Acoustically incorrect cooling?


Hey folks,

I come here seeking knowledge again. 

After listening to the wisdom of my fellow Agon'ers, I have been paying closer attention to the basics of system setup.

I have learned to experiment.  More importantly to listen to the differences.
So, after chasing my tail with absorption, minimal diffusion (varying size books on shelves behind listening position, etc.) I turned to DSP.

Ok. So now things are at a point where I am learning to recognize how each successive modification changes what I am hearing.

Now I am still just beginning to understand, appreciate and focus on what matters.
Instead of chasing the next, latest and greatest components, pay due attention to the listening room and it's potential contributions (and detriments).

Maghister, MC, OldHvyMec, Atmasphere, among others have been preaching things that I am just glad to have learned from.

So back to the point.  There was one last bit of glare (brightness, ringing?) that persisted in every room (two in the old place and three in the new place) I tried.

Cutting to the chase, I noticed that whenever anything brushes against, taps, etc. the heatsink fins on my monoblocks, the fins ring like a bell. 

I have each monoblock placed close to it's respective speaker (to minimize speaker cable length).
OldHvyMec pointed out that the steam radiators will ring like a tuning fork if I tap it with a piece of wood and to try throwing a blanket over it.

Worked like a charm!

Then I threw a moving blanket over each monoblock (just for a minute).

Problem solved!  I do not hear any ringing.

Now I know this is not a proper solution.  But quite a revelation (at least to a relative newbie like me).
I am curious if anyone else has noticed similar issues with ringing fins and how best to address it.

Thanks everyone!







hleeid
Some air cooled engines had rubber dampers between the fins so it’s not a new idea.
 Rubber chord is available from O ring stockists in a variety of diameters up to around an inch cross section and in different rubbers if you want to cut your own discs to size (not as easy as it sounds) but have a mind to how hot it will get, you don’t want it melting. Cork might work too and is easier to cut.
Silicone will withstand the heat. There is silicone tube in different sizes.

After you find the size between the fins, cut to length and place the tubes between the fins. IF the tubes WON’T hold their roundness (well enough)
Get a tube of silicone and put a bit inside the tubes and let it set for at least a day. Re install your rope (now its rope in places anyway) and your done.

I use to modify certain boxer engines in the late 70s early 80s for aviation use. Very reliable and super easy to turbo for high altitude and add a blower for rapid low altitude boost. Same principal as the mighty Merlin.

I used modified fin stabilizers because of crack that were developing at the base of the fins. Those cracks, NEVER formed on normally asperated or even with a turbo, but with a blower (belt driven) at low altitude, there is a LOT of pressure when detonation occurs. Those fins RATTLED and started to fracture.

At the time silicone was pretty new to the automotive world, old news in the aviation world and still VERY expensive. It worked and stopped ALL the issues that design was having. I worked with a guy named Smokey Yunick. Smart guy...

Well that was a long one.. Brought back a memory or two..

Silicone, man oh man the stuff it’s used for. Carol Doda, business woman of the year. least invested for the largest return.. ;-)
If your heat sink fins are so hot you need silicone you have bigger problems than ringing. My bet is they barely get warm to the touch. Take your material of choice- acrylic, MDF, cocobolo, whatever- slap some carpet tape on it and stick it to the fins. Done. 

Not only will this not take up any radiating space, but it will create a chimney effect drawing even more air through by convection.
You lost me MC how does it draw more air through? By enclosing an area? I hadn't though of that, I suppose it would work.  I've seen some weird ways of cooling things for sure.. Velocity vs area.. Could get a twofer if the insert were say cast aluminum. Dead quiet and good at transferring heat too. AND a little dab of silicone will hold them in place.. 
10-15.00 for scrap pieces.. of Forged stock.. maybe.. 

I'm weird about flammable stuff and the wife.. She can't smell AT ALL.. Can't see very well either.. No glasses no see.. Can't hear smoke.. Sure has good hearing.. :-)
Nice one MC!
I get it.
Like squeezing the end of a hose to achieve higher velocities.
Basic thermodynamics?

Loving the cast aluminum insert idea Oldhvymec!
Got my noggin spinning with ideas!
 
You lost me MC how does it draw more air through? By enclosing an area? I hadn't though of that, I suppose it would work.


I'm assuming the fins are vertical. So covering the ends turns the U-shaped space between the fins into a vertical column. When open the air towards the inside where the most heat is generated is sort of trapped by friction while the air further out is more free to circulate. But it has less energy to circulate because the heat out there is less. Closing off the ends draws air through the whole column and the whole column of air is rising not just at the ends. Also to the extent the cover material is thermally conductive then this will be a form of additional heat sink. If done right this is a win-win.  

Porsche by the way did something like this with the fins on their air-cooled flat six. German engineering, therefore it has to work. ;)

"Porsche by the way did something like this with the fins on their air-cooled flat six."

That crucial part was called...fan.