On the draining of resonance.....

I think the idea here is to remove excess or spurious energy from your system so it doesn't interfere with the good vibrations:-/ Whether it is internally or externally generated, resonance isn't an instantaneous or infinitely singular event that "happens" and then it's over, rather it involves vibrations or resonant movement within a system that usually decays over time. Draining unwanted or spurious "resonance" away from an audio component to an adjacent structure were it can be absorbed or dissipated as heat is a legitimate concept, at least in theory, to limit vibrations to those related to the relevant musical content, and not the frequency of your motor, transformer, etc. Try it for yourself, you might like the results.

kn

I am not quite sure what your point is:-/ That 1. The idea of internally generated vibrations being materially harmful to sound reproduction is unsound, 2. Even if it is harmful, which you doubt, (see 1 above), there is nothing to be done about it, and 3. A little point is less useful than a big point. Or maybe all three?

As for verifying points one and two above, I suggest you try it with a piece of gear with moving parts, tubes or transformers and see if it helps. Start with something cheap like small hard wood blocks directly on your support shelf to replace your rubber coated stock feet, and if that helps, you can try more elaborate and expensive "solutions".

As for addressing point 3, I think a mechanical engineer could add value here, but here is a lay person's take. Let's say you have a 35lb tube amplifier with big transformers that generate some internal resonance you want to "get out of the chassis". Your options are the 4 x 50 mm diameter rubber coated feet resting on your glass, wood or MDF shelf versus 4 x 1 mm points sunk slightly into a 4" thick hard wood slab (the same general size as you gear chassis or bigger, not to be confused with the small wood blocks described earlier). In the first case, the feet may slide slightly on the surface, reducing the transfer of energy to the shelf, and more likely, the rubber will act as a spring to some degree, storing and releasing energy back to the chassis, smearing over time any residual effect of the internal vibrations. In the second case, assuming a solid connection between the chassis and the body of the point, energy in the form of vibration from the chassis is transferred directly and effiently to the underlying wood slab, which then dissipates that energy as heat between and among the matrix of it's fibers. External vibration from the room can be minimized by isolating your shelf and or the wood slab with some kind of soft material that reduces effective transfer of vibrations to the wood and the chassis of your gear.

Ultimately, this is all just a bunch of words. You can continue to try to make some points, or you can just try points to see if they make a difference. Up to you.

Jafreeman, nice system! I would not recommend putting metal cones or spikes directly on a stone surface like the one depicted under your amp. In that case, the stock rubber feet would likely perform much better. My experience is that spikes or cones work much better in the conditions similar to those shown in these images, where they are used to couple gear to a large slab of wood, which is then in turn isolated from the room. http://www.mapleshadestore.com/galleries.php. YMMV.

kn

Wierd. That was not the link I intended. Trying again. http://www.mapleshadestore.com/galleries.php

kn

Cool, will be interested to see what you have come up with. I am big on home brew isolation solutions, and my opinions have been hard won! Lots of early attempts that were different sounding from stock, but not always better, as mentioned by someone earlier in the thread.

Ommmmmm. Of course you would ask me that! My wood blocks I was using on my old shelf (and when I say old, I mean like 175 years old!!) don't fit on my new shelf, so my turntable is sitting on the ground, which is OK, because the ground is a concrete slab over 300 tons (literally, don't ask) of crushed rock. My old Thorens TD150mkII sounds best in this configuration sitting directly on the floor on its little rubber feet. The bass is from middle earth somewhere. In my rather flexible old wardrobe, my CD player, table and amp all sounded better supported with cones on a large wooden slabs that were isolated from the actual shelf (purely home brew) as described above and in the images from Mapleshade. If you have a concrete basement floor resting on a large mass of rock, I might recommend trying your turntable or disk drive on their stock feet sitting right on the floor. I haven't tried my amp in this configuration. If/when I reconstitute old setup, will post photos.

I realize my suggestion to put gear directly on a concrete floor is something of a side light given the original post, and could be perceived as contrary to my earlier advice, so let me praddle on a bit further.

The conditions that made me resort to the more heroic isolation and "draining" were I think more typical of what others face, a shelf system on a wooden floor supported by joists. Everything flexed, and flexed further with loud music playing. My experience was that the biggest difference was made with the large, heavy wooden board directly under the piece of equipment, I assume because it adds resting mass and absorbs both external and internally generated vibrations. The second biggest difference was derived from using small metal cones to connect the equipment to the board. I have not used large brass cones, which some swear by. Without the large wood, the cones can sound bright. With the wood underneath, the cones added clarity without brightness. Isolating the large wood from the underlying shelf with something pliable like sorbithane dots added value, but proportionally less than the wood and the cones.

So why does the concrete floor work so well with my turntable (well enough to put up with bending down to change records)? I do not think that much internally generated vibration is goining into the floor. I think the value added is that the floor imparts diminishingly low amounts of vibration back to the table at any volume level or external input short of an earthquake. Imagine a 300 ton turntable platform. This kind of stability works effectively in concert with the sprung platter and arm of the Thorens. I haven't tried this with my amp yet, but am convincing myself as I write this that I should.

kn

Basement. We had problems with unstable fill on the building site so our basement slab now sits on top of $26,000 worth of crushed rocks. My turntable sounds great. Highly recommended. LOL

kn

I think part of the reason some people say a 4" wood block sounds better than a 2" thick wood block is because the greater mass as a part of the equipment-spike-block system resists being affected by external vibration to a greater degree than the smaller mass block. Independent of any potential benefit imparted by greater mass/material as sink for internal vibration.

I have a rather unremarkable rack that I am working to improve rather than replace because of unique aesthetic match to the room. Ultimately I will migrate the turntable to the rack with a set up similar to what I have recommended above.

Good luck with your resonance and vibration control efforts.