Summary:
I have to say first that I've always been skeptical of most of what appear to be the audio equivalent of snake-oil remedies. This experience has really challenged my previous beliefs about practical benefits of what I've always dismissed as stupid little tweak products for audiophiles in their never ending search for audio nirvana.

Audiodyne makes these nifty little ferrite cube-like collars that easily snap onto your power cords and interconnect cables. Installation is a snap (literally!) and takes less skill than it takes opening a beer can.

I live in a condo in urban Seattle. Within a three-mile radius, I have five TV broadcast towers, at least fifteen radio station transmitters, a major shipping lane and three cellular network towers to name the most obvious EMI/RF polluters. Oh, and a City Light electrical substation a block away. Living in a densely populated urban environment, I probably have at least a 100 neighbors using cordless phones and cellular phones within a 200 foot radius as well.

When I installed these I put them on every power cord at the point it entered each individual component's chassis. I put two side-by-side on the receiver's powercord. I also used one at each end of the 8 meter line level cable feeding my subwoofer. I understand you gain further benefit by putting one at each end of all line-level interconnects and not just long runs, for a total of two per cable.

My system is as follows:

Pioneer Elite VSD-26TX Receiver
Toshiba 3109 DVD Player/MIT Terminator 3 Digital Cable
Sony CA80ES CD Changer/Straightwire Toslink Digital Cable
Mission 774 Mains
Mission 77C1 Center
Mission 700AS Powered Sub
Mission 77DS Surrounds
MIT Terminator 4 Cables, Bi-Wired Discrete Runs to Mains
Panamax 1000 Line Conditioner

I have to admit, I went into this thinking I might hear a little reduction in background noise, and honestly didn't really expect to hear any drastic change. What I experienced rendered me totally speechless and still has me shaking my head in wonder! I even took them all off to see if I was imagining it. I quickly put them back on and will never take them off again!

First, the background noise I thought inherent in my system completely disappeared even when the receiver volume was set to 0db, a pleasant surprise. An even bigger surprise was the suddenly copious amounts of internal detail and soundstage information that NEVER existed in the system before now appeared so clear and abundant that I was left gaping in disbelief.

Out of an AV receiver? Albeit the newly designed Pioneer Elites are really light years ahead of previous versions, but c'mon! I haven't heard the Missions sound anywhere this dynamic, transparent and detailed since they were hooked up to a Naim amp/preamp combo a buddy of mine brought over. I'm literally rediscovering my entire CD collection. I'm also using the EMI/RF dampers on my Pioneer Big Screen TV, Laserdisc player, and Mitsubishi VCR powercords. Video is improved and colors are more saturated and there seems to be less smear on details, particularly when viewing composite video sources.

These are great! A $50 investment has given me an entirely new and dramatically better audio/video system whether listening to music or watching films on video. I can't think of another product that does so much and costs so little. My advice: Buy enough for every power cord and interconnect. My sense of it is that it's more effective if you block every avenue for EMI/RF entry into your system. This skeptic is a believer!

Strengths:
Shockingly effective in EMI/RF laden areas. Black jacket looks better than AudioQuest's equivalent product. Cheap (about $8.25 per pair), almost 25% cheaper than the AQ version. Direct sale on the internet(www.audiodyne.com) with superb customer service.

Weaknesses:
None found.

Summary:
I know about all the invisible garbage in the air (radio waves and static)that surrounds my audio equipment. With my tube amps I can hear some radio broadcasts in my tweeters. I found out about the Audiodyne Internet site that sells devices that will solve the RF problem (http://www.audiodyne.com). Indeed they do! I simply clamped their EMI-Traps onto my interconnects and no more radio programs playing along with my music! I think all serious listeners should use these even if you can't hear the RF. The music sound much smoother in the highs without out any glare caused by the RF riding on the cables.