I already had several DIY Panels in my listening room.

I have just bought 2 GIK 244's with limited range Flex Range tech.

I have these in the front corners of my room.

I have not measured the speakers responses yet but I can say its made a really big difference to an already partly treated room.

I do plan to add more to the back of the room - probs tri traps and I probably if funds allow replace the DIY with more GIK's as I dare say they will sound better.

Really helpful service from their Europe UK based office as well

861v4 LPSU, HD621, Bryston 9BSST
KEF Reference 3 and 2c, 2 X SVS SB13 ULTRA
Audio PC: JPLay, LPSU, JCAT, PPA Studio
Cables XLO Limited, Unlimited Edition and Signature
Sony VW500 Isotek Titan, DIY Mains and Clean Signal Earth Solution