2. speakers
  3. 153172-1252

DIY speaker isolation base for a wood floor

A definite sonic improvement in tightening up the bass. 
1. Start with 4 aluminum cones. I used some old Mod Squad Tip Toes.
2. 16x16 slab of granite.
3. 1/8 cork.
4. 1/2 inch neoprene rubber.
5. 1/8 cork.
6. Top with another 16x16 slab of granite.
7. Enclosed with a wood cradle to hide the mechanism.
  The granite is from scraps from a shop and was cheap. The added 1/4 inch of neoprene to 1/2 inch thickness did help. Let me hear your thoughts.
blueranger
audiozenology
362 posts
 
blueranger,

I am assuming each granite slab is about 25lbs, and the sorbathane is between them, so assume a 100lb total load.

georgehifi posted a link above to an Ebay seller. They sell 2.5" diameter disks of 70, 50 and 30 hardness. My rough calcs say that if you cut those in half (so half circle), and use 4 of them, they should depress about 25%.  That is not going to isolate the lowest bass frequencies, but will be a good improvement over what you have now. One area I agree with geoffkait on is that springs are best for low low frequency isolation.

I expect you have lots of cork around, so you can start experimenting. As opposed to single large sheets of cork, cut them into say 2" squares and stack them say 1/2" high, and use 4 stacks for stability. You want the cork supports small enough (and not too small) that the cork is compressing say 10-20%.
audiozenology
362 posts
 
Hey bdp24,

Do you have experience with ISODAMP. We used some for a project a while back, but my colleague was working on that and I did not have enough time for "info-osmosis". I think the foams are quite interesting, and the availability is good. Thanks for the reminder. I will probably get some in the next week or two to try out. I have more experience with Sorbothane so it becomes a go to.

I like this video:   https://www.youtube.com/watch?v=3HRbjfZUbe8

After the first simultaneous ball drop, listen to how loud the next bounces are from the regular rubber material. The foam absorbs the energy and releases as heat, not sound.
bdp24's avatar
bdp24
10,095 posts
 

@audiozenology, the only rubber I use for isolation is a set of Sims Navcom Silencers in place of the stock springs in my VPI HW-19 Mk.3 turntable, a favorite mod amongst HW-19 owners. While the stock springs provide the well-known isolation inherent in suspended subchassis tables, they allow a fair amount of relative motion between the subchassis (containing the platter and arm/cartridge) and the base-mounted motor.

The EAR Isodamp I use is not the constrained-layer damping model (C-1002), but the version made for the damping of vibrating/ringing metal panels and chassis (SD125). It is a heavy (about 1lb. per square foot), dense, stiff, 1/8" thick material with adhesive on one side. Applied to the metal chassis of hi-fi electronics, it is very effective at absorbing and dissipating their ringing resonances. Unless you consider electronics to be musical instruments---a silly notion imo---and should therefore be allowed to ring away, a very effective solution for eliminating unwanted resonances. While my phono amp, linestage, and power amps benefit from SD125, my very robustly built Esoteric digital player has no need for it---that 47 lb. box is very well self-damped. I guess I can't be a card-carrying member of the low-mass-is-a-gas gang, ay? ;-)

blueranger's avatar
blueranger OP
719 posts
 
Thanks for everyone's help!! I ordered the 8 springs today. They should be here Monday. Ih what fun. Let me put the ideas I have in my head.
1. Use the 4 springs on the floor directly coupled to two 16x16 granite slabs with nothing in between.
2. Same as above but with aluminum cones between the slabs.
3. Same as #2 except the cones on the floor and the springs between the slabs. 
4. Springs on the floor and sorbethane between the two slabs.
5. The springs on the floor with a cork and neoprene sandwich between the slabs.
Ok now which one should work best????? Where's a testing lab when you need one! I'm excited about trying these options. I'm off next week so I should be able to experiment. Again thanks for your input.
audiozenology
362 posts
 
6) The one where you get creative and figure out a way to have the springs and sorbothane between the two slabs at the same time ... or maybe the springs and a stack of lightly compressed cork. That way you get isolation and dampening.


Which springs are you getting? If you have them at the bottom, you need the right springs for 125lbs (spring and two slabs). The resonant frequency of the spring is a factor of spring constant and loading.
More to discover