PSP RetroQ offers PSP Audioware’s unique take on a musical equalizer with unique sonic character and low phase distortion. This makes RetroQ sound smooth and musically natural. It’s shelf filters are based on fabulous-sounding VintageWarmer’s filters, and PSP RetroQ’s addition of a mid-range filter is designed using the same internal architecture. An adjustable high pass filter is added to make the plug-in a complete program equalizer. It was optimized for use on groups and mixes, but it is equally at home in any situation in which you desire some gentle sweetening in your overall processing chain.

Quotes

Yes, there are a lot of EQ plug ins out there. But PSP EQs have good sound at a very affordable price. Add to it the fact that the limited frequency selection some titles narrow 'the world of endless twidlling', forcing you to pick a frequency and move on! - just like many of our analog consoles. (...) I wholeheartedly suggest readers try the free demo available from the PSP website.
Garrett Haines, TapeOp

Most DAWs already come with one or more equaliser plug-ins, but PSP equalisers do manage to capture that elusive warm and cuddly analogue vibe, and that's what you're paying for here.
Paul White, Sound on Sound

Four distinct flavours of EQ. Stunningly combats digital sterility. Beautiful interfaces. Easy to use. Light on your CPU.
Computer Music, Music Radar