marine_hm:
I was thinking npn/pnp but not used them either. I just ordered the subject chip because that's what is used in adafruits tutorial. So the NPN is going to pull the circuit to ground when voltage is applied, somewhat like a relay switch?
Yep. You use a pullup resistor from the pin to 5V to hold it high, then the NPN transistor pulls it low when it's activated. A 10K resistor would be fine.
If I were to use the chip I have, ALL the unused pins should be to ground?
All unused inputs, as I said. Definitely not the unused outputs. When using a chip for the first time, you should always check out the datasheet for guidance. It would make this point clear. It applies to all chips with CMOS inputs.
I think an NPN transister would be much easier as I am only using 1 pin for random sounds to be played.
What NPN specific should I be looking at? I'm sure there's probably thousands out there that do different things.
Probably the most common transistor for this purpose is the BC548, but any NPN small-signal transistor would do the job.
Besides the pullup resistor that I mentioned, you'd need a series resistor from the Arduino pin to the base of the transistor. Again, 10K should be fine.