(19-Jan-2019, 07:40)David A Wrote: Well, this thread has gone a long way off topic from clean power to end up in vibration control.
I first got interested in vibration control years ago after reading an article called "Bad Vibes" by Shannon Dickson on Stereophile's website. Anyone interested can do a search for it there. It gives a very good run down of the basics on the 2 opposing techniques people use, isolation and coupling, which work in opposite ways. Despite what many people think, cones and spikes actually couple rather than isolate. Devices like the Orea isolate. Both can produce improvements but mostly in my system I tend to isolate.
I experimented with a lot of different devices of various sorts, designing and getting my own rack built to my specifications, tweaking that like mad for a couple of years, and eventually ended up simply buying a Grand Prix Audio Monaco rack with their Apex feet (ball bearing based feet allowing the rack to move). That was probably around 12 years ago now and I'm still using the Monaco and I'm still as happy with it as when I first got it. At various stages I've experimented with using various cones or isolation devices between components and the shelves and every time I've tried that I've ended up removing the cones or other devices and gone back very quickly to just placing the component on the shelf. Trying to add other devices to the mix just degrades sound quality, the Monaco really does do what it claims to do in my experience.
I think there's a fair bit of personal taste involved in whether one goes for isolation or coupling, and/or for other options such as high or low mass platforms/supports. If there's one conclusion I came to during my years of experimentation before getting the Monaco, however, it's this: stick to one device and don't start building multiple layers of isolation and/or coupling between the floor and a component. I think I once ended up with about 5 different layers made up of shelves, cones, soft dampers, and so on between a rack shelf and my CD player. I forget what I first put between the player and the shelf and it made an improvement but left me with something I didn't like in the sound so I added something else to fix that, noticed an improvement but still wasn't quite happy, added another device to the mix and kept on going. Each time I added something I did A/B testing between the new setup and the previous setup, each time I felt I had reduced the issue that was annoying me. At no time did I ever do comparisons of the new device instead of the old device. One day I started wondering just how the setup would sound if I removed everything I had ended up with between the shelf and the player so I removed the lot, stuck the player straight on the shelf, and it sounded better than with all of the things in between. What I ended up realising is that no single device is perfect and it's all to easy to find yourself focussing on fixing a particular problem in the sound rather than listening to see whether the sound improves overall. It's easy to fix one problem and create a new problem somewhere else when you keep adding layers of isolation and/of coupling between the floor or a shelf and your component but adding more layers actually seemed to degrade the sound when I finally got around to paying attention to the sound as a whole rather than just to the problem I wanted to fix at the time, and just using a single layer of isolation or coupling, whichever one I preferred most, between the floor or shelf and the component gave me my best results. It was never quite a perfect result but it was better than any combination of multiple devices. Take what you like from that.
Re using something like the Oreas with a 440: I think you might get better results placing the 2 amp units side by side with a single set of Oreas between them and your shelf or floor rather than stacking the amps on top of each other and using one set of Oreas between the 2 amps and another set between the bottom amp and the shelf/floor. I always found stacked isolation devices a worse solution than stacked coupling devices or stacking a coupling device with an isolation device.
This is one area where I found it was usually better to keep things as simple as possible.
I definitely recommend the "Bad Vibes" article. I think you'll probably have to read it a few times and spend some time thinking about what's being said in order to get a good grasp on the issues and theory but if you're going to go the DIY route or use commercial footers of some kind, I think the effort is worth it.
Long read but I finally worked up the stamina too carry on through to the end...great post! I agree with most of your points and, incidentally, did wonder about stacking the two D's....don't currently have a second set of Bronze but will experiment at some point in the future...perhaps they are responding in identical modes so stacking may be advantageous...I certainly have no idea about most of this stuff but agree with your summary about simplifying the support structures by using one modality only, one or the other, so not mixing coupling and isolating systems. (as you posted).
