I read an old article about the use of air suspension devices under speakers and thought... oh you know the thought that says "here I go again"...
So of to the bike shop for 2 16" innertubes and the hardware for some MDF.
Now my speakers are Epos 14s which sit on dedicated stands. I have the stands on 450mm, 16 kilo concrete pavers which sit on 4 Vibrapods (no. 5). This is on a suspended floor, and building standards being what they are here in Queensland, its quite springy. BOING!
So I cut the MDF into 450mm sqares and half inflated the innertubes; put the tubes on the pavers, laid the boards on them and balanced the speakers as near vertical/horizontal as I could.
The result is a stunning improvement in imagins/soundstage and what sounds like more bass, which I was not expecting.
I thought it would sound lean, or even thin, but its rather lovely.
HAs anyone else done this and what did you find?
Would I be better off having the stands rigidly attached to the floor and putting the air between the stands and the speakers?
I can't be the onky person who has tried this, can I???!!!
Incredible isn't it how much info is on the recording as you start to clear the grunge out!
Under all my equipment, speakers included I have minimally inflated inner tubes. The differences have been eye-opening, especially in the area of spatial information that I had no idea was in the original signal.
I have been fooling around with a theory although it has practical and physical limitations. My theory is that each type of device is probably filtering some vibration, and what gets by one isolator may well be filtered by a different device. On the turntable this seems to have worked in spades.
Under my turntable, an old Thorens TD115, I decided to put several layers of isolation devices. First the inner tube, then a slab of granite from Home Depot, next three round sorbothane feet from audioquest, and on top of these audioquest half ball type sorbothane feet. There is a small air pocket between these two sets of feet due to the hollowed out portion of the first set. Finally the TT. The increase in detail and spatial information again increased dramatically.
Don't know how far this can be taken before we run into either the shelf above or, in no compromise situation, the ceiling!
Am looking forward to everyone experiments with isolation and damping. Lets keep this info flowing. Happy tweaking!
1. Get rid of the concrete pavers;
2. Couple the stands to the floor - use brass spike cups to protect the finish of the floor;
3. Stick the tubes between the stand and the speaker.
Try it - it won't cost you anything and you can easily put the pavers back if you feel the need, but I doubt you will.
Losing the mass of the concrete will raise the resonant frequency of the speaker/stand combination and that will assist in preventing the floor acting as a bass augmenter. I'm also finding that things sound "liver" without the mass - dynamics seem improved quite noticeably when some fo the energy isn't being absorbed by unnecessary mass. Isolating the speaker from the stand helps further. I'm convinced the closer the isolation layer is to the component, the better. After all, it's the component we want to isolate. Couple everything else as tightly as possible to achieve as close to a rigid system as possible. Don't add mass if at all avoidable.
By the way, I've just finished a second balsa isolation platform for the CD player and have just treated it with cellulose dope. I'm waiting for it to dry/cure or whatever it does - it's dry to the touch but the fumes are still bad so I'm waiting for them to dissipate. Hopefully I should be trying it by tonight. I remain impressed with the first one which is just a single layer of 25 mm balsa untreated in any way. The new one has the 25 mm balsa as the middle layer with 6.5 mm balsa glued cross grain top and bottom for increased stiffness, and painted with cellulose dope. I'm thinking of trying a fairly skeletal version - a "T" shape designed to simply support the CDP on 3 cones placed at the extremeties and made of 5 layers of 6.5 mm balsa. Total cost of my current one is around $16 Aus and the "T" shape would probably come in around $12 Aus. My first one would be even cheaper - around $10 if you cost the glue on a use basis. Talk about bang for the buck.
Well I tireed it!!
With wheelbarrow innertubes just a little inflated.
I put them inside two of my isoplatform carcesses and its worked very well.
I have also tried it with Vibrapods (4@V3 inside each platform) and that works well also.
I will try varying the amount of suspension from the pods and also from the inertubes and see which gives the better result.
I agree with Dave's findings about the sound altogether.
This is a good move.
Its also settled a bit of a hump which may have occured after I took to using the muffins!
Everyone allways talks about tightly coupling speakers to the floor with spikes and such. Well don't do it with a wood floor or the floor becomes part of the speaker, as far as producing sound goes. You have the right idea with vibration isolation, do it! I use the black foam tubing that they put around air conditioning lines under my speakers.
I cut it up into pieces long enough to just fit under the box, maybe four pieces under each one, with the tubing laying on its side, like logs. Works great!
Not innertubes, but I use elastomeric feet (made of a foam with open pores) which gives a compliance/isolation between speaker and floor (with a resonant f of 7 Hz in the x-y plane and 12 Hz in the z plane). The results are really great; better detail, less distortion, improved imaging and deeper more defined bass.
The recommendation for these feet I use is to put them as close to the source as possible (i.e. between speaker and stand). The important factor is to have a low resonant f and low damping. So for a innertube, you might need to play around with the air pressure to get the lowest compliance possible.
I may well try putting the floatation (!) between the speakers and the stand today. Its a public holiday here on Oz.
This ties in nicely with some things DAve Aiken has worked on, that is the light and rigid theory but with a soft layer as close as possible to the component.
On further listening I'm not so sure about the amount of bass I claimed before, but the sweetness and soundstaging are tremendous and the bass is clearer, so I need to work on more slam, which I had previously loved on this system.
Oh, well, it keeps me off the streets.
in the coupling-decoupling issue if you are interested.
I am currently building some isolation platforms using inner tubes! But am experimenting with even further damping! In the middel of
the top MDF plate I place a metal rod going down in the center of the tube into a grease pit!! (Rod= M5 screw, Grease pit= bottel cab with special dense grease fitted into hole in bottom plate) Mabye this would ad some slam to your bass??
Have fun ;o)
Yes it does sound interesting.
Keep us informed.
I have had a bunch of isoplatforms made up to try them with different "fillings".
Dave Aiken has one of them for his system.
I have had good results from multilevel EVA foam and especially sand filled bags.
I am coming round to his light and rigid theory.
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