If you own a sound card supported by OPENCP and have difficulties using the vapc drivers there is the chance that both drivers interfere. You may try to remove all native OPENCP drivers from the ini file. The corresponing lines should look like this:
playerdevices=devpVXD devpNone devpDisk devpMPx samplerdevices=devsNone wavetabledevices=devwMixF devwmixQ devwMix devwNone
The native-driver will use the soundcard, and windows will reserve the device for the OPENCP-task.7.1 If this occurs, you will find something like couldn't create dsound-object in the cphost-log. so, remove the other device-driver, restart the dosbox, and enjoy.
It must be possible to launch some direct-sound-output while the cp is running (not neccesarily playing). try a winamp or something first (using DirectSound, not WaveOut). If this works, continue using OPENCP with DirectSound.
When switching to the fileselector playback get interrupted even on very fast computers. Threre is no way to avoid this, because under Windows DOS programs get not enough interrupt ressources.
When I use the vapc driver and change into the fileselector while
playing, the playing stutters.
This is a well known problem. Windows doesn't give OPENCP enough priority for the background playing. Currently there is nothing that can be done about this.