Vibration isolation question

[Ethan Winer]

Interesting to see Ethan advocating a subjective approach.

The first thing I suggested is measuring the system using room measuring software. The second thing I mentioned is a blind listening test. A blind test isn't subjective if it's done properly. Sadly, all the people who insist the benefit of isolation under gear "is so obvious" and "the system as a whole takes a performance leap forward" live too far for me to visit in person to see if they really can tell With versus Without. And when I've offered to visit local people such as Michael Fremer, Myles B. Astor, and Jeremy Kipnis, among others, they always refuse. I'm sure I know why they refuse. So until proven otherwise, I'll continue to believe that isolation works mainly on placebo effect.

Transistors and ICs are susceptible to microphonics though not as much as tubes.

Unless you've tested this using sound generators, and measured output voltages versus frequency and SPL amounts, I doubt you have any idea how much air-borne vibration is needed to affect solid state equipment. As always, I'm glad to review any hard data you have.

Ethan is correct in that most vibration is airborne; an anti-vibration platform is effective at draining off such vibration if used correctly.

How can a pillow underneath a preamp reduce vibration into the preamp via the air? Please be very specific.

Bob Worzalla of Sound Anchors showed many years ago that speakers also benefit from platforms or stands. He did this by aiming a lazer at the cabinet of the speaker itself and observing how it changed when on a proper stand.

This is meaningless because artifacts can be measured that are too small to be audible. If he also did listening tests, but they weren't blind, then those were meaningless as well.

--Ethan

 

[microstrip]

Just to remember that equipment it self generates vibrations and forcefully gets airborne feedback - components dealing with vibration must isolate the device and simultaneously drain the vibrations out of equipment. Not a simple task!

 

[GaryProtein]

You could probably mount a solid state pre or power amp on top of a subwoofer and not notice any difference if you weren't looking at it.

 

[rockitman]

You could probably mount a solid state pre or power amp on top of a subwoofer and not notice any difference if you weren't looking at it.

Isolation makes a noticeable difference under my SS Power amps...clearly audible.

 

[JackD201]

I've got tubes in everything except my digital, clearly audible as well.

 

[LL21]

I've got tubes in everything except my digital, clearly audible as well.

do you use tube dampers at all? have you ever tried EAT Tube Dampers? Big fan here...I use them on Zanden DAC and 2 on CJ GAT.

 

[JackD201]

The EATs definitely look cool (pun intended ) but I've not tried them. Some of my NOS tubes have markings I want to preserve and some have odd shapes. I only use stock soft elastic dampers.

In the past when I started experimenting with Symposium Rollerball Jrs, I can think of only one set of gear that I would say I would fail a blind test with, old Levinson gear from the 3 series. That's about it. In the hear and now, the Da Vinci is the only piece of gear I couldn't definitively tell gained anything from the two different types of spikes provided, CMS RiZEs or CMS platforms. It's quite the battle tank/stealth fighter.

 

[LL21]

The EATs definitely look cool (pun intended ) but I've not tried them. Some of my NOS tubes have markings I want to preserve and some have odd shapes. I only use stock soft elastic dampers.

In the past when I started experimenting with Symposium Rollerball Jrs, I can think of only one set of gear that I would say I would fail a blind test with, old Levinson gear from the 3 series. That's about it. In the hear and now, the Da Vinci is the only piece of gear I couldn't definitively tell gained anything from the two different types of spikes provided, CMS RiZEs or CMS platforms. It's quite the battle tank/stealth fighter.

Got it...well if you do try them, let us know. I have removed the stock CJ rings which I actually did not like with Mullards...but vastly preferred EAT Tube dampers over the 'no rings' or 'stock rings' anyday.

 

[Atmasphere]

The first thing I suggested is measuring the system using room measuring software. The second thing I mentioned is a blind listening test. A blind test isn't subjective if it's done properly. Sadly, all the people who insist the benefit of isolation under gear "is so obvious" and "the system as a whole takes a performance leap forward" live too far for me to visit in person to see if they really can tell With versus Without. And when I've offered to visit local people such as Michael Fremer, Myles B. Astor, and Jeremy Kipnis, among others, they always refuse. I'm sure I know why they refuse. So until proven otherwise, I'll continue to believe that isolation works mainly on placebo effect.

Unless you've tested this using sound generators, and measured output voltages versus frequency and SPL amounts, I doubt you have any idea how much air-borne vibration is needed to affect solid state equipment. As always, I'm glad to review any hard data you have.

How can a pillow underneath a preamp reduce vibration into the preamp via the air? Please be very specific.

Not to put too fine a point on it but if you really think we are talking about pillows you have really got no idea what the subject is that we are discussing.

This is meaningless because artifacts can be measured that are too small to be audible. If he also did listening tests, but they weren't blind, then those were meaningless as well.

We did a blind test a few years back on a turntable that was mounted on a damping platform. We played the same track at a volume setting that produced about 95 db with the platform present, and did not change the volume when the platform was removed. We did not allow the participants to know what was what, other than that the variable was the platform. No-one had any trouble sorting out which was which as the different was striking. Something interesting- the volume always measured higher with the platform removed. Anyone can sort out why that was the case.

Ethan I have to call you out again. You denigrate anti-vibration technology when used in audio systems, but you don't have any proof that they don't work. Its easy enough to do- just set up a mic in the room, and test the energy of the high frequency spectra with and without the platform. You will find that the high frequency spectra is always reduced with a good platform. Some platforms introduce colorations on account of imperfect vibration damping (less active at certain frequencies due to resonance in the platform itself) while others do quite a decent job. A good damping platform can have audible effects in the bass as well.

Again, as always if you are saying they don't make a difference in amps and preamps, please present the numbers. But I know you don't have any because you have never made any such test. Pillows? Really?? Perhaps its best if you keep quiet on this matter to avoid further embarrassing yourself.

 

[mojave]

We did a blind test a few years back on a turntable that was mounted on a damping platform. We played the same track at a volume setting that produced about 95 db with the platform present, and did not change the volume when the platform was removed. We did not allow the participants to know what was what, other than that the variable was the platform. No-one had any trouble sorting out which was which as the different was striking. Something interesting- the volume always measured higher with the platform removed. Anyone can sort out why that was the case.

Ethan said that vibration isolation could help in three areas: turntables, speakers, and tube amps. Your example coincides with his statement. Why the ridicule?

Also, Audio Libra calls their vibration damping system a Vibration Damping Pillow.

First, the only devices I'm aware of that benefit from isolation are turntables and, less often, loudspeakers.

I should have included tube gear as possibly benefiting from isolation

 

[Atmasphere]

^^ Ethan also indicated that he thought a pillow was the sort of thing that was being talked about. In addition, he mentioned that speakers and transistor amps would not benefit, despite a measurement that is repeatable. It really caused me to wonder if he had any idea what this thread was about. I don't know anyone who uses pillows to any meaningful effect (although I would not be surprised that they are out there) in their system, but I know many audiophiles that use dedicated equipment stands, a variety of anti-vibration platforms and Tip-Toe-like devices to improve the sound of their systems, and are quite successful, even when the electronics are solid state.

We focused on a particular platform in our study, called the Ultra-Resolution Technologies platform (which is not longer in production). Ethan was challenging me on the blind listening test - yet we had done precisely that. I have seen him challenge other audiophile concepts (unrelated to this thread) where there were indeed measurements available (whereas he had none at all). So I think the ridicule is coming from that more than anything else- IMO before saying that something is 'worthless' or 'has no effect' or the like, its a good idea to have some numbers to prove it, rather than the appearance of just trying to maintain a world view.

 

[JackD201]

I too was wondering about Ethan's proposed methodology of setting a mike up at the listening position to see if there are indeed FR variations. What got me wondering was what signal or compound signals he would use as he didn't specify.

 

[Atmasphere]

Heck, you can use a sine wave and get information!

 

[microstrip]

I too was wondering about Ethan's proposed methodology of setting a mike up at the listening position to see if there are indeed FR variations. What got me wondering was what signal or compound signals he would use as he didn't specify.

Jack,

The electrical signal effects effects on solid state equipment would probably be too low to be measured using the standard measuring instruments - something similar to what we get in cables. There is however an important difference in this form of distortion - it is delayed compared to the main signal, and with specific sound signatures.

I have found that some times supporting equipment or isolation devices change the sound of some specific equipment, but do not improve the sound quality of the system.

 

[DonH50]

It is easy to measure the sensitivity of a component to vibration IF you have the equipment, but like all other objective measurements any results would be buried in a morass of arguments about their audibility. I have measured vibration effects down below -160 dBc in RF systems, and below -100 dBFS in audio, but do not have access to such equipment now and have zero interest in what I am sure would be a fruitless endeavor.

 

[Ethan Winer]

^^^ Yes Don, it's fruitless because people who have convinced themselves that iso pads et. al. are generally useful will continue to believe that regardless of the facts.

--Ethan

 

[rockitman]

^^^ Yes Don, it's fruitless because people who have convinced themselves that iso pads et. al. are generally useful will continue to believe that regardless of the facts.

--Ethan

Ethan,

to be frank and based on the consumer level of equipment (AV receiver, cd player ect) you choose to own, I don't think isolation would be helpful for your system. The resolution and transparency is just not there, thus I understand why you wouldn't get an improvement. For the rest of us who choose to assemble a much more resolving and transparent to the source system, isolation matters a lot.

 

[microstrip]

It is easy to measure the sensitivity of a component to vibration IF you have the equipment, but like all other objective measurements any results would be buried in a morass of arguments about their audibility. I have measured vibration effects down below -160 dBc in RF systems, and below -100 dBFS in audio, but do not have access to such equipment now and have zero interest in what I am sure would be a fruitless endeavor.

Don,

Van dan Hul, a dutch manufacturer mostly known for his cables and phono cartridges, has developed audio measuring systems going down to -140 dBFS. He referred that this type of resolution is needed to study this type of "small differences".

 

[Atmasphere]

^^^ Yes Don, it's fruitless because people who have convinced themselves that iso pads et. al. are generally useful will continue to believe that regardless of the facts.

--Ethan

Ethan, what is an 'iso pad'? Do you know anyone who has one, or have you heard of one in use? Its not a term I have ever seen used, although I know a lot of audiophiles that use damping and isolation devices.

You allude to the 'facts' but don't state them. Could you do so- and show that they are indeed 'fact' by backing them up with some measurements?

 

[JackD201]

Isolation Pads

marketed towards professionals for use mainly under monitors on meter bridges. Many companies make them the most popular being Auralex.