Springs Under My Speakers: What's Happening?

[Thomas_A]

The OP says in the end, after trying various isolation methods and spikes, he found it sounded best if the speakers were simply placed on the floor. Hard to say why but I suspect what's happening with a suspended speaker is complicated by various factors that may sometimes lead to worse results. I'm speculating about what might be going on. If the floor is resonating at certain frequencies due to airborne sound stimulation, which I would bet is causing far more audible effects than solid mechanical transmission in the majority of cases, that will be changed somewhat by putting heavy things like speakers, equipment racks, and furniture on the floor. And if those things are suspended in various ways that will have further effects. It may just end up shifting the primary resonance to different frequencies and different parts of the floor, which would explain why it sometimes sounds better and other times doesn't.

Or it could just be that some like this added distortion. It is not unususal.

 

[fineMen]

Only a note on scientific methodology. Once it was decided that science is a matter of counting, which leads to measuring and math.

What is seen here is the outcome of utter neglect. No measurements to start with, then after an irrelevant substitute is introduced. In consequence the speculations come from the tens to the thousends to the millions. Because any quantitative relation is missing!

A loudspeaker enclosure moves due to reaction forces (Newton). It is a 3-dimensional object, hence is able to rotate and tilt. Hence the point at which the reaction forces act is important. There is no use in the notion of a resonance built up from mass and spring forces alone.

Of course it is a stellar mark-up to ask for - was it actually 1200$ for one set of springs?!

For even half the price one should better ask a physicist ( scientist ) for advice. You might find one at some university. It doesn't have to be Cornell or the MIT, though. There should be something in between asking the internet for free, and paying 1.2k for something spectacularly unspecific.

No bad feelings, I just wonder.

CU

 

[Thomas_A]

Only a note on scientific methodology. Once it was decided that science is a matter of counting, which leads to measuring and math.

What is seen here is the outcome of utter neglect. No measurements to start with, then after an irrelevant substitute is introduced. In consequence the speculations come from the tens to the thousends to the millions. Because any quantitative relation is missing!

A loudspeaker enclosure moves due to reaction forces (Newton). It is a 3-dimensional object, hence is able to rotate and tilt. Hence the point at which the reaction forces act is important. There is no use in the notion of a resonance built up from mass and spring forces alone.

Of course it is a stellar mark-up to ask for - was it actually 1200$ for one set of springs?!

For even half the price one should better ask a physicist ( scientist ) for advice. You might find one at some university. It doesn't have to be Cornell or the MIT, though. There should be something in between asking the internet for free, and paying 1.2k for something spectacularly unspecific.

No bad feelings, I just wonder.

CU

There is no need paying a lot for isolating speakers from floor or stand. Sylomer pads, or just cut small pieces from those camping sleeping mats.

 

[Astoneroad]

I have Gaia IIs on my speakers. I like them esthetically, but can't hear a difference, but that could certainly be my inability to hear something that's there, versus the improvement isn't there. I'm going to sell them and use the money toward a minidsp shd studio. Message me if you're interested at $350, I'll split the shipping.

 

[sq225917]

I always wonder how much the cabs move in reaction to driver movement in these instances.

 

[Thomas_A]

I always wonder how much the cabs move in reaction to driver movement in these instances.

It can be calculated and this has been done many years ago. They will move significantly more at resonance.

 

[Tim Link]

It can be calculated and this has been done many years ago. They will move significantly more at resonance.

Is this at cabinet structural resonance, or speaker driver resonance? Or both?

 

[Thomas_A]

Is this at cabinet structural resonance, or speaker driver resonance? Or both?

The floor-speaker and its interface between forms one or several resonances, usually somewhere in the bass region if you use spikes. Using appropriate soft feet, the resonance will be below the lowest frequency that the speaker will reproduce. Similar to the fundamental cartridge-tonearm resonant frequency of a record player.

 

[MrOtto]

What about these pads? Buchardt recommended. Must be sorbothane? I have sorbothane pads, but they are not that flexible, link should start at 13:51

 

[Katji]

^^I see what you mean about flexible. Maybe it's based on sorbothane. ................Sorbothane is available in various densities and thicknesses..,

 

[MrOtto]

The problem with just using springs, is there is no dampening (yes, but the friction in the metall is very low, but there are some), shouldn't a system have proper dampening? Then some kind of rubber, or sorbothane is better, because there is internal dampening.

 

[Katji]

Of course, it's ridiculous.
And any audiophile gizmo with springs+damping.

 

[Thomas_A]

Made some initial measurements with my ACH01 accelerometer using hard coupling (metal bars) and cheap sylomer pads. Acc at top left corner of speaker.

Speaker (small two-way) on oak floor mounted on sand. Blue=soft feet, orange=hard feet)

Same speaker on a bench: Green=soft feet, blue=hard feet.

Another speaker on wood floor on sand, (same size by heavier and cabinet built with constrained layer damping). Green=soft feet, blue=hard feet.

 

[Chromatischism]

Thomas, are these repeatable? Is there much variability if you took the measurement multiple times?

 

[Thomas_A]

Thomas, are these repeatable? Is there much variability if you took the measurement multiple times?

I took some measurements several times and it was exactly the same. However, moving around the metal bars on different position of the speaker and floor position there will be some variability. I should have used spikes but I don't want to destroy the floor.

I've had plans to do some measurements with the ACH01 for many years but never had time. One thing is that I need to find out what the noise floor is. I had to crank up the volume quite some to get signal, and more so with the heavier speaker with constrained layer damping.

 

[Chromatischism]

Do you have a picture of the measurement setup?

 

[MattHooper]

Made some initial measurements with my ACH01 accelerometer using hard coupling (metal bars) and cheap sylomer pads.

Speaker (small two-way) on oak floor mounted on sand. Blue=soft feet, orange=hard feet)
View attachment 222136
Same speaker on a bench: Green=soft feet, blue=hard feet.
View attachment 222137
Another speaker on wood floor on sand, (same size by heavier and cabinet built with constrained layer damping). Green=soft feet, blue=hard feet.
View attachment 222138

Interesting. Thanks.

What did the differences sound like?

 

[Thomas_A]

No good one; I plan to do some more tomorrow, can take pics then. Below is the "impulse response" of the first speaker, accelerometer on top of the speaker (no constrained layer damping).

And the second speaker, cabinet with constrained layer damping.

 

[Thomas_A]

Interesting. Thanks.

What did the differences sound like?

Depends. Hard feet can sound distorted on bass signals due to transmission of vibrations. As I showed a few pages back, transmission through hard feet can cause distortion.

 

[Plcamp]

Kinda sorta maybe related…mounting my fullrange like this (by magnet) so that it was independently mounted from its baffle (through a hole) significantly increased high volume clarity on my PAP open baffles.

So I do suspect changing the vibration environment can make significant improvements.