找到解决办法了,官方的回答是
Please turn off the ASIO GUARD option for the Altiverb 7 plug-in through the plug-in manager in Cubase 8. After you did this you will find that Altiverb 7 will work in Cubase 8. Somehow Altiverb 7 cannot cope with this new Cubase 8 feature, we are working on a fix for this.