2. analog
  3. 127486-67533

Tapping on my table

Searched some threads and did not find an answer specific to my question, so I will try here.  My system is in my basement, which is a concrete slab with wall to wall carpet ( and carpet pad).  My TT is a Music Hall MMF 9.1 which has 3 plinths separated by sorbothane spacers.  The TT sits via its conical feet directly on a Salamander cabinet holding my amp and cd player plus some albums.  Total weight of the cabinet, equipment and albums is at least 150 lbs.  The TT weighs 40 lbs.

I have never experienced any issues with vibration, i.e when walking around while playing an lp.  I had assumed the concrete floor and thick carpet, along with the heft of the cabinet and contents, provided excellent isolation.  However,  this morning I inadvertently tapped the top of the cabinet while listening to an album and there was a very subtle but distinct thump emanating from the speaker.  Clearly the TT is not isolated from the cabinet even if the cabinet is isolating the TT from the floor.

Is there a good inexpensive solution to solve this isolation issue?  I do not want to lose the leveling benefit of the TT's feet - I have some Herbies cones under my cd player, but these would eliminate the leveling capability.
sjtm
ct0517's avatar
ct0517
2,041 posts
 

sjtm
I have never experienced any issues with vibration, i.e when walking around while playing an lp. I had assumed the concrete floor and thick carpet, along with the heft of the cabinet and contents, provided excellent isolation.

from my past experiences, the key imo is you want to turn your cartridge/system into a type of stethoscope for your room. Also poured concrete slabs are far from perfect containing air pockets. Your rig could be on one of them. How to find out ?

sjtm
Is there a good inexpensive solution to solve this isolation issue?

There is an inexpensive way and it can be kind of fun too.

With system on mute and set to the lowest volume.
Place record on the platter - not spinning - and lower your stylus onto it.
Unmute and slowly start raising volume to what represents a loud level for you.
Your cartridge/system has now become a stethoscope to your room.

So ....standing near the stand, start jumping up and down .......like you have won the lottery. (waving arms optional)
Dance in front of, beside, and behind it if possible. Is anything heard through the speakers when you do this ?

If yes your turntable stand is not on good ground. Move to another spot.

Good luck.

terry9
2,348 posts
 
There are two issues here, IMO. First is the stability of the cabinet, which is a function of construction, TT mass, and the ratio of the height to the smaller of depth and width. The second is sinking transients to ground.

The solution which I found, because my 150 lb TT dictated it, was to lengthen the width of my cabinet to 40 feet, by the simple expedient of bolting it to the frame of the house. This also served to sink transients to the frame and thence to the concrete foundation. Problem solved. Of course, the wife doesn't yet know there are holes in the Louis XIV desk ...
stringreen's avatar
stringreen
6,475 posts
 
A good trick to try is to use a turnbuckle attached to the wall and cabinet...tightening the buckles.......amazingly effective.
dustin_collman's avatar
dustin_collman
56 posts
 
ct0517,

When using the stethescope method, does one need to worry about damage to the cartridge or any other components?

I will be doing this in the near future and sound dampening everything.

Thanks,
Dustin
ct0517's avatar
ct0517
2,041 posts
 
Hi Dustin
let’s think about this.
Does it make sense to try this technique on an unsuspended turntable setup, that is directly coupled to suspended springy wood beam floors ? imo, no. why bother? Btw - how many Audio Boutiques have you been to where they are using a beautiful historic Brick and Mortar house, and have a turntable set up on the 2nd floor - wood floors ?
So a stable setup to begin with is needed.

There is always a higher risk with vinyl just by the physics nature of it. The horizontal platter/lp acting like a possible angle grinder on the vertical cantilever, especially on well endowed cartridges, comes to mind.

To help with any worries keep the turntable unplugged, and ensure your phono stage and amp are good quality and electronically stable.

btw

I have learned some good can also come from this exercise, if your wife catches you doing "this dance" in silence. She might think you have maybe just "lost it", ....gone over the top. So you may gain back some leverage.

If you choose to do the dance without the option of waving your hands around; she may also think you are auditioning for Riverdance.

https://www.youtube.com/watch?v=HgGAzBDE454

:^)

Cheers Chris
More to discover