Improving a stone rack


Hi all, I have a large stone rack for my system, in beautiful granite, which works great for stability, but maybe not so good for other aspects of the sound. I wonder if it contributes to some treble ringing and harshness. I want to improve the sound, thinking of felt damping on the wall behind the rack, some form of cloth to cover the reflective surfaces of the shelves, and adhesive rubber type mats on the bottom of the stone shelves. Is this the way to go? Experience based advice is very welcome. My rack weighs a ton. It is not easy to compare to a wood or composite rack. I need advice on how to counter the sound problems of stone or similar polished surface shelf racks. I want to try this, before I consider a new rack or shelf arrangement.

Ag insider logo xs@2xo_holter

Granite (sorry!)  I don't know how bad the rack is but it's probably not great. The turntable on top is probably the worst location, especially if you're on a suspended floor. Anyhow, try it all out first and worry about damping then. Otherwise you won't know if you've improved things. 

@ghdprentice 

I must correct myself- I think you’re correct that this stone comes from the Bushveldt Complex in South Africa- I just looked up the location in Google Maps!

My stone rack is made of Larvikite, found near Larvik in Norway, sometimes marketed as Emerald Pearl, or Blue Pearl. It is even claimed to be a Norwegian ‘national stone’ (though it is found also in Canada). I am sure that helps with the sound!

@noromance – yes, Nobsound springs may be interesting. I will first try my big Walker audio Valid points under the preamp, to see if they make a difference. Cerapucs might be even better, but aren’t high enough beneath the preamp to take over from the stock feet. You wrote:

«Are you assuming the shelves are ringing or reflecting the sound waves coming from the speakers, and adding a hardness? While that is valid, it’s not a major contributing factor. I’ve always thought of the challenge being more to do with the relationship between the supporting material and the component itself. It’s at that interface where the support-related sound quality is generated.»

Yes, I assume that the polished glass-like shelf surface plays a role. Somewhat like windows, changing the sound in the room. Although I don’t think ringing is a main problem. I would probably have to play music a lot louder than I do to achieve that. The rack is massive and inert.

I agree that the component / support relation is important. But how can I know if this is the main factor? Rather than reflective surfaces? These should be manifest in two different sound problems, no? In the direction of ‘glassy’ (reflection), and ‘smear due to vibrations’?

Small test result. Walker Validpoints under my preamp, compared to the stock feet, resting on the stone shelf. NB I am not able to do quick A/B comparisons. The preamp is too heavy and my back too poor.

First impression: this is larger. More distinct. But less treble, or softer treble? No. And softer more mushy bass? No not at first, at least. So the first test, plus one for Valid points, but with some unexpected results.

The Valid points are three large and heavy brass spikes that go into damping discs on the shelf. They rise the component and are undoubtedly good for ventilation at the bottom. Sonic results? Not sure yet. But I am sure these footers do something, they do have an affect. Walker have thought about this.

My Einstein The tube mk2 preamp is a one-box design with two massive power supplies in the front, and tubes at the back. A hybrid tube/s state design. The s-state power supplies get very hot, and I guess, these are the main cause of vibration (even with top German design). So I used two validpoints, one under each transformer, in the front, and one in the middle at the back. We'll see, if this works out. Like I said, my first impression was a bit mixed.

Second opinions are important too. Testing Oops, by Fujiya & Miyagi, from their LP Slight variations. A career height I think. With the stock feet it sounds good but bass heavy and somewhat restricted. With the Validpoints, it sounds larger, the timbre is mor convincing, the sound comes to life. Great, but there are some minuses also, some treble stands out too much, and not fully sure about the bass. The validpoints came with some extra tuning discs, placed on top of the components, to cure such ills. Have not tried yet.