Hats off to Shannon Dickson for his landmark article on vibration isolation and for his suggestion to attach a large auxiliary air canister to my single airspring Sub-Hertz Nimbus Platform via the air fitting on the airspring, thereby making the relatively small airspring think it was a great big SUPER airspring.
Active isolation; what can it do for music reproduction?
i was involved in a thread about stylus drag on turntables where my use of active isolation came up. it was asked for me to discuss my views and use of this approach for system optimization. i mentioned it likely needed it's own thread to do justice to the topic. here it is.
excuse me if i get too basic here to begin with. i've not seen this subject discussed in depth on Audiogon before.
active isolation devices use piezoelectric sensors in 6 axis to sense resonance and piezoelectric actuators in 6 axis to compensate for that resonance. in essence it's a feedback loop of read and compensate.
http://en.wikipedia.org/wiki/Piezoelectric_sensor
passive devices are more or less springs to one degree or another. springs float, settle and overshoot. active devices are relatively stiff; 500 times stiffer than passive since they can STOP and START. passive can't stop and start. you do see passive devices with automatic leveling, but otherwise they can only act passively as a spring.
an example of an active device; the Herzan TS Series;
http://www.herzan.com/products/active-vibration-control/ts-series.html
the limitations of active devices are mainly as follows;
---they are only really effective under 200hz.
---in stock form they typically have signal path corrupting switch mode power supplies.
---to be effective they need a solid base. which means a solid rack grounded to a solid concrete floor. suspended wood floors, or non-solid racks are going to compromise the performance.
---the gear being isolated cannot have it's own self resonance that might excite the active sensors. and not every piece of gear will benefit from active isolation. so active is very system context dependent. you can't just use it anywhere and expect a particular result.
there are very very good passive devices that approach what an active device can do; the Minus K, Stacore platforms, and Vibraplance are three popular examples. i'd recommend investigating these before considering any active devices. those examples do need the same solid floor and rack as active to be effective.
and another consideration is a passive isolation rack; the best example i can give is the Artesania decoupling rack systems. likely the best passive rack. again; a solid floor is going to allow the Artesania to perform at it's best.
finally; there is a website tutorial which can really get granular with deeper levels of information on active devices for those interested.
http://www.herzan.com/resources/tutorials.html
lastly i will say that active devices are something you consider when you've mostly done everything else you can do and want to take things further. cross otherwise impossible thresholds of performance. you have a system that is where you want it to be. active is the bleeding edge. it will allow the music to escape the confines of resonance in a way nothing else can do. it's just physics.
excuse me if i get too basic here to begin with. i've not seen this subject discussed in depth on Audiogon before.
active isolation devices use piezoelectric sensors in 6 axis to sense resonance and piezoelectric actuators in 6 axis to compensate for that resonance. in essence it's a feedback loop of read and compensate.
http://en.wikipedia.org/wiki/Piezoelectric_sensor
passive devices are more or less springs to one degree or another. springs float, settle and overshoot. active devices are relatively stiff; 500 times stiffer than passive since they can STOP and START. passive can't stop and start. you do see passive devices with automatic leveling, but otherwise they can only act passively as a spring.
an example of an active device; the Herzan TS Series;
http://www.herzan.com/products/active-vibration-control/ts-series.html
the limitations of active devices are mainly as follows;
---they are only really effective under 200hz.
---in stock form they typically have signal path corrupting switch mode power supplies.
---to be effective they need a solid base. which means a solid rack grounded to a solid concrete floor. suspended wood floors, or non-solid racks are going to compromise the performance.
---the gear being isolated cannot have it's own self resonance that might excite the active sensors. and not every piece of gear will benefit from active isolation. so active is very system context dependent. you can't just use it anywhere and expect a particular result.
there are very very good passive devices that approach what an active device can do; the Minus K, Stacore platforms, and Vibraplance are three popular examples. i'd recommend investigating these before considering any active devices. those examples do need the same solid floor and rack as active to be effective.
and another consideration is a passive isolation rack; the best example i can give is the Artesania decoupling rack systems. likely the best passive rack. again; a solid floor is going to allow the Artesania to perform at it's best.
finally; there is a website tutorial which can really get granular with deeper levels of information on active devices for those interested.
http://www.herzan.com/resources/tutorials.html
lastly i will say that active devices are something you consider when you've mostly done everything else you can do and want to take things further. cross otherwise impossible thresholds of performance. you have a system that is where you want it to be. active is the bleeding edge. it will allow the music to escape the confines of resonance in a way nothing else can do. it's just physics.
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- 52 posts total
Hats off to Shannon Dickson for his landmark article on vibration isolation and for his suggestion to attach a large auxiliary air canister to my single airspring Sub-Hertz Nimbus Platform via the air fitting on the airspring, thereby making the relatively small airspring think it was a great big SUPER airspring.off the shelf piezo electric active devices did not exist for us to buy in 1995 when Shannon Dickson wrote that article. back then it was air bladder passive for the state of the art......like my Rockport Sirius IISE turntable. my later Sirius III turntable which was introduced a year later in 1996. one relevant point regarding active from that article was that Mr. Dickson went to great lengths to say that once resonance is introduced into the system or rack you can’t get rid of it. you can only change the frequency or degree....the overall energy remains. but......now the game has changed. we are no longer limited to passive resonance attenuation. you can now actually ’STOP and START’ and compensate for that sensed resonance with active resonance attenuation devices and remove some that resonance from the equation in the specific most harmful frequencies. |
Yes, I have been following the developments. While it’s very nice that active devices are available, it’s remarkable just how far you can go with passives. Plus we had to start somewhere. Ha ha I can isolate an entire system with 2 Hz performance for about two bills. By devices are now pure springs, make things simple. I’m rather fond of the passive Minus K, at least in concept. I also like what Townshend is doing for speaker isolation. |
Jose, i would not want to hold myself up as any tech expert or authority. i have some opinions and observations only. that said here are a few products i know about. besides active; the top level of passive i’ve used myself are the air suspended Rockport turntables. which is analogous to a Vibraplane. http://positive-feedback.com/Issue50/vibraplane.htm as far as the best passive i’ve observed at shows; the Minus K would be very good, but it’s hard to maintain the balance so not very user friendly. http:///www.minusk.com/ the other top choice would be the Stacore shelf systems. that would be my first choice besides active. http://stacore.pl/en/ those are the big boy passive choices on my radar; but much less than my Taiko Tana TS active systems. next is an inexpensive platform system from Taiko Audio called a Daiza. i have 18 of these in my system. you buy them in custom sizes equal to the footprint of your gear. they are made of Panzerholtz.....and have footers included. from around $450--$1000 depending on size. http://taikoaudio.com/product/daiza/ i use 8 sets of A10 U8’s; decoupling footers from Wave Kinetics. i also use 4 sets of 2NS, under the spikes on my speakers. http://wavekinetics.com/products/a10-u8/?doing_wp_cron=1571866626.3730359077453613281250 i’ve used Stillpoints before; mixed experiences. Center Stage footers have many fans; not used them myself and not cheap. http://www.criticalmasssystems.com/productPages/CenterStage.html as far as racks there are two pathways. you can get a solid grounded rack and then treat each piece of gear individually. this is how i do it and i use Adona Reference GTX racks. the alternative is decoupling racks, and there are many choices. mostly good. but big investment, and very hard to sell if your needs change. this is only my own narrow answer to your question. and not meant in any way to be comprehensive. not sure if this thread is where we want 20 other recommendations from others, but i guess we just go with the flow. |
- 52 posts total