[Syrah]

Hi All,

I ran across this patent in looking to make a new shelf for my turntable –

http://www.patentstorm.us/applications/20070278170/description.html

It then led me to this site, selling this furniture –

http://www.gearmounts.com/xcart/Core_Titanium_Audio_Racks.html

Which also includes these things –

http://www.gearmounts.com/xcart/Lode_Stones_Titanium.html

I assume no one has tried this stuff.  Any thoughts on the science?

It looks like they’ve done their homework and their racks are stupid cheap by audiophile standards, bordering on Wal Mart cheap.

[decal]

From the picture, it doesn't look very sturdy. Just my opinion. Who knows though, it could be the next best thing since sliced bread.   

[srb]

Gearmounts has no details on these and the manufacturer has a little .... but not enough.
 
The manufacturer is Cambré.  http://www.cambreproducts.com/index.html
 
They have two lines:
 
Core^TM, which has solid aluminum posts
http://www.cambreproducts.com/core_audio.html
 
Titanium^TM, which has solid titanium posts
http://www.cambreproducts.com/titanium_audio.html
 
So Gearmounts calling them "Core Titanium" is a misnomer.  Both pages state "Amp stands come with spike feet and 3" solid Aluminum (or Titanium) tubes".  These aren't amp stands, and certainly the supports are not 3"D, so they obviously must be referring to 3"H, although no amp stands are pictured.  They refer to the supports earlier as solid rods, so not sure why they later refer to them as "solid tubes", as tubes are not solid.
 
There is a picture of the shelves with underside grooves (the resonance control) which "eliminate large standing waves between the shelves".  Don't know what they are made of, but my guess is MDF with super-thin Melamine coating, but who knows?  Don't know if they are 3/4" or 1" thick.
 
I would be more comfortable buying these in person, but they may be well worth the price.  It's just a bit confusing and they could certainly divulge more details. 
 
Steve

[mhconley]

There just is no f'ing way the 3" "Titanium^TM" tubing is real titanium.  One tube would cost more than the price they are asking for the rack.  One 3"OD x 0.049" wall x 36'' real titanium tube is $180 US.  That gearmounts site has the whole rack priced at $220 CAN.  Something seems fishy there...

Martin

[Martyn]

There’s not much science in this, in my opinion.

There are two ways of dealing with vibration: avoid it by isolation or damp it out.

External sources of vibration can cause resonances within structures. Again, we can deal with vibration caused by resonances by isolating the structure from the exciting sources or damping the structure. We can also increase the mass of the structure to lower the resonant frequency to a level where it is inaudible, or stiffen the structure to raise the resonant frequency (usually to a range where it is easier to damp). A more interesting way of dealing with a single resonant frequency is to add a second mass/spring system. If this is accurately tuned to the original resonance, it will dramatically reduce the resonant peak amplitude, but the price you pay is two new resonances, one each side of the original, but with much lower amplitude.

I have given the patent only a very cursory scan, but it appears to have very little real content. I particularly like paragraph 0056 which begins: "Without being bound by theory...". Heaven forbid that we should be bound by theory.

Let's take a look at the grooves idea. If we take a shelf of a particular size and thickness, it will have a particular stiffness and natural frequency(ies) of vibration - put a weight in the middle and it will deflect by a known amount. If we increase the thickness, the deflection will be less for the same weight, i.e. we will have increased the stiffness and thus the natural frequency. However, as I recall, the stiffness of a beam increases as the cube of its thickness. So if we increase the thickness of the shelf from, say, 1” to 2”, we will increase the stiffness by a factor of eight. Unfortunately, we have also doubled the weight of the shelf. Although doubling the thickness increases the natural frequency a lot, doubling the weight undoes some of that gain. Overall, we might expect a net result of a doubling of the natural frequency of vibration.

Instead of doubling the thickness of a solid shelf, we could start with a thin one, perhaps only ¼” thick, and add ribs 1 ¾” deep to the underside. This would be nearly as stiff as a solid 2” shelf, but would be much lighter. Even better, we could have two skins each ¼” thick separated by ribs 1 ½” deep – it’s still 2” overall, but is very stiff and light (it’s commonly called a box beam).

Let’s stay with the single skin for a moment…we could make this structure by fixing ribs to the underside of a thin shelf, or we could make it by starting with a thick slab and machining away the spaces between the ribs. I guess we could call those spaces “grooves”. In other words, there’s nothing special, or even clever, about machining grooves in the underside of a shelf. It will make the shelf a bit lighter, a little less stiff, and will move the resonant frequency somewhat, but so what? It's done every day in the manufacture of lightweight structures.

In the patent application, the shelf is 16 mm thick and the grooves are 5 mm deep and cover “preferably” 50% of the underside of the shelf. This sounds to me like an 11 mm thick shelf with lots of 5 mm ribs fastened underneath. Wow. It will be a travesty if the patent is granted based on claims like this, but then the US Patent Office has a bit of a reputation these days.

The next part of the patent application discusses the use of carbon fibre tubes for the supporting structure, rather than the more usual solid or tubular steel or aluminum. The author concludes that carbon fibre provides better damping and that varying the spacing of the shelves “….can significantly reduce vibrations at approximately 120 Hz.” Obviously, the original test system must have resonated at around 120 Hz, but now resonates at multiple frequencies but with reduced amplitude. This is exactly the reason that we vary the size of the panels in loudspeaker boxes. Hardly new technology.

At a more pragmatic level, note that the vibration testing was done using a loudspeaker mounted face down on one of the shelves. I suspect that if they had set the loudspeaker on the floor beside the rack, which would be a more typical arrangement, they wouldn’t have been able to measure significant levels of vibration anyway. Still, for those of you who worry about trace levels of vibration somehow affecting your modern electronics (other than turntables as per the OP), I suggest that you first de-couple your speakers from the floor by using the usual tip-toe type of points. Then de-couple your rack in the same way. For good measure, you might fill your rack’s support tubes (if they are tubes) with dry sandbox sand, and do the same for your speaker stands (if applicable). The sand will damp any vibration that follows that path. I’ve just saved you from spending $499 on “Lode Stones”…and the sand will work better.

Try this next one at your own risk: place a shallow dish of water on one shelf, crank up the sound, and watch for patterns on the surface of the water. Still water is very good at picking up vibrations. Now try the same thing with the dish on top of your speaker. If the patterns are stronger, so are the vibrations – you should put your effort into fixing your speakers before worrying about your rack!

Disclaimer: I’ve never tried the water trick, but I will because it sounds interesting and rather fun!

[doug s.]

There just is no f'ing way the 3" "Titanium^TM" tubing is real titanium.  One tube would cost more than the price they are asking for the rack.  One 3"OD x 0.049" wall x 36'' real titanium tube is $180 US.  That gearmounts site has the whole rack priced at $220 CAN.  Something seems fishy there...

Martin

my curiosity was piqued, having experience w/titanium in a prior life.  i agree it seems unlikely that these cambre shelves could be made from pure titanium.  so, i emailed the company; here's the reply i got back:

Hi Doug,

We use solid Titanium rods.

Thanks,

J*** W****

Cambre Products

not sure how that's possible.  and, the rods (both alum and "titanium")  sure don't look to be 3" in diameter.  hmmm...   

doug s.

[mhconley]

my curiosity was piqued, having experience w/titanium in a prior life.  i agree it seems unlikely that these cambre shelves could be made from pure titanium.  so, i emailed the company; here's the reply i got back:

Hi Doug,

We use solid Titanium rods.

Thanks,

J*** W****

Cambre Products

not sure how that's possible.  and, the rods (both alum and "titanium")  sure don't look to be 3" in diameter.  hmmm...   

doug s.

OK - I sent GearMounts a question about pricing...  We'll see what they say.  I may buy a rack just to resell the Titanium. 

Martin

[Syrah]

I hope they're not pulling a fast one by using "T"itanium with a capital.  The Cambre website uses "T"itanium (TM!) throughout.  Maybe you should write back and confirm if they mean "T"itanium (the brand) or titanium (the metal)?

It's pretty impressive that any shelf can be made for that price that has given any consideration whatesoever to audio performance though - might be worth a flyer.

[thunderbrick]

Look carefully.  They say "Titanium (TM) Audio Racks"  I think the "TM" refers to the phrase "Titanium Audio Racks", not the metal.  And any fool can put "TM" behind something yet not have the legal right to do so.  I'd guess just a bluff.  Or fluff.

[doug s.]

I hope they're not pulling a fast one by using "T"itanium with a capital.  The Cambre website uses "T"itanium (TM!) throughout.  Maybe you should write back and confirm if they mean "T"itanium (the brand) or titanium (the metal)?

It's pretty impressive that any shelf can be made for that price that has given any consideration whatesoever to audio performance though - might be worth a flyer.

i did notice that.  and i did consider querying them about it; perhaps i will.  but, the word titanium is also used w/o trademark.  we'll see what kinda response i get.   

doug s.

[doug s.]

ok, i sent a reply back:

hi john,

i have worked with titanium before.  i know its difficulty for machining, and its cost for buying it in raw material form.  when you say:

"We use solid Titanium rods."

do you mean you use solid "Titanium™" rods, or do you actually use solid titanium rods - you know - the element - "titanium"?  ;~)  and, is the diameter of the rods actually 3"?  it looks a little smaller than that...

thanks,

doug

we'll see what i get back from them...

doug s.

[Syrah]

Nice work.  Us lawyers appreciate a good cross examination.

[Speedskater]

They seem to be a company of very few words! Most of their competitors will write for pages and pages about how great their products.  This co. writes as if they are paying by the word like in olden times telegraph messages.

[doug s.]

Nice work.  Us lawyers appreciate a good cross examination.

um...  well...  i quit lie, uh, i mean law school in the middle of my second year.  that said, i am still up for a good cross-examination.   

in any ewent, the final answer i received its the rods are real titanium, not a trademark - solid rods - but 1" od, not 3".  amazing, none-the-less...

doug s.