Hello!
I am using an arduino Mega for my project and I am already utilizing all the hardware serial ports. As such, I had to connect my adafruit soundFX board through SoftwareSerial, which is actually used in the example code for the device.
The two main devices that connect to the hardwareserial pins are my rc receiver (Serial1 RX) & my Sabertooth 2x32 Motor controller (Serial 2, TX). The last hardware serial port is my hc-05 module where I upload code wirelessly.
Electrically wise, everything is wired up correctly. I isolated the soundfx board and tested it on a separate arduino to check it works.
When I enable the soundFX board code which utilizes softwareserial for digital pins 10 & 11, my rc receiver and sabertooth don't work. The moment I comment out the soundfx code, it works great.
How can I run my softwareserial connected device and my hardwareserial devices at the same time without them interfering with eachother?
They probably don't. About the only way to have them interfering is when you use software serial on hardware serial pins. You don't appear to say what you have on pins 0,1. Not all pins on a Mega are kosher for softwareserial. You might check that.
Maybe this is naive but since you are only using Serial1 RX and Serial2 TX, could you run them both off the same serial1 port and put your soundFX board on serial2?
SoftwareSerial disables interrupts while it sends each byte. At very slow bit rates, like 9600, this causes noticeable delays in interrupt-driven processes. It is a major source of Servo jitter.