My mission: feedback reduction.

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Agamble

New Member

• Aug 20, 2014

• #1

I love loud music. Who here doesn't, right? My current problem is that the threshold of bass feedback is reached FAR before the threshold of pain is even in earshot. Isolation by distance from the speakers isn't an option. My first thought was putting my TT in a padded ATA road case for a mixing console. I came here for advice, and in looking for it, I discovered Arcorob's BEAUTIFUL oak stained TT box in his stickied TT set-up video. Arcorob, if you are reading this: props, man.

I would love to pick the brains of any of you who have built boxes on the subject of what works and what doesn't. By "works", I mean reduces feedback. Foam floor? Foam everything? Rubber pad under bass? Let's hear it... No pun intended.

 

bobins08

Celebrating Life

• Aug 21, 2014

• #2

Putting your turntable on a solid wall shelf, mounted to wall studs, is a simple and cost effective method.

 

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Agamble

New Member

• Aug 21, 2014

• #3

Thank you bobins08. I'm not sure the little lady would go for a shelf.

 

marcmorin

RIP 1953-2020

• Aug 21, 2014

• #4

the two main ways the feedback is happening is through the air (acoustic) and through the house structure (mechanical).....it all becomes mechanical by the time the stylus "reads" it.

You need to find out which one, or both is the issue.

There is a recent thread where beatcomber showed how to create a basic suspension sytem with ashtrays and rubber bands to reduce or eliminate structure mechanical feedback from passing to the table. Cheap, effective, quick to make. That should then leave you with acoustic feedback, if any, to deal with.

 

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majick47

Addicted Member

• Aug 21, 2014

• #5

You can either go Rube Goldberg or as Arcorob did a DIY wall shelf and end the vibration once and for all. Check the photos of Arcorobs wall shelf, very WAF friendly and almost invisible.

 

rothwellaudio

Forums Sponsor

Sponsor

• Aug 21, 2014

• #6

Good turntables with a good suspended design are very feedback resistant to start with. More lightweight turntables with no suspension can be placed on a suspened surface to decouple them from structure borne vibration. The principle is simple enough - rigid shelf hanging from (or sitting on) something springy or spongy. The details of your particular domestic steup will determine what is practical.

 

woodj

Super Member

• Aug 21, 2014

• #7

Sound is "air vibration". Low frequency sound is quite a bit of "air vibrating". Low frequency loud sound is a lot of "air vibrating".
To re-iterate what marc said, you need to determine if the feedback is being transmitted through the room structure/stuff in the room (what your stuff is sitting on) or is impinging directly on the TT or both.

 

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Agamble

New Member

• Aug 21, 2014

• #8

Rothwellaudi: thanks... I'm just re-reading your post and scanning for points that are previously unmade in this thread. So far, I've got: my turntable is cheap. Let me know if I missed anything.

Everyone else: ACTUALLY thank you. I haven't started searching for arcorobs shelf yet, but I will. The rubber bands on ashtrays would be an awesome test to do to determine if my problem is sympathetic vibrations in the cabinet the TT sits on, or if it's airborne. If the rubber bands work, I'll build a fancy looking box with a rubber band suspension system inside.

 

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Agamble

New Member

• Aug 21, 2014

• #9

See the problem? The room is pretty small and my desire to absolutely BLAST music is not the #1 priority of the room. Repositioning the TT further from the speakers isn't an option. I'll let you guys know how it goes with the rubber bands. Thanks again!

Edit: maybe you CAN'T see the problem because the page keeps rotating my pictures. Upside down or sideways is all I can do.

 

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tomf63

Active Member

• Aug 21, 2014

• #10

Have/had the same issue. My table sits on a wooden closet system, handing from the studs in the wall within the closet. There's absolutely no acoustic feedback into the table from the structure, I can dance on that floor. However, when my sub starts pounding it's a totally different story. It's the acoustic air movement that's picked up and at loud volumes can become an overcoming feedback loop of earth moving base that will destroy the sub if I don't catch it.

The fix was easy, close the closet doors when I'm cranking up hard hitting base.

 

gadget73

junk junkie

Subscriber

• Aug 21, 2014

• #11

SOmething dead simple to try is removing the dust cover. They tend to pick up air vibration, especially if its open while playing.

 

woodj

Super Member

• Aug 21, 2014

• #12

Is there no one manufacturing The Cone of Silence" these days?

 

petehall347

the brandy coffee man

• Aug 21, 2014

• #13

try a cushion under the table .. if that doesn't help stand speakers on blocks .or spikes

 

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majick47

Addicted Member

• Aug 21, 2014

• #14

Suggest the OP reexamine his system and check to see if all the receiver/preamp settings are flat/neutral, possible the bass is being pushed and impacting the performance of the turntable. Also try repositioning the speakers away from the corners and walls.

 

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Agamble

New Member

• Sep 7, 2014

• #15

I'm all set for the suspension test. A set of plastic cups and a pack of rubber bands at target was less than $2. It's too late at night to test now. Will post results tomorrow.

 

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cgutz

AK Member

• Sep 7, 2014

• #16

Nice Sony Vfet. I've got the same one. Make sure it gets eniugh air circulation as they can run war and vfets are unobtanium if you smoke them.

Try some sorbothane pads under the feet of the turntable to isolate it.

Another way to isolate is to use a small size bike inner tube partially inflated and sandwiched between the stand and a thick piece of MDF board or plywood. Search AK for more information.

 

Last edited: Sep 7, 2014

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majick47

Addicted Member

• Sep 8, 2014

• #17

Agree the OP is going to smoke the Sony Vfet intergrated where it's located with no breathing room. Same with the turntable and speakers the OP has to read up on properly setting up an analog/stereo audio system, it can't be haphazard or the results will be poor as in this case and equipment can be damaged.

 

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Agamble

New Member

• Sep 11, 2014

• #18

Success! I don't have a dB meter, but I can turn it up well beyond where it started feeding back before. I hope this helps anyone in the future encountering the same problem.

 

marcmorin

RIP 1953-2020

• Sep 11, 2014

• #19

Agamble said:

I'm all set for the suspension test. A set of plastic cups and a pack of rubber bands at target was less than $2. It's too late at night to test now. Will post results tomorrow.

Click to expand...

acoustic susension works pretty well don't it :yes: Remember the names Mitch Cotter and Ed Villchur

 

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bossmustang7

Active Member

• Sep 20, 2014

• #20

i have gone through over a year,trying to isolate my rega tt from bass feedback,even at low volumes. i have floating wood floors,the worst scenario,period. just walking across the room,boom boom!so mover turntable here,there,in closet,even another room. still cannot even attempt to use my velodyne sub. was told by experts-its the cartridge,its the rega. i now have 3 decks,rega,d.d. denon,and technics sl Q2,modded. these 2 others are fine,can play loud ,but still , onset of bass feedback.i did read about the bike inner tube cure. so i bought a 12" tube. however the rega's motor is a rectangle,near the rear.i also removed the 3 cheap feet. i had to make up 2 rubber shims to level(old t.t mat) filled it to 4 lbs.Holy moly!YES!YES!YES!now it surpasses the other decks.nice tight bass,smooth highs. yes my friends,ITdoes work. and cheap!$4 bucks! will try under my amps, and 1 pair of speakers.(can't work for the dcm 700's)i even tried wall shelf mount. did not work on the rega.