Ubuntu 18.04 Host upgrade to Oracle 6 sound issues

[Pete_C]

Using W2003, W2008, W7, W2016 guests for Microsoft SAPI voices.

Ubuntu 18.04 is working great as a host for Virtual Box.

This (audio) has worked fine for Virtual box 5 for over a year now.

Using Virtual Box 6 lost audio to W2003. Audio for W2008, W7 and W2016 is really bad; distorted and muffled when using MS SAPI.

What's up with this?

Should I downgrade back to Virtual Box 5 or wait for a fix for Virtual Box 6.