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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.
mikelavigne

Showing 9 responses by mikelavigne

mikelavigne OP
2,149 posts
 
so what am i doing in my system with active isolation?

i’ve had stock Herzan active TS units in my system since 2013. i first tried one in 2002 in my old room and it was in the back of my mind since i heard what they could do then. in 2013 i found with my new larger MM7 twin tower speakers with the bass towers 6 feet away from my turntable that the bass energy radiated into my turntable was causing feedback. the Herzan’s apparently eliminated that feedback. my simplistic viewpoint back then has considerably changed, but i was not wrong. it was just never as simple as i had thought.

fast forward to today; i now use -5- Taiko Tana active shelves. a Tana active shelf is a Herzan TS shelf on steriods.

http://taikoaudio.com/products/taiko-audio-tana/

first off the SMPS (switch mode power supply) is removed, and a power port is installed. then a very optimized outboard linear power supply is substituted. you can see these -5- Tana active shelves on my system page, and note the linear power supplies with large panerholtz cases, sitting on Taiko Daiza platforms. these power supply mods greatly increase the accuracy and overall performance and also eliminate the SMPS noise into the system signal path. as always power supplies become the limiting factor.

each of these TS units is also modified as follows; a tapped aluminum top plate to substituted for the solid top plate; and a 10mm layer of panzerholtz is attached. then a thin rubber layer is laid down and a Taiko Daiza platform is set on top. these passive modifications extend the resonance attenuation effectiveness from under 200hz to the whole frequency range.

i have these -5- devices as follows;

-one ’each’ under each of my darTZeel 458 mono block amplifiers
-one under my darTZeel 18NS preamp
-one under the dac box of my MSB Select II dac
-one under my Wave Kinetics NVS direct drive turntable

my system information;

http://systems.audiogon.com/systems/615

mikelavigne OP
2,149 posts
 
what is the effect on the music?

generally; properly implemented, what a single active device will do is to bring a level of calm and naturalness to the music. it will allow moments of musical stress and energy to be more finely sorted out, to flow better. the musical focus will increase, but without an unnatural type of false edge or high frequency increase.

and the greater your dynamic expectations for your system, the more resonance attenuation matters, and the more active can take you further. if you look at my system it is designed to do big music effortlessly. i have a large room, very well tuned, headroom in my power grid, headroom in my amplification, and a high level of driver surface. i can really get lots of energy. which means lots of potential feedback into my signal path to smear and blur the musical message. active resonance control keeps the music pure on musical peaks and makes me want to listen more and allows me to immerse myself more in the music.

what is not always appreciated is (1) how electronics sing along with the music, and (2) how the environment around us compromises any electronics and adds it's own noise. you will never realize those things until you remove them and then it's an epiphany moment. 

having -5- of these devices in my system takes it all to another level because the normal feedback loop for the resonance corruption is completely broken. think about it. if your source is protected by active, but your preamp or amp is not, then the resonance in those devices will be picked up and fed back to the signal path into the speakers, then back into the system. active in each step has a multiplier effect on the degree of benefit.

it's easy for me to just turn the active effect off for my amplifiers briefly and the 3D effect in the music relatively collapses. turn it back on and the 3D is back.
mikelavigne OP
2,149 posts
 
What about people like mikelavigne who say they can hear a difference when they turn the isolation platforms off?

i welcome skepticism.

just to let you know, last Thursday i had visitors to my room who asked me if they could turn those Tana active platforms off and see the effect, so i said go ahead. that was their viewpoint. there were 4 of us in the room at the time.

here is a link to those comments;

http://www.whatsbestforum.com/threads/taiko-audio-sgm-extreme-the-cr%C3%A8me-de-la-cr%C3%A8me.27433/page-64#post-603082

come on over anytime and hear it for yourself.

twice in the last year i had some local audio friends come over and check my own perceptions on the active Tana shelves prior to buying the last couple. i wanted to make sure i was not being delusional.

this is not any subtle feeling over days of listening. this is poke you in the nose obvious.

would the effect be as obvious in every system? of course not. my system is all about hearing everything. as i said above, this is the kind of thing you do when you have done everything else, and you have the optimal environment to get the most out of the investment.

and having 5 of these in the system increases the effect since any resonance feedback restriction is broken by removing one. so that’s a bit of a multiplier effect on turning one off. not saying you are accepting that, but that is what i observe.
mikelavigne OP
2,149 posts
 
i would not begin to talk tech with Geoff. :-)

horses for courses.

solutions are scaled to the target situation. not sure electron microscope targeted tools (the intended scientific use for these active devices) is appropriate for the uses Geoff refers to. but.......science and industry has chosen these active units over other choices. and their tools ’work’ for our High Fidelity purposes with a few modifications.

i’ve not heard anything do what the Tana active devices do in my system.

far be it from me to suggest that maybe better choices don’t/can’t exist. i will watch for Geoff to introduce his new LIGO spec isolation hifi product line. i think that maybe when we build our rooms we do some of what Geoff refers to here. for instance; depending on the distance from major sources of ground noise we might use sand or some other material under our concrete floors. as i’m in the mountains, away from highways, surf, or train tracks, on glacial till, away from any urban center, in the middle of 5 acres, in a separate building from my house.......6 inches of concrete did the trick. does this go as far as the LIGO approach? maybe not. but those factors are passive things we do to set the stage for our other efforts.

i agree with the associated equipment comments; the link i posted above to the Herzan tutorial goes to great lengths to address that issue. ultimate resonance isolation needs a comprehensive approach.

i am planning on suspending my speaker cables from ’half rounds’ with a series of bungee cords. i have the bungee’s and am looking for the proper ’half rounds’ that will work. i want something in metal or hardwood that fits into my system vibe. even though i can quickly A/B on and off and hear the active contribution i know it will improve, as my speaker cables are heavy and i know it’s damping the reaction performance of those Tana’s beneath my amps.

and there are passive components to the Tana shelves. which i did describe above.

so i’d say i have no issue with any of what Geoff describes.
mikelavigne OP
2,149 posts
 
what i said was that the ’active’ part of the resonance attenuation is most effective under 200hz. there is still passive attenuation going on. purely passive isolation platforms ’in general’ work differently.

try as they might....passive platforms cannot STOP and START....they settle, overshoot, and float. they are springs. or they provide impedance breaks....or mass loading...or combinations of those attributes.

understand i have lots of passive resonance attenuation in my system and am a true believer in it. active is reserved for where i can justify it.

The vibration isolation performance of every TS table allows research instruments to maximize their resolution by removing ambient vibration noise from affecting their data. Essentially, any instrument sensitive to vibration noise less than 5 Hz can greatly benefit from the unique technology found within a TS Series table.

  • Active vibration isolation from 0.7 – 1,000 Hz
  • Passive vibration isolation from 1,000 Hz and beyond
  • 90% vibration isolation at 3.5 Hz
  • 99% vibration isolation at 10 Hz
  • 99.9 vibration isolation at 20 Hz and beyond
  • Up to 55 dB of vibration reduction beyond 20 Hz

mikelavigne OP
2,149 posts
 
Mike, everyone has a right to their own opinion. judging results based on the theoretical dots not connecting for you is your issue, not mine. i have satisfied my own concerns.

next case.

please visit me and listen for yourself if you like. many have.


mikelavigne OP
2,149 posts
 
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.
mikelavigne OP
2,149 posts
 
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.
mikelavigne OP
2,149 posts
 
what might be happening with speaker spikes on the concrete is that it’s digging in a bit on a molecular level so the depth is changing slightly. if you use some sort of disc under the spikes (copper pennies actually work well) then you will stop any tendency to dig in but retain the solidity. there are lots of examples on the market of discs with dimples to accept spikes. i would be surprised if you don't already have some laying around.

in my long list of tweaks i do list the 2NS from Wave Kinetics which are exactly what you ask for; decoupling footers speaker spikes can go into. and their decoupling action is designed for speakers; to allow the drivers to stay linear by not getting ground based acoustic feedback. here is a link.

http://wavekinetics.com/products/2ns/?doing_wp_cron=1572282455.7133500576019287109375

i use -4- sets of 2NS under my 4 x 750 pound tower speakers. so they are ready to rock with lots of dynamics.
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