Old Transformer testing and learning what makes whistle. sound, direction work

I did get through several other transformers and created a performance log for each one. I only had one other transformer with Sound and Direction buttons. And I saw a slightly different voltage pattern for Sounds. The Mikes Train House Z 4000 is my bazooka 400 Watt Transformer with 2 controllers. In my Initial testing I was seeing the two sides working together not independently. i had to disconnect the track hook ups to get them separated and some logical readings. I need to be sure I can isolate the two units. I must have some wiring and track issues. Oh Boy. But after i disconnected them I tried to get Sound and Direction button impacts on track power. I set the left unit to 10V for a 1st setup and measurement. At 10V pressing the Whistle presents 10.6 Volts while pressing the bell presents 10.3 Volts. ??? While the K LIne Transformer at 10V gave me 10.5 V for Whistle I thought it gave me 9.5V before it died. I saw on the Video 9.5. So now what i want to do is get my Lionel Sound Buttons and set them up on a transformer and put a Sound Car on the track and see what these buttons do to track power get the sound board to work. Meantime I need to research these sound boards to see just what they were designed to operate with. I know the basic units I have do include a data cable in addition to Hot and Ground that is designed to come from the old Commander control boards they were Lionel TMCC. I have an older huge button box that was $100 and detailed build plans for Lionel Button Boxes. But the challenge maybe the source for these Sounds boards is drying up. We may need to address a 3rd party Sound Board and how to make a button box to work with the sound boards we can get at a reasonable cost. the lowest Cost Lionel Board today is $130 for sounds. Which i think is crazy costs for our Model Train Hobby. I am testing Ngineering Sound boards that are $20 and $30 cot range. I don't have a remote means to use them yet. And they board only allows one sound at a time. Meaning if you are chuffing down the track and ask it to blow the steam whistle the chuff sound stops, I don't like that but for now its the best option under $50. What would you pay for a basic Sound Board.????/ Thank all you folks for subscribing and watching. I will be posting STLs soon. Dennis