I'm trying to control a Crestron Adagio AES via IR input. It mentions using the CNXRMIRD to do so but is that device simply the same as any other IR Receiver with a 3.5 mm plug?

The only Specs I can find for the CNXRMIRD list the following:
IR Wireless
IR Frequency : 36 to 38 kHz IR
Format: Crestron format, RC5
Range: Up to 50 ft line of sight (typical), dependent upon angle, obstructions, IR
interference, and IR remote signal strength

I'd rather not drop $125 on their IR receiver if a standard 5 dollar one will do the same job. Anyone know if that is a proprietary device somehow or if a standard IR receiver will work?

it isn't anything special, but you do know you still have to program the AES

The AES is programmable via the front panel with out of the box functionality. It will only do whole home audio but that's all I'm using it for.

It's a bit tedious having to name things and configure things with the front panel but doable.

My Harmony Hub actually has a device for Crestron AES but no idea if it actually works until I get the IR receiver for the AES.

In any event, I found a new IR receiver cheap on Ebay and 6 keypads as well so I'll give it a shot. At minimum, I can control with keypads in each zone but I'd rather have the option to use Harmony Hub blasting to the AES controlled via my phone.

You can't configure for an IR remote via the OOTB program.

Crestron isn't meant to be bought off ebay for DIY.

Unfortunate on the IR remote. I'll just have to use the 12 button keypads in each zone.

Whether meant to be or not, it does work great for doing solely whole home audio distribution. I'm not installing control for blinds, HVAC, lights, security, etc with touchpanels. For that, certainly a Crestron integrator is needed.