Footers and racks


#21

I currently have my BDR carbon fiber cones oriented with the tips supporting my kit with the base of the cones resting on BDR square “pucks”. Do you happen to have any experience that tells you one orientation (tips up or down) is better than another?


#22

The great isolation vs coupling dilemma. I am more worried about external sound energy waves creating vibrations (need for isolation) in my source equipment rack than dealing with inborne vibrations that require draining (coupling). In my room, I have pretty substantial mains speakers with very low bass extension - and I occasionally like to listen at concert levels. I not only hear the music, but literally feel the SPLs. That being said, this energy in my room created by my loudspeakers will certainly vibrate the chassis of any source devices I have in my room far more than what the device itself is generating. This is the reason I choose to isolate rather than couple this type of gear.

To reduce the cabinet resonances in my loudspeakers, which are inborne, I couple to create drain points.


#23

I can see how isolation would help with vibrations coming up from the floor and traveling through the rack, but I would think decoupling would drain air born vibrations the same way they drain internal component vibrations. To bad there is not a why to isolate and drain unwanted vibrations at the same time.


#24

Certainly, and that is where the footer design comes into play. I am not certain but it seems IsoAcoustics Orea’s are a hybrid design in that they are able to absorb device vibrations in the footers as well as absorb vibrations from the rack.

Lots of variables can out our equipment in motion as we listening. The rack itself can resonate from sound waves, even if isolated from the floor - especially with bass heavy tracks. The adverse effects are mitigated through rack design, material construction and sheer mass.


#25

Yes there is, I use these:


#26

This is the way to go:
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#27

TY, for the feedback.


#28

Vibrational analysis is a deep well, we here are just guessing and using trial and error. 30+ years ago worked briefly with PhDs who did vibrational analysis for huge fans and motors in power plants (didn’t want the washing machine to skip across the floor or shake itself apart). First step of solving any problem is defining what the problem is.

Are you trying to isolate or dampen? e.g. isolate speakers from floor, versus using isopods under audio pieces.

What are you trying to isolate from? Air borne (mostly horizontal) or via the floor (primarily vertical)? What kind of floor is it (concrete or wood)? What are the problem frequencies? What are the resonant frequency of each component of the assembly (rack, shelf, footer, audio piece). Note that resonant frequencies depend on material and shape. Coupled mass dampens vibrations and lower the resonate frequency. Coupling with materials having different moduli of elasticity will help ‘filter’ the resonances out if bearing stresses are kept within their elastic range (fully compressed shock absorbers do no good). Sharp points attempt to eliminate this ‘filtering’ effect.

Practically speaking have a concrete floor and turn the damn volume down! Next best, use headphones/earbuds. Second next best, move all the source/amplification gear to another room or inside a solid (high mass) concrete bunker or heavy metal safe. Or hire a structural engineer with a PhD in dynamics to design your system.


#29

Are these cones someway or another attached to the bottom plate of the DS or is the DS just resting on these 3 cones? In the last case, will it slip off or move when touched/pushed by accident?


#30

DS is just resting on these cones and doesn’t slip off, it’ll move a bit when touched/pushed by accident. Idem ditto with my PWT, resting on 3 Goldmund cones too.

Got a nice deal on a demo Finite Master Reference HD10 Pagode Edition, going tor try that under my Audio Research REF. 6 first, curious what that will do. Friday i’ll know :grinning:

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#31

Thanks for the link. I guess it is possible to isolate and drain unwanted vibrations. Which is the idea behind adding these squares under the DH ceramic cones.