Streamer recommendations for dummies.

The digital volume control in LUMIN products is independent of the AirPlay source volume setting. So that means even if a guest has their iTunes/iPhone volume set to max, but the LUMIN is set at 50%, the music will come out pretty quiet. It'll actually be lower than if you had selected 50% in iTunes (I just tried this to confirm).

Why would this gentleman need a Dac based streamer sucn a Node when the Hegel has a good dac built in?

The digital volume control applies to the digital outputs of the LUMIN products, and the LUMIN U1 and U1 Mini do not have analog outputs. What I confirmed last night was a LUMIN feeding S/PDIF out to an external DAC, with the digital volume control engaged.

In other words, if OP's guests AirPlay to a LUMIN, it will volume limit playback via digital out to any DAC (i.e. the Hegel H160).

For EQ, the new miniDSP SHD devices also accept AirPlay and have built-in DSP options. I don't recall if there is a preset volume setting you can control though, for when AirPlay would kick in. However the UX is less polished than some other devices which might create some annoyances for you in exchange.

Unfortunately I can't think of any other AirPlay-compatible devices at the moment that will override the source's volume setting.

I'm a strong proponent for Dirac Live room correction, over standard PEQ of frequency response. The time-domain correction is an incredible improvement, that pretty much everyone loves once they hear it.

miniDSP's boxes are the most convenient way to add Dirac to a speaker setup, although you can find Dirac integrated into other products from brands like NAD, Bryston, Emotiva, Arcam, and AudioControl.

There are other products besides Dirac that offer similar functionality, but none that are as easy to use and integrate into an existing system in terms of hardware or software in my experience.