GoodSoundClub - Romy the Cat's Audio Site - Mastodont DIY Rack: Wall Mount?

11-24-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	21
Post ID:	20299
Reply to:	20298

Viscoelastic interface

Paul, thanks! But the interface I'm thinking of is between the steel frame you see in the pictures and a slate plate that will come on top of it.
Something to put on top of the steel profiles, some good viscoelastic, comfortable in the constrained layer arrangement. Sorbothane is said not to be such. Not that I feel I need it badly,
just thinking.

Cheers,
Jarek
STACORE

11-24-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	24
Post ID:	20302
Reply to:	20301

Leather felt

Yes, I was thinking about lether too. Felt is also an option. However they both seem to me not
"viscoleastic" enough and good primarly at HF, while the damped steel profile vibrates
mainly at LF. I was thinking about solutions for car deadening either the old school bitumen based
or moder butyl rubber, but claims are they "deaden the sound"...however one interperets that.
Ideally, I'd apply a known good solution and would not have to do the typical DIY dance.
At the moment I'll leave it as it is, putting the slate directly on the frame and perhaps experiment later.
I'm much more interested in the performance of my monster vibraplane and a leveling roller feet idea
for the electronics cage:

Cheers,
N-set

Cheers,
Jarek
STACORE

11-24-2013

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,664
Joined on 10-12-2006

Post #:	25
Post ID:	20303
Reply to:	20302

Bedding

In the real world the slate alone will not actually make continuous direct contact with the steel frame. One way or the other you will likely need something to use as "bedding" between the slate in the steel. You might look to precision machine set up for ideas, including "products" you can try. Also, it seems to me that the sort of movement this thing would be most subject to would be very low frequencies, and that might even be exacerbated by fully de-coupling the slate from the steel. While I think you can tune it effectively if you are methodical and patient, I also think it will be a try-it-and-see/hear situation, regardless.

Best regards,
Paul S

11-25-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	26
Post ID:	20304
Reply to:	20303

Em-bedding

Paul, I've been definitely looking at the DIY CNC "market" for ideas!! Esp. regarding the frame construction.
The problem is that they are happy once all the frame resonances go to 3-5Hz, so they use
a lot of mass loading. Here, my airsprings resonate there, so I want to have the resonances higher up.
Changing sand+shots for perlite and additional bracing +/- gave me that.

The reason I'm lazy with steel-slate interface is that I do not have acoustic systems and listen
on headphones. So there is no acoustic feedback to tame, only footfalls and building vibrations.
I'll go more into that interface once I have the proper listeting environment and the table is embedded in
acoustic field.

Cheers,
N-set

Cheers,
Jarek
STACORE

11-26-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	27
Post ID:	20310
Reply to:	20304

TT stand ass-embly

Below are some pics of the final TT stand assembly. Visually it turned out
better than I thought (although width/heighth proportions are ugly due to space constraints).
The pneumatically suspended top is on it's place, with the
120kg slate slab on it. It does respond very nicely to excitations,
like a suspension of a luxurious car. Now I'm making initial tests for
leakages under the load and hope to put the TT soon and then everything
will be clear: have I lost 9 months and $$$$ or does it work?

Cheers,
Jarek
STACORE

11-26-2013

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,166
Joined on 05-28-2004

Post #:	28
Post ID:	20311
Reply to:	20310

Very nice but it is just a beginning.

Yes, it looks not particularly sexy but it I was made to fit and it is for sure very functional. You shall not worry about attractiveness as when I pile up on this thing TT and whatever else will be located on it then it will have completely different look and fell. My experience suggest that is a few month this thing will be coved with CD boxes in multiple layer, so you will not be seeing the thing. I am not sure you did not made a shelf or two at the bottom of the thing as the empty space looks a bit conspicuous. I presume that you have plans for it. Anyhow, I think shelves under the bottom will make the assembly more solid.

Yes, those pneumatic feet are marvelous. BTW, there are some of them with built in highs adjustment, including the auto-adjustments. I did look at them years back and they were quite expensive around $1000 for a set of 4. You need a small compressor to power this thing, get the smallest you can get but able to do 80-120pci.

The most important question how will it sound. For sure as the DIY project it is wonderful; the direct impact to sound is totally different matter. In some cases those type of tables do not have sonic effect, in some they do. It would be depending from many indigents, including type of your TT, what it will be sitting on, location in the room, type of speakers you use and many other things. I do not think that you will be able to get the direct relation between new TT and sound. I think the new table is a good based that clear some concerns and upon which it is sensible to built up your sound.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-26-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	29
Post ID:	20314
Reply to:	20311

Inner Cage

Romy, there will be an inner cage for electronics inside the TT stand:

This is a sand+shot filled steel frame topped with the same vulcanic slate as the TT stand.
I tried to put the cage a la RixRax but it did not work
(the picture&explanations are here: http://goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=19738#19738)
The plan is to decouple the inner cage from the floor via the leveling bearing feet I posted few posts up.
I wanted to put it also on the air springs but the center of gravity is too high I think.

As for the visuals, it's not that bad as the pics may suggest. Actually the ugly proportions and not-so-high-end
frame execution are quite nicely compensated by the material choices: hypnotizing Italian slate,
beautifully machined spikes, black anodized spring covers and mat powder coated steel.
All the pneumatic cabling is almost invisible. It is not a typical high-end furniture but neither a rough industrial one.
I guess I caught some interesting balance here.

Romy the Cat wrote:

I think the new table is a good based that clear some concerns and upon which it is sensible to built up your sound.

This has been my goal with the project, you've summed it up really nicely!

Cheers,
N-set

Cheers,
Jarek
STACORE

11-26-2013

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,166
Joined on 05-28-2004

Post #:	30
Post ID:	20316
Reply to:	20314

Very nice.

Ah, I see, you have an insert that goes into the belly on the rack and that do not touch the main frame. Very slick and very inelegant. Juts to ice the cake I would provision 4 hooks atop of the insert that would allow you to hang the insert to the air-suspended platform in case you find it worthy. Anyhow, all together it looks like you built a good rack. The insulting part of all of it that if you throw bike’s inner-tubes under a plywood board then it would produces a similar sonic result. It will not be as sexy and as elegant though…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-26-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	31
Post ID:	20318
Reply to:	20316

Slick inelegance

Romy the Cat wrote:
Very slick and very inelegant.

Hahaha, thank you Romy Smile

Romy the Cat wrote:
Juts to ice the cake I would provision 4 hooks atop of the insert that would allow you to hang the insert to the air-suspended platform in case you find it worthy.

Oh no, it's something I'm quite afraid of after version 1 of my rack I reported earlier. I'd have a big mass pendulum atached to the TT platform.
The springs would have to counter not only the floor/air movement but also the movement of the insert. As this is my 1st design, I feel much safer separating TT platform and the insert which will go on it's own roller bearings.

Romy the Cat wrote:
The insulting part of all of it that if you throw bike’s inner-tubes under a plywood board then it would produces a similar sonic result. It will not be as sexy and as elegant though…

Add to that marbles in egg holders and you have a real 6 axis decouplers, lightyears better than any audiopedofile $$$ spikes/cones/stillponts/HRS etc. Thank you Bary Diament for enlightning writings:
http://www.barrydiamentaudio.com/vibration.htm

Cheers,
Jarek
STACORE

11-26-2013

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,664
Joined on 10-12-2006

Post #:	32
Post ID:	20320
Reply to:	20318

Bike's Innertube?

Well, I hate to think N-Set's efforts equate functionally with such a "basic" solution. For a while I had my CD transport sitting on a wood platform that was "decoupled" by several blue rubber handballs that were stopped from rotating and interfaced by plastic sockets I found in the plumbing section of the local big box. At some point I ran a kind of A/B listening comparison and wound up abandoning this "isolation" platform in favor of sitting the platform/transport directly on carpeted floor near the wall. Reflecting, I think the handballs were too tall, with the particular accompanying movement that implies.

Best regards,
Paul S

11-26-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	33
Post ID:	20321
Reply to:	20318

Ball bearing

N-set wrote:
Add to that marbles in egg holders and you have a real 6 axis decouplers, lightyears better than any audiopedofile $$$ spikes/cones/stillponts/HRS etc. Thank you Bary Diament for enlightning writings:
http://www.barrydiamentaudio.com/vibration.htm

I'm actually thinking on how to add ball bearings below the air springs to have 6 axis decoupling. Here is my latest and most reasonable idea:

Cheers,
Jarek
STACORE

11-27-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	34
Post ID:	20322
Reply to:	20320

Why people buy Vibraplanes?

Paul S wrote:
Well, I hate to think N-Set's efforts equate functionally with such a "basic" solution.

In general of course I agree, Romy&Paul! But there are few niuances, although how importnat sound-wise I do not know.
First, Vibraplane & alike (incl. my clone) have damping reservoirs, so a fair comparison would be a tire connected to a
damping reservoir. Second, and this is more in the wishfull thinking cathegory, those horribly expensive industrial springs are supposed
to be engineered specifically for LF vibrations, so my expectation is they *should* work better (lower fres, higher internal damping,
higher durability, etc), but I've never seen any test of a, say, SLM mount vs. a bike tire...Would be fun if someone done it!
Third, with independent springs I can level the platform, and this is probably the biggest functional
advantage over a bike tire Wink

Cheers,
N-set

Cheers,
Jarek
STACORE

11-30-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	35
Post ID:	20325
Reply to:	20297

Steel-slate interface

N-set wrote:
I'm looking for a nice material to interface between the steel frame and the slate top
as a contrained layer--would be a sin to loos such an occasion for constr. lay. damping.
After some research, Sorbothane seems unsuitable as it leaks and looses it's properties under the load.
Rubber some claim "deadens" the sound whatever it means. Any ideas?

I think I've finally intelectually worked out a solution for the steel frame-slate interface. No rubber, leather, sorbothane, raw meat etc
but roller bearings, ideally under each slate slab:

Bottom rests on the steel frame, top glued to the slate, now I can experiment with whatever between the bearing and the steel/slate. The main decoupling and damping is there.

This came to me after reading a lot of Barry Diament writings:
http://forums.stevehoffman.tv/threads/attention-barry-diament-and-other-speaker-isolation-gurus.154013/
Apparently the mental mistake I've been making was that I intnded to put the bearings below the air springs, while
Barry advocates the other way around for whatever reason.
For me more logical was rollers first than springs but what do I know about audio vibration controll?
Anyway, the idea is now to put the rack insert on the airsprings too, not on the berings and fuck potential
stability issues---the daughter is quite grown up now, the insert is in the rack's belly,
the visitors who would run full speed into the rack aren't welcome anyway, so with a bit of care it should work ok.
All this vibration cotroll is just a plain pain in the ass...just like ground loops.
Cheers,
N-set

Cheers,
Jarek
STACORE

12-01-2013

Post does not mapped to Knowledge Tree

Jorge
Austin TX
Posts 141
Joined on 10-17-2010

Post #:	36
Post ID:	20326
Reply to:	20325

Roller Bearings color the sound too

I had been using Aurios roller bearings under my Cd transport for a long time, Every time I changed a transport I would immediately put them under, and they always helped: Untill I got the Forsell transport. When I first brought it into my listening room it was sooo heavy I just put it on a side rack and compared to the transport I had at the time head to head, needless to say the Forsell aboslutely killed the other transport (CEC TL1) so I finally took the TL1 out and put in the Forsell with the Aurios on the bottom: It sounded the same as the TL1 !!!
Took them off and the great sound was back!
I tried again the CEC TL1 without the Aurios and it didnt change that much.
Now I have the Aurios on the DAC... It gives it a bit more clarity.... maybe?

I use sand isolation for my rack now.

12-01-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	37
Post ID:	20327
Reply to:	20326

Aurios

Jorge, do you have any picture of those Aurios? Do they have two caps to hold the ball or one?
If two, did you attach the upper one firmly to the component or simply put it on it, using weight?
How would you describe the negative sound change?

Is Forsell still in business? I'm trying to find their webpage to see if the transport has its own suspension.

As for the sand I'm very-very sceptical about it. I still have it in the vertical
colums of th TT stand and they vibrate like a fucking gelly when knuckled.
Sand solidifies and creates a perfect "bridge" for ULF vibrations. The added mass lowers the resonance but also
lowers the damping at the same time. I'm conteplaiting taking the pain and exchanging
the sand for a foundry perlite ore, which my welders have put in the horizontal braces. Seems
to work better...at least with a knuckle test.

Cheers,
Jarek
STACORE

12-01-2013

Post does not mapped to Knowledge Tree

Jorge
Austin TX
Posts 141
Joined on 10-17-2010

Post #:	38
Post ID:	20328
Reply to:	20327

Aurios bis

I will get some pics for you in the afternoon, I put another bearing on a hole they have and that is what supperts the equipment on top.

The sound becomes airy and transparent, but looses dynamics and tone.

http://drforsell.com/home.htm

12-01-2013

Post does not mapped to Knowledge Tree

N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	39
Post ID:	20329
Reply to:	20328

Implementation

Ok, 2 thoughts:

1) Forsell seems to have some air suspension for the CD platter.
I don't know in which axis/axes it works but if in the same as the
rollers (lateral motion+torsion) then there is a potential for a trouble
with a double compliance system.

2) You mentioned the transport is heavy. What is the transport bottom plate the
bearing balls worked against? The balls may have micro-dented the bottom plate
(very easy to imagine e.g. with a powder-coated steel) and the bearing instead
of isolating started coupling.

I plan to experiment with 25-30HRC hardened steel, working surfaces micropolished and
thread coupled to the steel & slate. But this comes after I get used to the TT on a new stand.

Cheers,
Jarek
STACORE

12-01-2013

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,664
Joined on 10-12-2006

Post #:	40
Post ID:	20330
Reply to:	20327

Sand vs. Sand

There are lots of different types of "sand", including various sizes and shapes of the aggregates, not to mention the constituent materials, themselves. I thought that in most cases the idea of in-frame sand is to quench/diffuse "ringing", not ULF. Of course ULF has to be dealt with incrementally, usually by limiting and "tuning" infrastructure travel rather than trying to eliminate it entirely. In this case, the resonant modes might become more "complex" but still effectively better damped than a given "un-treated" spike or spikes that may result from - for instance - tightening screws "too tightly" or too strictly limiting travel in any one mode. Conversely, too much may be lost through simple entropy when damping is over done.

Any "pearlite" I am aware of is pretty damn light! Anyway. it seems like any frame filler should somehow "wick" away and diffuse the usual steel frame "skin" noises, but that same sand (or, whatever...) would be +/- useless for ULF (of course...).

Regarding decoupling the transports, my own Accustic Arts transport already has special built-in "feet" that - apparently - decouple/isolate the machinery well enough on their own; certainly the carefully-located stock unit sounds better than when I "double up" by adding a decoupling platform. My own (self-suspended) Sota TT is similar, but not the same. It sounds its best when mounted on a +/- "ridged" platform, but much closer attention needs to be paid to every aspect of the platform.

Best regards,
Paul S