Let me share an idea I had some days ago that's spinning round my head.
As I was experimenting with a few material combinations in order to build a CLD based platform for my DIY TT I came up with the following: Why not have a segmented design?
It may look like this:
My idea behind that was, that the feet of the TT as well as the motor unit will stand on separate segments. So for example the vibration propagation from one foot to the other would be less than with a standard platform where all feet and the motor unit would stand on the same plate.
Let me hear your thoughts on this.
Cheers
Stephan
As I was experimenting with a few material combinations in order to build a CLD based platform for my DIY TT I came up with the following: Why not have a segmented design?
It may look like this:
My idea behind that was, that the feet of the TT as well as the motor unit will stand on separate segments. So for example the vibration propagation from one foot to the other would be less than with a standard platform where all feet and the motor unit would stand on the same plate.
Let me hear your thoughts on this.
Cheers
Stephan
I've got an accelerometer that I use with my DIY tonearm and turntable designs.
I use a small hammer to tap on the test pieces that I put together and measure the resonances.
So when I would tap one segment I could measure the resonances on the next or even next but one and see if they differ from taping one segment and taking the measurement at the same segment.
I use a small hammer to tap on the test pieces that I put together and measure the resonances.
So when I would tap one segment I could measure the resonances on the next or even next but one and see if they differ from taping one segment and taking the measurement at the same segment.
Hi Stephan,
may I ask what frequency bands typical vibrations are at, what have you measured?
CLD works by shear, as the panel flexes the shear layer dissipates the energy and dampens the vibration. I have no deep knowledge on this, but thickness of the panels and shear layer affect performance. I would assume making strips / sections of one of the CLD panels would reduce performance as shear length would reduce. Typically hardest to tame resonances are the lowest, which on a platform means that middle of the platform vibrates, and to tame this you'd want full size panels for maximum shear.
But, gotta remember point is not the platform but vibration of the turntable. So the goal is to conduct vibration from turntable legs to plate as well as possible, which then dampens with the shear. Also, you'd want least possible amount of vibration from floor to the plate as separate but related issue, I think.
The CLD cannot dampen if it doesn't resonate, so perhaps it's not most effective dampening? Perhaps legs of the turntable itself should be with ~360deg 3D damping capability, like individual pieces of some foam / rubbery stuff under each leg. With short study on vibration dampeners it's the deflection that dampens, so hardness and size of such damping products matter. If your turntable weighted 20kg with four legs, you'd need material that has maximum damping (deflection) with 5kg weight for max effect. I imagine these are quite small and flexible thingies but might be good for turntable you do not have to do beat maching with
If you want especially the CLD system you might be able to make the CLD with quite thin sheets and use three or four points, spikes perhaps, underneath so that the turntable vibration could fully flex the CLD for max damping. I have no data for this, just some thoughts that might be completely wrong
I'm currently designing DJ furniture for a friend and want to address vibrations from floor to decks, but I have no data on any of this stuff so I just designed some freedom to experiment with it after built. Initial thought was to add vibration isolation between structure and platform the turntable sits on, but it might affect too much on how the turntables feel to hand when mixing / beat matching / scratching unless weight is increased so that forces from hand to resist the motor do not shake it. This is something I have no practical experience on so just initial thoughts about things that likely matters for a DJ. So, I'm thinking using vibration isolation between structure and floor, and perhaps weight below the turn table with ~rigid connection to rest of the structure for my application for very solid hand feel on the turntables while isolating most vibration from floor, but need to study and think about it more, then test after built. Hense interest on your topic. Thanks starting it!
may I ask what frequency bands typical vibrations are at, what have you measured?
CLD works by shear, as the panel flexes the shear layer dissipates the energy and dampens the vibration. I have no deep knowledge on this, but thickness of the panels and shear layer affect performance. I would assume making strips / sections of one of the CLD panels would reduce performance as shear length would reduce. Typically hardest to tame resonances are the lowest, which on a platform means that middle of the platform vibrates, and to tame this you'd want full size panels for maximum shear.
But, gotta remember point is not the platform but vibration of the turntable. So the goal is to conduct vibration from turntable legs to plate as well as possible, which then dampens with the shear. Also, you'd want least possible amount of vibration from floor to the plate as separate but related issue, I think.
The CLD cannot dampen if it doesn't resonate, so perhaps it's not most effective dampening? Perhaps legs of the turntable itself should be with ~360deg 3D damping capability, like individual pieces of some foam / rubbery stuff under each leg. With short study on vibration dampeners it's the deflection that dampens, so hardness and size of such damping products matter. If your turntable weighted 20kg with four legs, you'd need material that has maximum damping (deflection) with 5kg weight for max effect. I imagine these are quite small and flexible thingies but might be good for turntable you do not have to do beat maching with
If you want especially the CLD system you might be able to make the CLD with quite thin sheets and use three or four points, spikes perhaps, underneath so that the turntable vibration could fully flex the CLD for max damping. I have no data for this, just some thoughts that might be completely wrong I'm currently designing DJ furniture for a friend and want to address vibrations from floor to decks, but I have no data on any of this stuff so I just designed some freedom to experiment with it after built. Initial thought was to add vibration isolation between structure and platform the turntable sits on, but it might affect too much on how the turntables feel to hand when mixing / beat matching / scratching unless weight is increased so that forces from hand to resist the motor do not shake it. This is something I have no practical experience on so just initial thoughts about things that likely matters for a DJ. So, I'm thinking using vibration isolation between structure and floor, and perhaps weight below the turn table with ~rigid connection to rest of the structure for my application for very solid hand feel on the turntables while isolating most vibration from floor, but need to study and think about it more, then test after built. Hense interest on your topic. Thanks starting it!
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Thx for sharing your thoughts @tmuikku! And also for the link.
My TT - weighing apron. 15Kg - actually stands on a wall mounted base. So I'd assume that floor vibration will hardly make it to the turntable.
The effects of using CLD in the armnboards variants of my DIY turntable that I experimented with were clearly audible - although some of the set ups sounded really bad and I abandoned the idea and went a different, better sounding path. That's why I thought to use CLD for base design might be an idea. There are quite a few examples on the marked that already do so. bFly audio BaseTwo for example. None of them seem to be designed the way I am thinking about - probably for a reason - or two.
See, my motor unit which stands aside the player is not 100% silent. If I would place this on another segment as the player itself, the entire setup may benefit. Maybe I'll try to build two variants: one with only one segment for all turntable feet and the motor unit and one with a separate Segment for the motor unit and then measure both and see what the outcome is.
My TT - weighing apron. 15Kg - actually stands on a wall mounted base. So I'd assume that floor vibration will hardly make it to the turntable.
The effects of using CLD in the armnboards variants of my DIY turntable that I experimented with were clearly audible - although some of the set ups sounded really bad and I abandoned the idea and went a different, better sounding path. That's why I thought to use CLD for base design might be an idea. There are quite a few examples on the marked that already do so. bFly audio BaseTwo for example. None of them seem to be designed the way I am thinking about - probably for a reason - or two.
See, my motor unit which stands aside the player is not 100% silent. If I would place this on another segment as the player itself, the entire setup may benefit. Maybe I'll try to build two variants: one with only one segment for all turntable feet and the motor unit and one with a separate Segment for the motor unit and then measure both and see what the outcome is.
Yeah, I've spent only few hours studying this stuff but plan to have motor and rest of the kit on separate platforms sounds good idea to decouple motor vibration from rest of the kit.
I don't know how much vibration the belt would deliver, what is your experience? I'm imagining if motor was completely decoupled from everything it would vibrate quite a lot, which might transfer through the belt drive. If the motor was attached rigidly and vibrations damped, then the belt wouldn't deliver any either. Not sure how yours is implemented and whether any vibration delivers through the belt drive. In this sense using CLD base for the motor at least seems nice, solid thing to attach to with at least some damping, assuming the vibration delivers into the CLD. I do not know which axis it vibrates, or all of it in 3D?
It's actually quite interesting how turntables work and are implemented in this regard. Have you posted more about your project somewhere?
I don't know how much vibration the belt would deliver, what is your experience? I'm imagining if motor was completely decoupled from everything it would vibrate quite a lot, which might transfer through the belt drive. If the motor was attached rigidly and vibrations damped, then the belt wouldn't deliver any either. Not sure how yours is implemented and whether any vibration delivers through the belt drive. In this sense using CLD base for the motor at least seems nice, solid thing to attach to with at least some damping, assuming the vibration delivers into the CLD. I do not know which axis it vibrates, or all of it in 3D?
It's actually quite interesting how turntables work and are implemented in this regard. Have you posted more about your project somewhere?
I use a Maxon DC motor. The quality of that motor is second to none for my liking. The housing is made of a thick alloy tube in which the motor is fixed in a kind of rubber damped housing that decouples it from the box. I've made several iterations on that. You can only hardly hear it if you're close than 30cm or so. The unit currently sits on three o-rings of a rubbery material. If the motor unit would stand on its own CLD segment I'd like to replace these rings with spikes allowing the vibrations emerge into the CLD.
Currently I use strings and not belts. I've tried a few materials and am using something not 100% rigid which sounds the best for my liking.
Not sure if the unit vibrates 3d. As my sensor is unidirectional I might be able to measure.
Actually I didn't post a lot of pictures and/ or information on my builds anywhere on the web. One of the reasons is that I am not keen on comments of people not having any clue of what they are commenting on.
But luckily this forum is 100% different. Users here are very, very helpful and caring.
Currently I use strings and not belts. I've tried a few materials and am using something not 100% rigid which sounds the best for my liking.
Not sure if the unit vibrates 3d. As my sensor is unidirectional I might be able to measure.
Actually I didn't post a lot of pictures and/ or information on my builds anywhere on the web. One of the reasons is that I am not keen on comments of people not having any clue of what they are commenting on.
But luckily this forum is 100% different. Users here are very, very helpful and caring.
Thanks for the info, there is actually quite many threads about this stuff here on diyaudio. Most stuff you posted I googled and diyaudio links were listed It would be interesting to read yours if you decide to post some day. This is one sector of audio I've never looked into so find it all new and interesting.
Anyway, writing here to help my own thinking / learning, hopefully there is some nuggets that help you think about the stuff as well. Have fun with the project!
ps. It would be cool if you can post data on some of the resonances you have measured, ( frequency, amplitude and axis ) I guess all turn tables have more or less of the same kind. I haven't looked into this yet, perhaps this kind of data is already available online.
It would be interesting to read yours if you decide to post some day. This is one sector of audio I've never looked into so find it all new and interesting.I can only imagine this stuff right now, but it seems reasonable that forces causing vibration are certain axis, like unbalanced axel or something, and that CLD would be more effective on one axis than another, depending how it's all implemented. Perhaps all three axis dampen in the CLD platform if you mount the motor on middle of a platform and rigidly only to the surface layer. Then mount the bottom layer rigidly to your wall mount from corners or something, for all sideways movements to shear, but leave the middle of the platform boyant so that vertical movement also shears. I bet there is a lot of variables that determine how well anything works for what you want to achieve. Perhaps you already know what to do
Anyway, writing here to help my own thinking / learning, hopefully there is some nuggets that help you think about the stuff as well. Have fun with the project!ps. It would be cool if you can post data on some of the resonances you have measured, ( frequency, amplitude and axis ) I guess all turn tables have more or less of the same kind. I haven't looked into this yet, perhaps this kind of data is already available online.
Few more thoughts:
- you might want to use bad cheap motor for testing to really see whether your damping system works
- if I understood correctly vibration damping resources I stumbled on the damping is effective to frequencies above self resonance of the damper (sorry if terms are not correct), and lower vibrations transfer without attenuation. Few resources on TT motor vibration hinted some of it could be very low in frequency, like few hertz and harmonics. So, the CLD panel should likely be effective on very low frequencies and I don't know what it takes. Perhaps very low stiffness materials and thick constrained layer. I have no idea what this means in practice.
Before I try cheap motors I will measure mine first. There’s also sw that might be used to calculate damping of cld setups.
As always, endless possibilities and limited time and budget. I read a decent number of articles on CLD and also bought some stuff to try out.
But I have to finish off my Schröder clone tonearm wand iteration 3 or four. Then we will see.
As always, endless possibilities and limited time and budget. I read a decent number of articles on CLD and also bought some stuff to try out.
But I have to finish off my Schröder clone tonearm wand iteration 3 or four. Then we will see.