isolation issues...?

Hi All,

So I was listening to some vinyl the other evening and thought I would do a little tap test on my shelves to see whether it would be picked up by my turntable - sure enough and to my surprise, it did, as I noticed if I tap on the shelves on the rack (not so much the very bottom shelf), my speaker cones would react and fluctuate while the music is playing.

One obviously wouldn't tap the shelves and so it wouldn't normally be an issue, but I am questioning if I have things setup correctly with regards to isolation. Is this normal?

Here is a picture of my Rack setup as follows:


As always, any thoughts/guidance would be appreciated here, as I went and got a much better VPI rack which seems solid and sand filled going into concrete flooring and I just wouldn't have thought this would be an issue at this point. Could it be the Symposium Segue ISO spring loaded shelf? I did have some Symposium roller block juniors between the rack and the first MDF shelf and replaced with IsoAcoustics puck, which didn't seem to make any difference.

Cheers,
Vin.

 

Has anybody ever tried actually suspending a turntable with four hanging cables from the ceiling, fortified with springs? I know it doesn't seem easy, but curious if some anal-retentive audiophile has ever gone to such lengths.

(Or, perhaps the squirrels running around in the attic upstairs would cause too much noise...)

(and, you'd probably have to stop calling it a "turntable", at that point...)

 

I can’t say, but that’s a nice system.

 

You just get your cone pumping issues under better control and now you go looking for more problems?
Don't tap your shelves

 

That is surprising since it looks like you did everything by the book with quality components.

Have you tried re-tightening all the fasteners?
How are the shelves attacked?
Maybe loosen their fasteners a turn.
Or if floating some blue tac

 

Your TT does not have any suspension. Only turntables with soft (spring) suspension are isolated from the shelf. Examples are Sota and Oracle. If you want to keep turntable, then look at isolation platforms, like ones made by Minus-K.

 

Could you replace the turntable feet with some Isoacoustics Gaia?

 

They only true isolation I have found is with the Townshend Seismic Platforms [under equipment] and Podiums [under speakers]. You could use a Platform under your turntable. No experience of your Symposium shelf , is it solid or floating. I assume it should float if it has springs .

Most spikes etc just couple. For good information about isolation check out Townshend's web site.

 

I assume you upgraded the feet on your VPI? If so, try replacing the stock feet and see how they do. The stock feet on my old VPI worked very well.
Your current feet appear to be hard mounted.

 

I think this is a case where not everything is what it is cracked up to be. The OP has aftermarket isolation feet, an aftermarket isolation stand under the turntable and the top shelf of the rack has isolation pucks under it. Care to guess the cost
My stinkin stock VPI and stock Technics resting on a stock stinkin Ikea Besta rack are absolutely impervious to any bumps to the rack. Dead quiet.

 

You have made some serious efforts there and I understand your frustration. I wonder if the various footers are competing with each other, undoing benefits of any one on its own or actually serving to provide an easier path for vibrations back to your table rather than away. Rack is sand filled, so maybe try putting the first shelf directly on the pillars or, if you can put the VPI feet directly onto the Symposium, just to see if anything shifts. I hate to add new products here but I've had good success for footers with Herbie's stuff (search for Herbie's Audio Lab)- he has a range of cups that go under spiked feet that work well with my speakers and the spikes on my rack, maybe a set of those under the table's feet or under the rack might be worth a try -- at least he's good enough to answer if you ask him his advice. Keep us posted.

 

Looks like the turntable is coupled to the Symposium Segue shelf with spikes and coupler. Not surprised the turntable reacts when you tap the Segue shelf. Not that that’s a bad thing...

The Segue shelf and what’s below it is providing the isolation.

 

simple experiment- stock feet and eliminate the symposium.

 

Maybe it's over isolated? Too much give going on, or something cancelling out another's benefits?

 

Lovely system.

Agree with need to try isolation feet for your table. Its your only practical solution, unless you wish to go the sprung suspension turntable route.

 

I don't think so. I think the iso system is not isolating well enough- too many mid frequencies are making it to the plinth.

 

The legs are under compression, like a spring. When you tap a shelf they resonate.

as others have said perhaps isolation vs coupling under the TT

 

Keep it as is, the Symposium shelf and couplers are helping to drain vibrations from the turntable.

 

drains can flow two ways (unfortunately .

 

Height and length are the enemy of vibration isolation.....perhaps as suggested go back to the stock setup?

 

I think none of the individual systems you’ve combined has a chance to do its job.

Some suggestions . . . the IsoAcoustic pucks are placed on the top of the rack posts. That’s the one location on which nothing should ever be placed, most especially not flexible pucks. As set up right now, a platform is resting on four IsoAcoustics pucks (which are flexible), on top of which is sitting a Symposium Segue (its footer/spikes presumably slightly embedded in the platform below), on top of which are four Symposium couplers on top of which the turntable feet are positioned in the empty bolt holes on the top side of the couplers. It may be bit of an inherently micro-unstable tower.

Get rid of the IsoAcoustics pucks and the platform that is on them. Sell them, store them, or use them and the platform somewhere else because they’re not useful in their current application. Place the excellent Segue Iso directly on the top shelf of your rack (not on the rack posts). Store the Symposium couplers - they’re not functionally useful in their current application. Place the turntable on the Segue Iso and you’re done. Re-level the turntable using it’s excellent feet.

There is no rule or law or guideline or even suggestion that any turntable will ever be completely isolated from external influences. However, adding layer upon layer of footers and platforms and couplers and footers does nothing to help, but rather creates some instability because various systems that are supposed to work well all by themselves in a variety of setup applications have been combined and are working at cross-purposes (or at least not in any sort of complimentary way).

Tapping on rack shelves is causing low frequency thumps that pump your woofers? Why do you assign the problem to your turntable/cartridge? Intuitively, it may seem logical but the situation might call for a bit of technical analysis rather than intuitive analysis. In my experience it is more likely that a microphonic cable or microphonic component capacitor is the culprit. Either way, as long as neither you nor anyone in your household is kneeling in front of the rack and tapping a shelf while you’re trying to listen to music, nothing currently layered on the top of the rack under your turntable is helping. Once you set up more simply as recommended, I’d bet real money that some existing minor lack of clarity will be eliminated.

 

That’s fairly advanced level isolation you have going on. It’s going to take an isolation shelf on a load bearing wall to do better.

the tap test really doesn’t tell you if your speakers are sending vibrations to your stylus. That’s the isolation you are looking to accomplish. Unless you have your speakers pointing at your rack, I’m sure you are good to go.

 

Thanks for the excellent feedback everyone and especially Agitater. The shelves are sitting on top of the rack frame which I have used small tiny rubber moulded round bumpers so that there is something to help grip and provide some friction between.

@Agitater
I like your recommendations but what doesn't make sense, is I cant simply place the Symposium Segue ISO platform on top of the rack, as the spring loaded feet under the Symposium platform need to couple onto some flat platform and hence the piece of 1/2" MDF board I have between the rack and the Segue ISO platform. As I mentioned, I did actually have Symposium Rollerblock Jnrs between the rack posts and the MDF shelf, but that caused the same issue as well as the IsoAcoustic puck.

@avanti1960
I have also tried using different footers (The latest VPI footer pucks with the foam ring base as well as Avenger feet made of delrin and steel/metal with rubber ring base) and unfortunately no difference to the tapping. I also have the Symposium upgrade inserts into the VPI feet as a further upgrade. So as you can appreciate, I have tried a lot of different things here but there is something fundamental that needs changing to get things more solid in not allowing these vibrations to make it back into the turntable.

Cheers,
Vin.

 

Without a top shelf on your rack, it becomes an audio component stand that can’t correctly support a turntable - I get that. I suggest cutting out each corner of the piece of MDF to create a gap around each post, then use a few dots of Blutack to position and secure it on the rack rails. Place the Segue on that new top shelf and the turntable directly on the Segue. Again though, it’s doubtful that the tonearm/cartridge assembly can pick up tapping on the rack - it’s not mechanically possible.

If there are shelf mounting flanges on the inner edges of the top rack rails, that makes it even easier to secure the modified MDF.

 

A wall-mounted shelf has worked just fine for me, at a fraction of the price of those sophisticated (and useless) isolation platforms.