I have major issues with the guidance in this document. The biggest one is that they advise placing monitors on the longest wall thus firing them into the shortest room dimension. This is contrary to every studio designer I've spoken to as well as the folks at GIK where I purchased all of the acoustic treatments for my studio build. Universally the guidance was to place monitors on the shortest wall thus firing into the longest room dimension.
Perhaps just as bad they give poor advice on monitor placement relative to the front wall. They advise placing the monitors 1-2' out from the wall and cite soffit-mounted monitors in pro studios as the better way to do. They're correct that soffit-mounting is out of the reach of virtually all home studios, but placement of monitors 1-2' out from the wall is not a good solution. This calculator indicates why these types of placements are less ideal:
The Wall Behind The Loudspeaker (mh-audio.nl). For the best results with free-standing monitor speakers (i.e. speakers not meant to be soffit-mounted) there are two ideal positions: Either far enough away from the front wall to move quarter and half wavelength cancellation frequencies low enough that they become inaudible (i.e. greater than about 7' which is not plausible in most home studio settings), or as close to the front wall as possible without touching to move the quarter and half wavelength cancellations high enough that they're easily dealt with using readily available acoustic treatments.
Less egregiously they indicate to place the monitors such that your head is at the convergence of an equilateral triangle. This is commonly quoted but typically the better advice is to place your head such that the convergence point occurs between 12" and 14" behind your head.
They talk about placing your monitors at a point that's not halfway between the floor and the ceiling. Not bad advice, but a better starting point is to align the monitor's high frequency driver with your ear's tragus when in the mix position.
They also talk about room modes, which is excellent information, but only truly useful if you're building a room. Once the room is built the modes are what they are and there's nothing you can do about that. You can add acoustic treatments to modify the decay characteristics of certain frequencies, but the time to really care about modes is during the design phase before you've physically constructed the room your studio will occupy.
