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Isolation feet and speaker stands

Helen Bach said:
But placing the loudspeaker on 'isolating materials' only exacerbates the problem, as the cabinet vibrations have nowhere to go, and so build in amplitude as the music continues to excite the panels.
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Isolating materials like sorbothane absorb the vibration and dissipate it as heat. It does not remain in the cabinet. With spikes you couple to the surface (eg floor) and it vibrates as one with the speakers, so if you have a floor that resonates at an audible frequency you will have your floor "singing along" (vibrating sympathetically) with the speakers, which is a problem. This is generally the case for suspended wooden floorboards.

I'm happy to be corrected on the above by any mechanical engineers in the audience.
 
Sorbothane (a polyurethane) was developed to absorb shock rather than dissipate energy. And there is a problem. A vibrating structure (such as a loudspeaker) will only 'pass on' vibrations if the mechanical impedance matches that of the other structure. It can be useful under things like amplifiers as transfer from a support to an amplifier could be minimal. However, going the other way (a vibrating structure standing on sorbothane supports) will not do much, but exacerbate the problem. If one isolates a vibrating structure, then remedial action has to be taken to damp the vibrating structure in situ.

Think of a car with rubber tyres sitting on a road. The steel of the car will be vibrated by the engine reving, the rubber in the tyres will have a very different mechanical impedance from the steel in the car, so vibrations from the engine will vibrate the car body etc. but the tyres will prevent most of the vibrations from reaching the road. HTH
 
Patu said:
Interesting, but I guess there are different kind of requirements to absorb a milling machine vibrations compared to the very fine vibrations coming from a loudspeaker. If the feet are adjusted for 600kg machine vibrating like hell, it won't work as well for something much lighter. It'll probably just pass through the speaker vibrations.
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They come in different sizes depending on the loads etc. Similar things also exist for precision balances in laboratories. They're a bit smaller and softer. :)
 
I have evolved to this arrangement with my Tannoy DMT-15’s that began with the loudspeakers directly on the cork flooring.
1. Custom made MDF stands filled halfway with sand placed on the cork floor with no bottom spikes.
2. Three Symposium Roller Block Jr’s, the bottom cup has a threaded insert so is bolted to the top of the MDF stand.
3. I later had a Symposium Svelte Plus custom made to fit inside the flat base of the loudspeaker to give maximum contact area to the bottom of the cabinet.

I cut some initial comments and impressions from the original set of posts.

I ordered a pair of Symposium Svelte Plus platforms to place directly under my DMT15's. They use constrained layer damping that is suppose to sink vibrations from the speaker cabinet and stand. The platforms are intended to sit on top of their Rollerblock Jr's which provide isolation, they have a resonance frequency of around 2 Hz. I have been planning on doing this move for sometime and yesterday finally took the plunge after a long conversation with Peter at Symposium. I should get the platforms in a couple weeks as they have to be customized to fit the bottom of my speaker, their stock size was a half inch too wide. Hopefully they provide the performance you obtained. Stay tuned!

I had a long conversation with Peter from Symposium. Basically what I got out of it was that the Rollerblocks isolate and mostly help with the bass. The svelte shelfs directly under the speaker allows somewhere for the speaker cabinet and stand to dump vibrations and turn it into heat via constraint layer damping. The svelte shelf benefits mid bass and up. The goal of the design was not to impart any coloration to the speaker. Looking forward to getting them in place!

Got the Symposium Svelte Plus platforms yesterday. They arrived very professionally packaged and the build quality is superb. I was anxious to get them in place and get down to listening. I had them made to fit flush with the 18.5 X 14.5 recessed bottom of the speaker so had them made 18 X 14. This left a quarter inch gap clearance to place the 100 lb. speaker into. This was something I was a bit concerned about doing myself as no one was around to help till later and I wanted to get them in ASAP. I managed to get them in place without breaking anything or hurting myself in the process.

Here's a couple pictures I snapped this morning which shows how they look in place. I think they really look smart with the style of the speakers and stand.

65pH9ez.jpg

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I'm blown away with what the platforms are doing. Any positive music or hi-fi adjective you want to use to describe the sound or performance could be used here. I'm clearly hearing the largest boost in performance ever from this room in the 23 years in this home. The platform and roller bearings are being used just as the designer intended and the interface with the platform is allowing a maximum amount of vibrations to be dumped.

I was expecting an improvement but what I'm getting far exceeds that. Glad I took the plunge. Addressing the LP12 with a bit of Symposium product is next, but not for awhile. I need to get my head around and enjoy this for awhile.

 
In the interest of stability on thick carpeting until I have a chance to order the AUVA feet, I replaced the previously installed isolating feet (AcoustiFeet) with the spikes that come with the speakers. Now the bass is so overblown that the system is unlistenable. I can feel the floor vibrating. Not good. Eventually, after we've finished unpacking, I'll take some room measurements and dial in some EQ, but it's clear that the supports have a huge impact, so better to optimise that first. I look forward to comparing the options.

Edit: I'm enjoying testing with this song, wherein the second half has some clear, sustained tones around 40Hz. Perfect for the job.

Edit 2: I cannot express how disappointed I am that my system is suddenly so unenjoyable in my new living room. Even with all the shortcomings of my previous room (tucked into the corner, speakers too close to each other), it was nicely set up and sounding great. Looks like I have some work ahead of me.

Edit 3: AUVA 50s ordered...
 
I've been doing a lot of speaker assesment recently , had 4 different pairs in over the last month.
Didn't want to , but agree , isolation feet do work.
An improvent from spikes into the floor, the current favourites are on loan from a friend.
Graphite Audio ISSB 40
Not sure I'd pay the asking price, ( £400 ish ?) but do work well.
Also , being graphite, makes it easy to find tune the toe in, slide without too much effort.
 
I just fitted the AUVA 50's on my DALI Opticon 6 Mk2. Listening to the same track with significant bass content I mentioned in my previous post, I feel that the amount of floor vibrations are significantly reduced (albeit not eliminated). I need to spend more time with them, but I would say that the system is no longer unlistenable like I was feeling yesterday (some EQ will still be necessary to tame room modes, though). I may report back after a couple of weeks.


(Please overlook the still undecorated and not-yet-fully unpacked state of the room, as well as my reflection in the -- acoustically nightmarish -- window behind me)
 
Oh, I just listened to my standard stereo field test track, "Bronchusevenmx" by Autechre. This is pretty much my go-to test track. It's electronic, so no true notion of "hi-fi", but I've found that as I've improved my system, I can "hear farther" into all of the layers upon layers of stereo echoes. I've already listened to it a few times in my new room and it was a disappointing, confused mess. Anyway, with the AUVA 50's in place (and the speakers and seat in the same position to the cenimetre) it has transformed completely into a massive wall of sound with a very clear left-to-right spectrum of audio events. Impressive. I'm looking forward to more listening but, alas, unpacking beckons.
 
gustav_errata said:
Oh, I just listened to my standard stereo field test track, "Bronchusevenmx" by Autechre. This is pretty much my go-to test track. It's electronic, so no true notion of "hi-fi", but I've found that as I've improved my system, I can "hear farther" into all of the layers upon layers of stereo echoes. I've already listened to it a few times in my new room and it was a disappointing, confused mess. Anyway, with the AUVA 50's in place (and the speakers and seat in the same position to the cenimetre) it has transformed completely into a massive wall of sound with a very clear left-to-right spectrum of audio events. Impressive. I'm looking forward to more listening but, alas, unpacking beckons.
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Pleased that you are enjoying the AUVA 50's so far.. very pleased with mine too.
 
gustav_errata said:
Oh, I just listened to my standard stereo field test track, "Bronchusevenmx" by Autechre. This is pretty much my go-to test track. It's electronic, so no true notion of "hi-fi", but I've found that as I've improved my system, I can "hear farther" into all of the layers upon layers of stereo echoes. I've already listened to it a few times in my new room and it was a disappointing, confused mess. Anyway, with the AUVA 50's in place (and the speakers and seat in the same position to the cenimetre) it has transformed completely into a massive wall of sound with a very clear left-to-right spectrum of audio events. Impressive. I'm looking forward to more listening but, alas, unpacking beckons.
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Among other improvements, I also noticed the increased depth of the soundstage.

I'm going to keep mine attached for a while now and then at some point, will put the regular spikes back just to be sure about the differences.

I wonder if it makes any difference to use Auva's with the spikes (three per feet) vs the felt pads.
 
Patu said:
I wonder if it makes any difference to use Auva's with the spikes (three per feet) vs the felt pads.
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I thought the idea was to position the speakers whilst using the felt pads and then spike them when you were happy with the sound in that location.
 
Just put the GAIA2’s on my new hORNS Aria 3’s. For me, in my room (suspended wooden floor) the effect can’t be overstated. I couldn’t be without them in my room. Excellent bit of kit.
 
Fergus said:
I thought the idea was to position the speakers whilst using the felt pads and then spike them when you were happy with the sound in that location.
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This is from the manual:

"Each isolator also comes with 3 spikes that screw into the underside for use on carpet coveredsurfaces. A protective adhesive felt pad is also supplied for use on hard floors. Please note: onceapplied the felt cannot be removed. It has cut-outs that still allow the spikes to be fitted later if youruse changes. They come in sets of 4 for each speaker. Instructions for fitting the AUVA isolators areshown in section 1."

In my 50's, the the felt pads were installed already in the factory.
 
I have two friends who use them and their Auva’s came factory fitted with the felt pads. One has his speakers on a hard surface but the other was told to position his speakers in his carpeted room then spike them. Not in the manual but seems reasonable given that the Auva's use will affect the room’s response.
 
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Patu said:
Among other improvements, I also noticed the increased depth of the soundstage.

I'm going to keep mine attached for a while now and then at some point, will put the regular spikes back just to be sure about the differences.

I wonder if it makes any difference to use Auva's with the spikes (three per feet) vs the felt pads.
Click to expand...
I think you may well notice a difference depending upon floor and floor covering type. I personally have the spikes attached to my AUVA 50's on a carpeted solid concrete floor, I haven't tried them without the spikes myself though as I don't think they would then work as well on a carpeted floor. Also the 3 spikes really add to the stability versus the original single spikes on the speaker stands.
 
Tom60300 said:
I ordered yesterday a set of the Auva 50s. I will report back with my honest impressions and decide to keep or return them afterwards as there is a 30 day trial period. We shall see...
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Unfortunately had to cancel my order and request a refund because 10 calendar days after ordering they were still unable to ship.
 
Tom60300 said:
Unfortunately had to cancel my order and request a refund because 10 calendar days after ordering they were still unable to ship.
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Strange. Did you get in touch with them? Sounds like something went wrong. I received a personalised acknowledgement from Stack shortly after placing my order.
 
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