Springs Under My Speakers: What's Happening?

[Thomas_A]

Good way to avoid answering a serious direct question.

Giving the speaker a push is not relevant for how the speaker cone affects the movement of the cabinet during play. I gave you the answer in the second point; it's the woofer mass vs. cabinet mass that is the relevant one.

 

[Sal1950]

Giving the speaker a push is not relevant for how the speaker cone affects the movement of the cabinet during play. I gave you the answer in the second point; it's the woofer mass vs. cabinet mass that is the relevant one.

Still it would tell you how rigidly the cabinet is anchored to the floor via spikes vs flexable feet.
I just pushed on the top of my JBL's with soft feet and it wiggles both F-B and S-S very easily.
I can promise you if I changed to the supplied spikes they'd be much harder to wiggle.
If you don't believe me, come by and help me lift these heavy suckers and we'll change them.
Hell I could even pull out a dial indicator from my tool box, zero it on the back of the speaker, and measure the difference to a .001"

 

[xanalog]

I don't understand why manufacturers mostly insist on 4 feet when 3 would provide a more stable platform? True for not only speakers but electronics too.

Safety and distribution of weight (ADD: Only when properly leveled- re:4v3), but remember they use metric system in other countries!

 

[Chrispy]

Still it would tell you how rigidly the cabinet is anchored to the floor via spikes vs flexable feet.
I just pushed on the top of my JBL's with soft feet and it wiggles both F-B and S-S very easily.
I can promise you if I changed to the supplied spikes they'd be much harder to wiggle.
If you don't believe me, come by and help me lift these heavy suckers and we'll change them.
Hell I could even pull out a dial indicator from my tool box, zero it on the back of the speaker, and measure the difference to a .001"

What JBLs are those?

 

[Thomas_A]

Still it would tell you how rigidly the cabinet is anchored to the floor via spikes vs flexable feet.
I just pushed on the top of my JBL's with soft feet and it wiggles both F-B and S-S very easily.
I can promise you if I changed to the supplied spikes they'd be much harder to wiggle.
If you don't believe me, come by and help me lift these heavy suckers and we'll change them.
Hell I could even pull out a dial indicator from my tool box, zero it on the back of the speaker, and measure the difference to a .001"

It only tella you that the wiggle when pushing. If they wiggle at 2-5 Hz you are also sure that nothing what the speaker cone does within the audible band will make them wiggle. If you push a speaker with spikes you will just load it with energy higher in frequency. This is physics. For the same reason you have the resonance frequency of a tonearm/cartride around 10 Hz to avoid the audible spctrum. No one disputes that so why would a speaker be different?

 

[Sal1950]

Safety and distribution of weight (ADD: Only when properly leveled- re:4v3), but remember they use metric system in other countries!

I've got a digital one that I can switch to metric if you like.

 

[Sal1950]

What JBLs are those?

4 HDI-3600s. Click on the link in my sig.

 

[audiofooled]

It would take a ton of research to accurately describe the phenomena. Variables are too many. You may get a glimpse of just how many by having a look at other complex interactions within systems that are also dependent of frequency, time and particularly phase:

Resonances and synchronizations are everywhere, loudspeakers and rooms are no exception. Phase is the key and what you do to nudge it a bit to miss the undesired objects resonant frequencies, be it isolation pads, phase manipulation and what not. But It has to be solved for the unique setups and environment conditions. This is why solutions are not one size fits all and it is only fair to be sceptic about commercial offerings based on FUD marketing.

 

[Heinrich]

It would take a ton of research to accurately describe the phenomena. ... Resonances and synchronizations are everywhere, loudspeakers and rooms are no exception. Phase is the key ... FUD marketing.

First, who does the research, is it the audio community? It sounds a bit hollow to expect reasearch from somebody else, and use the disinterest as an argument. The case is clear and closed theoretically and practically for ages, but the audio industry makes money with the persisted ignorance of their customers.

Sure, resonance and sync is a phenomenon, but is is clarified since ages. Current work has a focus on other nice things, that the audio community doesn't know about a quantum bit. Phase as a buzzword, c'mon.

Don't you all see how the topic gets reheated every other day by just plain old ignorance from somebody else? Talking in spirals without any focus, and in this case, with all due respect but really, it sounds like BS bingo.

What would come out if I opened a survey on who of us is actually familiar with that undergraduate physics, which is in charge here? May be not familiar, may just heard of it exsisting ...

Add: won't ever recommend that otherwise, but give post #530 to a technically literate AI - no questionaire needed, just hand over the text as a question in itself, and learn, Tried it with CoPilot (µsoft), and ChatGPT (?), good, correct analysis, explanations for the freshmen included. Can be extented.

 

[Curvature]

Spikes & Isolation: The Art of Speaker Decoupling for Optimal Audio Performance

This contributed article by IsoAcoustics' founder and president is an interesting piece that sums up his vast experience in the field, working with professional audio engineers, loudspeaker designers, and music lovers all over the world. The article explores how speakers physically interact with...

audioxpress.com

Recentish article on Isoacoustics. More of an advertisement, really.

They posted this chart, which is hard to read and even misleading in some ways.

If you look at the frequency response, you get these tiny, tiny deviations (well under a dB) in an anechoic setting between speaker spikes and the Isoacoustics GAIA II feet. They also include a secondary axis for velocity measurements using a laser vibrometer, which look much more dramatic. I'll just note here that the bungee cord measurement is at best only academic, since they introduce rocking modes into playback. The writer (the founder Dave Morrison) says as much:

The testing shows that the GAIA isolators perform similarly to the suspension scenario with bungee cords (blue line) in minimizing vibrations, though the latter suffers from poor sound quality due to the instability of the freely swinging speaker.

I extracted the GAIA II and spike velocity measurements and converted them to dB using the following formula.

I imported the results into REW. The results at best are about a 10dB reduction vs. spikes.

Here's the same information, plotted against the minimal hearing and vibrotactile thresholds.

The question is how much any of this matters.

You certainly can't feel the difference with your feet.

We have to consider that none of these vibrations will be heard by themselves. The above sweeps were made at around 90dB SPL. Speaker multitone distortion allows maybe 30dB distortion-free range at that level. Maybe 40dB. On top of that, the vibrations will integrate and sum with the response of the speaker, and contribute directly to the measured frequency response. And Morrison states directly that the FR deviates by less than 0.3dB! Think about that: the contribution of the 10dB attenuated vibration is less than 0.3dB at 90dB SPL.

Say the directivity of the vibrations is different from the directivity of the music. That's probably true. I would still guess that the audibility would be subtle-to-none at best. In the range of effectiveness, room modes, SBIR and reverb are active. On top of that you introduce masking from the music itself.

I think this is one of those products that makes sense but only as the tweaker's last rational stand. It might also make sense, as an expensive fix, where there is a prominent vibration problem for some idiosyncratic reason to do with what the speaker is on.

The last thing I'll say is that the more important comparison would not be spikes, which couple the speaker to the floor, and not bare cabinet on carpet, hardwood or concrete, but the normal rubber or elastic dots that most manufacturers include on speaker bottoms. I would imagine the measured difference would be much less significant compared to something so basic.

 

[Thomas_A]

Spikes & Isolation: The Art of Speaker Decoupling for Optimal Audio Performance

This contributed article by IsoAcoustics' founder and president is an interesting piece that sums up his vast experience in the field, working with professional audio engineers, loudspeaker designers, and music lovers all over the world. The article explores how speakers physically interact with...

audioxpress.com

Recentish article on Isoacoustics. More of an advertisement, really.

They posted this chart, which is hard to read and even misleading in some ways.

View attachment 463618

If you look at the frequency response, you get these tiny, tiny deviations (well under a dB) in an anechoic setting between speaker spikes and the Isoacoustics GAIA II feet. They also include a secondary axis for velocity measurements using a laser vibrometer, which look much more dramatic. I'll just note here that the bungee cord measurement is at best only academic, since they introduce rocking modes into playback. The writer (the founder Dave Morrison) says as much:



I extracted the GAIA II and spike velocity measurements and converted them to dB using the following formula.

View attachment 463619

I imported the results into REW. The results at best are about a 10dB reduction vs. spikes.

View attachment 463620

Here's the same information, plotted against the minimal hearing and vibrotactile thresholds.

View attachment 463622

The question is how much any of this matters.

You certainly can't feel the difference with your feet.

We have to consider that none of these vibrations will be heard by themselves. The above sweeps were made at around 90dB SPL. Speaker multitone distortion allows maybe 30dB distortion-free range at that level. Maybe 40dB. On top of that, the vibrations will integrate and sum with the response of the speaker, and contribute directly to the measured frequency response. And Morrison states directly that the FR deviates by less than 0.3dB! Think about that: the contribution of the 10dB attenuated vibration is less than 0.3dB at 90dB SPL.

Say the directivity of the vibrations is different from the directivity of the music. That's probably true. I would still guess that the audibility would be subtle-to-none at best. In the range of effectiveness, room modes, SBIR and reverb are active. On top of that you introduce masking from the music itself.

I think this is one of those products that makes sense but only as the tweaker's last rational stand. It might also make sense, as an expensive fix, where there is a prominent vibration problem for some idiosyncratic reason to do with what the speaker is on.

The last thing I'll say is that the more important comparison would not be spikes, which couple the speaker to the floor, and not bare cabinet on carpet, hardwood or concrete, but the normal rubber or elastic dots that most manufacturers include on speaker bottoms. I would imagine the measured difference would be much less significant compared to something so basic.

I have not followed the market the latest years but if the manufacturers have left out spikes and use soft feet, it is a good thing. This is espeically good when using speakers on desks and consoles.

 

[MarkS]

Looking at that velocity chart, the peak value is around 7.5 x 10^(-6) m/s at a frequency of around 250 Hz. This corresponds to a displacement (velocity divided by frequency) of 3 x 10^(-8) meters. That's the distance the speaker is moving in one cycle of vibration. The size of an atom is about 10^(-10) meters, so we're talking a displacement of 300 atom widths.

I don't see how that could possibly be audible.

 

[Curvature]

Looking at that velocity chart, the peak value is around 7.5 x 10^(-6) m/s at a frequency of around 250 Hz. This corresponds to a displacement (velocity divided by frequency) of 3 x 10^(-8) meters. That's the distance the speaker is moving in one cycle of vibration. The size of an atom is about 10^(-10) meters, so we're talking a displacement of 300 atom widths.

I don't see how that could possibly be audible.

I already converted to dB in that post and commented on the results.

 

[RexrothPigeon]

Looking at that velocity chart, the peak value is around 7.5 x 10^(-6) m/s at a frequency of around 250 Hz. This corresponds to a displacement (velocity divided by frequency) of 3 x 10^(-8) meters. That's the distance the speaker is moving in one cycle of vibration. The size of an atom is about 10^(-10) meters, so we're talking a displacement of 300 atom widths.

I don't see how that could possibly be audible.

pfftt found the guy without the magic golden ears

/s

 

[xanalog]

In a binary world, and looking for simple answers; the Luddite in me, still cannot resolve which extreme is more favorable:

A well-anchored speaker or a well-floated speaker?
I had always thought that it was the former, which made speakers as the designers had intended.

But based-on OP (@MattHooper) observations (though, considered purely subjective by some) indicate that there may actually be a valid 'something' in what he is certain he does hear (the there-there).

It appears that we are no closer to any of the potential reasons/answers, 28 pages later.
Or are we and I have missed them?

Refuting his observations by resorting to ad-hominems, and/or even using logs to create a wall-of-impossibilities, has not advanced this interesting-subject forward.
[imo and I am sticking to it! ]

 

[Sal1950]

It appears that we are no closer to any of the potential reasons/answers, 28 pages later.

IMHO there is no "right" answer. The best measurements can only give results for that particular room / floor / speaker.
It's your thing, do what ya wanta do.

 

[xanalog]

The best measurements can only give results for that particular room / floor / speaker.
It's your thing, do what ya wanta do.

We could only wish it was that simple...

The objectivists -believing in Klippel (which align w/anechoic-room) measurements- insist on a 'well-anchored' test specimen as irrefutable.
But it does not make OP delusional, in askance for help and explanations.

 

[Sal1950]

It appears that we are no closer to any of the potential reasons/answers, 28 pages later.

We could only wish it was that simple...

Well your the one that said it. LOL
Anywho, the subjective results Matt posted whether true or delusional, can only be the results of his speakers, in his room, on his flooring.
It can tell you little to nothing about what might occur in your or mine or anyone else room.