https://valhalladsp.com/2015/11/08/valhallaplate-the-reverb-modes/
With that out of the way, the ValhallaPlate reverb modes:
Chrome. This is a good starting point for the plugin. This is a fairly neutral sounding plate. The attack is not super sharp, and the tone is kinda bright, but not too bright.
Steel: Similar to Chrome, but darker.
Cobalt: This has a deeper attack than both Chrome and Steel (i.e. the sound seems to come from a more distant sound source). The tonality is fairly dark. There is a bit of resonance in the very low midrange, that was dialed in from a specific EMT140 we tested at Avast Recording here in Seattle. Most of the other ValhallaPlate modes were deliberately designed to have a more neutral tonality, but this low midrange resonance was key to getting close to that specific sound.
Brass: Much sharper attack than the first 3 modes. If you listen to the signal 100% wet, it almost sounds like there is some dry signal in there. This is a characteristic of some of the plates we heard during the development process. The tonality is fairly bright.
Aluminum: MUCH higher modal density than the first 4 modes. With the SIZE parameter set >100%, Aluminum can sound much more like a chamber than a plate. There is a slight metallic sound to a well tuned plate, that the first 4 reverb modes have. Aluminum (and Copper & Unobtanium) have less of this metallic sound, and can sound much clearer. The overall tonality of Aluminum is fairly bright.
Copper: High modal density, but deeper and darker than Aluminum. The sound seems to come from deep within the plate. Set the SIZE up to 200%, and add a touch of modulation, and you have an open sounding reverb that works on almost any source material.
Unobtanium: High modal density, bright, with a longer high frequency decay than the other plates. This is my take on the Ecoplate sound, but without the metallic ringing artifacts. Turn up the modulation, and you have a perfect reverb for synths.
