Subwoofer Isolation, what do you think...

Hi TWL,

I believe that you may have misinterpreted Newbee's post. He was not discussing whether to isolate or couple the subwoofer. He was suggesting that air-borne vibration was the major issue in Sailfishben's system and that he should attend to that at the turntable. Newbee also suggests that Sailfishben try decoupling the turntable so it is shielded from the vibration from the subwoofer. Maybe Newbee can clarify.

I would say that sending more of the subwoofer's vibration and energy into the floor through rigid coupling is not the best method to control that vibration because the vibration will travel through the floor towards the other equipment in the system and have negative sonic effects. If the other equipment is also rigidly coupled to the floor the vibration will have a direct path into the equipment through the supports. A rigid coupler (whether it be a point, a spike, a slab of stone or wood, etc.) does not have the ability to send vibration in only one direction (out of the component). By virtue of its rigidity it allows vibration to travel in BOTH directions - also up INTO the component.

Best Regards,

Barry Kohan

Disclaimer: I am a manufacturer of vibration control products.

Hi Sailfishben,

Each large size IsoNode foot can support a maximum of 10.5 pounds. They are normally sold in sets of four and the set can hold a maximum of 42 pounds. If the component or speaker exceeds that weight, additional IsoNode feet can be put in place underneath so that the load weight can be supported properly. We generally do not recommend that the user be at the maximum load for optimum performance. I would recommend that 14 - 15 large size IsoNode feet be used under a 120 pound speaker.

Best Regards,

Barry

Hi Newbee,

Thank you for your clarification.

Yes, it is critical that the support that is under the component not add its own negative contribution. That is why the choice of materials is very important. I do not recommend using materials that tend to ring (metal, stone, glass, etc) or are known to be significantly resonant (wood, acrylic, plastic, etc) as they will impart those qualities on to the signal that is flowing through the component.

If a damping device is used to control vibration it should absorb as much vibration out of the component as possible without subsequently releasing it back into the component. The more well designed the device is the more able it will be able to achieve that goal.

The "sandbox" you asked about (and which is widely discussed on many internet forums) is our Big Rock platform. The Big Rock was created by me in 1985 and I was granted a patent on the design in 1993. When the Big Rock is set up according to our easy to follow instructions the Plinth (top plate) upon which the component or speaker rests does not flex or deflect in reaction to speaker's movement. It is held firmly in place so that Doppler shift is minimized. If a person does not follow our set up instructions properly or does not use the leveling tool that we supply with the Big Rock it might be possible for the speaker to not be supported as well as it should be. We always recommend contacting us directly if a person has a set up questions.

We do have laboratory measurements that show the improvemnets to a speaker's performance when used with our products. Those interested may view the measurements here:

Link

I have also posted an extensive discussion of vibration control as it pertains to loudspeakers at this Audiogon thread:

Link

Your comment about air-borne vibration that is affecting the component is well considered. If the air-borne vibration is allowed to affect the signal that is flowing through the component, how can "draining" it after the fact return the signal to its previous, pristine state? The same would hold true for internally-generated vibration.

Best Regards,

Barry