[Sampsa]

What are the cheapest, effective diffusors on the market, including DIY models?

The models I know are: RPG Skyline (2D, 125 Hz - 16 kHz) is about $280/2, Decware P1324 (1D, 1125 Hz - 12 kHz) is about $120/2 (assembly required), and ART Diffusor Model E (1D, 125 Hz - 16 kHz) is $300/4.

What others are there?

[JLM]

Bookcases.

Vary the book sizes, spacing, etc.  Try other materials on the shelves.  Vary the depth of the cases.  For built in bookcases it might work well to install partial depth shelves that have vertical reinforcement pieces front and back.

[PhilNYC]

Bookcases.

Vary the book sizes, spacing, etc.  Try other materials on the shelves.  Vary the depth of the cases.  For built in bookcases it might work well to install partial depth shelves that have vertical reinforcement pieces front and back.

If you don't read a lot or own a lot of books, this could be more expensive than the audio products...!  

(unless, of course, you go to some kind of used book fair and buy a ton of used books...)  

[Smeggy]

Go to the pound and pick up a few stray moggies, nail them in strategic places around the room and enjoy the superior absorption properties of felinicus absorbius.

[Sampsa]

Bookcases.

Vary the book sizes, spacing, etc.  Try other materials on the shelves.  Vary the depth of the cases.  For built in bookcases it might work well to install partial depth shelves that have vertical reinforcement pieces front and back.

That's an idea. How effective are they? What kind of vertical reinforcement pieces do you mean?

[JLM]

"Vertical reinforcement" for shelves for deep bookshelves, let me try to verbalize with an example ...

With two 1"x3" boards (the vertical reinforcement pieces) and the 1"x12" shelf board you can form a sort of a "Z" shape.  Lay the shelf on the horizontal (duh, unless your one of the three stooges).  Attach one of the 1"x3" boards on the edge of the 1"x12" to make an "L" shape.  That will reinforce on edge of the 1"x12".  Do the same for the opposite edge of the 1"x12" with the other 1"x3", but have it extend in the opposite direction to form the "Z" shape.  

When finished you'll have the front 1"x3" piece flush with the top of the shelf and hanging down (it can have decorative patterns milled into it) and the back piece flush with the bottom of the shelf and extending up to serve as a ledge to keep stuff from falling off the back and can also hide indirect lighting.  And/or the front piece can also hide puck lights to high light your stuff below the shelf.

Of course you can put about anything on the shelves to help with diffusion, busts of your favorite composers, CD's, dead cat collection, pillows, beer bottles from around the world, whatever.  BTW, does everyone have hundreds of books, magazines, CD's, and just general clutter?