Price Paid:  $59.00 from amusicdirect.com

Summary:
This is my 2nd review for mk3 and mk4. I made further improvements in my system. First I put granite under the audio rack which is Finite Element's Pagode, carrying all my equipments even my big power amp Audio Research VT-200 at bottom. Previously the rack was sitting on the carpet. This improved dynamics and soundstage significantly, but with metal spikes under the rack the sound was too bright. I put a combination of MK4 and MK3 cones under the rack over the granite, and the result was so satisfactory. Then I put a second block of granite under my power amp and a combination of MK4 and MK3 between them. A huge improvement again, details, dynamics, soundstage all improved. I changed cones under my cd player from MK4 to MK3 and also put BDR Source Shelf under my cd player and another set of cones (all MK3) under the shelf and pagode rack. Marvellous! Source Shelf is something every serious listener should consider. A big step over cones. Finally I put granite and mk4 under my speakers which originally sitting on the carpet with ordinary metal spikes. It was such a significant experiment for me how distortion due speaker movement was degrading the sound. Total result is a very dynamic and detailed system with a better soundstage without being too bright or over-analytical. Black Diamond Source Shelf and cones gave me the sound that I have never realized or dreamed before with the same equipments I have. A very serious upgrade due to lowering distortion. Definetely recommended. Do not attemt to upgrade your equipment unless feel confident about distortion performance of your system!

Strengths:
Minimizes distortion, increases everything better resolution, dynamics soundstage, deeper bass, extended highs, detailed mids etc. For me, MK3 worked well with Cd player and MK4-MK3 combination worked for power amplifier and rack sitting on granite. Speakers enjoyed MK4.

Weaknesses:
Not detected yet. It is a painful process to judge which combination of MK4 and MK3 suits best for each component. MK4 is stronger in details and has a linear character but in bright systems it increases harshness etc, MK3 is smoother and is better with bright systems but less detailed wrt MK4.

Price Paid:  $20.00 from Ron Meyer

Summary:
Adding BDR cones to a system in my experience is equal to upgrading equipment one level. But, it could be a greater increase depending on the installation. For me, it was greater than speaker cable, almost the same as going from an Adcom cd player to a Wadia.

In short, the highs were instantly snappier, the based gained texture, the voice quality was more real. Even when I expected some gain, the degree to which sound improved was more than I could have expected. It does help to support all of your equipment and speakers, and not just one piece. The installation calls for three cones per piece. Here in Dallas, Mr. Ron Meyer sells this stuff, and here's what he did in my system.

Ron snstalled it first under the CD Player (Wadia). Wow. Then under the Amp (Citation, and Adcom). Again, great. Then under the speaker, wow again. Then the pre-pro (Rotel) good again. Each add increased the sound quality in about equal amounts.

He then added the BDR round pits under the amp and cd player and the sound elevated again, in about equal amounts for each add. Next for me would be to add pits under the pre-pro and the speakers.

Note that I have a mfb 'rack'. Shevles are wood and fiberboard. The BDR cones really help with these shelves, I guess they don't work as well on glass.

Highly recommended.

Strengths:
Professionally made, excellent sound tweak, easy to install, easy to add to, good looking.

Weaknesses:
Needs 3 per piece of equipment, speaker.

Similar Products Used:
Vibrapods

Price Paid:  $80.00 from Creative Audio

Summary:
The $80.00 is for a set of 4 of these little black beauties (including the threaded posts). I had found that, while my 12" 120W Mirage Subwoofer had the necessary bottom end I craved in movies and music, it rolled off dramatically around 35Hz and the floor was shaking more than my teeth should have been.

I removed the threaded spikes from the sub and replaced with the BDR Cones, cued up Sheffield Lab's Track and Drum CD and was simply amazed - not only could I increase the volume on my receiver 15db higher than normal, I could feel every hit on the floor tom and bass with authority I never experienced before.

With some adjusting of the sub's crossover frequency (which I increased from around 55 to 75 - a much better match with my Mirage 190i's which bottom out at 45Hz) I replayed the same track with another 10db increase. This time I concentrated more on the vibrations in the floor vs the sound quality.

With both feet firmly placed on the floor I felt - nothing.

I headed into my basement, grasped the floor joist directly underneath the sub and felt - nothing.

Absolutly amazing! It was like getting a second 120W amp added to the sub and having it hover just inches off the floor! I was finally getting all the sound out of the box that I had originally paid for.

Next step, replace the spikes on my L/R speaker stands with the same cones because now the sub is much cleaner and faster than my mains!

This is a tweak that really works folks - get some and try it out under any component that produces a signal (even TV sets) you will be amazed at the difference they will make.

Strengths:
Finally, a tweak based on science and not magic.
No break in period required
Small price for huge gains

Weaknesses:
Humm, having my equipment firmly seated on the equivalent of 17 feet of solid granite - none that I can determine.

Summary:
I have used almost ALL BDR products except fot the T.Table clamp.

These represent the greatest bargain in High End Audio tweaks. They don't need any kind of break-in and will sound great right out of the box.

I put them under my CD player, DAC, preamp, T.Table but did not have much luck on my power amp.

Sense of space improved dramatically, midrange to kill for, bass firm with slam, soundstage with 3 dimentions.

Highly recommended! Great deal too!

Associated equipment:

Audio research CD2
Audio note DAC 4
Audio Research LS3B preamp
Oracle Delphi 3 TT
SME arm
Grado reference Master Catridge
Mark Levinson no.331
Dunlavy SC 4 speakers
Audio note Silver cables exclusively

Strengths:
Midrange bloom, spacious sound, clean transparent sound w/o being sterile, bass with more slam (less doubling), improved image height, better image focus and 3D soundstaging. Makes CD's sound more listenable.

Weaknesses:
Some people might preceive loss of bass because of apparent increase in firmness (less doubling).

Summary:
if you own the new arcam 7se, you have to try these things out, just made agood sound better, money well spent.

Strengths:
greater seperation of instruments, and image ,tighting of bass, works very well with arcam 7se.