low freq feedback

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FISH_MAN

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it seems I am getting some low freq feedback from my project TT threw my spires when this happens things get out of control I need help. my system is on the second floor and I did not build the house as if I did the floor would not be made of sponge lol. any tricks to getting rid of this? I can put my TT outside my room if necessary has anyone ever done this it seems like it would really help with speaker interference.
 
I've been lucky with my 1.2 in that regard. How close is your tt to the nearest speaker? Check that out, and it may help to place the tt on something heavy like a piece of granite from a shop that does counter-tops. Quite often they'll gladly cut you something from a rem / blem they'd otherwise throw out. And are you using the cover? That helps hugely to have it down during use.
HTH!:D
 
it seems I am getting some low freq feedback from my project TT threw my spires when this happens things get out of control I need help. my system is on the second floor and I did not build the house as if I did the floor would not be made of sponge lol. any tricks to getting rid of this? I can put my TT outside my room if necessary has anyone ever done this it seems like it would really help with speaker interference.

Does the FB occur at all volume levels or just at high levels?
 
pretty much at all with certain source material
 
pretty much at all with certain source material

Sounds like mechanical (looping through the speakers-floor-TT and back) feedback. Acoustical feedback tends to be volume dependent. Moving it to an adjacent room on the same floor might not help because the floor is, as you write, made of sponge and will probably flex just like the one in your room.

I would try a wall shelf if at all possible. Make sure to use a load bearing wall if at all possible and attach the shelf to the studs with carriage bolts. Walls tend to be much more rigid than floors. This may solve your problem
 
I would agree with Tube60. If you can't hang your TT on a wall bracket, then MASS is your savior.

I've got my TT on a big slab of 1" thick slate, which sits on top of 4 rubber "practice" lacrosse balls. My current listening room has a sprung wood floor, and with my current configuration, I can do jumping jacks in the middle of the room and the TT doesn't even register it. There are some pics of my setup on my "member system" profile. The guys on the Carver Forum are always teasing me about my "big pink balls", but I don't care how it looks to them--it works, and that's all that really matters. ;)

If you want to get REALLY aggressive, you can even add more mass to the stand your TT sits on. When I lived in Virginia (in the direct flight path of Dulles International airport!) I used to have a wood stand for my TT that had 5 solid cinder blocks on it's shelves (3 on the bottom, 2 in the middle) in addition to the above-mentioned slate. The whole thing weighed about 200lbs, and was as solid as a proverbial rock.

In the analog world, mass is your friend...

--Richard
 
Yeah, I'd agree with both Risabet and Dreamer. Mass load the stand your turntable is sitting on. My VPI sits on top of a Bright Star Audio base filled with about 85lbs of sand which sits on top of a Salamander rack spiked directly to the floor. Not only can I do jumping jacks in front of it, I can wrap my knuckles directly on the shelves of the rack and nothing translates up to the turntable.

Mass is definitely your friend when it comes to turntable isolation.
 

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I was writing this post while Mitt posted the device above

Here is an old school trick..

Build yourself a "sand box"

Build a 5 sided box about 2" wider, and 2" deeper than your TT plinth. Make the box at least 3-4" tall. Fill it 3/4 way with playbox sand (available at Home Depot) and fit a top that is just slightly smaller that the inner diminensions of the box considering the thickness of the sides. The idea is to have the top "float" on the sand.

Place the TT on top....enjoy
 
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