most effective bass traps

GIK, SensibleSoundSolutions, ASC, RealTraps, etc. use compressed fiberglas which is very effective. Foam is generally less effective for bass, especially.

As I said above, see the data at www.realtraps.com or look up the Wikipedia article on bass traps or consult studiotips website.

Kal

Ignoring the WAF, rolled up carpet remnants work wonders. I've seen these used in various rooms at the CES. If the WAF must be appeased, then they can be covered with grill cloth, like parts express sells. You should be able to do two corners for about $100.00

As Stevecham noted, the Auralex products do a very good job and are cost effective. My room was a charcoal gray color before I installed mine so they blended nicely.

Anyone tried the bass traps from the company the 'foam factory'? They seem cheaper than the others and there is also free shipping on orders over $75.

The ones in the corners.

Depends on the frequencies you want to trap. Although I'm skeptical of their product claims to go as deep as they state, I'm in no position to argue. The methods of measuring sabines for an individual trap have little to do with a typical listening position or overall effectiveness. It might be fun to have a shootout between the brands with a single microphone in the same room. Should the constraints be dollars or square footage? Would it be relevant? Probably not. It wouldn't be your room and your speakers.

The science of these is not complex, often misunderstood and, sometimes, misrepresented. What it comes down to is addressing your unique situation, which is the probably the least understood. However, no matter which brand or type, most who have just taken a stab at it have been impressed with almost everything, which seems to indicate it's all worthwhile.