Friedemann Kootz wrote an extensive and detailed review (in German). We highly recommend to check it out! Here’s a little English summary:
Hermes:
“Hermes was the messenger of the gods and the god of traffic, in Greek mythology, so he is not at all badly suited as a name giver for a device which has the task of distributing and interconnecting signal paths. SPL’s Hermes has the subtitle ‘Mastering Router’, but can do much more than a simple insert matrix.”
“A great thing about Hermes is that you can assign the two parallel mixers to any of the eight insert points. This makes each of the connected devices ‘dosable’.”
“Especially the assignment of the parallel mixers is a great thing, because the non-linear behaviour of the analog devices gives you even more different timbres and also intermediate stages, which the devices can’t do at home. The controls are logically arranged and the feel is, as usual with the other units of the series, excellent. With clear pressure points and cleanly running potentiometers.”
“The two active parallel stages sound wide and open, do not color the signal and have almost no effect on the perceived width.”
Gemini:
“Gemini is an M/S processor that splits the stereo signal into its sum (mid) and difference (side) components.”
“What’s great is that in bypass mode, when the M/S function is deactivated, the device still routes the signal through the insert. So a connected device can be used in stereo and M/S without any restrictions.”
“Let’s get to the sound of Gemini.
The result remains controlled and clean…”
Hermes & Gemini:
“Working with Hermes and Gemini becomes a matter of course after a very short time and one does not want to miss either of them. Gemini is also a great tool for creative work, with its help some devices develop a whole new potential.”
“Hermes on the other hand is a tough workhorse without compromise. Unfortunately, both test devices have to go back into their boxes, but we will definitely miss them and shed a tear for both of them.”
Conclusion:
“Both devices offer great added value over and above the mere performance of their tasks, which cannot be easily replaced. If you want to work with M/S, you need a Matrix, which you can get from Gemini in very high quality. Those who need parallel processing can get it from Hermes. So both devices are not pure luxury, but real workhorses that save you time and therefore money in daily operation. With their quality they fit perfectly into the SPL Mastering Series.”
“Gemini and Hermes are great tools for which there is nearly zero competition on the market at this level. Once again excellent work, dear SPL team!”
Find the complete review (in German) in Studio Magazin (edition 3/2020).