Floating Tangential Tonearm

[Panayotis Kritidis]

Two uses of the "Magic sponge".

1. Several years ago a Greek colleague proposed to use the melamine foam, wider known as "Magic Sponge", for stylus cleaning. The cartridge is left free to fall on a plane and immovable surface of the Magic Sponge, from a height of 3-4 mm. This is repeated several times. For more safe operation, one can do it using the tonearm lifting mechanism.

2. I use the melamine foam also as tonearm damper. Balsa is quite 'dead' acoustically, but filling the Π-shaped internal part with the foam has an audible damping effect in the sound of the knocked tonearm.

A remarkable feature of the Magic Sponge is its extremely low specific weight: only 0.0088 g/cm3. Therefore, the tonearm volume of 24 cm3 filled with it adds a mass of about 0.25 g (the foam is applied in a lightly stressed form - in horizontal direction).

One more test recording:

W. A. Mozart
Concerto No1 For Violin And Orchestra in B-flat Major
David Oistrakh
Melodia CM 03883
USSR, 1973

Mozart Violin Concerto No1 Allegro Moderato.flac - Google Drive

 

[Panayotis Kritidis]

In the case of warped disks (and they all are, in one or another degree), the combination "short tonearm + high axis of tonearm rotation" (the second becomes a necessity if the tonearm is short) results in certain alterations of the effective tonearm length and a related sound "wow". In the scheme below I consider the most mild possible warp of ±0.5 mm - that with period of 1.8 s - one 33 1/3 LP revolution. In the real life, shorter periods and higher warp amplitudes are quite often.

The inner disk stabilizer helps somehow, but to really reduce the warps amplitudes one has to use both inner and outer (ring) stabilizer.

 

[Panayotis Kritidis]

Piano test recording:

Ferenz Liszt
Hungarian Rhapsody No1
Erica Lux - Piano
Hungaroton ‎– LPX 11488-90

Experimental link:
https://www.driveplayer.com/#fileIds=1dCq7bycodO-95rZ8CtkLofsqSIvF172g&userId=111052998615453353044

 

[Panayotis Kritidis]

For those interested in the statistic of LP grooves geometry and velocities.

YouTube

The basic data in text mode.
Dg = distance between grooves, mm
Vg = the horizontal velocity of the stylus following the grooves, mm/s

LP Part ...........................Dg min - max …….. Dg aver ......…….Vg min - max ...….. Vg aver

Initial grooves .........….…. 0.44 - 0.65 ...….….. 0.52 .........……….0.25 - 0.36 .........… 0.29

Modulated grooves …..... 0.055 - 0.205 ….….. 0.119 ...........….. 0.031 - 0.114 …..… 0.066
Of which:
Pop, rock .......................................…......… 0.120 ..........................................… 0.067
Pop, special editions ...................…............. 0.203 ......................................……… 0.113
Jazz ....................................................….. 0.088 .........................................… 0.049
Classic ...............................................……. 0.080 ............................................… 0.044

Pauses ......................….. 0.44 - 0.67 ...……… 0.56 ......…..……. 0.25 - 0.37 ...…..…… 0.31

Final grooves ............…….. 2.7 - 3.5 ...........…. 3.2 ...............….. 1.5 - 1.9 ...........… 1.8

A part of the clips refers to an older project and is obsolete today.

 

[ubergeeknz]

If I may, how does your floating arm respond to vibration, or even gross movement of the turntable base?

As might occur if bumped or if not fully isolated from the floor etc.

Does it cause ripples, does it affect the stability of the tonearm?

I'm genuinely curious, as sometimes the "intuitive" answer, which is that this might be a limitation of the design, isn't the right one.

 

[Panayotis Kritidis]

If I may, how does your floating arm respond to vibration, or even gross movement of the turntable base?

As might occur if bumped or if not fully isolated from the floor etc.

Does it cause ripples, does it affect the stability of the tonearm?

I'm genuinely curious, as sometimes the "intuitive" answer, which is that this might be a limitation of the design, isn't the right one.

The tonearm aquarium and the platter part stay on a common wooden base. This base is elastically suspended on the system 'ground zero'. The details are given in the clip:

YouTube

Under normal conditions, the suspended base is remarkably immovable.

To answer your question about the effect of aimed and strong external disturbances, I will design an experiment and will post the video results during the next days. So far, the answer is that the water surface may expose some minor waving, which decays quite soon. The amplitudes and the audial effect are similar to that of the disk warps, which influence EVERY type of tonearm. I will try to determine these quantities as well.

 

[super10018]

Two uses of the "Magic sponge".


One more test recording:

W. A. Mozart
Concerto No1 For Violin And Orchestra in B-flat Major
David Oistrakh
Melodia CM 03883
USSR, 1973

Mozart Violin Concerto No1 Allegro Moderato.flac - Google Drive

Don't you realize that all your digital rips can't faithfully reflect your arm performance because of extended editings by you?

 

[Panayotis Kritidis]

Well, ubergeeknz, thanks to your question I could make some interesting measurements.

First of all I started to apply some 'standardized' knocks to the system's basement and the most severe of them (with intensity never existing in practice) I could view some very slight water movements and measure their effect on the floating base (the 'boat'). But it was quite difficult to distinguish between the water movements and the turntable suspension oscillations. So I decided to go straight and measure the effects of water 'waves' directly introduced by actions on the water surface.

The tonearm arrangement is: the stylus down on an LP surface, the platter immobilized with respect to rotation. The stylus force = 2 p - the recommended for AT95EX. The effects are recorded in the usual manner (wav 48 kHz 32 bit) and edited following my standard procedure. The clip I supply contains 2 parts: the first one with the natural level of the recorded sound after 3 water activations (not audible) and a repetition of the same scene with the sound level up by +40 dB. The most important values:

Water surface amplitudes: maxima of 2 - 2.5 mm
Peaks of the recorded noise: -40 dB
Noise RMS maxima: -50 - -55 dB (for the three water movements. The second one 'knock' is not visible in the clip)
Decay rate of the noise: nearly -20 dB for 1 second
Typical noise frequencies: within 20 - 100 Hz
Noise level at 1 kHz: -66 dB with respect to the 50 Hz level.

Conclusion. The noise created by a severe disturbance of the water surface is practically not audible*. In the real life the "waves" of the aquarium water are nearly 2 orders of magnitude lower and the related noise - negligible.

* Let's have in mind the equal-loudness contours.

3 Waves Sound 0 dB +40 dB.mp4 - Google Drive

 

[Panayotis Kritidis]

One more test recording.

Le Grand Orchestre De Paul Mauriat
L'oiseau Et L'enfant
Philips 9120 222
Greece, 1977

Music Player for Google Drive

 

[Guerilla]

Don't you realize that all your digital rips can't faithfully reflect your arm performance because of extended editings by you?

You could be right, but sounds good. Nice and sympathic idea to preserve and share rare recordings. I may not edit as much if I did it, and many remasters should never have been published. Too many have been engineered by half-deaf musicians or technicians who dont dont have a clue. Many reissues have been sold only because of the "digitally remastered" describtion, even when the result was much poorer than the original. Its hard to judge where the line is between improvement and destruction

Cheers!

 

[Panayotis Kritidis]

You could be right, but sounds good.

Sorry, Guerilla, but to me it sounds comic. Before reading my answer, read again please what "sounds good" to you... So, let's go, taking the editing procedures one by one:

1. The disk clicks and pops are not a feature of the tonearm, but of the disk. Lowering their level does not result in some perception of higher quality of the tonearm.

2. The surface disk noise is not a feature of the tonearm, but of the disk. Lowering it's level does not result in some perception of higher quality of the tonearm.

3. The linearity of the playback frequency response is a feature of the couple "cartridge-preamp". It's correction has nothing to do with the perception of the quality of the tonearm. Experienced people do it often by changes in the input capacitance and/or resistance of the preamp.

4. The presence of very low frequencies is usually a result of a) the excitation of the principal tonearm resonance Fr by disk warps, but also, of course, b) of the platter's rumble. In a) the tonearm is involved somehow, by the value of Fr, which depends on tonearm's effective mass. A cartridge of different dynamic compliance may improve the situation, by achieving an Fr within 8 - 12 Hz. In b) again we have something not related to the tonearm.

Summarizing, almost all of my editing procedures concern features not related to the tonearm. Their correction can not mask any tonearm problems, it only can do them more noticeable!

Its hard to judge where the line is between improvement and destruction.

Here I fully agree with you. I could write, in some future, a detailed article on the editing decisions in every one of the procedures I use. There are a lot of parameters one may vary and, finally, there is something called "experience", which is difficult to describe in all details.

It is important to say that my editing scheme has not been established in relation to the TTT project. I have used it long time ago, with classical pivot tonearms. Only a number of changes happened during the last 10-15 years.

 

[Panayotis Kritidis]

High Fidelity versus Audiophility. Some more thinks on the recent subject.

High Fidelity does not mean fidelity to the "Holy Disk Recording", with all its clicks, pops and added noise.

High Fidelity refers to the original sound, without any clicks, pops and noise added in the Holy Disk.

Therefore, the intelligent* removing of clicks, pops and noise from a vinyl recording is a step towards Hi Fi.

In contrary, considering clicks, pops and noise as a part of the sound "true story" is a brutal and quite comic deny of the sense of Hi Fi!

* Intelligent corrections can be generally defined as those changes, which bring a given part of the audio as close as possible to its' original state. This definition is logically highly correct, but its' implementation is quite difficult to achieve. Especially in the case of noise reduction. Where the "maximum proximity" is difficult to define numerically and becomes, in some extent, a matter of personal taste.

 

[alighiszem]

So far, the answer is that the water surface may expose some minor waving, which decays quite soon.

You could add some light oil to the water. Oil can calm troubled water, as sailors in the 19th century knew.

 

[Guerilla]

So, let's go, taking the editing procedures one by one:

1. The disk clicks and pops are not a feature of the tonearm, but of the disk. Lowering their level does not result in some perception of higher quality of the tonearm.

2. The surface disk noise is not a feature of the tonearm, but of the disk. Lowering it's level does not result in some perception of higher quality of the tonearm.

3. The linearity of the playback frequency response is a feature of the couple "cartridge-preamp". It's correction has nothing to do with the perception of the quality of the tonearm. Experienced people do it often by changes in the input capacitance and/or resistance of the preamp.

4. The presence of very low frequencies is usually a result of a) the excitation of the principal tonearm resonance Fr by disk warps, but also, of course, b) of the platter's rumble. In a) the tonearm is involved somehow, by the value of Fr, which depends on tonearm's effective mass. A cartridge of different dynamic compliance may improve the situation, by achieving an Fr within 8 - 12 Hz. In b) again we have something not related to the tonearm.

Very good overview. Maybe put it in the opening post?

If I knew how I would do the same procedure. I think its a brilliant idea to korrigate the frequency response. Point 1-3 to me only preserves and conway the rare recordings more true than without cleaning. The only thing I wouldnt do is number 4, unless I knew a guaranteed method of analysing, if there are musical content below 30hz on each recording. I think that this highpass filter should be left to the person playing the recording, to deside if it should be applied.

This thread is about an arm-mount system, but also about philosophy about preserving musical content(Edit: I agree with all in post 152 ). They should have each their own thread, cause the two topics clash a bit.

Cheers!

The reason I say Super could be right, is that I simply dont have the tecnical knowledge to judge if your recordings are as

 

[super10018]

1. The disk clicks and pops are not a feature of the tonearm, but of the disk. Lowering their level does not result in some perception of higher quality of the tonearm.

Although pops and clicks are not parts of tonearm functions, some tone arms are “noisier” than others. Some of the tonearms are “quiet”. Pops and clicks can be amplified through arms. A well-damped arm has less possibility to amplify pops and clicks. In my experience, my DIY air bearing arms are much quieter than Graham 2.2. So, how loud the pops and clicks is a part of the quality of tonearms.

2. The surface disk noise is not a feature of the tonearm, but of the disk. Lowering it's level does not result in some perception of higher quality of the tonearm.

Surface noise is a part of information embedded in the information of LP. Surface noise is also a part of mechanical contact of stylus and groove. The noise generated by contacts of stylus and groove is also a part of tonearm performance.

3. The linearity of the playback frequency response is a feature of the couple "cartridge-preamp". It's correction has nothing to do with the perception of the quality of the tonearm. Experienced people do it often by changes in the input capacitance and/or resistance of the preamp.

This is the most ridiculous argument. Let’s assume there is a signal 8 kHz, 1 dB embedded in LP, but your arm can only output 8 kHz, 0.5 dB. It means that your tonearm can’t correctly track the waveform and output at the same level. So, it is a part of tonearm performance, too. Then, you use software to rise that signal at 0.5 dB in your digital copy. You say it has nothing to do with the performance of tonearm. This is complete nonsense. If Audio Technica gives a chart of the frequency response of their cartridge with digital alterations, they are cheating on you! They should give the chart based upon actual measurements without any alterations.

4. The presence of very low frequencies is usually a result of a) the excitation of the principal tonearm resonance Fr by disk warps, but also, of course, b) of the platter's rumble. In a) the tonearm is involved somehow, by the value of Fr, which depends on tonearm's effective mass. A cartridge of different dynamic compliance may improve the situation, by achieving an Fr within 8 - 12 Hz. In b) again we have something not related to the tonearm.

First of all, you cut all the information under 30 Hz, your digital copy is at least not the original copy. I think that the purpose to cut all the information under 30 Hz is your arm can’t perform well under 30 Hz. On my arms, I just don’t see the need to cut all information under 30 Hz because I don’t see anything such as rumbles so on. Warps have negative effects not only on playing back information under 30 Hz but also on playing back information above 30 Hz. A good tonearm can handle warps well, but not an inferior one.

Summarizing, almost all of my editing procedures concern features not related to the tonearm. Their correction can not mask any tonearm problems, it only can do them more noticeable!

In summary, all the editings you did have to do with the performance of your tonearm. The purpose you post your digital copies here is to indicate how good your arm is. Therefore, you should post original and unedited copies only. Otherwise, they don’t reflect the performance of your arm.

 

[super10018]

You could be right, but sounds good. Nice and sympathic idea to preserve and share rare recordings. I may not edit as much if I did it, and many remasters should never have been published. Too many have been engineered by half-deaf musicians or technicians who dont dont have a clue. Many reissues have been sold only because of the "digitally remastered" describtion, even when the result was much poorer than the original. Its hard to judge where the line is between improvement and destruction

Cheers!

For the purpose here, he should not edit the digital copies at all. It is not his excuse if others don't do it right.

Listening is a very subjective matter. I am not going to argue if you say it is great from listening.

 

[Panayotis Kritidis]

This thread is about an arm-mount system, but also about philosophy about preserving musical content (Edit: I agree with all in post 152 ). They should have each their own thread, cause the two topics clash a bit.

Yes, it would be better if there was a specific thread on vinyl sound editing. When I decide to describe in more details some of the procedures I use, I will open a new thread. But it is important to point here, that in the listening reviews we read here and there, the authors are describing their perception of the music material and not of the clicks and pops, if and where they exist. I prepared a small parody on this matter:

- The tonearm A is exposing more accurately the specific flavor of the mild clicks and pops, while the tonearm B is superior in describing the enhanced tactility and declarativity of the early LP disks surface noise.

- The tonearm C is treating more correctly the lower 20ies of the rumble, which are not exactly audible, but create a nice and moisture feeling during the silent passages. The tonearm D lacks the gentle promotion of disk cracks by C, but is superior in the exposure of even the finest pops of electrical supply origin, with a remarkable fatness and viscosity.

It is true that one can use some disc noise(s) to determine certain parameters of the system. E.g. a "nice" sharp click may give some information, after the analysis of it's decay part, about some properties of the tonearm/cartridge pair. The frequency analysis in the region F < 20 Hz may provide information about some resonances of the same pair. But this does not mean that we need to keep all this added parasite sounds "as they are" in order to evaluate the quality of sound reproduction and/or to enjoy the music.

It is quite late here. I will add some comments tomorrow. Greetings!

 

[Panayotis Kritidis]

Guerilla, some more comments on your post 154.

If I knew how I would do the same procedure. I think its a brilliant idea to korrigate the frequency response. Point 1-3 to me only preserves and conway the rare recordings more true than without cleaning. The only thing I wouldnt do is number 4, unless I knew a guaranteed method of analysing, if there are musical content below 30hz on each recording. I think that this highpass filter should be left to the person playing the recording, to deside if it should be applied.

1. Correcting the frequency responce is something quite usual amongst the hi fi people. Some do it digitally, other by selecting optimal values of the phono preamp input impedance and capacitance. Some examples:

Phono Pre-Amp cartridge settings | Stereophile.com
EQ-500 | PHONO AMPLIFIERS | PRODUCTS | LUXMAN | Seeking higher sound quality
Phono Box RS – Pro-Ject Audio Systems

2. As I wrote in another post, the cutoff value I use in removing the very low frequency components may be easily changed form 30 Hz to 25 Hz, 20 Hz or whatever. If I am editing a Grand piano recording, I will select 25 Hz. For a big Church organ I may go to 20 Hz. But in many cases there are no instruments creating basic frequencies below 30 Hz. For example - a chamber orchestra, a brass band, the choir voices ea.

3. The procedure I use for very low frequency removing is digital - FTT with very sharp slope - higher than 60 dB per octave. I do not know if this slope rate can be achieved by use of analogue circuits.

In addition, one more comment on the opinion that the digital removal of clicks and other noises "beautifies" the tonearm and turntable performance. If we accept this opinion, we will have to extend it to certain hardware add-ons. For example - the external ring stabilizer of the disk. This very useful add-on, in addition to an internal stabilizer, may considerably reduce the disk warps and so improve the grooves trackability. Can we abandon the benefit of this add-on, declaring that it "beautifies" our turntable? The same is valid for correcting the disk eccentricity. Do we have to leave it un-corrected, because the correction increases the trackability, decreases the wow and "beautifies" our turntable?

BTW, I made some new measurements by use of the sweep method described in a clip I already posted here:

YouTube

The frequency response in the region below 40 Hz has a 5 dB increase around 13.5 Hz - the principal tonearm resonance and quickly diminishes below 12 Hz.

 

[Guerilla]

For the purpose here, he should not edit the digital copies at all. It is not his excuse if others don't do it right.

Listening is a very subjective matter. I am not going to argue if you say it is great from listening.

I didnt listen critically. Only listened on the phone which probably has a fine dac, using headphones that has been recomended as very good by people who lare into head-fi


Comments to your previous comment:


you are right, that PKs files dont document the quality of the arm. To do that we would need a known reference and expert-widnesses to confirm that both the reference and PKs arm was set up optimally. PK is only posting files as he makes them for preservation. We could discuss if his method is sound, but that doesnt have to do with the "Floating Tangential Tonearm", so should be in another thread. PK chose to post them in this thread, and if he hadnt done it, the thread would have been more about its original topic.


You just seem to attack every single aspect of PKs work and I would say that the files at least documents, that however far from optimal his design is - he cant have been wrong in every decision he made.

You keep coming back to your own air-bearing. Just remember that if someone posts a new idea to diy a tonearm- Its not an attack on your work. Reading your comments could lead one to think that you think, that all people should stop designing arms cause you already perfected tonearms to a degree that further experiments are futile. Sorry. But thats how it comes out. You didnt come with any ideas for improvement - or I missed it

Cheers!

 

[Guerilla]

One more test recording.

Le Grand Orchestre De Paul Mauriat
L'oiseau Et L'enfant
Philips 9120 222
Greece, 1977

Music Player for Google Drive

I dont have time to listen to this, but I was blown away so 30 minutes disappeared . Such colletion of talents. -If one of them could compose and made original pieces, they would have been world-famous.

However. Some things sounds way of on the recording. It sounds like someone is randomly raising and lowering levels on instruments and eq in lower part of the spectrum. Like there are some thresholds which initiates an effect and then times out to turn it of. I first heard it on my tv-system with shitty Bose-speakers and now on headphones. On tv-system it sounded very bass-heavy even speakers are not. Kick-drum is dominating throughout. Higher frequensies sound perfect to me on both headphones and tv-system.

All this listening was done on not so great equipment since my "reference" is not connected at the moment. Havent heard the original so all the bad points could stem from the albumcontent. Wow the acoustic guitar sounds great.
When I click your link it says Im not authorized or content no longer exist. I only heard it cause youtube suggested it to me.

Cheers!

Edit: It wasnt this recording, but the 1974 one of same orchestra that I heard