Yesterday's TT bake off got me thinking about TT placement as I made my way home on the train.
Usually, threads discussing what folk use beneath their decks result in a stand war of some description, so perhaps this one can be constructive :)

Some go to great lengths in attempting to isolate the deck from the surroundings while others don't give it such high priority. To me it is of vital importance because I believe that less than optimal placement can introduce so much crud into the system as to make the differences between even a £50 phono stage and one costing many £ks seem trivial by comparison.

So, as its a boring Sunday afternoon I made a couple of recording which might be of interest here.
One is with the TT placed on a light SO table placed between and slightly behind the speakers - about 2ft from each I'd say.
The speakers are panels and so cancel in the middle to some degree. Results are likely to be worse with a box speaker!

The other recording is taken with the deck sitting on a wall shelf, above the plane of the speakers and about 6 feet away. In both cases the stylus was allowed to rest on a stationary record - all you are hearing is sound via mechanical and acoustic coupling. The volume used was representative of how I'd usually listen to the track.

Same gain used for both, so have a listen and see what you think, and remember that what you are hearing gets superimposed onto everything you play.
I used the Talk Talk track we used yesterday.

http://www.mediafire.com/download.php?4zq3tukty5z

http://www.mediafire.com/download.php?vkoitnq35tm

The first is obvious , the second much much quieter. Tell me the first one was between the speakers .

Placement imo is as much about isolation as energy drainage. I have been having fun with two mdf boards with cut up coolie cans sunk in to them, between the cans bottom dimples (cups) sit big marbles. Sort of a roller block platform on the cheap...

A Funk Achroplat underneath a TT also works quite well.

I've never been that bothered in the past & hearing people putting the TT in a seperate room always seemed OTT to me - my equipment is quite basic & ordinary with no specialised phono stage - but reading here on the Bake off that you can hear people talk - well that shows the sensitivity of the amp & in which case I can start to understand the problem.

As it happens my TT is set in a corner but happens to be fairly close to the Left speakers
I'll give these a listen

I've been thinking about the same thing recently as I redecorated the living room and moved my amadeus from the quadraspire wall shelf to the top of an old Ikea stand that's a bit wobbly. Unfortunately the wall shelf is now in the shed, so it's tricky to do an a/b.

Of your samples, the first one has a strange double thump that's audible (a bit like the start of DSOTM...) and the second is clearly quieter.

Maybe I'll have to dig my wall shelf out again and try re-fixing it, but they are such a bugger to do.

Here is what the two files look like:


http://img.photobucket.com/albums/v637/zippy670/Stand.jpg

http://img.photobucket.com/albums/v637/zippy670/Wall.jpg


The sudden bump two thirds into the second was a noisy van driving past.


You wouldn't tolerate a tenth of that noise from your electronics so banish it from your turntable.

I really have to agree with everything Robert is saying here.

Excellent topic Robert. I remember the Hi-fi mags going on about this in the early 80's.

It'd be interesting to repeat your experiment with the turntable in a different room with a solid brick wall between them.

And also to repeat it with a vibration isolation table or platform such as this one:
http://www.minusk.com/content/products/standard/bm-8.html
I suspect that $2700 for one of those could prove to be a cost effective upgrade for systems like Flatpopely's where he's rather restricted on where he can put his TT due to the need to fit things like sofas into his living room - and where a wallshelf isn't an option.


Sadly, most living rooms in the UK are not what I'd call Hi-fi friendly. Too small to fit everything in and windows and doors often getting in the way of what would otherwise be a good place to put speakers or speaker cables. As well as bouncy wooden floors transmitting all that feedback...

I really have to agree with everything Robert is saying here.

I need a whisky :D

quickly!

I really have to agree with everything Robert is saying here.

But the PL71 was nowhere compared to the LP12. I thought you said that the Linn was a rubbish design that required special positioning, now you are saying that positioning is a consideration. Please clarify why you agree with Robert.

I agree with Robert also but don't consider it a problem for my deck in my system. That'd just my opinion about my LP12s placement.

I need a whisky :D

quickly!

Don't take it as a precedent, by the law of averages you have to be right occassionaly.

I need a whisky :D

quickly!

Sorry Robert I have replied!

But the PL71 was nowhere compared to the LP12. I thought you said that the Linn was a rubbish design that required special positioning, now you are saying that positioning is a consideration. Please clarify why you agree with Robert.

I agree with Robert also but don't consider it a problem for my deck in my system. That'd just my opinion about my LP12s placement.

With all due respect, Andrew; I've never met an LP-12 that wasn't influenced by the surface it sat upon. Think of it in these terms, if it's good now, how much better could it be with additional isolation?

effected by the proximity to the loudspeakers. The folk who sold stands never told you , you can get the same "improvement " and some more by moving your TT well away from the speakers ..cos they wouldnt make money out of fools.

perhaps the suspended nature of the LP12 makes it more prone to placement issues than some unsuspended decks?

I havent measured this as rob clearly has

Have you measured with other decks rob?

I'm so glad this has come up for discussion as I believe placement of the TT away from the speakers is very very important but due to most peoples hi-fi being used in normal living , it puts constraints on us and we have therefore to compromise.
I've listened in the past to some very very nice speakers but nearly all had to be used away from the walls and into the rooms. Now I like a peaceful life and so I tried desperately to find some that gave good sound and could be put against a wall, hence my choice of Kans. Now I know these are seen (heard) by many as less than ideal but along with my Naim amps, I beleive they give a very good sound indeed and I'm more than happy with what they give out. To me, this is the most important thing - being happy with what you have.
I do have one of my speakers quite close next to my TT but the TT is on a proper isolated table and I will try further ways of damping any airborne vibrations out as I have always thought this will give a better sound. As for the bake-off, at least all the TT's were subjected to the same sitting of the decks and speakers and so as a comparisson it could be classed as fair but isn't there something to be said in how each deck deals with any airborne vibration? Any Rega owner who wants the best from their decks with the solid plinths understands the needs to site their decks to get the best from them so surely the same should apply to suspended ones too. And to me no matter how good the deck, close to a speaker isn't one of them.

The audio files really do make it clear just how much can get back into the system if placed too close. The big difference 6 feet makes, does pretty much suggest that putting it in the other room might be a bit OTT, as well as being downright inconvenient, unless a deck were overly susceptible. Mine moved from a floor bound stand about 4 feet away to a wall shelf, more like 15 feet and around a corner in an alcove about 4 years ago and it made a noticeable difference.

You've made a really good and useful demonstration here. You could use the same technique for testing degrees of microphony in any component - valve amps being the obvious.

So what is this indicative of ? I noticed this a few days ago when recording.

Screen shot of Level Meter Toolbar

TD160 with platter spinning & Arm in rest No music or any other noise. The graph recording on Audacity shows a flat line.

My other deck shows zero ie absolutely nothing

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871 see jpeg

Uncle Ants - I'd love to see Rob try the same with solid state electronics like amplifiers and CDPs. Simply use amps that demonstrate a noticeable change when moved from one surface to another. Now, record the differences for all to hear and measure them publishing graphs as well.

Proximity of transducers is always important no matter what transducer. Distance is the cure, but tables help in some designs.

This was all gone through with the thread about the Epping bake-off and talking about concrete float flooring. http://www.pinkfishmedia.net/forum/showthread.php?t=64716&page=30 post #444

The PL-71 largely doesn't give a toss where it sits and what it sits on apart from being next to a loudspeaker when it is bound to feed back mechanically and accoustically. The SP10 will feed back acoustically but the mechanical earth (sink) of the slate mass will very much helped it mechanically. Plus using a phono stage that makes a very good microphone in its own right sitting next to the speaker I would have thought would have largely invalidated the experience, as it seems to me you were probably hearing more feedback than fundamental.

The other turntables I don't know but all should be affected one way or another by this.

perhaps the suspended nature of the LP12 makes it more prone to placement issues than some unsuspended decks?

I havent measured this as rob clearly has

Have you measured with other decks rob?

Yes, but many years ago. It was to cassette tape which gives you some idea :)

Suspended and non-suspended decks respond differently to airborne and structure borne influences. There are so many variable - the materials from which the decks are constructed and of course the methods of construction. How various bits of the TT are damped and how they pass energy onto other parts of the structure.
The more you dig around looking for clues the more you find on this subject.

I think it is fascinating that you can actually hear the design rationale in the file from the P9. Listen to it carefully and what you hear is pretty clean and intelligible, there is little or no overhang or smearing.
it reflects the low mass yet rigid design in the feedback signature.

I've heard the signature from a sprung deck with resonant sprung parts, coupled to thin wood sections, and the result is quite different. You can hear the stored energy - the thing acting like a capacitor, and a different capacitor at different frequencies to boot.

The effect on music in interesting. The former, while still audible is less objectionable IMO because there are less time smear related effects.
Energy storage in a hi-fi system is generally bad news IMO, with a few exceptions such as PSU caps!

I'll stop there as I suspect I'm still on Richard's wavelength and agreeing twice in one night gets scary ;)

Uncle Ants - I'd love to see Rob try the same with solid state electronics like amplifiers and CDPs. Simply use amps that demonstrate a noticeable change when moved from one surface to another. Now, record the differences for all to hear and measure them publishing graphs as well.

Done it worn the t/shirt in the 1980's, 1990's and some recent work. More fundamental than standing surfaces is case material and construction.

So what is this indicative of ? I noticed this a few days ago when recording.

Screen shot of Level Meter

TD160 with platter spinning & Arm in rest No music or any other noise. The graph recording on Audacity shows a flat line.

My other deck shows zero ie absolutely nothing

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871 see jpeg
Whatever it is it's very low level - does the plot of the recording in audacity look like a straight line if you look at it closely with the magnifying glass feature or if you amplify it (in the effects menu)? If it doesn't (and I'm guessing it doesn't) then using the plot spectrum feature you can see at what frequency the noise is, and it might give a clue.

I used something like this sort of technique (except I did it both arm in stand and recording an unmodulated groove) to investigate what the primary sources of noise were, and tried a few things to try and work out what routes it was taking when I was doing up my Lenco. Where it was really handy was seeing what effects on the noise floor various modifications, adjustments and ideas for damping had (some made it worse).

If it really is flat, then I don't know. If it does show something, then its either signal related or mechanical. Is it there when the deck isn't spinning? If it isn't then it's mechanical - either bearing rumble or something in the drive mechanism getting into the arm somehow - given the design, bearing rumble is more likely. Doing the spectrum analysis should help tell which. What's the other deck?

Done it worn the t/shirt in the 1980's, 1990's and some recent work. More fundamental than standing surfaces is case material and construction.

Excellent. Can we see the graphs?

Excellent. Can we see the graphs?

Nope! anyway you should know by now I judge by what I hear I only measure for gross as that is all you can measure. It may be a surprise to you but when I do these things I do them for me and my design process, not for you!

I can very easily design a case to F'up the sound and one not to, you can have a bake-off between them if you want :p

So what is this indicative of ? I noticed this a few days ago when recording.

Screen shot of Level Meter Toolbar

TD160 with platter spinning & Arm in rest No music or any other noise. The graph recording on Audacity shows a flat line.

My other deck shows zero ie absolutely nothing

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871 see jpeg

It'll probably be registering residual hiss/noise from the phono stage/pre/analogue input.

Nope! anyway you should know by now I judge by what I hear I only measure for gross as that is all you can measure. It may be a surprise to you but when I do these things I do them for me and my design process, not for you!

I can very easily design a case to F'up the sound and one not to, you can have a bake-off between them if you want :p

:rolleyes:

It'll probably be registering residual hiss/noise from the phono stage/pre/analogue input.

Except he says he doesn't get it with the other deck - though that's a little surprising as I don't know thinking about it that I've ever hooked a deck up to a PC using Audacity and not seen the meters trembling away slightly down there, whatever deck or phonostage - and had assumed it was hiss or a low level hum.

Like I said when I was messing with the lenco - recording with and without the deck spinning, you can get some idea what is residual and what's coming from the deck itself (edit: and amplifying to an audible level and having a listen also gives a clue of course).

I can try a similar experiment by placing the amp right next to the speaker. Previous experience tells me that with a SS amp the signal produced will be so small as to be buried down in the noise floor. I'll give it a whirl during the week.

Phono stages are different because of the gain involved. Valve stages can be very microphonic and so can SUTs. I have SUTs, valve and SS stages so can show you how they respond to speaker proximity, and floor coupling via a stand.

Here is the Spectrum frequency analysis if that's what you mean Uncle

Totally inaudible btw & the recording graph when magnified is a teeny bit wavy (but that's the same for both decks)




http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871

Done it worn the t/shirt in the 1980's, 1990's and some recent work. More fundamental than standing surfaces is case material and construction.

It wouldn't surprise me in the least. Unlike some individuals I don't buy into the idea that manufacturers paying attention to vibration control do it to milk the cow;-)

Here is the Spectrum frequency analysis if that's what you mean Uncle

Totally inaudible btw & the recording graph when magnified is a teeny bit wavy (but that's the same for both decks)

That's looks like 50hz to me, so possibly noise from the Thorens AC motor.

That's looks like 50hz to me, so possibly noise from the Thorens AC motor.

Shouldn't 50 Hz be audible?

I can try a similar experiment by placing the amp right next to the speaker. Previous experience tells me that with a SS amp the signal produced will be so small as to be buried down in the noise floor. I'll give it a whirl during the week.

Phono stages are different because of the gain involved. Valve stages can be very microphonic and so can SUTs. I have SUTs, valve and SS stages so can show you how they respond to speaker proximity, and floor coupling via a stand.

I'd think you'd just need to make sure the amp under test is audibly affected by changing surfaces first or we'll have the same old cries of there's no such thing as microphonics. For example, IIRC, fox once stated his ATC preamp is immune to vibration. If so, it wouldn't be good for this type of test.

I suspect you're correct and the change would be difficult to distinguish from the noise.

Have Fun, yes except change the parameters. Increase where it says 1024 to the max value and change linear freq to log then look. you'll be able to see the detail down at the bottom end. Any frequncy noise will be inaudible if the level is low enough to be inaudible and it looks pretty low level but it's hard to tell with the graph as is.

The sudden bump two thirds into the second was a noisy van driving past.


You wouldn't tolerate a tenth of that noise from your electronics so banish it from your turntable.
Robert,

What kind of floor do you have where the measurements were taken and what deck did you use?

John

I believe the 2nd 'tester' didn't have his arm on the platter. One thing the platter is exceptional at doing is coupling vibration to the cartridge, the test is pretty much moot without this.

Try magnetically levitating your main bearing and watch that noise floor disappear...

Have Fun, yes except change the parameters. Increase where it says 1024 to the max value and change linear freq to log then look. you'll be able to see the detail down at the bottom end. Any frequncy noise will be inaudible if the level is low enough to be inaudible and it looks pretty low level but it's hard to tell with the graph as is.

Hello Uncle Ants

Here is the log spectrum plot over 20 secs set at max

Recording level was at my standard volume input

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871

Robert, can you take test what only moving TT 6 feet away from speakers do to the sound. So that you do not put TT on wall shelf, just what distance makes to background noise.

What do you think, is that thumbing coming from floor coupling near speaker or via air by shorter distance?

Sadly I have my Xerxes very near to ES14's. :rolleyes: Lack underneath Xerxes almost touches the stand of Epos's.

Hello Uncle Ants

Here is the log spectrum plot over 20 secs set at max

Recording level was at my standard volume input

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871

A nice big 50Hz spike as Robert suggested. What does it look like with the motor off?

Robert, that is a very interesting and very valid comparison you have made. I also strongly believe in isolation and have gone to significant lengths to achieve it in my own designs. Often manufacturers believe (choose to believe) that high mass, on its own, is sufficient to achieve isolation but that is not the case (though not having a suspension does make life very much easier for the designer).

With regard to the bake-off; whilst the turntable positioning could have been even better, it could also have been worse. At least each turntable got a light, rigid stand that was level and not directly in front of the speakers. At the end of the day the system positioning at Andrew's house is very representative of the way many 'real life' systems are set up. At the end of the day manufacturers have made their decks to play records - I don't think it is fair for them to sidestep their design responsibilities by demanding (or at least requiring) very specific positioning, or mounting, requirements.

As it happens, I have suggested to Andrew in the past that we reposition his deck and indeed we did just that (it did sound a bit better too). Unfortunately, the new positioning did not lead to domestic harmony and so was abandoned - welcome to reality :). Lindsay's idea that 'ugly' hi-fi issues can be overcome with a fancy holiday is, in my experience, just not true - I know Mrs. P well enough to be sure that she wouldn't have the EMT in the house under any conditions (she did rather like the Dais though).

Previous experience tells me that with a SS amp the signal produced will be so small as to be buried down in the noise floor.

Even if it is "buried down in the noise floor" it might still be heard because it's related to the music and not the amp's noise.

You can't simply assume that a lower level 'noise' will be concealed by unrelated higher level 'noise'.

I also strongly believe in isolation and have gone to significant lengths to achieve it in my own designs. Often manufacturers believe (choose to believe) that high mass, on its own, is sufficient to achieve isolation but that is not the case (though not having a suspension does make life very much easier for the designer).

What have you found to be effective so far? I'll be giving this topic some thought shortly as I have a new 40mm thick slate plinth for my 301. It clearly needs to stand on something as the motor and main bearing hangs 90mm beneath the chassis, so I get to play with different feet etc. My starting point will be very rigid, I had some discs cut out of the discarded slate, so I'll begin with the plinth on these and spikes. I guess I should try decoupling too, e.g. rubber feet. The problem being that I really need adjustable feet here as I'll need to level the deck. It narrows the choice somewhat.

Tony.

The problem being that I really need adjustable feet here as I'll need to level the deck. It narrows the choice somewhat.

You could try fixed feet and shims. I found I preferred squash balls in ply 'legs' to slate and spikes with mine.

What have you found to be effective so far? I'll be giving this topic some thought shortly as I have a new 40mm thick slate plinth for my 301. It clearly needs to stand on something as the motor and main bearing hangs 90mm beneath the chassis, so I get to play with different feet etc. My starting point will be very rigid, I had some discs cut out of the discarded slate, so I'll begin with the plinth on these and spikes. I guess I should try decoupling too, e.g. rubber feet. The problem being that I really need adjustable feet here as I'll need to level the deck. It narrows the choice somewhat.

Tony.

Car valve springs!

So, Italian Cars for Opera, American big V8s for Jazz and R&R, SUVs for C&W, Jags for Brit Pop ....?

You could try fixed feet and shims. I found I preferred squash balls in ply 'legs' to slate and spikes with mine.

That is interesting. My other plan is to try some upturned 1970s skateboard wheels (very solid and inert polyurethane cylinders about 55mm x 55mm), these have indentations for the bearings which one could easily and securely sit a squash ball in to make them more compliant. The only issue is they are non-height adjustable. I was also thinking of trying them with the little adjustable cones (http://cgi.ebay.co.uk/4-pcs-Black-Audio-Equipment-Vibration-Isolation-Feet_W0QQitemZ310156268654QQcmdZViewItemQQptZLH_De faultDomain_0?hash=item4836c1146e&_trksid=p3911.c0.m14&_trkparms=65%3A13%7C66%3A2%7C39%3A1%7C293%3A1%7C29 4%3A50) I have.

My table is non-audiophool and very heavy indeed (pic here (http://farm4.static.flickr.com/3404/3274531974_976dc7ccef_o.jpg)) - the Garrard is just the wrong shape to fit on any of the usual hi-fi tables, my slate plinth (http://farm4.static.flickr.com/3359/3632297285_f2b76761fa_o.jpg) is 450 x 450 x 40mm so should look great on the 500 x 500 x 500mm oak table.

Tony.

PS I'll move this tangent to a fresh thread later if it looks to be diverting from the original topic.

Car valve springs are ok if you have a huge load on them, otherwise they are a pointless injection point for high frequency oscillation, all springs ideally require additional damping to be most beneficial.

A nice big 50Hz spike as Robert suggested. What does it look like with the motor off?


Weird is the answer

Jpegs show one with platter not spinning & the other with the deck switched off at the mains - remarkably similar

I conclude I am recording the amp from the phono

I have 2 phono inputs - my other deck is on 1 & the TD160 on the second
I'll switch over to see if there is any difference

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871

Car valve springs!

Interesting, but I'm reluctant to use springs - it's like taking the LP12s problems of wobbliness / high centre of gravity etc and applying them to a deck that simply doesn't have those issues at all.

Tony.

That is interesting. My other plan is to try some upturned 1970s skateboard wheels (very solid and inert polyurethane cylinders about 55mm x 55mm), these have indentations for the bearings which one could easily and securely sit a squash ball in to make them more compliant. The only issue is they are non-height adjustable.

You may find that you need to try a few different approaches - an unmodulated groove on a test record and the volume cranked is useful to hear what effect different feet can have. Recording and analysing it may help further - and help with comparisons. Certainly I found with the Lenco project that different feet made an audible and measurable difference both in terms of rejecting outside vibrations and in terms of lowering any low level noise coming from the deck itself.

I wound up using compliant feet (isopods), but there are a lot of factors (the deck itself, the plinth construction, the shelf construction etc.) - I suspect I could have had very different results if one or more of those factors were different. I'd experiment and then worry about how to get them adjustable. One of the more effective sets of feet I used was an old set of of RPM9 feet - a sort of cup with a thread in the top (for adjustment) with a blob of sorbothane and then a flat foot under that. You can have them if you want - I only didn't use them because they made the whole thing too tall to be aesthetically pleasing.

... but there are a lot of factors (the deck itself, the plinth construction, the shelf construction etc.) - I suspect I could have had very different results if one or more of those factors were different.

I 100% agree.

One of the more effective sets of feet I used was an old set of of RPM9 feet - a sort of cup with a thread in the top (for adjustment) with a blob of sorbothane and then a flat foot under that. You can have them if you want - I only didn't use them because they made the whole thing too tall to be aesthetically pleasing.

I've also got a set of Micro Seiki MSB-1 feet (http://farm4.static.flickr.com/3184/2351082548_969f31fb28_o.jpg), though they are just too short to be of use on their own, I suspect the deck / plinth might be a bit heavy for them too. Could you possibly send me a pic of the RPM9 feet? If they look like they'd work with either the slate disks or the skateboard wheels I'd very much like to try them.

Tony.

Weird is the answer

Jpegs show one with platter not spinning & the other with the deck switched off at the mains - remarkably similar

I conclude I am recording the amp from the phono

I have 2 phono inputs - my other deck is on 1 & the TD160 on the second
I'll switch over to see if there is any difference

http://www.mediafire.com/?sharekey=b2a2ad8fd732c20b6b21be4093fab7ace04e75f6 e8ebb871

No change after switch over - the spectrum graphs are near identical

The Level Meter Toolbar on The TD160 always shows a flutter / splash of red

What have you found to be effective so far? I'll be giving this topic some thought shortly as I have a new 40mm thick slate plinth for my 301. It clearly needs to stand on something as the motor and main bearing hangs 90mm beneath the chassis, so I get to play with different feet etc. My starting point will be very rigid, I had some discs cut out of the discarded slate, so I'll begin with the plinth on these and spikes. I guess I should try decoupling too, e.g. rubber feet. The problem being that I really need adjustable feet here as I'll need to level the deck. It narrows the choice somewhat.

Tony.

At present I'm using springs which are silicone damped with significantly higher resistive load in the lateral mode compared to the vertical (adjustable)- an element of pneumatic damping is also present. However, the centre of gravity of the system also need to be considered and in my case it is all integrated into the plinth structure rather than being an 'add on'. Also, if you want really broadband isolation you need to have a high suspended mass, not just a low resonant frequency.

Easy things to try are a slab of something heavy (wooden chopping block or paving slab) positioned on a gently inflated inner tube (three or four will make the whole thing a lot more stable). A paving slab on four valve springs from a Mini also works well (not chopping block as it won't be heavy enough). Pete uses four valve springs with a big slab of slate on the top on his SP10 but the resonant frequency is still a bit high and I know he is considering some more complaint springs. Also Decathlon sell racket balls (like larger, softer squash balls) and if a paving slab is put on four of those you will get a pretty low frequency isolation platform. Once you have the result you like a better looking solution can be made :).

Different spikes really alter the coupling of the system and don't actually decouple at all.

No change after switch over - the spectrum graphs are near identical

The Level Meter Toolbar on The TD160 always shows a flutter / splash of red

So you get the same results, motor on and motor off? Then whatever is causing it, isn't mechanical withinthe deck. The 50Hz peak is mains induced hum from somewhere, earth loop? poorly shielded cables? .... If it's inaudible I shouldn'y worry about it too much, a very low level of hum and noise is fairly normal in a phonostage.

yeah thanks uncle

No I'm not worried I was just surprised that the Meters showed it

There is no earth wire or ground on the TD160 & is not required as far as I recall

Interesting, but I'm reluctant to use springs - it's like taking the LP12s problems of wobbliness / high centre of gravity etc and applying them to a deck that simply doesn't have those issues at all.

Tony.

No wobbliness with valve spring especially if you use truck ones :D

Go look at the nude photo of the Pioneer P3a to see my point - high mass plus decoupling - seems the best solution.

http://www.thevintageknob.org/PIONEER/P3/P3.html

...

Pete uses four valve springs with a big slab of slate on the top on his SP10 but the resonant frequency is still a bit high and I know he is considering some more complaint springs.

Yep, there are feet around them to give some lateral stability, though they don't seem particularly wobbly without. Still, it looks nicer. :) Originally there were some O-rings around them which constrained the motion to about 1mm vertically, but these have come apart and it's a wee bit less stable now. Softer springs are definitely in order, I just need to calculate what rate and lengths I need. The high CoG is not ideal, but I can't see an easy way of suspending 60kg of slate!

I know Guy (Pure Sound) has some issues with acoustic feedback with his similar setup until he damped the springs, I believe by pushing foam up the centre of the spring. I wonder if some kind of coating (spray on foam?) might help here.

In the olden days, LP12 owners were told to put their decks on light rigid tables. These days one often sees LP12s atop stacks of Fraims and heavy amps. On enquiring how come, I was told that the new Trampolinn renders the support irrelevant. I don't believe it. Based on classical orchestral and instrumental recordings, I find such LP12s - even fully spec'd SE varieties - have a hardness about the sound and a loss of air and space compared to my definitely midrange LP12. I use a dedicated lightweight Audiotech table under Sonority isolation and no baseboard, and this seems to work a treat for me. What's the pfm consensus about this?

The foam will increase the lateral stability but should, to a point, reduce the actual isolation. Ideally, I would cut four holes in the corner of the slate and fashion cups so that the springs are, essentially, inset into the slate - this will significantly lower the centre of gravity and increase lateral stability.

These deflex superpods make good turntable feet, I have them under my Garrard 401
http://cgi.ebay.co.uk/DEFLEX-SUPERPODS-X-4-HiFi-Audio-Isolation-Damping-feet_W0QQitemZ170349968760QQihZ007QQcategoryZ96957 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Alan

The foam will increase the lateral stability but should, to a point, reduce the actual isolation. Ideally, I would cut four holes in the corner of the slate and fashion cups so that the springs are, essentially, inset into the slate - this will significantly lower the centre of gravity and increase lateral stability.

Yeah, that sounds like the way to go, I will have to try that at some point. Will have to speak to some stone masons about drilling it.

Robert,

What kind of floor do you have where the measurements were taken and what deck did you use?

John

Suspended wooden floor, with fitted carpet.
The Sound Org table spikes were presed down to contact the boards and there was no wobble.
TT was a P9.

Tonight I'll run some tests by placing an integrated amplifier (Rega Elex) on the floor close to the speakers, fire the normal system up nice and loud and record the output from Elex. Then do the same with the speakers muted.

I expect to hear now't but swishhhhhhhhhhhhhhhh.
Should be interesting and I'll put the files up for all to hear and look at.

Rob

Have you still got those bits of Mana?

You could, once and for all.....

(ducks)

Jonathan

Interesting, but I'm reluctant to use springs - it's like taking the LP12s problems of wobbliness / high centre of gravity etc and applying them to a deck that simply doesn't have those issues at all.

Tony.

I wouldn't worry Tony - Richard is right, give them a try.

Floating the entire shebang on springs is quite different to the Linn way, with the subchassis able to move relative to the motor. I don't think the latter is a problem for the Linn but the two methods are very different regardless.

I had several LP12s and used a target tt wall mount. The best base though was when I moved and put the deck on a wooden shelf in a doorless wall cupboard of a Victorain flat. That was the best!

Rob

Have you still got those bits of Mana?

You could, once and for all.....

(ducks)

Jonathan


I have and I will :)

I wouldn't worry Tony - Richard is right, give them a try.

Floating the entire shebang on springs is quite different to the Linn way, with the subchassis able to move relative to the motor. I don't think the latter is a problem for the Linn but the two methods are very different regardless.

Is there any advantage to springs over rubber, e.g. squash balls? I'd have thought squash balls had the isolation without the 'boing'. I may try a set though. I notice from eBay one can source suitably 1950s English valve springs for the Garrard too, e.g. BSA, Triumph, MG, Austin Healey etc.

Tony.

Squash balls don't actually provide very low frequency isolation.

Is there any advantage to springs over rubber, e.g. squash balls? I'd have thought squash balls had the isolation without the 'boing'. I may try a set though. I notice from eBay one can source suitably 1950s English valve springs for the Garrard too, e.g. BSA, Triumph, MG, Austin Healey etc.

Tony.

Go for it.

Back in the day I had my old JVC QL7 with it's plinth filled with concrete sitting on four big springs and it worked very well.

For folks with suspension-less turntables, this link (http://www.symposiumusa.com/rollerblocks.html) might be worth checking out, especially the section: Rubber Feet, Rubber Balls and Sorbothane Pads.

I have tried Vibropods under my replinthed Lenco but these made the bass a bit soft and poorly defined. Today I placed it on a set of Something Solid Dissipating Feet, much,much better, I think these will be a keeper and a bargain at £20 for a set of three.

Just a thought:-

Wouldn't white noise be the best way of seeing which unwanted frequencies get into the cartridge?

Audacity can generate white noise. This could be played from the computer, or copied to CD and played from a CDP if simultaneously playing and recording on the computer is a problem.

Frequency analysis would then show what's getting through.

Good point.

My Dac can also generate white noise (it uses it for the room correction functions) so that can be arranged.

Just a thought:-

Wouldn't white noise be the best way of seeing which unwanted frequencies get into the cartridge?

Audacity can generate white noise. This could be played from the computer, or copied to CD and played from a CDP if simultaneously playing and recording on the computer is a problem.

Frequency analysis would then show what's getting through.

One is with the TT placed on a light SO table placed between and slightly behind the speakers - about 2ft from each I'd say.
The speakers are panels and so cancel in the middle to some degree. Results are likely to be worse with a box speaker!

The other recording is taken with the deck sitting on a wall shelf, above the plane of the speakers and about 6 feet away. In both cases the stylus was allowed to rest on a stationary record - all you are hearing is sound via mechanical and acoustic coupling. The volume used was representative of how I'd usually listen to the track.


Would be interesting to use the SO floor table for both recordings. A wall shelf is probably a better support compared to a floor stand on a suspended wood floor.

It would be interesting to discuss what's at play here. Is it the speakers vibrating the floor and that vibration coming up the stand to the turntable. Or more so the bass vibrations from the speakers hitting the stand/shelf, plinth, arm affecting it that way.

The LP12, because of it's tuned suspension, is suppose to deal with acoustic vibrations within the music range quite well. It will be interesting to hear Andrew's recordings once he gets the time to get them out there.

Would be interesting to use the SO floor table for both recordings. A wall shelf is probably a better support compared to a floor stand on a suspended wood floor.

It would be interesting to discuss what's at play here. Is it the speakers vibrating the floor and that vibration coming up the stand to the turntable. Or more so the bass vibrations from the speakers hitting the stand/shelf, plinth, arm affecting it that way.

The LP12, because of it's tuned suspension, is suppose to deal with acoustic vibrations within the music range quite well. It will be interesting to hear Andrew's recordings once he gets the time to get them out there.

Going to do them tonight if after listening through headphones I can hear anything!

I had a lot of problems with my LP12 on a suspended wooden floor loads of feed back and foot fall when walking across the room the track would skip so I bought a custom design wall shelf and all my problems where solved the linn really started to shine then. incidently I found a wooden shelf was better than the glass shelf supplied.
On the ball bearing theory I was experimenting with the fixing an my OL250 arm on my Garrard 401 and I found that the sound really tightened up and became more dynamic when I mounted the arm board on 4 small ball bearings, the arm board still has 2 screws through into the plinth but the ball bearings must give some isolation from vibration in the plinth
http://i259.photobucket.com/albums/hh290/337alant/linnlp12.jpg
http://i259.photobucket.com/albums/hh290/337alant/garrard401b.jpg
http://i259.photobucket.com/albums/hh290/337alant/garrard401.jpg
Alan

In the olden days, LP12 owners were told to put their decks on light rigid tables. These days one often sees LP12s atop stacks of Fraims and heavy amps. On enquiring how come, I was told that the new Trampolinn renders the support irrelevant. I don't believe it. Based on classical orchestral and instrumental recordings, I find such LP12s - even fully spec'd SE varieties - have a hardness about the sound and a loss of air and space compared to my definitely midrange LP12. I use a dedicated lightweight Audiotech table under Sonority isolation and no baseboard, and this seems to work a treat for me. What's the pfm consensus about this?

I've never been a fan of the Trampolin and think it's a compromise for a compromised setup. I'm interested in the Sonority isolation shelf, is this (http://www.sonoritydesign.co.uk/Products_turntable_base.htm) the one you're using? I'm using Symposium Rollerblocks under my speakers and I'm quite impressed. It looks like the Sonority products use a rollerblock arrangement between the shelfs, is that correct? Can the shelf move freely in all directions?

Connected the phono stage up to my headophone amp and turned volume to full. Used my ipod to feed the main system with Talk Talk, volume at bake-off level.

Put headphones on and went into another room and shut the door.

Zero and I mean ZERO break through into the headphones. Turned it effin loud, still nothing.

Tapped tonearm and could hear it very loud in headphones so the wiring was correct etc.

Tried experiment again, still nothing. Audiotec -TrampolinII and LP12 suspension isolate the cart from airborn and mechanical coupling in my system in my room.

I won't even bother to record it as there is nothing to record.

Connected the phono stage up to my headophone amp and turned volume to full. Used my ipod to feed the main system with Talk Talk, volume at bake-off level.

Put headphones on and went into another room and shut the door.

Zero and I mean ZERO break through into the headphones. Turned it effin loud, still nothing.



Good idea, think I'll try same(ish). CD instead of Ipod which I don't have.

Stylus resting on a record ? ;-)

Stylus resting on a record ? ;-)

That is crucial - it must pick up something as no stand can isolate a TT from airborne influence (think about that..... it is impossible). Not in this universe at any rate :)

Springs will certainly do the job on mechanical stuff coming in via the support - above their resonant frequency which is about 4hz on a Linn.

That is crucial - it must pick up something as no stand can isolate a TT from airborne influence (think about that..... it is impossible). Not in this universe at any rate :)

Springs will certainly do the job on mechanical stuff coming in via the support - above their resonant frequency which is about 4hz on a Linn.

Honestly, whatever it was was below the noise floor of my headphone amp, I'll record it anyway and post it on here.

I replaced the feet on my TT with Nordost Pulsar Points:-

http://www.nordost.com/images/products/a-ppa_425.jpg

They were a drop in replacement and resulted in a very worthwhile improvement.

Regards,

Mus

Honestly, whatever it was was below the noise floor of my headphone amp, I'll record it anyway and post it on here.

It may simply be that it's far enough away from the speakers for it not be an issue.

It may simply be that it's far enough away from the speakers for it not be an issue.

It slap bang next to them, thats what started this all off!

Bollocks!

Just recorded and listened back WITHOUT the music playing, there's quite a bit going on.

I guess it was below the 'bleed' of sound from one room to the next and thats why I could not hear it through my headphones.

No Music - Gives you an idea of the noise floor of my system.

Test - No music.wav (http://www.zshare.net/audio/62932920752bce40/)


Music Playing - Talk Talk at Bake-Off levels, I turned it up a bit more as well half way through.

Test - Music playing LOUD.wav (http://www.zshare.net/audio/62932976d4ddbed9/)


Knocking - First knock is on floor next to stand, second is on the Audiotec table leg, third is me knocking the stylus out of its groove (AAARRRRRGGGGHHH) so ignore and last one is me knocking the LP12 plinth.

Test - Knocking.wav (http://www.zshare.net/audio/629329505709a4a0/)



Robert you were correct but there is nowhere else I can put the deck and it does sound better on the Audiotec than on a wall mounted support.

Try it with the lid closed, maybe that will help.

Try it with the lid closed, maybe that will help.


It sounds great and its not going anywhere else, it just can't. I did the recording with the lid up as this is how I normally listen.

Hmm..I would also try the same with the lid closed and the lid completely removed - you may well find it picks up less with no lid at all.

It sounds great and its not going anywhere else, it just can't. I did the recording with the lid up as this is how I normally listen.
I would never listen with the lid on, take it off when listening, it acts as a soundboard.

Don't even bother fitting the lid, my Rega lid never even came out of its box. What you need now Andrew are some little 'pillows' suspended from the ceiling on wires to deflect and absorb any airborn sources of noise from your deck. You could paint clouds on them...

This is fabulous, the ultimate 'audiophile' activity; listening to equipment without the distraction of music! Seriously though I think this is why my Briks wouldn't work in my room. When I think about it the Briks were close to the wall and although the turntable is well away the rear spikes of the Briks shared the same floor plank as the front spikes of the turntable. When I dropped the stylus on a still record I got a feedback loop at about eleven o clock and that was with no music and a Mana Reference table. The current Neats are big isobarik floorstanders but are well out from the wall so share no planks. Its a suspended oak floor very solid though as it used to be a victorian Billiard room. I need to be at three o clock to get a loop now. Looking back I think it would have been quite easy to bypass the floor altogether by concreting four steel posts into the earth floor below the void and allowing them to protrude through the wooden floor by an inch or so and resting a slab of some sort on them.

Ah. I hadn't realised, sorry. I see the recording is showing something now. Robert's right. Even if a deck/support provided perfect mechanical isolation, it can't do anything about airborne energy, distance would be the only thing for that. Such a setup would fare a lot better than something on a floor which transmits floorborne vibes and the wrong stand though - a laminate on concrete floor combined with a glass/metal thing designed for a big TV the worst floor I've come across - you could rap the floor with your knuckles and see the woofers move. I guess decks with more limited surface area might fare better perhaps aganst airborne. At the end of the day though if you can't move the deck, you can't move the deck. It may be no consolation but I doubt any other deck would cope any better.

Robert you were correct but there is nowhere else I can put the deck and it does sound better on the Audiotec than on a wall mounted support.

Andrew, at the end of the day, the deck sounds great where it is and there are always practical considerations when positioning hi-fi.

What is important is that you've proven to yourself that you can eek a little more from the Linn at some point in the future, effectively for free.

Also, in that situation, a good suspended deck is probably the best option because at least it deals effectively with one source of feedback.

Don't fuss on it though.


<edit> Just played your file and that really isn't bad at all - I expected worse given how close the TT is to the speaker.

Andrew, at the end of the day, the deck sounds great where it is and there are always practical considerations when positioning hi-fi.

What is important is that you've proven to yourself that you can eek a little more from the Linn at some point in the future, effectively for free.

Also, in that situation, a good suspended deck is probably the best option because at least it deals effectively with one source of feedback.

Don't fuss on it though.


<edit> Just played your file and that really isn't bad at all - I expected worse given how close the TT is to the speaker.

I won't let it worry me Robert, cheers.

Is here any Xerxes guys around?

I'm thinking of additional plinth beneath my Xerxes mk1. Not going buy Roksan own expensive upgrade plinth but do it myself. From 12-18 mm plywood.

http://i2.photobucket.com/albums/y32/poindexterdexter/Pict0005.jpg

What do you think about damping and spiking? Should I try spikes beneath support or for example some cork cones? Maximal damping (5 cn layer of foam :-) ) isn't always good for music reproduction, I think. Or have anone experience of foculpods (http://www.hifix.co.uk/sku.lasso?item=5b63316aaa813d628e0e0a61d213369c01f e39af833b201e)? Do they work fine under the TT?

inner tube and something heavy.