There is another volume control that you seem to have missed. This has probably nothing to do with your problem, but you should be aware of it anyway.
In the
System Preferences... > Sound preference panel, make sure the
Sound Effects pane has been selected. There, in addition to the
Output volume, there should also be an
Alert volume, both in the same window.
there is a volume adjustment for Universal
Access Voice Over but I do not use that;
I wasn't talking about Universal Access' Voice Over. Anyway, as far as I know, there is no volume control for Voice Over, so I don't really understand what are you talking about here.
I use Voice-to-Speech
I suppose you mean
Text-to-Speech, right?
and there does not seem to be a voice to
speech volume adjustment specifically.
Correct. I didn't mean there was one either.
voice of voice to speech makes no difference, and
that should not be the solution in any case.
No, it shouldn't be a solution. I suggested it for troubleshooting only.
the main problem is as I stated earlier
I understood the problem then and I understand it now and I don't really know why this happens to you nor how to solve it. I'm just trying to help by ensuring that you're aware of all the system settings that could have a bearing on this.