Just curious as to the science behind this ... If you were to suspend your main speakers from the ceiling, using a heavy duty bungee cord set up, BUT keeping the speakers the same height off the floor, as if they had standard speaker floor spikes on them. So same height and placement, just not touching the floor by maybe one inch/....
What happens? Should it not help isolate some of the cabinet's vibrations to the floor and wall?
What happens? Should it not help isolate some of the cabinet's vibrations to the floor and wall?
Hi,
Yes it should. But it'll depend of structural build of ceiling/walls/floor.
If you implement decoupling in the way you'll fix your rope to ceiling then yes it could be considered almost fully decoupled ~ floating.
Yes it should. But it'll depend of structural build of ceiling/walls/floor.
If you implement decoupling in the way you'll fix your rope to ceiling then yes it could be considered almost fully decoupled ~ floating.
It just moves the direct vibration propagation to the ceiling and walls instead of the floor first and walls. I’ve seen and heard suspended speakers. Very “hippy” and introduces as many problems as it was supposed to solve, one being the difficulty of moving the speakers.
Residential ceilings are worse for noise and vibration compared to floors, and there are several structural and material reasons for this.
I also heard a club installs like this, although the speakers were suspended up high, but they still sounded terrible.
Residential ceilings are worse for noise and vibration compared to floors, and there are several structural and material reasons for this.
I also heard a club installs like this, although the speakers were suspended up high, but they still sounded terrible.
You missed the part where I said bungee. Not cables or chains. No vibrations are going up to the ceiling.
I certainly did not. You’re going to have vibration across the drywall corresponding to resonance frequency of the sprung poly elastic cord.
That is also some type of spring. I don't see any advantage over normal types of springs or the initially mentioned bungee cord.
Regards
Charles
Regards
Charles
One thing I found to work, was a large mass between the speaker and the floor. This was with a pedestrian two-way Dahlquist M905 pair.
I took a 14" round paver and cemented an 18" tall red clay chimney flume pipe to it. Then I filled it with cement, leveling 3 metal cups, each capturing a small ball bearing. The cabinet bottom would sit upon the three spheres, coupled to the cement through the holding cups.
These were heavy and I had to use a hand truck to move them. They definitely improved the sound of those speakers. I assume the mass of the cement stands absorbed cabinet vibrations that were otherwise being conducted into the floor.
I took a 14" round paver and cemented an 18" tall red clay chimney flume pipe to it. Then I filled it with cement, leveling 3 metal cups, each capturing a small ball bearing. The cabinet bottom would sit upon the three spheres, coupled to the cement through the holding cups.
These were heavy and I had to use a hand truck to move them. They definitely improved the sound of those speakers. I assume the mass of the cement stands absorbed cabinet vibrations that were otherwise being conducted into the floor.
The bungee cords are elastic and on tension (weight of the speaker) and therefore got a resonance frequency. Excited the 'right way', they will start vibrating and while the direct sound will be likely too weak to be audible, they transfer the vibrations to where they are mounted - the ceiling. If that's a problem depends on if the resonance is exciting them is emitted by speakers and if the cords have enough inner damping to cancel the resonance by absorption. That means, you want the resonance at a frequency your speakers don't reproduce or are too high to get them excited, you are filtering it out or you tune its fs down by adding a weight (change on the fs) on them asymmetrical (no identical taps) and on every of the rope at a different position.
You are still exciting the room modes though, it just reduces the direct coupling to the floor by a certain ammount (expectedly by quite a bit). Unless you have floor vibrations, it will not change the noise in other rooms. Acoustical treatment (i.e. absorbers in the corners etc) can reduce that and - as a very welcome side effect - clear up the bass and gives a lot more precision and linearity. If you like the boom-y bass, you'll not like that kind of room treatment though.
One needs lossy absorbing materials to damp vibrations and not ones that store and release energy (springs/threads). This is much similar to resistive vs reactive in the electrical world.
It would have to sound different especially in the bass. Consider that coupling the enclosures to the floor limits the enclosures movement while the woofer is producing lower frequencies. The more the enclosure moves the less bass impact you notice. Bass will probably have less definition as a result of hanging the enclosures. I'd think this would be more noticeable with larger woofers.
A guy could try coupling vs decoupling the enclosure from the floor to see the difference first. I would think that going through the hassle of rigging the enclosure(s) vs just decoupling from the floor is not worth the extra effort.
A guy could try coupling vs decoupling the enclosure from the floor to see the difference first. I would think that going through the hassle of rigging the enclosure(s) vs just decoupling from the floor is not worth the extra effort.
If a mass is suspended from a spring, it will have a natural resonance frequency (we all know this). If that mass is a source of broad band vibration, the portion of the vibration energy above the natural resonance will be absorbed by the spring. This is called decoupling, and it is a fundamental technique used in vibration isolation. The portion of vibration energy below the natural resonance will be conducted through the spring to the ceiling. So we can think of the spring as a low pass filter. Damping is not required for this process to work.
So if our speaker here is suspended from bungee cords, and its motion has a natural period of about 1 second, this means a natural frequency of 1 Hz. This would very effectively isolate the speaker from ceiling. There would be no structural transmitted vibration from the speaker to the room ceiling, walls, or floor.
The speaker’s motion would not simply be up and down however, it would be free to swing like a pendulum in any direction, and it could also have rotational / twisting modes. All of these oscillations would need to be well below the lowest frequency that the speaker would generate. If all of these motions had natural resonances in the 1 Hz to 5 Hz range, then yes, the speaker would be structurally isolated.
Would it sound better? I don’t know. I have heard speakers that were improved by partially decoupling them from the floor, and I have heard others that were improved by rigidly coupling them to the floor.
j.
So if our speaker here is suspended from bungee cords, and its motion has a natural period of about 1 second, this means a natural frequency of 1 Hz. This would very effectively isolate the speaker from ceiling. There would be no structural transmitted vibration from the speaker to the room ceiling, walls, or floor.
The speaker’s motion would not simply be up and down however, it would be free to swing like a pendulum in any direction, and it could also have rotational / twisting modes. All of these oscillations would need to be well below the lowest frequency that the speaker would generate. If all of these motions had natural resonances in the 1 Hz to 5 Hz range, then yes, the speaker would be structurally isolated.
Would it sound better? I don’t know. I have heard speakers that were improved by partially decoupling them from the floor, and I have heard others that were improved by rigidly coupling them to the floor.
j.
^+1.
Ime it depends from the structural architecture: when floor is soft better coupling, if it's hard better decouple.
May i add one point to your def Hifijim? At resonant freq of a decoupled system there is high Q peak of transmission. The higher it is the more efficient it is at decoupling and the lower in freq. This means too that the system may oscillate for a very long time at this freq ( i've seen 2d seismic decoupling system oscillate for minutes at 1/2hz freq).
Ime it depends from the structural architecture: when floor is soft better coupling, if it's hard better decouple.
May i add one point to your def Hifijim? At resonant freq of a decoupled system there is high Q peak of transmission. The higher it is the more efficient it is at decoupling and the lower in freq. This means too that the system may oscillate for a very long time at this freq ( i've seen 2d seismic decoupling system oscillate for minutes at 1/2hz freq).
Yes, Krivium, I believe that is true, based on my recollection. I am away from home right now so I don't have my text books with me, but that sounds quite correct.
Large equipment in factories is often mounted with fully elastic isolation mounting (springs, no damping), but these can be very large mounts. The lower the frequency that the machine produces, the lower the natural resonance of the isolation mount must be. Sometimes damping is used because there is not enough room for a huge spring system, and there is an overlap between the vibration of the machine and the isolation mount natural frequency. Damping helps deal with this.
The interesting thing is that the math and physics of what is happening is very well understood, but we still can not predict what will sound good in a given situation. I have no idea or theory about why some speakers are improved by spikes, or heavy weights on top, while others are not. Some like isolation, some like to be rigidly coupled.
Large equipment in factories is often mounted with fully elastic isolation mounting (springs, no damping), but these can be very large mounts. The lower the frequency that the machine produces, the lower the natural resonance of the isolation mount must be. Sometimes damping is used because there is not enough room for a huge spring system, and there is an overlap between the vibration of the machine and the isolation mount natural frequency. Damping helps deal with this.
The interesting thing is that the math and physics of what is happening is very well understood, but we still can not predict what will sound good in a given situation. I have no idea or theory about why some speakers are improved by spikes, or heavy weights on top, while others are not. Some like isolation, some like to be rigidly coupled.
That is how my current TT is mounted. But i did have to execute some flying buttresses to stop the wall from moving ewhen someone shut the door too hard.
dave
dave