TW Raven Acustic AC Owners

Halcro,

You sound like a broken record. Chill out on this already. How many times do we have to read it.

Dgad,
Go and police some other threads and don't tell me where to do my postings.
You might also like to re-read the posting questions and my initial answers?
There are very few on this forum who have structural and acoustic qualifications or experience so that when they read a posting which purports to contain 'facts and truths', they are liable to accept such posting at face value.
There are no down-sides to wall-mounting a turntable if the weight can be accommodated.
This is a simple fact of physics and acoustics and will never change.
To frighten people into thinking it is 'rocket science' and therefore best to take the easy route of placing the deck on a floor-mounted stand as you have chosen to do, is irresponsible advice in the quest of better analogue sound.
Mark Doehmann who designed the Caliburn floor-mounted stand which costs $25,000, agreed that at best......it equals the isolation performance of a wall-mounted shelf.
Pity that you'll never hear that?

Halcro,

You stopped at the first terminology you didn't understand! You only read the first sentence! Please keep reading the article, it's very informative.

+++++ what you speak.........any 'not so well executed' wall shelf (and can you please describe what you mean by this as I can't even imagine?)++++

Well, it's very simple: a 'not so well executed wall shelf' means a shelf mounted on a wall that has not been designed and constructed taking into account static and/or dynamic loads. In fact, it is actually a good idea to talk to a civil or structural engineer and ask him or her to do the calculations for you since we're dealing with probably 150 lbs cantilevering off of a wall. It's a very simple job and they probably won't charge for it.

Halcro, this is not a discussion about my 'wall shelf' can beat your 'floor mounted stand'. A fellow audiophile asked a question and we are simply providing our opinion about it. It is ok for somebody reading this post not to agree with me or not to agree with you. It's called 'freedom of speech'.

Halcro,

Can you post your comments on any of the threads re: Suspensions & turntable Platforms etc. You have hijacked a few threads on a few forums in this direction. It would be a more appropriate location for your comments. I think the tone here needs to get back to constructive and become relevant to the title of the thread.

Isanchez,
Do you know what cyclic loadings are?....I doubt it as you fail to answer the question on your qualifications?
And prey tell what 'cyclic loadings' have to do with a cantilevered wall shelf?
Just to dispel your other inaccuracies for any readers who think you actually may know of what you speak.........any 'not so well executed' wall shelf (and can you please describe what you mean by this as I can't even imagine?), will beat hands down, any WELL executed floor mounted stand!

Stilkin, thanks for the kind words. I recommended a closet because I do think isolation is paramount if not always practical. Do what you can. But you can get too smart and design what you think is just what you need - like me. In my case I designed my solution only 24" wide. Not really wide enough for double arm TT's to be used by clumsy hands the likes of me. Most closets are wider. Sometimes what's at in a normal house is better than custom. You just have to look, or maybe the wall is better after all.

Halcro,

http://en.wikipedia.org/wiki/Fatigue_(material)

Enjoy it,

Isanchez what is your profession?
Your talk of material fatigue displays an ignorance of structural principles.
Apart from ' metal fatigue' which can occur when metals approach their elastic limits after repeated cycling of loads, there is no material ' fatigue' in structures that I am aware of and certainly not in regards to cantilevered wall shelves.
Tightening screws and bolts has nothing to do with metal fatigue.

GerryM.
Nice system!...
One up from your closet spot, set up of a front end in an adjoining room is by far the best solution...
Especially for those that listen to their music at eye denting levels.

I know how well this works, if you can do it.
Not many can.

Even set up in another room, turntables themselves are resonating devices and I would still try out methods to drain the resonates off.

This solution is not practical for most and I realize the my not be possible for you. How about thinking out of the bigger box into a smaller box. Put you entire front end in a near by closet on your choice stand solution. Maybe you can spend less money on a stand. Maybe it's slightly more costly and goes grain of having the shortest possible cables in all positions. This approach gives the great isolation from all air and most floor passed vibration. If you have a slab floor then there's no floor vibrations. I've done and hear great results. IMHO having lived with this now, I would never-ever put my front end in open space in my sound room, regardless of great (usually) stand solutions.

There are other benefits too: My musical experience is improved also for another reason because I'm not looking at my equipment while listening - my weakness not yours. My wife loves it readily gave up that closet for this.

Halcro,

I do happen to have architectural, structural and acoustic qualifications because of my profession. I wasn't commenting on your specific case, but on cantilevering shelves in general.

Cantilevering shelves made out of wood or mdf will tend to bow over time under such heavy load, hence my use of the term "material fatigue". An engineer can calculate the load of the equipment and design the structure to successfully support that equipment. If material fatigue didn't occur in structures, then there will be no need to inspect buildings and bridges for wear and/or structural failures. Screws attaching a vibrating structure will tend the get loose over time as well, which is why it is recommended to check them from time to time.

I don't know the construction details of your shelf structure, so I can't comment on your specific case. If you used an engineer or an architect for the job, I'm sure it is well-executed.

I agree that a well-executed wall-mounted shelf will work properly, but a not-so-well-executed one will do more harm than good.

Regards,

iSanchez

Hi Isanchez, thanks for the pics. It does look like a BM-8 or 6. I will ask Minus K.

As a long time user ,since 1983, of Quad electrostats and Magnepan speakers with a Linn LP12 front end right up to 2001.

I never had to deal with sound pressure levels , foot falls yes.

Back then ,the Linn was one of the best tables you could buy on the planet.

A wall mount shelf was a must with suspended floors.
Back in the day resonant devices were in their infancy, remember Mod Squad tip toe's? I used them under my speakers and table to good effect.

By the mid 1980s I had added a home made sand box platform to the wall shelf,a idea thats been around for a long time.
This improved the music on the neutral side of things, easily heard through the Quads.
Vocals were even more life like to my delight.

A myriad of active variables are at play with in a system and room.
Taming resonates is just one of many that should be addressed which can have huge sonic pay offs.

Whether its a home made box with sand in it or a $20,000 plus turntable platform.
Experiment ,what ever works for you and your budget.

http://forums.avguide.com/viewtopic.php?t=3588
Please see the link above for diagrams and further explanations about AIR-BORNE and STRUCTURE-BORNE sound propagation.
Unfortunately, some posters without architectural, structural or acoustic qualifications presume to post fallacies.
If the brackets and bolts are sufficiently sized to accommodate the loads imposed, there will be no ' material fatigue' over time just as there is none in properly designed floor or roof fixing brackets and bolts.
Insulation placed in stud wall construction will NOT prevent sound from traveling between rooms. At best, it will REDUCE the sound but at only certain frequencies. Those below 200 Hz will effectively pass straight through the insulation.
It is the de-coupling of the wall-mounted shelves that (as shown in my explanations) is the salient benefit.
A properly executed wall-mounted shelf will NEVER ' do more harm than good' .
The only harm I can see is ill-informed uneducated pontifications posing as scientific fact.

Alectiong,

This is a link to a Raven AC3 on a Minus-K platform and it looks like an BM-8 or 6, but it is larger. You may want to ask Minus-K which model this is. The image is at the bottom of the page.

http://www.audiofederation.com/hifiing/2006/RMAF2006/report/1500/part2/index.htm

Regards,

iSanchez

I am intriqued by the Minus-K platforms. They seem to offer some technological and practical advantages over the other platforms mentioned (wall-mounting is unfortunately out for me). However, after checking out its website site, it looks like the only Minus-K platform wide and deep enough for the 3-motor Raven is the BM-1, which is 9" tall and costs over $4000!

Dear Elinor,

Congratulations on your new turntable. It's an excellent choice and everybody seems to be more than happy with it.

I would suggest to look into Minus-K, SRA and HRS. I know that High Water Sound has used SRA and Minus-K at audio shows with great results. SRA has some sort of collaboration with TW-Acoustic, so I would feel confident that their products will perform well together. HRS platforms are ordered for a specific weight-range, which can be changed should you need to use the platform for another equipment. Minus-K offers state-of-the-art vibration control at an affordable price. Based on what I've read from their website, it seems to be one of the most efficient ways to approach vibration control.

Extra planning is needed if going with the all mount shelf alternative. Most cantilevering shelf-mounted structures under such heavy load will likely suffer from material fatigue over time. That means that all connections and all materials should be checked once in a while for wear and/or structural failure.

In a room built with with studs and sheet-rock, one has to take into a count that airborne energy becomes structural energy when playing at mid to high DBs. It's a well known fact in the US construction field that a sheet-rock wall needs sound insulation in order to prevent sound from traveling from one room into the other. The sound insulation between sheets won't prevent the wall from vibrating, but will prevent the sound from that vibration to go into an adjacent room. This type of construction is quite sensitive to changes in sound pressure, which will turn into vibrations. Therefore, in this particular case a wall-mounted shelf may do more harm than good.

Every type of wall structure will provide a different performance. If you have a concrete or masonry wall, then it's quite possible that a well conceived and executed wall shelf isolates well from mechanical vibrations in the room. But again, planning and execution are key for this to work successfully.

I've been using an HRS platform for about two years now and it works extremely well in my room. The other choice I seriously consider because it has superior technology, is the Minus-K BM-8 platform.

Regards,

iSanchez

I,m another happy guy which will be taking delivery of my Raven One at the end of the month.

My current dedicated turntable stand is made of Canadian hard rock maple.
True butcher block, three shelf 2 inch thick vertical grain, 20 inches by 20 inches by 40 inches high.
Three legs,tripod style , 3 1/2 inch by 3 1/2 inch legs.

It was put together by mortise and tenant joints, no screws or glue.The feet are the superb large Finite Element.

This worked very well over the years though I may look into other stand options or add to with what I have now with Silent Running Audio ect or some home brew sand box ect.
I am expecting some fire works at times with my new system.

A wall mount is not an option for me, this would of been my first choice.

For those here that can use this method, cutting out the finished wall material, dry wall or what ever.
You can beef up and damp the studs and bottom plate.
It would also be a good idea to make sure what is added to the studs is plumb / level.

Then cover the cut out with some nice cabinet ply finished/stained or painted to match your decor.
Then your set to lag bolt your turntable shelf.

Mount the TT on a shelf firmly cantilevered from the wall.
Sound is transmitted it 2 basic ways:
AIR-BOURNE
STRUCTURE-BOURNE
90% of audiophiles mount their TTs on racks sitting on the floor.
This is a disaster for both types of transmission.
Even a concrete floor (which is not generally bouncing around like a timber-framed one) is a great transmitter of sound, so that any rack sitting on the floor is receiving BOTH types of transmission.
This is why Continuum Audio Labs create a rack for their Caliburn that costs $25,000. That's how much technology is required to overcome this basic problem of physics.
When you cantilever off a wall, you are disconnected from the floor (USA stud frame tradition can often short-circuit this advantage).
The materials to fix to the wall, project from the wall and form the shelf for support, generally act to physically 'de-couple' the shelf from the wall.
Thus all or most STRUCTURE-BORNE and AIR-BORNE sound transmission within the floors and walls are eliminated.
The only transmission to now worry about, is the AIR-BORNE transmission directly into the supporting shelf (and here is where Jon's granite shelf is NOT a good idea.
Granite rings like a bell and transmits sound deliciously throughout many audible frequencies without much absorption or dampening. Timber is a better insulator and dampener.
However it may be academic because all one has to do is DE-COUPLE the turntable from the supporting shelf to eliminate the transmission of this air-bourne absorbed sound.
Stillpoint cones with ceramic balls is a good way and there are many others.
Then the only sound transmission to worry about is the AIRBOURNE sound which the TT base and platter are able to absorb THEMSELVES.
This is where the turntable designer earns his crust with the elimination, absorption and dissipation of this air-bourne feedback setting his TT apart from the rest.
Of course the ability of the tonearm and cartridge to absorb and dissipate this same air-bourne transmission (feedback) is equally important but the frequencies are much higher and smaller.
So the moral is......do everything possible to wall-mount your turntable.

I am a Raven AC user myself and have been wondering if my isolation is adequate. My Raven sits on a Japanese made TAOC rack. When I knock on the rack or the shelf, i hear a fair bit of acoustic feedback. Is that a sign of inadequate isolation? My Raven comes with the Stillpoint feet. When I do the test, the stylus is on a stationary LP and the volume is turned up to normal listening level. Comments appreciated.

Elinor,

Please look up my system page to see what i did. I made my own stand via springs etc purchased from Machina Dynamica. In my system I had feedback which caused some lack of resolution due to the bass. All these problems were removed with the deployment of the stand. Not all rooms will have the same needs but in my system the bass is down to 20 Hz w. subwoofer & fullrange speakers. It was clearly audible. I also agree wall mounting (if you can do it) probably is the best solution short of a very expensive rack or a DIY job.

HI Elinor

Nice table you have chosen. Your rack is probably more than adequate, from the pics I have seen of them for sale. If it is the low type of Adona racks it would probably be better, lower center of gravity, less chance of it swaying, and vibrations being trapped in a bigger taller rack.
For a shelf Thomas of TW uses and recommends a type of slate found in Europe. Prior to getting the Minus-K I just used the rack I built made ot of birch ply almost three inces thick. I found isolation to be very good as the TW handles if farily well. You could try maple butcher block type boards of at least two inches thick. Make sure it is good white hard maple not the cheap soft stuff some guys pass off as butcher blocks. Birch ply is cheap and something you can do yourself. Glue stack and cut to size. Home Depot sells it in 48"x24" sheets.

I have seen custom built wall mounts that can support serious weights, and have heard stories of guys making some to support over three hundred pounds(Vibraplanes supporting an SME 30). But unless you have access to run long bolts through a wall with support plates on the other side, forget about that. I would not trust just some good lag screw to support such a crazy structure. If you do a wall mount keep in mind your location of that table is fixed to that spot in your room, and if later it becomes a bad spot that you have some more work to do.

If you can try either the HRS or SRA, which BTW has a working relationship with TW and High Water Sound, is probably more informed on the TW than any other isolation manufacture. Neither are cheap if you can try before you buy look into it. The HRS stuff is more generic, and SRA is purely custom. I will say SRA improved the sound of my SME 30 when I used it under that, and the guy that bought my old setup will say the same thing enthusiastically.

If you have a concrete floors you will not have to worry as much about vibrations as someone on a upper floor, like me. But I found mine to work very well without any vibration cancelling assistance.

Paul
Paul

I have a Clearaudio MontBlanc dedicated turntable stand and it never ceases to amaze me, I can play music loud until their is bass in your chest and the Transrotor Apollon / Clearaudio rack combination are something I never have to worry about. I do not get any acoustical or resonance feedback into the source. My basement is entirely concrete, with double concrete double insulation exterior walls and a concrete ceiling with about a thickness of about 15" inches. yes, the basement is my bomb shelter, haha. I think with the mass of the AC, I would add more mass via a heavy rack for a combined weight of whatever the rack and AC weigh. The Apollon and the Clearaudio rack together are almost 400lbs of mass. I am just too skeptical of adding such heavy weight to the wall, it is a viable option for some, but to me, I rather use a rack first then wall mount last. It seems way too scary for me to see your work of art sitting so high off the floor and then held in place by a rack with anchored points on the wall. See my rack option in my virtual gallery.
Ciao,
Audioquest4life

I currently have my AC Raven sitting on a custom platform constructed by K-Works. That sits on modified short table.
Nothing too fancy but I probably need to look at possible other options.
The table is short however, (18" high?) which I was told is good. The lower the better. The Table/TT sit beside the solid equipment/record cabinet.
Hope that helps.

Rick (RWD)

I know that one member here uses a Minus-K support, used for things like lab equipment I believe, (microscopes, etc), for his Raven AC.

When mine shows up it will be going onto the top of my Arcici Suspense rack. I have toyed with the idea of getting the top cover replaced with a custom cut 3/4" piece of slate as that is supposed to be a recommended support from TW-Acustic. Hopefully with the air bladders, that is sufficient because I don't really have other options, (wall mount in my living room where this will be going isn't an option).

Thanks

As with ANY turntable (unsuspended OR suspended)......placing on a cantilevered wall-mounted shelf is hard to beat.
The Raven AC is heavy so that a masonry wall is recommended or really rigid bolting directly to studs in a plasterboard is necessary.
To mount on a rack sitting on the floor.....you need to spend $20,000 like the Continuum Audio Caliburn stand for a similar result to wall mounting.