I’m in the process of creating a mobile DiT station/production unit. I’m going to use a Blackmagic Atem 1ME production studio 4K as both a vision mixer for multicamera productions and as a router for DiT applications. This unit has the ability to route any input or the PGM or Preview bus to any one of 3 auxiliary outputs using buttons on the front panel, so it can act as a basic hub. They can be picked up used via ebay or places like MPB for around £300-£400 ($300-400).

However, from the factory these units are extremely noisy. The fans that Blackmagic use are LOUD. It is too noisy to be used on set as it is, so I decided to replace the fans with some quieter ones. If you can solder this is a pretty easy job.

There are 3 fans that blow air out of the chassis. I replaced these with Noctua NF-A4x20 PWM fans. Make sure you get the PWM versions!
These are 4 wire PWM fans. Blackmagic use a smaller fan connector than used in most computers so you will need to cut the connector off the original fans and solder this to the leads from the replacement fans. 

For the Noctua fans see the image below for which coloured wire is connected to which.

Blue original goes to Noctua Blue. 

Yellow original goes to Noctua Green

Red original goes to Noctua Yellow

Black original goes to Noctua Black

The other 4 fans were replaced with AAB Cooling Super Silent Fan 4’s, these are normally available from Amazon and are quite a lot cheaper that the Noctua equivalent but equally quiet. Again you will need to re-use the connectors from the original fans, but the wire colours are the same.

The reduction in noise is already dramatic after the fan replacement. But if you drill out the vent grill for the exhaust fans the unit will be even quieter.