creates an audio delay. I require a user to be able to feed a stereo audio signal into the 'line in' input of a computer soundcard, and for the audio to then be stored by the software until played back out of the 'line out' of the soundcard after a delay of specifiable amount of time. (between 0-10 seconds, or more if possible). This would then create an audio delay. This would be a continuous process, ie audio is constantly being fed into the 'line in', stored for the required amount of time, then played at the 'line out'. I require the delay to be able to 'build' over a reasonably practical period of time - ie three or four minutes max. To begin with, audio fed in at the soundcard's 'line in' would be passing straight through the soundcard and immediately being played at the 'line out' (ie, it is 'live' - zero delay). However, upon the click of a button by the user, the software would begin to 'build' the delay - inaudibly starting to store audio data before playing it back at the 'line out'. Over time, the delay between what was 'live' and what was 'delayed' would slowly increase. When a pre-specified period of delay was achieved the delay would stop building, and the delay period would become fixed. In additional, the software needs to be able to 'drop' the delayed audio at any time, ie if the user clicks a button, any stored audio is lost and the audio being fed to the 'line in' instantly passes straight through the soundcard with no delay and is played at the 'line out' (back to 'live' - zero delay). During this whole process, the audio needs to remain free of crackles, clicks or audible deterioration. In other words, an average person listening to the audio that was being delayed would have no idea that it was being processed through the delay software. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows XP If this project could be completed using Visual Basic 6 this would be perfect!