Active isolation for loudspeaker: Seismion Altas Dynamic

[TLi]

Everyone in audio field agrees vibration control has vital role in sound quality. That's why we have this section in WBF.

The equipment that vibrates most has to be loudspeaker. Ideal situation for any "boxed" loudspeaker is minimal vibration in cabinet, only movement comes from driver diaphragm. Manufacturers use two ways to try to address this. Build a cabinet that is very rigid and make the cabinet very heavy. Rigid cabinet reduces distortion of the box which in turn reduces distortion to the sound. Increase the mass lowers shaking of the whole loudspeaker by having more inertia. All these are passive methods to improve the performance. There is a practical limit on how heavy loudspeaker can be for domestic use. Very few people can accommodate a pair of say 5000 pound loudspeakers.

There is a place for active isolation. By actively controlling vibration of cabinet will have the same effect of increasing the mass, any vibration is actively damped. The response time has to be quick otherwise attack of a drum strike will not be real. The counteracting force of active isolator has to be larger than other isolators for static equipment. These are challenges for active isolator for loudspeaker.

Last year in Munich Highend Show, Seismion demonstrated active isolation with Sigma Acoustics loudspeaker. The result was promising but problems were identified and improvement was made. One thing that had to improve was the response time. Seismion comes up with Altas Dynamic which has significantly faster response time than the original Altas model.

I ordered a set of Altas Dynamic for my Magico M7. The set consists of 8 pieces of isolators together with separate distribution boxes and power supplies. MPod under M7 was removed and the base rests directly on Altas Dynamic for best isolation. Although I had heard the demo in Munich, the improvement in sound is still quite shocking. All aspects of sound are enhanced. Quite a few of my friends have come to listen and they all agree the sound is very clean and detailed. Resolution in treble, midrange and bass are increased. This is real improvement, not just shifting from one side to another. It is like changing to a higher model loudspeaker.

It makes me think why no loudspeaker is made with built in active isolation. It certainly sounds much better. This idea needs to be further explored.

 

[MatthewC]

Everyone in audio field agrees vibration control has vital role in sound quality. That's why we have this section in WBF.

The equipment that vibrates most has to be loudspeaker. Idea situation for any "boxed" loudspeaker is minimal vibration in cabinet, only movement comes from driver diaphragm. Manufacturers use two ways to try to address this. Build a cabinet that is very rigid and make the cabinet very heavy. Rigid cabinet reduces distortion of the box which in turn reduces distortion to the sound. Increase the mass lowers shaking of the whole loudspeaker by having more inertia. All these are passive methods to improve the performance. There is a practical limit on how heavy loudspeaker can be for domestic use. Very few people can accommodate a pair of say 5000 pound loudspeakers.

There is a place for active isolation. By active controlling the vibration of the cabinet will have the same effect of increasing the mass, any vibration is actively damped. The response time has to be quick otherwise attack of a drum strike will not be real. The counteracting force of active isolator has to be larger than other isolators for static equipment. These are challenges for active isolator for loudspeaker.

Last year in Munich Highend Show, Seismion demonstrated active isolation with Sigma Acoustics loudspeaker. The result was promising but problems were identified and improvement was made. One thing that had to improve was the response time. Seismion comes up with Altas Dynamic which has significantly faster response time than the original Altas model.

I ordered a set of Altas Dynamic for my Magico M7. The set consists of 8 pieces of isolators together with separate distribution boxes and power supplies. MPod under M7 was removed and the base rests directly on Altas Dynamic for best isolation. Although I had heard the demo in Munich, the improvement in sound is still quite shocking. All aspects of sound are enhanced. Quite a few of my friends have come to listen and they all agree the sound is very clean and detailed. Resolution in treble, midrange and bass are increased. This is real improvement, not just shifting from one side to another. It is like changing to a higher model loudspeaker.

It makes me think why no loudspeaker is made with built in active isolation. It certainly sounds much better. This idea needs to be further explored.

View attachment 159150

Thank you Thomas for doing this experiment and inviting us to ear-witness the effect. I must say I didn’t know what to expect when the concept was first mentioned. One thing that crossed my mind initially before the listen was whether dynamics will be reduced or enhanced. It’s entirely possible that the reactive forces from the isolation device may, for certain frequencies, cancelled out the drivers’ movement. But hearing is believing…. The resolution (especially in the lower frequencies) was significantly increased, which is not that surprising. And fortunately the overall sound remain coherent from top to bottom, which was a relief. Overall the system’s resolution and especially layering is notably enhanced. The tonal balanced shifted slightly to be warmer, which I guess was because previously the speakers were on hardwood/concrete flooring. But at the same time the attacks / leading edge of percussions were sharper while the tonal balance was warmer…. A very interesting set of changes. Do agree w/ Thomas that this should be investigated by speakers designers. This just might be the next level up for speaker designs!

 

[ctydwn]

Everyone in audio field agrees vibration control has vital role in sound quality. That's why we have this section in WBF.

The equipment that vibrates most has to be loudspeaker. Idea situation for any "boxed" loudspeaker is minimal vibration in cabinet, only movement comes from driver diaphragm. Manufacturers use two ways to try to address this. Build a cabinet that is very rigid and make the cabinet very heavy. Rigid cabinet reduces distortion of the box which in turn reduces distortion to the sound. Increase the mass lowers shaking of the whole loudspeaker by having more inertia. All these are passive methods to improve the performance. There is a practical limit on how heavy loudspeaker can be for domestic use. Very few people can accommodate a pair of say 5000 pound loudspeakers.

There is a place for active isolation. By active controlling the vibration of the cabinet will have the same effect of increasing the mass, any vibration is actively damped. The response time has to be quick otherwise attack of a drum strike will not be real. The counteracting force of active isolator has to be larger than other isolators for static equipment. These are challenges for active isolator for loudspeaker.

Last year in Munich Highend Show, Seismion demonstrated active isolation with Sigma Acoustics loudspeaker. The result was promising but problems were identified and improvement was made. One thing that had to improve was the response time. Seismion comes up with Altas Dynamic which has significantly faster response time than the original Altas model.

I ordered a set of Altas Dynamic for my Magico M7. The set consists of 8 pieces of isolators together with separate distribution boxes and power supplies. MPod under M7 was removed and the base rests directly on Altas Dynamic for best isolation. Although I had heard the demo in Munich, the improvement in sound is still quite shocking. All aspects of sound are enhanced. Quite a few of my friends have come to listen and they all agree the sound is very clean and detailed. Resolution in treble, midrange and bass are increased. This is real improvement, not just shifting from one side to another. It is like changing to a higher model loudspeaker.

It makes me think why no loudspeaker is made with built in active isolation. It certainly sounds much better. This idea needs to be further explored.

View attachment 159150

incredible. has to sound amazing. i do think the sink in right corner might be the key underrated component here. absolutely envious of the system

 

[Seismion]

Thanks for this detailed report, Thomas!
The Seismion Atlas Dynamic was developed for industrial use in semiconductor manufacturing and quality control. These systems typically weigh several tons, may include moving stages, and impose very stringent settling-time requirements. While all our isolators respond instantaneously thanks to fully analog control, the Atlas Dynamic delivers significantly higher control forces—essential for systems with moving stages as well as for loudspeaker damping and isolation.
We fully agree that closed-loop vibration control for loudspeakers makes a great deal of sense and holds real promise. That said, isolation becomes increasingly challenging as system mass grows, so there are certainly more forgiving applications than high-end loudspeakers—perhaps one reason it has seen limited adoption to date.

 

[spiritofmusic]

Any issues with altered height of drivers (especially the tweeters)?

 

[TLi]

Any issues with altered height of drivers (especially the tweeters)?

The loudspeakers are raised by about two inches. I also had the same worry that the image may be too high and bass energy may be reduced.

After actual audition, there is no such problem. The image is still very good and nicely centred in front. Bass is not reduced and more details is presented with more impact and energy.

 

[mtemur]

An active isolation platform generates its own counter-vibrations to fight against those coming from the cabinet—but it also reacts to vibrations produced by the drivers, which, by the way, is called sound. An active isolation platform doesn’t know, and cannot know, the source or nature of a vibration. It cannot distinguish whether it’s dealing with cabinet resonances, residual vibrations, or sound energy produced by the drivers. It counters all of them indiscriminately.

The reason you perceive increased detail is that, regardless of how it’s built, an isolation platform cannot respond to high frequencies as quickly as it responds to low frequencies. The weight of the cabinet also limits its ability to react fast enough. As a result, it suppresses low frequencies more effectively than highs, which can create the impression of greater detail. It’s similar to reducing the lows with an equalizer. An active isolation platform is clouding what the drivers produce. It adds its own vibrations as counter vibrations. Using the is wrong in my opinion.

 

[spiritofmusic]

An active isolation platform generates its own counter-vibrations to fight against those coming from the cabinet—but it also reacts to vibrations produced by the drivers, which, by the way, is called sound. An active isolation platform doesn’t know, and cannot know, the source or nature of a vibration. It cannot distinguish whether it’s dealing with cabinet resonances, residual vibrations, or sound energy produced by the drivers. It counters all of them indiscriminately.

The reason you perceive increased detail is that, regardless of how it’s built, an isolation platform cannot respond to high frequencies as quickly as it responds to low frequencies. The weight of the cabinet also limits its ability to react fast enough. As a result, it suppresses low frequencies more effectively than highs, which can create the impression of greater detail. It’s similar to reducing the lows with an equalizer. An active isolation platform is clouding what the drivers produce. It adds its own vibrations as counter vibrations. Using the is wrong in my opinion.

Can you make the same argument against using active isolation on TTs and even CDPs which are designed to move?

 

[mtemur]

Can you make the same argument against using active isolation on TTs and even CDPs which are designed to move?

Absolutely I can and I do.
I would also extend it to include amplifiers and back that up with actual test we (a couple of friends and I) did. We all preferred amplifiers and turntable without active platform.

 

[spiritofmusic]

I did a little a/b on my CDP a few years back, comparing it on a Kuraka active (Herzan equivalent) v Stacore passive.
Initially the Kuraka sounded fantastic, but the Stacore was the easy winner.

 

[TLi]

An active isolation platform generates its own counter-vibrations to fight against those coming from the cabinet—but it also reacts to vibrations produced by the drivers, which, by the way, is called sound. An active isolation platform doesn’t know, and cannot know, the source or nature of a vibration. It cannot distinguish whether it’s dealing with cabinet resonances, residual vibrations, or sound energy produced by the drivers. It counters all of them indiscriminately.

The reason you perceive increased detail is that, regardless of how it’s built, an isolation platform cannot respond to high frequencies as quickly as it responds to low frequencies. The weight of the cabinet also limits its ability to react fast enough. As a result, it suppresses low frequencies more effectively than highs, which can create the impression of greater detail. It’s similar to reducing the lows with an equalizer. An active isolation platform is clouding what the drivers produce. It adds its own vibrations as counter vibrations. Using the is wrong in my opinion.

Sorry for the late reply, I am on the road.

Welcome mtemur to join the discussion. His opinion is always a reference point. Audiophile impression tends to diversify quite a bit.

At least, mtemur agrees there is something clouding the sound produced by loudspeaker. We have a common point. Apart from the vibration of driver diaphragm which should be the only thing moving, all other vibrations are detrimental to the sound. Active isolators control or reduce the vibration of the cabinet, that should only be beneficial. Like noise cancelling headphones, it produces a 180 degree out of phase sound to reduce ambient noise. Yes, it produces sound but you can’t hear it.

Bass is always the biggest problem. If music that we love is limited to 200 hertz and above, our stereo system is much smaller and cheaper. Active isolation aims at lower frequency, there is nothing wrong with it, that’s where the problem starts.

There is a difference between reducing bass and better bass. Active isolation gives you better bass. Quality is improved not quantity. Some loudspeakers rely on the vibration of cabinet to boost the bass. Reducing it will reduce the bass, but fortunately I don’t use that kind of loudspeaker.

I must be standing on the opposite end of mtemur’s position, it doesn’t matter, as long as we are both enjoying our system. Happy listening.

 

[mtemur]

Sorry for the late reply, I am on the road.

Welcome mtemur to join the discussion. His opinion is always a reference point. Audiophile impression tends to diversify quite a bit.

At least, mtemur agrees there is something clouding the sound produced by loudspeaker. We have a common point. Apart from the vibration of driver diaphragm which should be the only thing moving, all other vibrations are detrimental to the sound. Active isolators control or reduce the vibration of the cabinet, that should only be beneficial. Like noise cancelling headphones, it produces a 180 degree out of phase sound to reduce ambient noise. Yes, it produces sound but you can’t hear it.

Bass is always the biggest problem. If music that we love is limited to 200 hertz and above, our stereo system is much smaller and cheaper. Active isolation aims at lower frequency, there is nothing wrong with it, that’s where the problem starts.

There is a difference between reducing bass and better bass. Active isolation gives you better bass. Quality is improved not quantity. Some loudspeakers rely on the vibration of cabinet to boost the bass. Reducing it will reduce the bass, but fortunately I don’t use that kind of loudspeaker.

I must be standing on the opposite end of mtemur’s position, it doesn’t matter, as long as we are both enjoying our system. Happy listening.

Hi TLi,
I’m afraid you completely misunderstood me. Please read my post again.

IMHO:
Nothing clouds the sound of a speaker as long as the cabinet is well designed — and I’m pretty sure the Magico M7’s cabinet qualifies. It’s rigid, well-constructed, and more importantly, very heavy. The only real mistakes you can make are placing it on a carpet or suspended floor, or using rubber feet like IsoAcoustics — or worse, a Seismion.

All you really need to do is make sure the speakers are resting firmly on their spikes on a rigid floor, preferably wood, and tighten all the feet evenly so the speakers stand completely still.

When you use a Seismion or any other active isolation base, it fights against all vibrations — including those intentionally produced by the drivers. It can’t distinguish between cabinet resonances and the sound itself, so it ends up working against the drivers. Active isolation systems mainly kill the bass because they can’t generate counter-vibrations as quickly as the tweeter. In practice, using one is like adding an equalizer — it alters and kills the sound.

You mentioned it works like noise-cancelling headphones. But think about it — can you imagine a recording engineer using noise-cancelling headphones while recording?

 

[Mike Lavigne]

Hi TLi,
I’m afraid you completely misunderstood me. Please read my post again.

IMHO:
Nothing clouds the sound of a speaker as long as the cabinet is well designed — and I’m pretty sure the Magico M7’s cabinet qualifies. It’s rigid, well-constructed, and more importantly, very heavy. The only real mistakes you can make are placing it on a carpet or suspended floor, or using rubber feet like IsoAcoustics — or worse, a Seismion.

All you really need to do is make sure the speakers are resting firmly on their spikes on a rigid floor, preferably wood, and tighten all the feet evenly so the speakers stand completely still.

When you use a Seismion or any other active isolation base, it fights against all vibrations — including those intentionally produced by the drivers. It can’t distinguish between cabinet resonances and the sound itself, so it ends up working against the drivers. Active isolation systems mainly kill the bass because they can’t generate counter-vibrations as quickly as the tweeter. In practice, using one is like adding an equalizer — it alters and kills the sound.

You mentioned it works like noise-cancelling headphones. But think about it — can you imagine a recording engineer using noise-cancelling headphones while recording?

if you can eliminate acoustical feedback and even ground noise from a speaker cabinet that is a huge step forward.

will every speaker have the mass and structure to still give the drivers sufficient leverage to overcome lack of grounding from the active isolation device? my guess is that the Magico M7's are one of those that qualifies. but others might not give you the net gain that the M7 does. where the smear of the driver gets reduced.

active advantages are very contextual. particular cases, not universal.

 

[Jeff4598]

if you can eliminate acoustical feedback and even ground noise from a speaker cabinet that is a huge step forward.

will every speaker have the mass and structure to still give the drivers sufficient leverage to overcome lack of grounding from the active isolation device? my guess is that the Magico M7's are one of those that qualifies. but others might not give you the net gain that the M7 does. where the smear of the driver gets reduced.

active advantages are very contextual. particular cases, not universal.

A rigid and heavy cabinet cannot erase vibrations- it can only TRANSMIT vibrations quickly and with little addition of harmonics. The vibrations have to go somewhere. The choice is into something under the speaker or back to the drivers. What do you think sounds better? It is not uncommon for increased clarity of bass to sound at first like less bass volume. I assume this is because the third harmonic of 2Khz does not sound much like 2 Khz while the third harmonic of 30hz is harder to distinguish from 30hz and is percieved as "bass". This makes sense evolutionarily because the difference between a human and a bird vocaliing is far more significant than the exact size of an animal shaking the ground as it gets closer to us. But, as L Cohen wrote, I could be wrong.

 

[mtemur]

A rigid and heavy cabinet cannot erase vibrations-

It certainly can. High mass is one of the most common approaches to overcoming vibration. Other methods include using elastomers and springs. They’re effective at different frequency ranges, but it’s a physical fact that a heavy cabinet can absorb vibrations down to very low frequencies, depending on its weight. For this purpose, the speaker should sit on a very rigid, non-suspended floor, using its own spikes and footers.

 

[Jeff4598]

It certainly can. High mass is one of the most common approaches to overcoming vibration. Other methods include using elastomers and springs. They’re effective at different frequency ranges, but it’s a physical fact that a heavy cabinet can absorb vibrations down to very low frequencies, depending on its weight. For this purpose, the speaker should sit on a very rigid, non-suspended floor, using its own spikes and footers.

What happens to the vibration? What do you mean by "absorb"?

 

[mtemur]

What happens to the vibration? What do you mean by "absorb"?

It turns to heat.

 

[Jeff4598]

It turns to heat.

How would a solid (heavy) mass turn vibration to heat? The heavier the cabinet the less it moves and the more the vibrations go back to the drivers- or to flexible or very light elements in footers. By your conceptual framework a 120 lb runner would transfer more of its energy into a 300 lb stationary person than into a 160 pounder. And even more so if it was a 300lb slab of granite. I don't think that would work. Any actual engineers here who could explain? I think F= MA may be relevant.

 

[QuadDiffuser]

Back to basics. It's worthwhile revisiting the fundamentals of the pros/cons of coupling vs decoupling of loudspeakers. Energy generated by loudspeakers WILL transmit into structural elements of the listening room when directly coupled, so attenuating this energy is important.

 

[mtemur]

How would a solid (heavy) mass turn vibration to heat? The heavier the cabinet the less it moves and the more the vibrations go back to the drivers- or to flexible or very light elements in footers. By your conceptual framework a 120 lb runner would transfer more of its energy into a 300 lb stationary person than into a 160 pounder. And even more so if it was a 300lb slab of granite. I don't think that would work. Any actual engineers here who could explain? I think F= MA may be relevant.

By absorption.
A properly made cabinet doesn’t ring and absorb vibrations. Vibration turns into heat upon absorption. You totally missed the point. It’s a form of energy turning into another form of energy.