One thing that makes me happy with this subject is that people are paying attention to measurements! I can't say I've been able to identify a sonic issue related to DAC vibrations myself. Regardless, the process of achieving vibration isolation and measuring the results with accelerometers is interesting to me. It would be fascinating if someone could show DAC output measurements that correlated to the improved vibration isolation. A simple listening test could involve attaching an exciter or bass shaker to a DAC to see just how bad it can be made to sound. Maybe very specific frequencies are problematic, others completely benign. Maybe some frequencies help! You never know until you try.
Quiz about adding dense mass to a vibration isolation application!
There are two steps in this quiz:
1) Hypothetically, you have a DAC that is very solidly built on all sides and weighs 25 lbs.
This DAC currently has three Nobsound vibration isolation devices under it, the springs of which are about 50% compacted and are damped by foam ear plugs inserted inside of them. The vibration isolation effect with this setup is merely middling according to a cell phone seismograph app.
2) You add a 25 lb granite slab to the top of the DAC with a 1/8-inch rubber mat between it and the DAC, and then add the appropriate number of ear plug foam damped springs to each Nobsound device in order to get all Nobsound device springs back to about 50% compacted.
The question: What do you think is the sonic result of step 2?