Corner Basstraps (Chunk Traps) - build and outcomes

I have a dedicated listening room in my home measuring approximately 7m L x 5m W x 2.8m H. The room has a carpeted concrete floor, painted brick and plaster walls and a gypsum ceiling. When I initially set up my hi-fi in the room the acoustic response was terrible - the room was loud, boomy and an incoherent mess that dictated listening at very low levels to avoid listening fatigue and a headache. At some point I had some acoustic treatment done to dampen the room a little - basically four panels containing PET on the front wall and two on either of the side walls, covering first reflection points. On top of that I also had the same PET panels (2 of) installed in the room corners. Overall the room showed significant improvement and listening was a lot more enjoyable. I could begin to appreciate my kit and my music collection. Whilst it was a large improvement over what I initially had, I wasn't satisfied that things were as good as they should be - this was confirmed every time I found myself in a listening space that had been properly treated. Bass was either absent or boomy, midrange wasn't as detailed as it should be and occasionally I found myself thinking things were missing from some songs I knew well - had I listened to different releases as a kid? I added an in ceiling IB subwoofer comprising 4 x 15" woofers powered by a Crown XTi 1000 amp and the bass response and soundstage definitely improved, but to my mind the midrange still lacked detail and bass was occasionally boomy and wasn't articulate - kind of what people refer to as "one note bass".

In any event, I resolved to look into additional treatments, but this time to take things into my own hands rather than just hand over cash to someone. After much reading, confusion and contradiction I decided that the best thing to do was to build and install chunk traps using high density mineral wool boards. The boards came in 1200mm x 600mm dimensions so I sized the chunk traps by cutting the board in half and then halving each resulting board diagonally, yielding 4 triangular mineral wool sheets per board. Dimensions of the triangles were 600mm x 600mm x 848.53mm (see Right Triangle Angle And Side Calculator). I used 19mm 2.4m x 1.2m plywood sheets cut along the "grain" into 75mm widths to build 8 triangular enclosures in which to place the mineral wool triangles. These were sized approx 615mm x 615mm x 870mm (ensuring that the triangular mineral wool sheets could be easily placed). I chose to make 8 stackable enclosures rather than four very tall enclosures so that it would be possible for one person to place/ move the traps if necessary. I'll let the pictures do the talking where the build is concerned. That green stuff is PET - lined the frames to keep the mineral wool inert.







More to follow...