Firstly know that the FirePod has been discontinued for many years and has reached the End of Service. These products can no longer be repaired. There are also no drivers for these products to work with current computers and operating systems.
You can find any available driver and the systems that are supported here.
You should also use this article to ensure that your computer's firewire driver is set to Legacy. This is only needed for Windows 7.
To troubleshoot your issue,
Test your drum mic. Do they work properly ?
Are you connecting the drum mics with XLR cables ? If not, may be you need to.
How does recording a line level source sound ? Normal or also low ?
Try monitoring from the FirePod alone. Remove the HP4 to test.
