Review Details

1.5" Dia Sorbothane Hemisphere Rubber Bumper Non-Skid Feet with Adhesive

1.5" Dia Sorbothane Hemisphere Rubber Bumper Non-Skid Feet with Adhesive

Product Review (submitted on January 26, 2016):
First, let me say that I used these Sorbothane Hemispheres to dampen low frequency microphonic feedback coming through the cartridge on my Well Tempered turntable. At first, I thought the feedback issue was coming through the aluminum conical feet which were supposed to have been an upgrade. I placed foam under the feet to isolate any vibrations, but the feedback was still present. I then went to the dampening in the arm, etc. Nothing seemed to work. I then looked at the subwoofer and started noticing a difference with the placement. I never had this problem with my other Well Tempered table, so now, I'm really getting frustrated !!! I then replaced the aluminum feet with the original rubber/Sorbothane-like screw-in feet from my other table. This made a significant difference !!! So, now on to improving the platform. I then replaced the Target wall mount shelf with a 3/4" granite slab, new Sorbothane 1 1/2" x 3/4" hemispheres (50 Duro), and turned the subwoofer 180°...and viola !!! The Sorbothane isolated the vibration significantly, probably 50%, due to the larger surface area than the original feet, but 'huge' improvement over the alumimum 'upgraded' feet. In fact, with the aluminum feet, the feedback (at listening levels, 10:00 o'clock) was as if the drummer lightly 'tapped' the kettle drum, but then slowely turned up the volume to around 12:00 o'clock. The feedback became utterly unbearable !!!
I would say that, depending on the weight of the equipment, special attention must be paid to the 'Duro' rating. In my case, the turntable weighs 30 lbs., so (divided by 4, roughly 8 lbs. each) the 50 Duro rated Sorbothane is perfect.
I would highly recommend using the Sorbothane products for vibration/feedback issues on electronic equipment, especially when the cartridge of the turntable is actually acting as a microphone, accentuating any flaws in the system. Now...I can literally turn the volume up to 4:00 o'clock, way beyond listening levels, and only then do I start to get harmonics from the subwoofer !!!