As I see it, it is any vibration from the speaker that one wishes to isolate mechanically, not only cabinet resonances. A "usual" sub bought from a hifi store has such small outer dimensions so one shouldn't expect any cabinet resonances at or lower than the frequncieas the sub plays, up to 120 Hz or whatever. -Still we hear about subs "walkning around" on the floor or a wooden floor getting in resonance.
But the only vibration that can be transmitted by a coupling device are those that it is in contact with.
dave
It intrigued me how my sorbothane feet had the primary function of stopping the cabinet flexing at low frequency (I used a tone generator) and at highish volume it was visibly twisting at the top (I think the added mass I put on top made it worse), that was with hard rubber feet. So in my experience the soft decoupling not only reduced transmission to the floor.
Where do I begin...first of all, consider the impact of a good drum solo while your walking in front of a rather high volume...say JBL 4300 series three-way...these pressures are literally felt on the body. The pressure waves traveling across the four meters worth striking the back wall, the 25+ square meters worth of drywall, these waves putting this wall in motion.
Also, while this is happening, stride over to the speaker & put your hand atop the cabinet...which will have the most vibrational value? The cabinet, or that big wide back wall?
When Townshend offers up all the dramatic wording, "wider & deeper soundstage, enhanced clarity, improved "definition" , more real"...so many subjectives, zero data.
And the one I love "sound becomes independent of the speaker"...? Isn't that what we are trying to achieve? An illusion of sound?
----------------------------------------------------------------------Rick.............
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If this force is every small compared to cone movement how will it vibrate the floor? Unless you're living in a paper bag this just doesn't make sense. Alternate facts?
This is getting really silly! The sounding board of a stringed instrument is very thin, is only supported at it's edges and also is in the same plane as the strings so as to give maximum effect.
Unless your speakers are firing downwards (or upwards) then the very thick floor isn't going to do anything with the minuscule amount of energy being transmitted to it by the spikes other than absorb it in it's longitudinal and resonantly dead plane.
Demidon, it is possible to measure the reaction forces of a dome tweeter on the rear side of an enclosure, using an accelerometer! Reaction forces don't go away, they need to move something. Always. And if a large flat object such as a floor vibrates, even with very small movements, it is acoustically so well coupled to the air, that those small movements may generate appreciable sound.
Even a very thick floor will need to move first before it can absorb the forces being transmitted to it by spikes. But obviously, in a Californian house, with a slab of concrete poured directly over a rocky subsoil, the situation is different from that with a suspended concrete floor, and a wooden floor is again very different from that.
Let me ask a silly question: do you perhaps have speakers with spikes underneath?
Even a very thick floor will need to move first before it can absorb the forces being transmitted to it by spikes. But obviously, in a Californian house, with a slab of concrete poured directly over a rocky subsoil, the situation is different from that with a suspended concrete floor, and a wooden floor is again very different from that.
Let me ask a silly question: do you perhaps have speakers with spikes underneath?
Please define "appreciable" in this context - sound generated by a floor caused as a direct result by the reaction forces of a tweeter coupled by spikes to said floor.
The tweeter's diaphragm is designed to be very light so that I might move air and make high frequency sound. I don't see how the reaction forces from this movement transmitted imperfectly through likely a gasket, then a cabinet and spikes then to a floor that is millions of times as massive can make any kind of sound that you or I would hear.
The same goes for a woofer cone weighing perhaps 15 grams.
The opposing force may be equal and opposite but the masses involved are orders of magnitude different. Then consider that the sound-producing parts of the driver are not only shaped optimally for sound reproduction but are also suspended as freely as possible so that they might move and make said sound...
Any sound produced by the reaction forces acting down through all the parts of the (not completely rigid cabinet) and on the millions of times more massive and 'not optimally designed for sound production floor' is going to need NASA to put together a system to first cancel out the sound from the speaker so that they then might detect it...
When they then show me evidence that this sound is noticeable to the average human ear over and above the sound of the music (and it wouldn't have been without spikes fitted) then I will concede that you are right. Until then logic and physics must dictate otherwise.
That's a lot of words to state the obvious.
Of my perhaps 18 or 20 pairs of speakers (currently) two pairs have spikes and that's because the manufacturer supplied them that way.
I know, I tried. However some people just don't get physics.
I'm not. The ones I listen to the most are on spikes and they sound great!
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I'm taking my chance to post something here before it gets locked and/or moved to the lounge. Different types of feet do so little in my (!) experience that the topic seems ridiculous. Controlling vibration goes a long way when it is cabinet/baffle vibration and there the crucial part is easily done with a bit of bracing. For "bass" the right amount of stuffing of a cabinet plays a role and is easily determined with the Altec 9V battery trick.
(What about driver selection, crossovers, cabinets, horn flares? Sure, baby!)
(What about driver selection, crossovers, cabinets, horn flares? Sure, baby!)
Our experience is different. I would encourage people to experiment, every situation is different.
I can’t speak for typical tweeters because i don’t use them. They are probably more impacted by the reactive force of the woofer but that is a different issue.
As to the woofer — or in my case usually a FR — the impact of the movement of that cone can significantly affect the box. With each new build we play music and listen to various parts of the box to see what sound it makes. If it makes too much sound we go back to the drawing board. With lots of practise we are getting pretty good. But many a typical box is not, MDF boxes in particular tend to be offenders.
If the box is producing significant sound then it sounds boxy or makes the box more audiable destroying any hope of producing the illusion of a 3D image.
A box panel is a large raditor and doesn’t need to move much to effectively radiate enuff sound to be obtrusive. Which panel vibrates of course is important. The back or bottom for instance usually aren’t as critical as the baffle — a panel you have to really watch since with those holes cut in to it are weakest.
The average listener, typically untrained to listen (it is an average after all) is incapable of hearing many things. But with training and esxposure to better than average kit can become a better than average listener. A good reason to have better than average kit so that they can grow their listening experience.
dave
Also the driver/s are more directly coupled to the baffle and the baffle is in the same plane as the driver/s (unlike a floor) so it's critical that it's not resonant.
Agreed. I started my 'critical listening' in the late 1970s doing sound mixing for a band at live gigs, something I did full-time for three years. There's something about setting up a known system in different venues every week and then having to dynamically compensate for the damping effect of varying numbers of people, sometimes dancing near the speakers, sometimes sitting listening as the evening progresses that teaches you to hear nuances of sound. Since then I've never stopped listening critically. Ultimately I'd like to have speakers and an environment that I can't hear (instead hearing just the music...) and I keep striving towards that aim.
Cheers,
Shaun.
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My pick:1.
Basically the centre of gravity nearly always tends to be towards the front. The drivers mounted there would help that too, magnets and all.
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