Are Floor-borne Vibrations Really the Enemy?

[stehno]

I've put out a similar thread several years ago but I figured I'd try once more and try to keep it simple this time.

I've got two 15" subwoofers weighing 110 lbs. each solidly anchored to the subflooring using my own custom points. With mass-loading each subwoofer actually weighs about 160 lbs. In the center is my custom rack weighing about 250 lbs. with my custom points fastened at the bottom to ensure it too is solidly anchored into the subflooring.

The distance side-to-side between the nearest subwoofer points and my rack's center point is about 24-inches. The front-to-back distance between the subwoofers' closest point and the rack's center point is maybe 4-inches. It's entirely possible that one or both subs and the rack are sharing the same sheet of plywood (subflooring). The probability that the two subwoofers and rack are sharing the same floor joist is extremely high. Everything is also extremely rigid including their mounting to the subflooring.

For those who've strived all their lives to squash or quell floor-borne vibrations, isn't my configuration the biggest no-no ever? Am I not defying some law of high-end audio physics here? If so, why don't these recordings sound like mashed potatoes? Why isn't the resolution swinging high and low with every deep bass note? Why does there seem to be a tremendous consistency in articulation whether it be a high note or low note? If there's any truth whatsoever to the evils of floor-borne vibrations, none of this should be happening. Yet, everything I throw at it, the articulation and level of musicality remains consistent and IMO extremely musical.

I think of the millions others have spent trying to isolate their equipment from floor-borne vibrations. With so much dogmatism about the evils of floor-borne vibrations, surely there must be somebody out there somewhere that can provide an in-room video or two demonstrating how much more articulate the bass and overall musical presentation can be when floor-borne vibrations have been "isolated" from the playback system.

 

[Addicted to hifi]

I've put out a similar thread several years ago but I figured I'd try once more and try to keep it simple this time.

I've got two 15" subwoofers weighing 110 lbs. each solidly anchored to the subflooring using my own custom points. With mass-loading each subwoofer actually weighs about 160 lbs. In the center is my custom rack weighing about 250 lbs. with my custom points fastened at the bottom to ensure it too is solidly anchored into the subflooring.

The distance side-to-side between the nearest subwoofer points and my rack's center point is about 24-inches. The front-to-back distance between the subwoofers' closest point and the rack's center point is maybe 4-inches. It's entirely possible that one or both subs and the rack are sharing the same sheet of plywood (subflooring). The probability that the two subwoofers and rack are sharing the same floor joist is extremely high. Everything is also extremely rigid including their mounting to the subflooring.

For those who've strived all their lives to squash or quell floor-borne vibrations, isn't my configuration the biggest no-no ever? Am I not defying some law of high-end audio physics here? If so, why don't these recordings sound like mashed potatoes? Why isn't the resolution swinging high and low with every deep bass note? Why does there seem to be a tremendous consistency in articulation whether it be a high note or low note? If there's any truth whatsoever to the evils of floor-borne vibrations, none of this should be happening. Yet, everything I throw at it, the articulation and level of musicality remains consistent and IMO extremely musical.

I think of the millions others have spent trying to isolate their equipment from floor-borne vibrations. With so much dogmatism about the evils of floor-borne vibrations, surely there must be somebody out there somewhere that can provide an in-room video or two demonstrating how much more articulate the bass and overall musical presentation can be when floor-borne vibrations have been "isolated" from the playback system.

Thanks for these great clips.

 

[Argonaut]

Whilst there is no audio playback available on this demonstration YouTube one might extrapolate an audible effect from the visual results.

 

[stehno]

Whilst there is no audio playback available on this demonstration YouTube one might extrapolate an audible effect from the visual results.

It seems you missed my point entirely as does the video you provided. Please reread the OP again.

 

[Argonaut]

It seems you missed my point entirely as does the video you provided. Please reread the OP again.

I think that I wont bother thanks !

 

[Addicted to hifi]

I don’t think floor borne vibrations are a problem especially if you have a concrete foundation.

 

[rDin]

It's entirely possible that one or both subs and the rack are sharing the same sheet of plywood (subflooring). The probability that the two subwoofers and rack are sharing the same floor joist is extremely high. Everything is also extremely rigid including their mounting to the subflooring.

Sounds like you need to answer this yourself. However, the way you write [your] original post suggests you've already made up your mind. But easy enough to test. Get an accelerometer app on an android phone, or an actual accelerometer and measure on the rack when the subs are active. Or just put your fingers on the rack - can you feel it vibrate?

 

[Peterpills]

I've put out a similar thread several years ago but I figured I'd try once more and try to keep it simple this time.

I've got two 15" subwoofers weighing 110 lbs. each solidly anchored to the subflooring using my own custom points. With mass-loading each subwoofer actually weighs about 160 lbs. In the center is my custom rack weighing about 250 lbs. with my custom points fastened at the bottom to ensure it too is solidly anchored into the subflooring.

The distance side-to-side between the nearest subwoofer points and my rack's center point is about 24-inches. The front-to-back distance between the subwoofers' closest point and the rack's center point is maybe 4-inches. It's entirely possible that one or both subs and the rack are sharing the same sheet of plywood (subflooring). The probability that the two subwoofers and rack are sharing the same floor joist is extremely high. Everything is also extremely rigid including their mounting to the subflooring.

For those who've strived all their lives to squash or quell floor-borne vibrations, isn't my configuration the biggest no-no ever? Am I not defying some law of high-end audio physics here? If so, why don't these recordings sound like mashed potatoes? Why isn't the resolution swinging high and low with every deep bass note? Why does there seem to be a tremendous consistency in articulation whether it be a high note or low note? If there's any truth whatsoever to the evils of floor-borne vibrations, none of this should be happening. Yet, everything I throw at it, the articulation and level of musicality remains consistent and IMO extremely musical.

I think of the millions others have spent trying to isolate their equipment from floor-borne vibrations. With so much dogmatism about the evils of floor-borne vibrations, surely there must be somebody out there somewhere that can provide an in-room video or two demonstrating how much more articulate the bass and overall musical presentation can be when floor-borne vibrations have been "isolated" from the playback system.

I offer a way to resolve this query. Instant A/Bs, measurable too!
We all accept that low frequency bounce filters frequencies above that.
'Winbag' architectural builders decices are very robust, proportional inflatable cushions, designed for a builder to temporarily lift an object into place.
I have inserted three (or four) of these under a subwoofer. Also under loudspeakers too, actually.

How does it sound?
I like it. Have I measured with an iPhone accelerometer on the suspended wooden floor nearby? Before while inflated, then again once each is deflated?
Heck no. I'm enjoying the music too much. And a wibbly wobbly loudspeaker is so confronting to the conventionally wise. Who know I'm not serious because no measurements.

Winbag from Denmark, on Amazon etc $29 each. Inflated about three puffs and YMMV. Other brands abound, no cheaper nor as good I reckon.

 

[stehno]

@TheMooN, @rDin, @Peterpills.

I presume you three didn't read my post. Or you read it but did not comprehend it or you took it entirely out of context.

Everything vibrates. Duh? If I attached an accelerometer to my toaster and then a sledgehammer to the toaster, yes the shock and impact and ensuing vibrations will register. Just like in the Townsend video. So what? Speakers vibrate constantly. So what's a few more vibrations, right? In fact I consider speakers to be the epicenter of one source of vibrations but it's a source for which I don't care. BTW, I hate to burst your bubbles but performance isn't determined by measuring vibrations. You just think it is.

Additionally, my thread title question was not me asking for the others to answer as if I were facing a dilemma. Rather the question was for others who are in a dilemma swearing that floor-borne vibrations are the enemy. If you bothered to listen to the in-room videos I provided, each of these videos should demonstrate at least for those with a discerning ear that floor-borne vibrations are nothing but 30-year old folklore aka chasing windmills. But it does take a discerning ear.

Even so, none of that is my point. In fact, if you actually read my OP you would have noticed I was not seeking any comments from anybody. Rather you would have noticed that OP was directed at those committed to quelling floor-borne vibrations requesting that they produce their own in-room recordings demonstrating how much more musical their efforts are trying to isolate from floor-borne vibrations than my own videos.

None has produced any yet and I seriously doubt they ever will. Certainly Townsend can't produce one.

Those whom I directed this thread toward know who they are (including vibration mgmt mfg'ers) but they won't produce an in-room video with greater levels of musicality because I'm guessing they can't.

 

[Blackmorec]

I don’t think floor borne vibrations are a problem especially if you have a concrete foundation.

That VERY much depends on the type of concrete foundation. Concrete floors come in many different types.
1. Simple concrete above Earth
2. Reinforced concrete suspended between load bearing walls
3. A thin additional concrete ‘layer’, laid on top of 1 or 2, isolated from the underlying concrete by some form of insulation like polystyrene and from walls by means of a gap. Typically electrical wiring and plumbing are run between the 2 layers of concrete

Some of these floors will ‘ground’ components‘ vibration but connect them to any ‘seismic’ (ground borne) vibration. Others will form an energy loop where floor and component are connected and both isolated.

By anchoring components to the above you could be:
grounding your components
connecting your components to seismic vibration such as that caused by traffic
coupling your components to a large, vibrating sheet of concrete that stores vibration

In my experience, coupling components to huge mass can have a profound impact of the rhythmic ability of the system, to the point where drummers for example sound like they’re about to fall asleep and musicians sound like they’re ‘bored’ with the music they’re playing. The music tends to ‘drag’ instead of ‘bounce’

Ideally, IMO, the best, most reproducible sonic results come from properly dealing with both component generated and ground borne vibration……which means that component’s vibration should be converted to another form of energy (heat, work) while at the same time isolating them from any ground-borne vibration.

 

[Argonaut]

• #9

@TheMooN, @rDin, @Peterpills.

I presume you three didn't read my post. Or you read it but did not comprehend it or you took it entirely out of context
.

For my part I really don’t care ... Have a good day.

 

[stehno]

For my part I really don’t care ... Have a good day.

So it seems. You could go listen to some of Bonzo's in-room recordings which are usually pretty entertaining.

 

[Tim Link]

I've been thinking about the significance of floor vibrations too, especially after reading all the accolades for putting speakers on springs. It occurs to me that since E=M*V^2, the problem of the speaker cabinet being mechanically vibrated by the woofer is greatly negated if the cone velocity is reduced for any given output, such as by using multiple large woofers instead of a single smaller woofer that requires higher excursion. Of course it's possible that there are other vibrations happening, such as flexing of the speaker box.

 

[stehno]

I've been thinking about the significance of floor vibrations too, especially after reading all the accolades for putting speakers on springs. It occurs to me that since E=M*V^2, the problem of the speaker cabinet being mechanically vibrated by the woofer is greatly negated if the cone velocity is reduced for any given output, such as by using multiple large woofers instead of a single smaller woofer that requires higher excursion. Of course it's possible that there are other vibrations happening, such as flexing of the speaker box.

Tim, it seems you're making a number of assumptions here with your hypothesis. For example.

1. Since you make no mention of the crossover, you're presuming unwanted vibrations impacting performance are limited to the woofer and/or cabinet. Not sure why you'd overlook the crossover. Near as I can tell, the crossover is perhaps the most vulnerable and potentially performance compromising sector since we already know drivers vibrate continuously as intended and that can't really change much. Same with speaker cabinets as they will vibrate as anticpated to some degree no matter how inert / damped since they are attached to the drivers. But I've yet to hear anybody say crossovers are intended to vibrate. If anything, I'd consider the crossovers as mini-components and hence, if I were to assume anything it would be that the crossovers are a speaker's most potentially compromising element performance-wise.

2. Since your suggested remedy is to muliply the drivers with less excursion, you seem to be forgetting that indeed there is less excursion but now you have 2 or 3 times the volume area of a single driver with greater excursion. How might your proposal be a superior performance solution?

But I digress. You've already said twice in other threads you intended to produce your own in-room recording to substantiate your point. Care to share a video here to substantiate your point?

BTW, the point of my OP had nothing directly to do with speakers and their unwanted energy. Rather it has more to do with the electronic components and their supposed negative impact by floor-borne vibrations. Which I call folklore.

 

[BlueFox]

I would assume that floor vibrations would depend on your floor. My speakers are on a wooden floor, which is on a concrete slab, that is on the ground; i.e. no basement. When I added the footers the sound did improve, but it was a slight improvement.

 

[pjwd]

Q

 

[Tim Link]

Tim, it seems you're making a number of assumptions here with your hypothesis. For example.

1. Since you make no mention of the crossover, you're presuming unwanted vibrations impacting performance are limited to the woofer and/or cabinet. Not sure why you'd overlook the crossover. Near as I can tell, the crossover is perhaps the most vulnerable and potentially performance compromising sector since we already know drivers vibrate continuously as intended and that can't really change much. Same with speaker cabinets as they will vibrate as anticpated to some degree no matter how inert / damped since they are attached to the drivers. But I've yet to hear anybody say crossovers are intended to vibrate. If anything, I'd consider the crossovers as mini-components and hence, if I were to assume anything it would be that the crossovers are a speaker's most potentially compromising element performance-wise.

2. Since your suggested remedy is to muliply the drivers with less excursion, you seem to be forgetting that indeed there is less excursion but now you have 2 or 3 times the volume area of a single driver with greater excursion. How might your proposal be a superior performance solution?

But I digress. You've already said twice in other threads you intended to produce your own in-room recording to substantiate your point. Care to share a video here to substantiate your point?

BTW, the point of my OP had nothing directly to do with speakers and their unwanted energy. Rather it has more to do with the electronic components and their supposed negative impact by floor-borne vibrations. Which I call folklore.

I'm sorry I misunderstood your OP. Other posts I've been reading about lately have been concerned with putting springs under speakers to keep them from mechanically activating the floor. As far as floor-borne vibrations negatively impacting components, that is not something that I have personally experienced except with record players.

1. Indeed, I wasn't talking about the crossover. I only specifically mentioned the woofer but the midrange and tweeter matter also.

2. Yes, multiple drivers or bigger drivers will have more mass and surface area but they will move slower. Added motion adds energy much faster than added mass because in the equation, speed is squared but mass is not. That's why gunpowder puts a lot more energy into the bullet than the gun, even though momentum is equally distributed. Isolating the cone from the cabinet as B&W does has been mentioned in other posts (maybe on other forums) so I am understanding that it is the mass of the cone motion that is primarily what is believed to be causing the speaker cabinet to move, not pressure from it moving against the air.

I want to make a video that can demonstrate the difference between an untreated room and the same room with treatments added. I don't yet have the resources at my personal disposal to do that. Our room here at work is currently unavailable, and I don't have a vehicle at the moment that can move the acoustics needed for me to test at home. I apologize but there's nothing I can do about that at the moment. When I do it you'll be the first to know!

 

[stehno]

I'm kinda' surprised not a singal vibration isolation evangelist has stepped forward with an in-room recording to demonstrate that methodology's superiority. Hmmmmm, maybe it can't be done? That's my guess anyway.

 

[Blackmorec]

Hi stehno,
I added SPODs to my Magico S1MkIIs and was delighted with the results. Similarly I placed Cerabases under my network Pagoda MR stand and was similarly impressed. I just dont feel the need to go to the trouble of making videos to convince sceptics. If you don‘t believe, don‘t spend the money. There’re plenty of alternate places to go for improvements

 

[stehno]

Let's try this again.

I'm kinda' surprised not a single vibration isolation evangelist has stepped forward with an in-room recording to demonstrate that methodology's superiority. Hmmmmm, maybe it can't be done? That's my guess anyway.