Matt; I too am just getting into SS. I acquired it 2 weeks ago for too much $. But I worked for NASA for over 40 years so I had to have it when one came available.
I am also having sound problems; two actually. The first was a noise problem that I have temporarily addressed with some braid wrapped around the shielded 2 conductor cable coming out of J 16 of the big circuit card. I think the root cause is that the cable connectors used are not really suited for wire braid resulting in a poor connection to the circuit card. I will investigate it further the first time that I remove the circuit card. Meanwhile the temp fix eliminated at least 95% of the noise which was driving me crazy when the machine was powered on.
You can read the conversation thread about my second problem on my post further down in the list.
What does your machine do in response to the two sound diagnostic tests? I get no effect when I press diagnostic S/W 2 on the large circuit card located just to the right of the batteries. In response to the diagnostic sound test I get no sound for numbers 00-05 in the match display, a single sharp sound for 06, and what I think is the Shuttle blast sound for 07. Then it recycles back to 00. Note that in the manual it says the match display will cycle from 00-06, not 07.
I too get speech that is not as expected and missing speech as well. At the start of most balls I get "ready pilot abort" instead of ready pilot one.