Help! Tweaking My Lovan Rack for new Big A**ed Transrotor Turntable!

BTW, interesting test results:

In putting away some audio boxes I re-discovered my old Auralex Subwoofer platform that I never really used. It’s a thicker-foamed version of the turntable platform. I tried a little experimenting with the Auralex and my Townsend pods, using my iphone seismic measuring app placed on various surfaces.

First, I have tried the app on top of my Lovan, where the Transrotor table is now sitting. Right now I have a 3/4" sheet of MDF sitting on top of the lovan rack, then the thinner Lovan MDF shelf, then the Turntable.

What’s interesting, maybe a bit alarming, is that when I place my iphone with the siesmic vibration measuring app on the top of the MDF shelf, and rap the other side of the shelf (that is rapping the top of the shelf to the far left of the iphone), there is impressively little transmittion occuring. The raps show a small spike, but almost no ringing.

But when I place the iphone on the turntable platter and rap the same part of the shelf, there is actually a little bit larger bump registering, with a tiny bit MORE ringing. And I would have thought all the heroic efforts at dampening with this turntable would have yielded the opposite - less vibration transmission.

Then I tried the app on various surfaces. Putting it on my kitchen granite countertops and rapping about a foot from the iphone yields very little result on the app - so little vibration transmission. Pretty solid I guess.

Then I went downstairs to our pool table, placed the iphone on the table and measured the effect of rapping the table with my knuckle about a foot away. Definitely registered some bumps. Then I put the Auralex platform on the pool table, the iphone on top, and rapped the pool table top again. Still quite a bit of vibration registering. Hmm. (I found the same when I tried the Auralex on my wooden dining table).

Ok, pulled out the Micro Seiki turntable, put it on the pool table, iphone on the turntable platter. Rapped the pool table at the same spot....whoa! BIG seismic vibrations registering! It’s like the turntable platter amplifies vibration and ringing. Graphically on the app, it looked quite bad. Then put the turntable on the Auralex, rapped the pool table. STILL big vibration registered through the turntable platter, almost the same as without the Auralex. This was surprising to me as my intuition presumed such a big thick platform full of foam would have done better than that.

Next, tried putting the turntable held up by the Townsend Isolation Pods.
Rapped the pool table and...this time MUCH better! The height of the spike was much smaller and most of the awful ringing was gone.

I tried some other combinations - pulled out a squat, thick wood speaker stand I’d built a while back. Placed that on the pool table, then an MDF shelf from the lovan, and I measured raps on the pool table in that configuration, and putting in the Auralex, and switching the Auralex for the Pods. Placing the iphone on top of the speaker stand, under the turntable showed fairly significant vibrations on all axises traveling up through the stand from rapping the pool table.

As before, it got even worse placing the iphone on the Micro Seiki turntable, and was barely mitigated by the Auralex. And as before, putting the Townsend pods under between the speaker stand top and the MDF shelf holding the turntable - far less vibration transmission and ringing! In fact, though there was still some vertical vibration transmitted a bit, all the other axis L/R axis vibrating virtually disappears completely.

When I put my hand on top of the MDF shelf that the turntable was sitting on, and rapped the pool table, I could really feel the vibrations in my hand resting on the stand.  But moving my hand on to the turntable base, which was held up by the Townsend pods, and then I could barely feel any vibration transmission at all.  It was quite a difference and pretty impressive.

One thing though: actually rapping the turntable itself lightly yielded slightly different results. On only the turntable sitting on the stand, rapping the table near the tone arm yielded minor vibration spikes - interesting far less vibration registered than rapping the surface the turntable sits on. Putting it on the Auralex yielded similar results, but if anything maybe a slight reduction in vibration. But when on the Pods, rapping the turntable actually yielded, if anything, slightly more vibration or ringing than the turntable by itself. Though of the several times I tried this, it didn’t seem like a big difference. To the extent that was accurate, I wonder if that means the Townsend Pods are better at isolating from exterior vibration, vs interior coming from the table.

Anyway, those are my results thus far.

Seeing the results, I’m less inclined to buy the Auralex turntable platform than I was before. (Though, in fairness, if isolation should be matched closely with equipment weight, the Micro Seiki turntable may have been too light for the Auralex to do it’s thing. Then again, it’s also significantly lighter than the Townsend pods are rated for - I got the pods rated to hold up about 80 lbs - the Transrotor and it’s coming thick wood-block base. The micro seiki is far lighter than the pods are rated for, so I don’t think they were at their best either).

Thanks for posting that; extremely detailed and informative, and interesting! I'm going to parse through it again. I think this can help others, if nothing else to get us thinking about things. The isolation/coupling interfaces for high-end turntables are so crucial!

mulveling,

Glad you found it useful.

Though after a conversation with another audiophile pal - who has long been into turntables - I’m unsure how useful the info is. He suggests that when I’m doing the tapping test around the turntable with the iPhone app, I would be creating resonances well below those that are actually important sonically. That is: they may tell me about how well the turntable can be isolated from lower frequency foot traffic or whatever getting into the table, but aside from being bad enough to skip a record, that’s generally not the vibration interference frequency range I need to be concerned with (especially if no one generally walks around the turntable when I’m listening).

Rather, we have to be more concerned with resonances more likely to infect the signal, e.g. those coming from the turntable operation itself, which manufacturers seek to diminish with various approaches (e.g. mass loading in the case of the Transrotor table).

So I’m not sure how I can use the iphone app to actually measure those types of vibrations.

BTW, I received a package I’d ordered of sorbathane pads (1/2" thick). Doing the same tests, the sorbothane didn’t seem to really decrease the vibrations showing up through the turntable, on the iphone app. But, again, not sure how to interpret that. Sorbothane surely does absorb vibrations as it is successfully used to do so in various industries. So maybe my iphone app just isn’t measuring the right frequencies where I’d see the difference.

I’m also caught somewhat between two worlds, when asking for advice on this. On one hand I’m a long time audiophile, very familiar with the audiophile world of Stereophile/Absolute sound etc. On the other, I’m a skeptic about lots of what goes on as "knowledge" in the audiophile world, because audiophiles generally don’t have a very reliable method of testing claims, so it’s something of a wild-west mix up of technical conjecture and subjective bias effects, mixed into whatever may really be happening. Researching isolation control in the audiophile community, with all the differing opinions that include IMO dubious claims doesn’t give me a lot of confidence I’ve bumped into someone who has really figured this out, in a reliable fashion.

Still, I do like to take in various viewpoints and advice to see which ones make sense to me.

@prof I think you have been badly advised regarding the deleterious effects of sub sonic interference on turntables. Seismic noise is everywhere (traffic, construction, micro quakes) and eliminating it is highly beneficial. Hence manufacturers such as Doehmann build minus k platforms into the Helix turntable and users such as me use active platforms like the Herzan. You might also like that these types of solutions are well scientifically documented and proven to work - although at a costs 

While, as I’ve previously commented, I think your solution will amplify rather than reduce sub sonic interference it would be completely wrong to assume that seismic noise is not causing problems for any turntable

folkfreak,

Appreciate the input.
 
What aspect specifically of the design do you think would amplify sub sonic interference?