|'); } // End -->|
Like an LP12 or a Thorens?
OK, plinth-gurus ... can you give me your reasoned opinions on whether concrete would be a good material for a plinth?
BTW, as far as I understand it, the purpose of the plinth (apart from just holding up the top plate! :-)) ) is to conduct vibrations engendered in the top-plate "down and out"!!
A knowledgable (and GEA) tinkerer friend of mine recently made up a plinth for a Thorens out of 1" thick Oz hardwood (mountain ash) - to replace the stock plinth which was fairly lightweight (solid) wood, being only 1/2" thick. He has two Thorens t/tables ... one has this thin plinth, another has a much beefier plinth - and this latter one always had more bass "heft" than the thin-plinth one.
Anyway, his new 1" thick plinth changed the sound of that Thorens for the better - now it has the same or better bass than his other "beefier-plinth" one!! :-))
The above being a preamble ... if:
a) a heavier solid-wood plinth makes the Thorens sound better (what was anaemic bass becomes good bass!), and
b) the purpose of the plinth is to drain vibrations away
... would a plinth (for an LP12) made of cast concrete be a good idea or not (compared to the stock LP12 wooden plinth)??
It would not be too hard to "form up", say, a 1" thick plinth for an LP12 which had appropriate nuts embedded in the concrete to take bolts for the top-plate and used chicken-wire as reinforcing.
But I don't want to waste the time doing this if you hexperts out there tell me concrete is not a good material becoz ... etc. etc.
(And don't tell me it would look crummy bcoz I know I would have to spend some effort finishing off the surface of the cast concrete!!)
The Linn LP-12 was designed to be low mass/low energy storage. I don't think it presents a very good platform to turn into a high mass design. If you are working with an LP-12 I would experiment with low mass/low energy storage/constrained layer damping material along the lines of Ken Lyon's Neuance platforms. As Linn, Avid, Roksan, Rega, J A Michell, and a few other have show high mass is not the only game in town. Although I've heard some good sounding high mass tables I've also heard some wretched ones. Mass alone is no magic bullet.
Yes, I agree the LP12 was designed to be low mass/low energy storage - and that is key in terms of any replacement plinth. I think I've got enough feedback here to suggest that my thoughts of a concrete plinth are definitely in the worng direction! :-))
So I'll explore other options - like resin concrete or ceramics ... or even cast aluminium!
Cetech's replacement sub-chassis makes such a significant improvement over the stock pressed steel ... this inspires me to search for a plinth material which will similarly improve the sound (which wouldn't necessarily be suitable for cost-effective mass production).
You really want the resin style concrete rather than plain concrete. It offers a better modulus for resonance control.
For instance on the Kenwood KD-550 that I owned, the owners manual shows that they utilize a CLD approach to resonance control with the plywood bass controlling high frequency and the resin concrete plinth controlling low frequency. In this way they are tuning out resonance before it becomes an issue.
Suspending a table does not require any specific material composition. It is just a way to isolate foot falls for example.
...its massive, resonant "petrified cream of wheat" plinth. These things were very poorly designed, with plenty of resonating hollow cavities and a ringing marble-like cast material that made the TT sound lumpy, inconsistent, and lackluster.
> > > "Suspending a table does not require any specific material composition. It is just a way to isolate foot falls for example."
You're just making this crap up as you go along, as usual. Material selection is of paramount importance, suspended or no. A well-designed suspension isolates the 'table from its motor and its support. More importantly, it allows a knowledgeable designer to utilize light, rigid materials, rather than relying on crude, PRaT-killing, energy-storing mass to "isolate" the TT from its environment.
To answer the original question, massive supports and suspended TTs are a poor match. Try a light, rigid Neuance or Mana shelf, or a cheap Ikea Lack. Stone and thick wood under a suspended TT sounds comparatively dull, warm, slow, and bloated.
And then you discount the Kenwood which actually incorporates actual science to capture and control resonance within its honey-cone matrix below the turntable. They mixed proprietary blends of resin and stone to attenuate specific frequency ranges. They selected specific grades and thickness of plywood to control high frequencies. The ringing of the platter is controlled by the specific rubber mat they selected.
The whole thing sounds awesome with the right tonearm and cartridge and easily beats many expensive turntables.
Actually the choice of a plinth material has nothing to do with whether that material can be suspended or not. You can suspend popsicle sticks if you care to take the time or trouble. Suspension is accomplished to eliminate accoustic feedback from the pick up. Some designers use springy suspensions (SOTA), some taut suspensions (THORENS), some silicone dampened suspensions (BASIS) and others with combinations of springs, silicone, foam or other more exotic materials.
Just what would make any plinth material unsuitable for suspension? Moreover what suspension technology exists that precludes any material from being properly suspended?
Fretless you are spooning out drivel. It is designers choice.
So go ahead and add to the conversation but please list your personal opinions as such. I do not care if you want to attack me for whatever reasons you feel necessary, I just wish you would take some time to actually conduct some sort of professional discourse on an important topic.
By the way HP once wrote that a Kenwood Trio which incorporated that concrete resin base was the best sounding turntable he had ever heard. So do I trust you or do I trust HP?
Thanks for the tip - that certainly sounds promising.
However, I've never heard of "resin style concrete" before ... can you give me a link so I can read up about it?
BTW, I think a plinth ideally does more than just isolate footfalls - ie. external vibrations from getting to the stylus. It also needs to help drain away vibrations produced in the turntable by external and internal means ... and, as my mate's experiemnt with the 1" thick hardwood plinth for his Thorens, certainly makes a difference to the sound of the turntable! :-))
Give him a PM and perhaps he can scan these and send them to you. There might be a manual available on Vinylengine.com.
The Kenwood literature specifies what frequencies they were attenuating and I found a great deal of material such as reviews by googling Kenwood KD500/550.
HP of VPI once wrote that the resin crete Kenwood platform with an upgraded arm and cartridge was the best turntable he had ever heard. He bought it. Of course the high end VPI's pretty much sonically toast a Kenwood table now. Just take a look at Ray O Stat's set up under inmate systems. He has a nicely arranged VPI platform.
But the resin crete material has a superb modulus to attenuate low frequency. Much better than any material I know of from the literature I have examined. There was a great paper in Speaker builder of a guy that used quartz sand, ground rubber tire pellets, and builders epoxy to build a high modulus speaker cabinet.
VE does indeed have the Instruction Manual for the KD-500 ... so I was able to read that! :-)) It only mentions the resin-crete plinth once, though, and doesn't go into any technical detail about frequencies.
But I would just google "KD500/550 reviews" and see what comes up in the search field. Check Yahoo too, sometimes I get better results from one or the other.
Andy You might want to page mosin he's put some serious thought into concrete plinths and know from where he speaks with design / engineering.
From my limited knowledge base I don't believe massive Plinths are
necessarily a good thing for nicely engineered suspended tables like the LP 12, regardless of the materials used.
I think your concrete plinth would be more worthwhile for an Idler drive.
I will PM mosin.
And I've emailed U re. posting.
Regards from downunder! :-))
...I did have a turntable on my concrete (tiled) floor for a long while (because it seemed like the right thing to do), and when I mounted it on a thick solid maple base, off the floor, the sound improved immeasurably. Even the speed seemed to be more constant. If you think about it, anything as dense and solid as a concrete plinth is going to reflect, not absorb vibrations.
I quite liked some of the stands I saw at timbernation.com, suggested in one of the responses below. Perhaps one of those stands mounted on a concrete plinth would be a good idea.
Trouble is, of course, now you have a 'D' after your name ... you're no longer to be trusted!! :-))
I can understand that when your turntable was resting straight on a concrete slab, it didn't sound as good as when you moved it ... but the issue of what is a good substance to make a plinth from is perhaps a different thang to what is a good material to rest a plinth on?
But I agree ... concrete is too dense and solid.
maybe check with www.timbernation.com to get a maple plinth.
With my turntable, i'm finding that materials from which instruments are made from sound the best in all applications...brass & tonewood.
"Tonewoods" are those that have good resonant characteristics for musical instruments; i.e., they resonate freely and copiously; exactly what you don't want for a turntable platform. The ideal support for a suspended TT is one that releases resonant energy quickly without coloring the sound. A wood plinth stores resonant energy and feeds it "slowly" back into the TT, causing bloated bass, dull note attack, and poor pacing.
> > > "A wood plinth stores resonant energy and feeds it "slowly" back into the TT, causing bloated bass, dull note attack, and poor pacing."
Should have read "A wood support ..."
Gotta give these posts a once-over before hitting Submit : (
I would'nt use concrete! Concrete will probably not "drain" away vibrations of any magnitude. Heaviness alone is not necessarily a good indicator of the suitability of a given material for your purposes. All heavy materials do not shed vibrations effectively - they might simply store the vibrational energy internally for a slightly longer time than lighter materials will. Concrete is known to "ring" when struck, and I'm betting it would probably act more like a vibrational mirror than a vibrational drain...
Yeah, good point, Abel (about weight not being the be-all and end-all!).
However, you say "Concrete is known to "ring" when struck" ... well, I'd have to say if you made two (drum)sticks out of the kind of wood which Linn use for plinths (cherry, afromosia ...) or the Oz hardwood which my mate made his Thorens plinth from, and struck them together, they would ring too!!?? :-))
In fact I suggest that if I took one of these (drum)sticks and hit the concrete plinth with it ... the resulting "ringing" sound would be duller than if I hit the other (drum)stick with it.
So maybe concrete rings less than wood?
To me the vital question is ... does it have a better vibration sink/vibration-propagation quality than hardwood? That I do not know!! :-))
To my mind, the ideal "vibrational drain" would, for our purposes, be made from materials that store little energy and employ a compliant system of some kind. Sheer mass would be a secondary consideration at best, I think. Any material that rings is storing vibrational energy - that much is certain. The vibrational draining schemes employed by manufacturers like Caliburn, SME, Grandprix Audio, and Finite Element (to name a few) make the most sense to me. Too bad I can't afford many of their products...
be made from materials that store little energy and employ a compliant system of some kind ... yes, absolutely! :-))
Back to the drawing board!
Guess what? There is nothing new under the sun. Thorens made a TT with a concrete plinth at one time, as did Opus 3. Both were reviewed quite favourably. While I agree mass is not everything, it can be helpful for some TTs.
Thanks for your input ... I had no idea that concrete plinths had ever been made! :-))
Now, re. "For a Linn, I would go for a better platform underneath" ... well, my LP12 already sits on what I consider to be a pretty unbeatable platform - a wall mounted shelf made from two 3" square, aluminium right-angle sections projecting out from (and welded to) a 1/4" aluminium plate bolted to the wall. It's light - as per Linn recommendations - and rings less (and sounds better) than a similar shelf made of mild steel!!
You also said "rather than turning your LP12 into something no one else will buy". You make a wrong assumption here ... that I am interested in selling it! :-))
Owning a good turntable (and not being able to afford the many thousands of A$ which it would take to either buy a new LP12 or buy a different-make turntable which was "better"), I am interested in doing what I can to extract the most sonic gain I can out of it. Yes this will certainly change the sound of the LP12 - but hopefully add, rather than subtract, to its sonic qualities.
This includes replacing the sub-chassis with a Cetech carbon-fibre sub-chassis, possibly replacing the Linn motor with either an Origin Live DC motor or a motor & controller developed by VA's Mark Kelly ... and maybe substituting a new plinth.
Alas, risabet, I believe Cetech has disappeared ... so the carbon-fibre sub-chassis is no more! :-(( (I also read a review in TNT-Audio by Geoff Hisband dating from 2000, concerning a carbon-fibre shelf made by Cetech, which is also now no longer available!)
Re. the OL ... trouble is, the reviews I've read have not been unanimously positive (unlike for the Cetech sub-chassis) ... so I've held off.
This post is made possible by the generous support of people like you and our sponsors: