Innovative Headshell - The Nasotec Swing

[Guest]

John - I do not see this, even with off-centre records, with my air-bearing linear tracker.

 

 

It is absolute that the tonearm will not move if the cantilever is not displaced. Displacement of the cantilever is what provides the force to move the tonearm. The question is: how easy is it to see a degree or two of movement of a cantilever that is only a few mm long? The next time I get a linear tracker, I will put the two channel output from a wow & flutter test track up on a dual channel CRO and look for the phase coherence between the channels. I think I already know what I will see.

[Owen Y]

As said much earlier, I think we probably are over-rating the significance of tracking arror.

Sure, it is audible, but tracking stability is more audibly significant, IME.

 

IMHO, removing A-Skating/Skating, is a bigger improvement with non-pivoting, linear tracking arms

Music signal is louder, has greater dynamic range.

 

Some say that 12" tonearms without A-S - eg Schick, etc, give similar improvement.

 

Re. Tracking Distortion (eltech's post above).... Bill Firebaugh (Well Tempered) created his new Amadeus TT with fixed Offset Angle & no Overhang adjustement - he argues that tracking error/distortion is not sonically that important....

https://welltemperedlab.wordpress.com/2009/02/18/tonearm-geometry/

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

[Owen Y]

It is absolute that the tonearm will not move if the cantilever is not displaced. Displacement of the cantilever is what provides the force to move the tonearm. The question is: how easy is it to see a degree or two of movement of a cantilever that is only a few mm long? The next time I get a linear tracker, I will put the two channel output from a wow & flutter test track up on a dual channel CRO and look for the phase coherence between the channels. I think I already know what I will see.

 

We tend to always look at things as black & white, rather than in degrees

Esp in a subjective pursuit audio.

 

The  air-bearing linear tracker literally floats, on an air film, it moves with a wisp of breath 

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

Edited April 5, 2016 by Owen Y

[Guest]

If the Well Tempered Amadeus does not have overhang adjustment it simply means that the overhang (and tracking error distortion) will be determined choice of cartridge. And I repeat that anyone who has complained about end of side distortion knows all about tracking error distortion.

[Guest]

We tend to always look at things as black & white, rather than in degrees

Esp in a subjective pursuit audio.

 

I tend to agree. Turntables are a balance of compromises at many levels, regardless of design principle. And a well implemented design is better than a poorly implemented design, regardless of design principle. My participation in this thread is a result of a questionably implemented design element dressed up as a *magic bullet* that can somehow negate several other levels of poor implementation.

 

Turntables that work well and sound good are a result of getting each and every mechanical component working well and working synergistically, not the result of a small magic component made of unobtainium.

[eltech]

Owen, yes I basically agree that tracking error distortion on a properly aligned cartridge is unimportant. By that I mean when using a conventionally accepted alignment such as Beyerwald or Stevenson because they are designed to provide minimum distortion possible using conventional arms. I wouldn't intentionally set up an arm to provide highest possible distortion across most of the record because that would be audible because I'm sure doing that could achieve above 4% distortion. I observe that a microline stylus not properly aligned appears to generate what i describe as "chatter" whilst tracking. I'm fairly sure this is due to one side of the groove being in contact with a longer contact patch from the stylus than the other side of the groove, and based on the sound is what I believe is 3rd order distortion. Though it only occurs in midrange frequencies. I'm fairly sure the well tempered article was discussing spherical stylus?

Edited April 5, 2016 by eltech

[Guest rondine]

.. but tracking stability is more audibly significant, IME...

What is tracking stability?

ron

[Newman]

Tracking error distortion is clearly audible by everyone who has complained about end of side distortion. Of course, the level at which tracking distortion becomes annoying is a function of the listener's entire playback system noise and distortion levels, not just those of the pickup.

 

Linear tracking arms may and commonly do suffer from tracking distortion as well. In most designs, lateral force from the stylus is needed to move the tonearm and cartridge laterally to follow the spiral groove inwards. Lateral force on the stylus will displace the cantilever so that it is no longer tangential to the groove. If you look very carefully at the cantilever of a cartridge on a linear tracking arm, and you can see that the cantilever is moved away from its central position while the record is playing, then there will be tracking distortion as a result. Out of round records can play havoc with some linear tracking tonearms, as the stylus dances back and forth trying to pull the cartridge and tonearm along with the eccentric grooves.

 

The tracking error in linear tracking arms has two components, just like regular tonearms. First there is the angular error which raises harmonic distortion and introduced phase shift between the channels. Secondly there is modulation distortion which is a function of cartridge linearity; some cartridges have a very small 'sweet spot' and when the cantilever moves outside of that area, the output level drops.

It is absolute that the tonearm will not move if the cantilever is not displaced. Displacement of the cantilever is what provides the force to move the tonearm. The question is: how easy is it to see a degree or two of movement of a cantilever that is only a few mm long? The next time I get a linear tracker, I will put the two channel output from a wow & flutter test track up on a dual channel CRO and look for the phase coherence between the channels. I think I already know what I will see.

 

This force is pathetically small. Analysis will reveal that it is a tiny fraction of the eccentric hole forces on the arm.

 

Displacement of the cantilever in order to move the LT arm from lead-in groove to lead-out groove is truly insignificant. If you are witnessing cantilever displacement with an LT arm, then something else is wrong and causing it.

 

Poul Ladegaard discussed and measured the eccentric hole forces on an LT arm. With a truly massive and exaggerated 300g arm he measured the lateral force from a poorly centred record to be 50mg. He compared this to the 1800mg tracking force, and the pivoting arm's 100-200mg skating force of which about 100mg is dynamic and thus uncorrectable, and declared that it is 'insignificant'. 

 

Thus when we factor this down by about 8x [edit: 6x] for the roughly 50g of a modern LT arm and cart compared to Ladegaard's 300g, and another multiple of 2x-5x for reasonably well centred records, we are approaching forces of a milligram or two, and that would only cause flopping about of a broken cantilever, honestly. Bearing in mind (pun) that the same cantilever suspension is holding up the 2000mg vertical tracking force.

 

And that is for the eccentric record forces. The force on the stylus for slowly moving the LT arm 90mm across the record over 20 minutes is a tiny fraction again of the above. In fact, for an air bearing and constant groove width, it is zero.

 

I once read an account of someone whose mate with an LT arm had a permanent twist in his cantilever, which he thought was due to the force required to move the arm towards the spindle, and he concluded that LT arms were burdened with this 'deficiency'. Well, frankly, something must be wrong with an LT arm for that to occur because, as described above, there is no such unbalanced force of any significance in a properly functioning setup.

Edited April 5, 2016 by Newman

[Guest rondine]

.......In fact, for an air bearing and constant groove width, it is zero. ........

If the force was zero it wouldn't move.

ron

[Newman]

Once moving in the first groove, the force to keep it moving is zero, too. Virtually frictionless air bearing.

Edited April 5, 2016 by Newman

[Guest]

I have worked on about ½ dozen linear trackers this year and none are immune to off centred records. There is even a special word to describe this facet of linear trackers: 'warp wow' - a topic that gets discussed in pretty much every linear tonearm forum. There may also be yaw-induced, variable phase differences between the channels as the stylus nudges the armtube carrier along its track.

 

"A secondary issue that relates to air-bearing arms is that such arms often have much higher lateral mass than they do vertical mass. This causes the cantilever of the cartridge to move back and forth (left and right) relative to the arm. This motion can often mean that a radial (pivoting) arm will have lower tracking angle distortion. This issue can be reduced by decreasing the compliance of the cartridge, but doing that may not agree with the vertical tracking mass."

 

https://forum.audiogon.com/discussions/linear-tracking-arms-and-compliance

 

"One the down side, linear tracking is much more complex, and consequently more expensive to execute well. The entire arm must be moved along a track tangent to the record-a difficult engineering challenge. The problems associated with many linear-tracking arms usually result in greater tracking errors than you'll find in a properly set-up pivoted arm. Any linear arm that permits yaw - which can be caused by a variety of mechanical conditions - will describe, instead of the desired radius, a series of differing arcs across the record surface."

 

http://forums.stevehoffman.tv/threads/linear-tracking-tonearms-are-they-worth-it.75901/

[Owen Y]

I observe that a microline stylus not properly aligned appears to generate what i describe as "chatter" whilst tracking. I'm fairly sure this is due to one side of the groove being in contact with a longer contact patch from the stylus than the other side of the groove, and based on the sound is what I believe is 3rd order distortion. Though it only occurs in midrange frequencies. I'm fairly sure the well tempered article was discussing spherical stylus?

 

I suspect that, with the Well Tempered, their unique fluid damped pivot has some mitigating effect - over the yrs, I have noticed that conventional ball-race bearings do 'rattle', exaggerating undamped energy generated by MC carts. Even unipivot bearings are less problematic.

 

Whilst the Amadeus is not a flagship model, WT might expect hi-end carts to be fitted.

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

[Owen Y]

What is tracking stability?

ron

 

Gidday ron - sorry, I should have said, tracking instability.

 

We know that inward Skating force is generated by pivoted tonearms with 'offset' angled h'shells - we try to.'balance' this with outward-pulling Anti-Skating mechanism of some sort.

However, the Skating force is not constant, it varies....across the record (inner grooves/lower groove speed), with different stylus profiles, tracking force, groove modulations (recorded music). 

A-Skating mechanisms are a rough solution at best, in balancing these 'de-stabilising' side forces.

 

We hear this instability mostly with dynamic music, at peaks, crescendoes - esp with low compliance MC carts.

When Skating/A-Skating is removed (I'm not trying to promote Linear Trackers  ), overall, reproduction is more dynamic & relaxed - as if the stylus is tracking 'easier'.

 

[some reading if you wish...."Forward Drag & Stylus Profile", R.A. Deane & "Bias Correction & Dynaimic Conditions", John Wright - Hifi News, Oct '69]

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

[Owen Y]

Poul Ladegaard discussed and measured the eccentric hole forces on an LT arm. With a truly massive and exaggerated 300g arm he measured the lateral force from a poorly centred record to be 50mg. He compared this to the 1800mg tracking force, and the pivoting arm's 100-200mg skating force of which about 100mg is dynamic and thus uncorrectable, and declared that it is 'insignificant'. 

 

[snipped]

 

I once read an account of someone whose mate with an LT arm had a permanent twist in his cantilever, which he thought was due to the force required to move the arm towards the spindle, and he concluded that LT arms were burdened with this 'deficiency'. Well, frankly, something must be wrong with an LT arm for that to occur because, as described above, there is no such unbalanced force of any significance in a properly functioning setup.

 

Over the yrs (decades!) messing with pivoted toneams, I've come across mis-aligned cantilevers more often than I'd expect & I've suspected Skating/Anti-Skating being the cause, not QC or abuse.

 

Ladegaard's DIY air-nearing linear tracker was a truly seminal piece of work.

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

Edited April 5, 2016 by Owen Y

[Guest]

Once moving in the first groove, the force to keep it moving is zero, too. Virtually frictionless air bearing.

 

It isn't friction, but mass that needs to be overcome (f=ma). With an off centre record each revolution the tonearm has to be pushed in to the centre then out again to follow the groove. The force to do this comes from the displacement of the cantilever. The greater the weight to be moved (i.e. the tonearm + cartridge mass) and/or the greater the eccentricity, the greater the displacement of the cantilever each half revolution, and the greater the resultant tracking error and distortion.

 

A 9-inch pivoting tonearm should have a maximum tracking error of 1.4 degrees. For a cartridge with a 6mm long cantilever, 1.4 degrees of deflection over 6mm equals a lateral deflection of just ~0.14mm at the stylus tip - barely noticeable. Pivoting tonearms also need to be pushed back and forth by the cantilever, by the mass 'seen' by the cantilever is much, much lower in a pivoting arm than a linear tracking arm.

[Owen Y]

I have worked on about ½ dozen linear trackers this year and none are immune to off centred records. There is even a special word to describe this facet of linear trackers: 'warp wow' - a topic that gets discussed in pretty much every linear tonearm forum. There may also be yaw-induced, variable phase differences between the channels as the stylus nudges the armtube carrier along its track.

 

"A secondary issue that relates to air-bearing arms is that such arms often have much higher lateral mass than they do vertical mass. This causes the cantilever of the cartridge to move back and forth (left and right) relative to the arm. This motion can often mean that a radial (pivoting) arm will have lower tracking angle distortion. This issue can be reduced by decreasing the compliance of the cartridge, but doing that may not agree with the vertical tracking mass."

 

https://forum.audiogon.com/discussions/linear-tracking-arms-and-compliance

 

"One the down side, linear tracking is much more complex, and consequently more expensive to execute well. The entire arm must be moved along a track tangent to the record-a difficult engineering challenge. The problems associated with many linear-tracking arms usually result in greater tracking errors than you'll find in a properly set-up pivoted arm. Any linear arm that permits yaw - which can be caused by a variety of mechanical conditions - will describe, instead of the desired radius, a series of differing arcs across the record surface."

 

http://forums.stevehoffman.tv/threads/linear-tracking-tonearms-are-they-worth-it.75901/

Hi John,

I don't think that this side-force question is much different between LTs or Pivoted arms - both types require the groove to 'move' the stylus inward.

This is v slow movement & as far as stylus tracking is concerned, the stylus 'sees' a rigid/stationary tonearm - because it 'sees' Effective Mass.

 

Effective Mass:

Yes typically LTs have much higher horiz Eff Mass than in the vertical plane - something that bothered me too initially.

And Eff Mass is something that we know can cause arm/cart resonance and/or warp-tracking problems - the assembly becomes unloaded, power delivery ceases & potentially damage to the cartridge.

 

However, this occurs in the LFs & vinyl recorded LFs are mostly mono mixed cuts - ie. only horiz groove modulation - so the high horiz Eff Mass of typical LTs can be beneificial - and this is what I hear, tremendous LF power delivery. Low vert Eff Mass is still able to avoid warp-tracking problems - like a pivoted tonearm

 

Off-centre records:

Properly set-up, an air-bearing L-Tracker 'drifts' easily back & forth on an off-centre record - just like a pivoted arm should do - this lowwww freq oscillation 33rpm = 0.55Hz) has no effect in the music bandwidth.

 

Having used an air-bearing L-Tracker for a couple of yrs now, I've found no problems relating to such side-force issues (can be tricky set-up) - nothing is perfect of course & LTs can have other issues 

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

[Owen Y]

 Pivoting tonearms also need to be pushed back and forth by the cantilever, by the mass 'seen' by the cantilever is much, much lower in a pivoting arm than a linear tracking arm.

 

Hi John - damped tonearms (such as SME. Graham, Townshend, WTT, etc etc) increase Horiz Eff Mass to good effect I believe & without damaging effect AFAIK?

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

Edited April 5, 2016 by Owen Y

[Guest]

We know that inward Skating force is generated by pivoted tonearms with 'offset' angled h'shells - we try to.'balance' this with outward-pulling Anti-Skating mechanism of some sort.

However, the Skating force is not constant, it varies....across the record (inner grooves/lower groove speed), with different stylus profiles, tracking force, groove modulations (recorded music). 

A-Skating mechanisms are a rough solution at best, in balancing these 'de-stabilising' side forces.

 

We hear this instability mostly with dynamic music, at peaks, crescendoes - esp with low compliance MC carts.

When Skating/A-Skating is removed (I'm not trying to promote Linear Trackers  ), overall, reproduction is more dynamic & relaxed - as if the stylus is tracking 'easier'.

 

 

I cannot agree with what appears to be a notion that appropriate anti-skating applied properly degrades sound quality. Equal contact force on either side of the groove is always the objective, regardless of how it is achieved.

 

In my experience, dangling weights on fishing line are a dreadful idea. The friction of the line over the hook is different in each direction and results in modulation of the anti-skating force with off centre records. Also the weight is a pendulum that can easily be set swinging, and as it swings the anti-skating force is significantly modulated. SME tonearms deal with the first problem by using a pulley, but still suffer from the second problem.

 

Many Japanese tonearms use a spring to apply anti-skating force. This implies some friction, but in the well constructed mid-range Technics, etc, it seems to be well implemented.

 

Many turntables use magnetic repulsion to supply the anti-skating force (e.g. Rega, Clearaudio). In my experience this approach can work extremely well. Yes, the anti-skating force varies across the record surface and yes, the anti-skating force required is a function of tip profile, but these are minor issues that are easily dealt with by design and calibration respectively, at least in my experience. 

 

By far the biggest problem I find in setting anti-skating is azimuth error, which affects particularly inner groove anti-skating. Of course is azimuth is incorrect, then crosstalk, tracking, channel balance and other factors, not just anti-skating, will be sub-optimal. When the anti-skating for any turntable I set up doesn't seem to be behaving as expected, azimuth is the first thing I check. In my experience error of in azimuth just 0.5 degrees is enough to upset the anti-skating settings in a pivoting tonearm. Note that this is the error at the stylus tip, including the mounting of the stylus which isn't necessarily perfect; you can't tell by looking at the cantilever!

 

Linear tracking arms are not free of the issues that anti-skating is addressing in a pivoting turntable either. An off centre record with introduce cyclic imbalance in the side wall force differences. On the other hand, azimuth error will not aggravate the side wall force imbalances in a tangential arm, but of course will still affect channel balance, crosstalk, etc.

[Guest]

Off-centre records:

Properly set-up, an air-bearing L-Tracker 'drifts' easily back & forth on an off-centre record - just like a pivoted arm should do - this lowwww freq oscillation 33rpm = 0.55Hz) has no effect in the music bandwidth.

 

 

The problem is not a function of the frequency of eccentricity or the friction (or lack of it) in lateral movement, the problem is that the lateral displacement of the groove introduces a tracking error and associated distortions and channel phasing errors. As the groove 'wanders' the cantilever is pushed off tangential until it has applied enough force to move the tonearm lateral mass back into a tangential position. This is a greater issue for linear trackers, because the effective lateral mass of a linear tracking arm is much greater than that of a pivoting arm.

 

BTW, some friction is desirable in the linear tracking arm, otherwise the arm will overshoot the tangential position until force is increased on the cantilever enough in the other direction to correct the overshoot.

Edited April 5, 2016 by Guest

[Guest]

The pitch shifting caused by and off centre record is clearly audible, although the ease with which it is heard will be program dependent; piano and other sustained notes will expose it more easily.

 

I came across an interesting interaction between drive belt and record eccentricity recently. The best wow & flutter test track I have is the Clearaudio Trackability Test Record (by best I mean the one with the least innate wow & flutter). 

I was using this record to test upgrade belts. I found one belt where the cyclic pitch variations waxed and waned over a cycle of several seconds. A plot of the wow & flutter showed the typical 'beat' effect of mixing two slightly different frequencies, where the beat frequency is the difference of the two frequencies. It turned out that the 'upgrade' belt had a thick half and a thin half. For each revolution of the belt, there was a cyclic speed variation of the record.

 

The time for the drive belt to do one revolution is slightly longer than the time for the platter to do one revolution. So at times the belt's thick half was running through the pulley as the record was turning fast due to eccentricity and the two effects were additive. At other times the belt's thin half was running through the pulley as the record was turning fast due to eccentricity and the two effects were subtractive. In this case the beat frequency was the difference between the platter rpm and the belt rpm.

 

https://en.wikipedia.org/wiki/Beat_(acoustics)

[Newman]

Once moving in the first groove, the force to keep it moving is zero, too. Virtually frictionless air bearing.

 

It isn't friction, but mass that needs to be overcome (f=ma). With an off centre record each revolution the tonearm has to be pushed in to the centre then out again to follow the groove.

 

You are writing about a different force to the one I mean with the 'zero' comment. My earlier post #308 distinguishes between two sources of lateral movement (and hence force on the stylus): one, the movement of the stylus from the start groove to the end groove of the LP, being about 90mm over 20 minutes, and two, the oscillating movement caused by record eccentricity. The forces required to deliver the first movement are stupendously small, and for an air bearing effectively zero, once the arm has started its motion. The forces for the second movement are considerably larger, but as per Ladegaard, still insignificant.

 

Although there is no confusion of these two forces in my post #308, by writing about them both in the same post I might have confused you. Apologies.

[Guest]

You are writing about a different force to the one I mean with the 'zero' comment. My earlier post #308 distinguishes between two sources of lateral movement (and hence force on the stylus): one, the movement of the stylus from the start groove to the end groove of the LP, being about 90mm over 20 minutes, and two, the oscillating movement caused by record eccentricity. The forces required to deliver the first movement are stupendously small, and for an air bearing effectively zero, once the arm has started its motion. The forces for the second movement are considerably larger, but as per Ladegaard, still insignificant.

 

Although there is no confusion of these two forces in my post #308, by writing about them both in the same post I might have confused you. Apologies.

 

Apologies for my mis-understanding.

 

Ladegaard is incorrect on the insignificance of lateral acceleration of a linear tracking tonearm; I am not saying his calculations are incorrect, but his conclusions about audibility certainly are (if he in fact drew that conclusion - I am not sure he did). The lateral forces on a linear tracking tonearm are large enough to cause and do cause audible tracking angle error distortion with off centre records. When the stylus lifts the tonearm due to a warp on the record, its compliance is acting against the effective vertical mass of the tonearm. When a stylus moves a tonearm sideways due to an eccentricity on the record, its compliance is acting against the effective sideways mass of the tonearm. The effective sideways mass of a linear tracking tonearm is more than 10 times the tonearm's vertical effective mass, and often much more. Both types of perturbation, vertical and horizontal, are audible in my experience. As Ladegaard points out in his papers, the rubber suspension in the cartridge is not linear for large excursions, and that introduces audible sidebands. If you can see a cantilever moving, that is a large excursion in the context of this discussion.

Edited April 6, 2016 by Guest

[Newman]

I think we agree that the forces involved in moving an arm from the edge to the centre of an LP, are much less than the forces resulting from eccentricity of the hole. So let's confine discussion to the latter.

 

Referring to Ladegaard's #3 (final) DIY arm, he wrote:

"The arm and carriage weigh 160 grams altogether, which was increased up to a total of 300 grams with two triangular lead weights. [for the purpose of demonstration -Newman]

 

"Now one might fear that poorly centered records would provoke the stylus too much when it has to move so much 'baggage'. .... On the arms described here, the load was typically around +/- 50 milligrams. This is insignificant compared to a normal tracking force of 1.8 grams."

 

This is on an arm weighing three hundred grams! A typical Airtangent-type has maybe one eighth of this sliding mass.

 

How significant is one eighth of 'insignificant'? And that is only with (quote) poorly centred records. I once looked into it and found that most LP's have an eccentricity about one-fifth or less of a poorly centred example. So, doing the arithmetic, 50 milligrams for a 300g 'fattened-up' LT arm becomes about 6 milligrams for a modern LT arm, which becomes about 1 milligram for the eccentricity of most LPs. One milligram is a joke, not significant. So is six, actually.

 

Another perspective: let's look at the uncorrected lateral forces on a stylus attached to a typical pivoting tonearm. A typical figure for constant skating force is 200 milligrams, plus a modulation skating force (signal-dependent) peaking at 200 milligrams (Kogen, 1967). Even assuming a best-case scenario for anti-skating compensation perfectly applied (200 milligrams constant plus half of 200 milligrams modulational), the uncorrectable skating force will be 100 milligrams modulational. That doesn't look good compared to one or 6 milligrams. And it is present on all records, not just poorly centred ones.

 

Your discussions of anti-skating mechanisms above, @@johnmath, ignore the uncorrectable and large modulation component of pivoting arm skating force. And it is signal-dependent: not good!

 

Therefore, any performance effect of lateral stylus forces in a linear tracking arm will also be present in pivot arms, but much more strongly, and much more often. Even if the pivoting arm has perfect static anti-skating correction.  We have a clear winner.

 

(I am not making any claims about audibility, just about relative magnitude, linear vs pivoting. Who knows why Ladegaard said 'insignificant'; maybe he meant in the scheme of things, compared to other LP effects and issues, starting with the pitch-shifting and azimuth issues you have mentioned)

[Guest]

As far as I am aware, no-one else in this discussion is actually doing the measurements. No amount loquacity changes what I see and what I measure with real turntables.

Edited April 6, 2016 by Guest

[rocky500]

Hello, Head shell on its way to W.A. @@Rocky

Enjoy

 

Thank you.

Really looking forward to setting this up, sitting back in my nice comfy lounge chair and listening to some tunes.