What is mix summing D box? How to use it, when to use it.

Ok now for some Sunday questions to make your days more knowledgeable.

What is a summing box? or should I say, what is mix summing? When should you apply it to a mix, is it really necessary or can it be left behind.

sunday thinking

Some people prefer the sound of a mix when each track is D-A converted and mixed together in the analog domain, ie a copper wire, rather than using an algorithm in the digital domain to sum channels together.

Of course, it requires lots of converters, and they'd have to be of high enough quality so that you weren't adding tons of conversion artifacts to the mix, which would very much defeat the purpose.

As for the actual summing device, it's a simple enough device to build. You'd need a box, connectors, wire and a bunch of 1% resistors.

i see so you wold need really good I/0 then.

Absolutely.

so basically a typical example of summing in this case would be, lets say you have a song finished and it consist of 40+tracks with automation. You would send each track to a summing mix and tweet the EQ's?

I'm thinking them you would have to assign all of the outputs to a buss to load it in, what would be a typical sequence of assembly you think? or anyone that is familiar with the topic.