LP 12 felt mat care

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Tony Tune-age
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Re: LP 12 felt mat care

Post by Tony Tune-age »

By the way, what else did you use the vibration monitor app for?
Tony Tune-age wrote: 2022-02-01 19:50
springwood64 wrote: 2022-02-01 08:26 You can download vibration monitor apps to your phone, and I was using one while experimenting with different tweaks on my Quadraspire rack. I was interested in seeing the impact of different tweaks on the degree and nature of vibration transmitted by shelving.

Tunedem tests resulted in me ditching all of the tweaks, despite the differences I saw in the vibration monitoring.

However, it was interesting to see the impact of the felt mat on vibrations recorded by the phone: they drop down to near zero.

Remove the felt mat and record directly on the turntable (while playing digital music at high volume), and the phone records significant vibration transmitted by the platter. On the mat it's negligable.

I guess it's not surprising, but it is also quite cool to see the difference on the phone!
That is quite cool to see the difference on your cell phone. The vibration monitor app could be a handy tool to have around for some people.

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springwood64
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Re: LP 12 felt mat care

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Tony Tune-age wrote: 2022-02-02 03:01 By the way, what else did you use the vibration monitor app for?
I was experimenting with intermediate supports placed on the rack. I had a spare Quadraspire shelf to which I attached spikes and placed under the turntable. The vibration app showed a peak at different frequencies compared to the shelf it sat on. It sounded worse by tunedem: more apparent detail, but not engaging.

I also experimented with birch plywood under my Hakai. I could not interpret the pattern of vibration difference (it just seemed randomly different), and musicly it also sounded worse.
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Tony Tune-age
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Re: LP 12 felt mat care

Post by Tony Tune-age »

springwood64 wrote: 2022-02-02 08:23
Tony Tune-age wrote: 2022-02-02 03:01 By the way, what else did you use the vibration monitor app for?
I was experimenting with intermediate supports placed on the rack. I had a spare Quadraspire shelf to which I attached spikes and placed under the turntable. The vibration app showed a peak at different frequencies compared to the shelf it sat on. It sounded worse by tunedem: more apparent detail, but not engaging.

I also experimented with birch plywood under my Hakai. I could not interpret the pattern of vibration difference (it just seemed randomly different), and musicly it also sounded worse.
Your efforts were worthwhile Springwood, you certainly learned from those experiments. With some technical specifications the numbers may look good, but the sound may not be good.
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Re: LP 12 felt mat care

Post by ThomasOK »

springwood64 wrote: 2022-02-02 08:23
Tony Tune-age wrote: 2022-02-02 03:01 By the way, what else did you use the vibration monitor app for?
I was experimenting with intermediate supports placed on the rack. I had a spare Quadraspire shelf to which I attached spikes and placed under the turntable. The vibration app showed a peak at different frequencies compared to the shelf it sat on. It sounded worse by tunedem: more apparent detail, but not engaging.

I also experimented with birch plywood under my Hakai. I could not interpret the pattern of vibration difference (it just seemed randomly different), and musicly it also sounded worse.
This echoes some testing I helped with several years ago on LP12 plinths. I tested a number of Woodsong Audio plinths (now unfortunately no longer available) and a few Linn ones on identical LP12s (as close as possible) and reported the musical differences elsewhere on this forum. There were significant musical differences between the different plinths. I tried to figure out if there was a way to quantify what was responsible so that it might be predicted which woods would make the best plinths. I made a spreadsheet with the plinths I had tested and found measurements for the woods used like hardness, density and the weights of the different plinths. Nothing correlated to the sound. I mentioned this to a customer who was trying to make his own speaker better than a Kan (I don't know if he ever succeeded, but he wasn't having an easy time of it). I lent him 5 of the plinths so that he could test their response to an impulse with an accelerometer. His findings? There was no correlation between which plinths sounded the best and how they measured in his tests. Similar to what was found by springwood64.

In the end the only reliable test for how good a plinth would sound compared to another plinth was the tap tone the plinths made when nothing was mounted to them. Over time I heard enough different plinth tap tones that I could give a pretty close ranking of how they would sound on the LP12 by the tap tone of the plinth. The plinths that were the most musical had a tap tone that sounded very harmonic, with a good spread of frequencies and a little ring but not too much. A long ring would lead to a midrange forwardness. Plinths that had a dead tap tone sounded dead, those that had a hashy tap tone sounded hashy and frequency imbalances in the tap tone, like lack of bass or soft highs. carried through to the turntable when assembled. I was glad I found some indicator that worked but I would have been glad to just be able to go by some measurement. But that seems to be the way it works.
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