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To give the reader some perspective on my biases regarding tweaks in general, I thought to follow Art Dudley's lead (see this January’s Stereophile review of the Quantum QX-4) into the tweak confession booth. I’ve never bought Shakti Stones, Mpingo discs, Marigo dots, Cable Jackets and certainly no Brilliant Pebbles.


Most audiophiles consider coupling slash decoupling devices to be almost mainstream now. I’ve been through my share of them going all the way back to the Sorbothane pucks, various cone devices and iso bearings. Some of them have helped my system considerably. The list of system tweaks I have tried and continue to use includes:


1) Star Sound Technologies Audio Points/Coupling Discs. These were highly effective under my Audio Physic Step speaker stands.
2) Marigo Audio Lab Orpheus Crossbow CD mat.
3) Isoclean fuses.


Considering one of the fringe tweaks, I would swear I heard an audible improvement in the demo of the Acoustic ART resonators in the Luxman/Giya room at RMAF 2009. 


In fact I hope to experiment with these or the Acoustic System resonators from Franck Tchang some time soon. For now I would have to say that the Audio Prism Ground Control devices rank up there as one of the most cost effective tweaks to have crossed my doorstep.


The resistor for the Tron finally arrived and I replaced it (one of the spot-welded leads had broken next to the resistor body and would not take solder). With my prized Tron 211 back, I listened again for the effects of the GC devices. To save time and writing, suffice to say that I heard the same improvements. As my listening concluded, it became time to put some perspective on my impressions of the Audio Prism Ground Control devices with a couple of questions that readers may be contemplating.

How large is the effect of these devices? More than I hear from the Isoclean fuses but not as much as an interconnect or speaker cable upgrade. However, what the GC devices do may be unattainable from a cable upgrade. I have rarely, if ever heard this combination of virtues from a cable upgrade.


Is the effect easy to hear? At first, the effect seemed deleterious. After the GC devices settle in, the best way I found to hear their effect was to have someone remove them while music was playing and I was in the listening seat. It still takes time to hear everything they do. I will admit not wanting to take part in a blind listening test with these.  However, I am not in the camp that believes that blind listening tests must rule our buying decisions.

In the final week, I invited my audiophile friend Dan over. We started with the popular demo CD I'd picked up at RMAF 2009, Blue Coast Records' Spring Sampler I: Various Artists [BCRCD SS12]. Dan had trouble hearing any difference when I removed the GC devices during playback. He asked me to play a CD that he knew better. Enter Damien Rice’s 2003 debut album O [Vector Recordings 48507]. This a superb recording with brilliant song crafting.  On "Volcano", Dan was first able to clearly pick up on the bass improvement, noting the greater impact and cleaner leading edge. Then he began to hear the soundstage improvements (larger soundstage, better focus, more bloom in front of the speakers). 


Surprisingly the last thing he picked up on was the greater body on Damien’s voice with the devices in place.  I repeated inserting and removing them about five times replaying the same passages and he became increasingly confident and vocal in his praise of the effects. In the end, he decided he was going to purchase a pair. Lastly I tried the RCA input version of the Ground Control device for a final time. This was not audible to me. Bryon said the effect of this version depends on the grounding scheme of your preamp. Some readers may be shaking their heads at this point, questioning why anyone would want to purchase a tweak that might prove difficult to hear. 

I will go so far as predicting that some audiophiles might not hear any improvements either due to their systems not revealing them or their lack of sensitivity to the particular sonic benefits the GC devices convey. On the other hand, Bryon told me that Genesis Loudspeakers plans to include GC devices with every pair of speakers they sell. That’s quite an endorsement.


Over time, the GC devices grew on me to the point where I would not want to be without.  The longer they spent in my system, the more I appreciated their benefits. I don’t know of another tweak that provides such a wonderfully natural improvement to the music up and down the frequency range for this price. However, as forum posters are wont to note, YMMV!  One thing for sure, the objectivist measurement camp will have an absolute field day with these!

Quality of packing: Not much packing was necessary and it was fine.
Reusability of packing: N/A.
Ease of unpacking/repacking: N/A.
Condition of component received: Perfect.
Quality of owner’s manual:  None provided. A small insert with directions and tips on use might be useful.
Completeness of delivery: Complete.
Warranty: Six months.
Human interactions: Friendly and responsive.
Pricing: Reasonable.
Final comments & suggestions:  The website description could use some clarification.

Audio Prism website